Project Reporting and Review BIFS 2003
 


PROJECT REPORTING AND REVIEW


AB 3383, and by extension AB1998, require that the program director, in consultation with the Program Advisory Review Board, “annually review pilot demonstration projects and determine which projects shall be renewed.” (Section 594. (d)). Each project submits six-month and annual reports to UC SAREP, which are reviewed by the BIFS board and UC SAREP staff. Along with the written annual reports, principal investigators (PIs) are asked to give a presentation on their project during the BIFS board meeting. After a question and answer session and discussion, the board provides feedback to project PIs on the direction of their projects and votes on which projects should receive continued funding to provide a recommendation to UC SAREP’s Director.

During the last two years, four projects came to completion: Walnut, Citrus, Strawberry and Rice. The Apple BIFS and Dairy BIFS projects will conclude in March 2003. The Prune BIFS project has begun a second cycle of BIFS funding and a new winegrape project was awarded a three-year BIFS grant beginning in April 2002.

At the April 2002 BIFS board meeting, PIs from the prune, strawberry, walnut, and rice projects met with board members to summarize their projects’ accomplishments and to discuss their overall assessment of the BIFS program. This provided BIFS board members and UC SAREP staff with a good opportunity to hear the perspective of project PIs on both the common and unique benefits and challenges of conducting a project using the BIFS approach. Board members agreed that this would help them to guide future BIFS projects. The Prune and new Winegrape BIFS projects were reviewed in November 2002, found to be making good progress, and their funding renewed. The board’s meeting dates and projects reviewed are listed in Table 3. Comments and decisions of the BIFS Program Advisory Review Board and UC SAREP staff are officially communicated to projects through an award letter and through the BIFS Coordinator.

Table 3. Meetings of the BIFS Program Advisory Review Board

Date of Meeting Project Reviewed
June 12, 2001 Dairy, Citrus
November 13, 2001 Apple (plus evaluation and review of new proposals)
April 17, 2002 Prune, Strawberry, Walnut, Rice (final review of ending projects)
November 20, 2002 Prune (new funding cycle); Winegrapes

CRITERIA FOR EVALUATION
To qualify for continued funding, a project must demonstrate and document continued and expanding grower participation, progress in agricultural chemical use reduction, and adoption of BIFS practices. To these ends, BIFS projects are evaluated by the board and UC SAREP staff in three basic areas:

1) an organized program of monitoring key biological, agricultural chemical, and economic variables
2) on-farm demonstrations of an innovative biologically-based farming system
3) a collaborative outreach and extension model.

These three areas build on one another. All projects collect data (#1), both for BIFS farm management and project evaluation. Some projects are more developed in implementing a well-defined, biologically integrated, production system (#2), while others are more accomplished at promoting the project with extensive outreach and extension (#3). During evaluation, it is necessary to consider the stage of development of each project.


EVALUATION OF PROJECTS
Each BIFS project is located in a different geographic area and works with a different cropping system. In general, perennial tree crops (such as prunes, walnuts, and apples) have developed a BIFS production system more quickly than the other BIFS projects working with annual crops (rice, strawberries).

BIFS program goals remain 1) increasing the adoption of reduced use/risk practices and whole farming systems, 2) reducing the use/reliance on the most environmentally damaging agricultural chemicals (pesticides and fertilizers), and 3) assessing the impacts of projects. Each project is assessed for how well it is accomplishing these goals.

The following evaluation of projects and how well they accomplished their original project goals, which generally coincide with the overall BIFS program goals, is based on 1) the BIFS board review of project annual and final reports, 2) SAREP program staff reporting to the Board on project progress, 3) survey results (when conducted), and 4) pesticide use analysis (when conducted).

The Walnut BIFS project successfully demonstrated the use of a biologically integrated orchard system in walnuts. This project showed that it is possible to greatly reduce the use of conventional pesticides and maintain comparable yields through the use of pheromone mating disruption technology and the use of cover crops and enhancement of natural enemies. Yields were comparable for the three years of the project (with averages ranging from 1.6 dehydrated in-shell tons per acre to 2.5). Motivation was high among growers, and outreach efforts were varied and by the third year more extensive throughout the county. However, the economics of mating disruption in walnuts using the current application technology are such that, without a price premium (for example, one that is gained through organic certification), growers will not be able to adopt the practices. Annual average codling moth management costs in conventional blocks ranged from $76 to $112 per acre. By comparison, reduced risk plots use mating disruption, and based on rough retail prices of $110 per acre per application for Isomate C+ plus application costs of $50 to $90 per acre, mating disruption costs cannot compete (Joe Grant, pers. comm.) Applications using the sprayable emulsion formulation (now available from Suterra, Inc. and 3M Corp.) averaged $7 per acre per application in project tests. Therefore, if shown to be effective in ongoing tests, these offer the prospect of achieving good control at lower costs than the hand applied products. The survey of San Joaquin County walnut growers confirmed that growers believe that mating disruption is not economical. Survey results also show that many growers were not aware that mating disruption could effectively control codling moth. This suggests that if the costs are reduced, further education on the use of mating disruption has the potential to increase its use. (See the Walnut BIFS excerpt in the next section for more details of the project).

The core focus of the Prune IPFP/BIFS project was reduced risk pest management but it also included innovations in water use efficiency and reductions in synthetic fertilizer use throughout the prune growing regions of California. Participating growers have eliminated their use of diazinon in the dormant season while on average 30 percent of a key county, Sutter, prune acres still receive a dormant application of this surface water contaminating organophophate. Average yields (and damage ratings) were comparable between the conventional and BIFS orchards in 1999-2000; yields were 4,387-5,139 lbs/acre compared to 4,705-4,903 lbs/acre, respectively. The use of a plant based assessment for irrigation needs (pressure bomb) enabled project growers to reduce their use of irrigation water by 40% with costs savings that will be calculated. This project involves a large number of key industry Pest Control Advisors, who through their work with clients will speed the statewide adoption of these practices. At the end of the first three-year funding cycle, it was determined that the team had made substantial progress towards establishing a series of protocols on which growers could base their pest management decisions. This project began by designing the alternative system and is now engaging in broader implementation of these alternative practices. A cost analysis of the BIFS system will be conducted during the next funding cycle. A survey is currently being designed for this commodity in cooperation with UC IPM, UCCE, and the California Dried Plum Marketing Board. The project managers had predicted that industry-wide adoption of the BIFS prune practices will take seven to ten years. The continued BIFS support will be key in realizing that prediction. (See the Prune BIFS excerpt in the next section for more details of the project).

The Apple BIFS project focused on the use of mating disruption to control codling moth, the most critical pest in apple and pear production, as a means of reducing the use of organophosphate and carbamate insecticides. In 2001, pesticide use in BIFS orchards was 33 percent lower than that of the conventional comparison orchards. This represented a decrease of 27 percent from the last year these BIFS orchards were managed using conventional practices. Transitioning to the use of mating disruption in apples can be expected to take two to three years in order to reduce codling moth populations to levels low enough that mating disruption can be the primary control. During this time, growers typically need to use one to three supplemental insecticide sprays, further increasing the cost of employing a mating disruption program. In 2001, the cost of managing an orchard using mating disruption in BIFS orchards was estimated to be $357/acre, which is $158/acre more than the average costs from the conventional comparison orchards, ($199/acre). To offset these high costs during the transitional years, the Apple BIFS project provided enrolled growers a 50 percent cost share for mating disruption products. Unfortunately, the poor apple market in the last two years resulted in the removal or abandonment of many surrounding orchards, which greatly increased the codling moth pest pressure. Consequently, the project will be unable to demonstrate lowering codling moth populations to the point that mating disruption is the primary control. The project has made substantial progress in identifying and demonstrating the products and procedures to use in orchard monitoring that are necessary for the successful implementation of mating disruption. The principal investigator frequently extends this information to a statewide audience of growers and pest control advisors through presentations at meetings and conferences, and published articles in statewide trade magazines. (See the Apple BIFS excerpt in the next section for more details of the project).

The Citrus BIFS project went through many changes during the project. Mid-way through the project, the principal investigator and project manager changed. The citrus industry faces many challenges: new restrictions on simazine use, possible restrictions on organophosphate insecticide use, and a falling market for citrus. Despite a slow start, the Citrus BIFS project demonstrated certain biologically integrated methods of managing citrus production that are environmentally friendly and economically viable. These include the use of cover crops, reducing the size of herbicide treated areas on the orchard floor, and the use of moisture sensors for increasing irrigation efficiency. The project experienced two major obstacles: 1) The project was reorganized when the original principal investigator resigned and a new one was identified after the first year of the project, and 2) In response to September 11th attack, the project manager was called away for extended duty with the California Air National Guard two times during the third year of the project. (See the Citrus BIFS excerpt in the next section for more details of the project).

The Dairy BIFS project has been very successful at developing, fine tuning, and now extending a new liquid manure management system that has been shown to reduce groundwater contamination. The Dairy BIFS project has an active group of enrolled dairies and all are highly interested in using dairy waste as fertilizer and protecting groundwater. The project has determined that growers saved an average of $55 per acre and as high as $116 per acre by using the liquid manure and not applying unneeded synthetic fertilizer. Forage silage corn yield data ranged from 20 to 35 tons per acre with no significant differences between the conventional and the improved treatments. In addition, nutrient content (% N, P, and K) of harvested corn silage also show no significant differences due to treatment. The information on comparable yields and reduction in fertilizer costs has been key in increasing the interest by other dairy and forage crop growers around the state. A survey is currently being designed for this project and dairy producers as a whole to assess current state of practices and the potential for increased adoption of these practices through greater outreach and education. (See the Dairy BIFS excerpt in the next section for more details of the project).

The Rice BIFS project focused on herbicide and fertilizer use reduction. Of the alternative practices demonstrated in this project, the practice of straw incorporation coupled with reduced nitrogen fertilizer application was identified as having the greatest potential for widespread adoption. BIFS sites using this practice produced yields that were similar to those sites using the standard rate of nitrogen application. Averaged across years and locations, reduced N fields yielded 88 cwt/acre compared to 85 cwt/acre in conventional fields. This project conducted several complete economic analyses of specific alternative practices; they found that for the straw incorporation and reduced nitrogen, at 2 of the 3 sites, the net return per acre was higher, ranging over the three years from -$18 to $49. The survey of rice growers confirms that growers would be willing to adopt this practice with data showing that 33 percent of respondents used this practice in 2001 on an average of 61 percent of their rice acreage. The principal investigator conducted a very comprehensive PUR analysis of county trends and used this information in its program implementation. This project successfully shared project information through a frequently updated Web site, project newsletters, field days, and presentations at conferences and other meetings. This project identified gaps in a rice biological farming system that are now being researched through six projects that range from fine tuning nitrogen management to understanding water temperature and how it influences rice yields and populations of threatened and endangered fish species. (See the Rice BIFS excerpt in the next section for more details of the project).

The Strawberry BIFS project evaluated several biologically based alternatives to methyl bromide, as well as alternative practices to control above ground pests such as lygus in the strawberry fields of enrolled growers. A completely integrated and effective BIFS system for growing strawberries has not yet been developed. Project results showed that several bacterial and mycorrhizal inoculants as well as weed suppressive treatments, which were tested, did not prove to be beneficial. While negative results, it is still useful information for growers to have so they do not waste dollars and time using such materials. Positive results were found in studying the impact of vacuuming trap crops with a tractor-mounted insect vacuum. This was found to significantly reduce lygus in the strawberry fields. This practice, along with others, will be included in an Organic Strawberry Production Manual that is currently being developed by project cooperators. Supplemental funding for the manual is being made available from a California Specialty Crop Block grant. (See the Strawberry BIFS excerpt in the next section for more details of the project).

The Central Coast Vineyard Team Winegrape BIFS project, which began in January 2002, has developed a Positive Point System that describes an integrated vineyard farming system appropriate for California’s Central Coast. The point system will be used to evaluate the extent of adoption of sustainable practices being used on a participating farm as well as other farms in the three-county region. A higher score indicates more environmentally friendly management. The integrated farming system will be demonstrated at each vineyard and scores over time will be checked to measure progress. This project is building on several years of grower and grant-supported work and as such has a high chance of success. This project has strong grower support and represents a collaborative partnership of growers, wineries, farm advisors, researchers and consultants. The project has potential not only for chemical use reduction, but reducing off-site movement of soils and water. It will collect chemical use data to determine whether there is a correlation between a high score on the Positive Point System and reduced use of agricultural chemicals. (See the Winegrape BIFS excerpt in the next section for more details of the project).


Summary
The prune, walnut, and apple projects made the most progress in terms of pesticide use reduction, data collection, the development of an integrated production system, and in outreach. Prunes, walnuts, and apples are the most advanced projects, mainly because extensive background work has already been done in these, or similar crops. The pheromone mating disruption technology used in apples and walnuts to control codling moth has recently been refined and become more widely available for use. This has allowed the dramatic reduction in the use of broad-spectrum insecticides for control of codling moth.

The Dairy BIFS project was a first for the BIFS program in supporting greater integration and careful environmentally sound management of an animal production system with forage crop production. Liquid manure is a resource that can be managed through the use of the flow meters and nitrogen quick tests and can reduce the synthetic fertilizer bill for forage crop production. The development and extension of the BIFS dairy system is going to be used in educational programs to assist California dairies in complying with new regulations in protecting water quality. It has played a key role in supporting the development of farming system that will enable dairy producers to more easily understand and complete their Comprehensive Nutrient Management Plans that will be required of all dairy producers by 2006. These regulations were finalized in December 2002.

While farmer-to-farmer techniques and hands-on fields days are important parts of the BIFS approach, written documentation is also key to reach those farther away from the actual demonstration projects. The walnut, prune, rice, and dairy projects developed newsletters that communicate to a larger audience the practices and results of their projects (see attachments C & D for examples). In addition, the prune, rice, dairy and winegrape projects have created web sites that provide timely information on program developments (see http://dairybifs.uckac.edu; http://www.agresearch.nu/ipfp.htm, http://www.buttecounty.net.htm, www.vineyardteam.org, http://www.lodiwine.com). In addition, key peer-reviewed publications have been produced by the BIFS projects and include a recent publication by Andrews et al. 2002 (see attachment E), which describes the development of a new tool for assessing soil quality for cotton on the San Joaquin County’s west side. This publication is of interest to other academics as it uses multivariate statistical techniques to quantify something of great interest to growers, how alternative practices affect their soils, yields and quality.

The BIFS projects generally excel at developing and refining the alternative farming practices, and are increasing their efforts to encourage statewide adoption. BIFS projects with the best collaborative extension programs are locally based to maximize effectiveness, but this can leave non-BIFS counties without access to the new techniques developed by the BIFS projects. To make the most of the successful projects that just completed their third year, UC SAREP was able to successfully compete for new federal block grant funds through the California Department of Food and Agriculture to build on four of the BIFS projects ($100,000 for two years). However, additional funds are still needed to truly implement the current BIFS environmentally sound and economically viable practices on a statewide level, and to extend this approach to the hundreds of other commodities in California.

 

MODIFIED EXCERPTS FROM ANNUAL REPORTS

MODIFIED EXCERPTS FROM
WALNUT BIFS—YEAR-END AND FINAL REPORT, FEBRUARY 15, 2002


Principal Investigator: Joseph A. Grant
Farm Advisor, UC Cooperative Extension
420 S. Wilson Way, Stockton, CA 95205
Telephone: (209) 468-9490 Fax: (209) 462-5181
E-mail: jagrant@ucdavis.edu


Introduction
California produces 99 percent of the walnuts grown in the United States and 38 percent of the world’s walnuts. Over 40 percent of the California crop is currently exported. More than 15 walnut varieties are grown commercially; numerous other varieties are planted on a smaller scale. Sacramento and San Joaquin valleys lead California counties in walnut production and San Joaquin County alone comprises about 20 percent of the total walnut production acres.

Walnut pest and disease pressures impact both the farming economy and the environment. These vary from region to region depending on soil, climate, presence of natural enemies, chemical resistance, pesticide application, availability of effective pest control measures and the knowledge to use them. Historically, these problems have been treated chemically. Impending impacts of the 1996 Food Quality Protection Act, concerns over surface and groundwater contamination, and escalating costs and uncertainties of chemical control have heightened the urgency of efforts to find effective and cost-efficient ways of producing walnuts with minimal use of pesticides, herbicides, and synthetic fertilizers.

Walnut varieties vary in susceptibility to diseases, nematodes and insect pests. Codling moth is the key insect pest and growers typically apply one to three treatments of organophosphate insecticides annually on certain varieties. Feeding by codling moth larvae causes direct damage to developing nuts, and also predisposes them to navel orangeworm and mold infestation. Chemical treatments for codling moth are also generally disruptive to the biological control of aphids and mites. Therefore, additional treatments are often used for these pests where broad-spectrum insecticides are applied. Organophosphate insecticides account for approximately 65 percent of insecticide use in walnuts, and much of this is for codling moth suppression.

Like codling moth, navel orange worm (NOW) and walnut husk fly attack nuts directly. To suppress NOW, broad-spectrum insecticides are frequently used, causing secondary pest outbreaks. Broad-spectrum insecticides are also applied for walnut husk fly, but they are not as disruptive because they are applied later in the season.

Overuse of nitrogen fertilizers is another environmental concern. Nitrogen fertilizers are applied to walnut orchards for growth and production needs. Application of around 100 pounds of nitrogen per acre is considered sufficient. However, most walnut orchards are fertilized at rates that exceed this guideline. Tools for assessing nitrogen fertilizer needs such as nitrogen budgeting and leaf tissue analysis are rarely used, even though widely promoted and fairly well understood by growers and fertilizer sales personnel. Reducing supplemental nitrogen applications to levels more consistent with actual demand would save growers money and reduce the potential for leaching and groundwater degradation.

BIOS for Walnuts in the San Joaquin Valley
The Biologically Integrated Orchard Systems (BIOS) approach is holistic, combining biologically intensive farming practices with a hands-on, farmer-to-farmer educational model. It seeks to reduce pesticide use and improve yield and quality through soil building, intensive field monitoring, biological control, and beneficial insect habitat enhancement to control pests. Using a collaborative management team and outreach model, it brings together growers, PCAs, pest management professionals, researchers and extension personnel, government agencies and other agricultural community groups to find solutions to common problems and implement ecologically and economically sustainable farming methods. The UC SAREP-funded walnut BIOS project, implemented from 1998 through 2001, aimed to adapt and extend the model initiated by the Community Alliance with Family Farmers (CAFF) in Yolo and Solano counties to fit the biological, economic, and infrastructure conditions of the walnut farming industry in the northern San Joaquin Valley.

Key accomplishments
In the first year, 1998-1999, a management team was organized and established the infrastructure to accomplish project objectives. By 2000, twelve growers enrolled in the program and allocated a portion of their acreage to BIOS demonstration blocks. The management team provided technical guidance to project growers and PCAs throughout the life of the project. An intensive monitoring program was developed to guide orchard management decision-making and provide information for assessing the effectiveness of BIOS practices. In addition, the project:

Walnut BIOS Alternative Farming Practices
A number of farm management practices comprise a BIOS approach. In this project, the key practices of the BIOS approach were contrasted with their conventional counterparts over a three-year period, 1998—2001 (Table 1).

Table 1. Conventional and BIOS alternative practices for managing key elements of walnut orchard systems in central California (Appears as Table 5 in Walnut BIFS Final Report, March 2002)

Orchard management issue Conventional system BIOS alternative
Pest management
Codling moth 1 to 3 spray applications per season of chlorpyrifos, azinphos-methyl, methyl parathion, esfenvalerate, tebufenozide; spray timing based on insect phenology. Pheromone mating disruption and sprays of non-disruptive insecticides; tactics combined on case-by-case basis and crop damage to determine need for time, sprays.
Navel orangeworm Winter sanitation of mummy nuts (overwintering larvae), prompt harvest, late-season insecticide sprays. Sanitation, prompt harvest, emphasize reducing sources of predisposing damage (sunburn, codling moth, blight) by sound management.
Walnut husk fly Full coverage insecticide + bait sprays based on presence and phenology of adult flies as determined by trapping. Alternate row and/or low canopy insecticide + bait sprays; spray decision based on trapping and phenology of gravid female flies.
Walnut aphid
Dusky-veined aphid		 Sprays of diazinon, chlorpyrifos, or endosulfan; treatment thresholds poorly documented and/or utilized. Reduce use of disruptive codling moth insecticides and navel orangeworm to promote parasitoid abundance and activity; vigorous orchard monitoring to assess need for control; cover crops to promote generalist predators.
Two-spotted mite
European red mite		 Miticide sprays based on pest abundance; treatment thresholds poorly understood/utilized. Intensive population monitoring; limited use of disruptive insecticides for codling moth and navel orangeworm, cover crop and/or insectary plantings to promote generalist predator abundance.
Orchard Floor Management & Fertility
Nitrogen fertilizers Annual applications of 100 to 400 pounds soluble N fertilizer per acre. Nitrogen budgeting to rationalize N applications; leaf tissue analysis to monitor N status and adjust N application rates; cover crops to supply part or all of N need.
Weed control Combination pre- and post-emergence herbicides in bands along tree rows; herbicide selection per weed surveys. Cover crops to suppress unwanted vegetation; minimize herbicide band width; emphasize post- over pre-emergence materials.
Soil condition
Orchard pruning disposal Burn Chip or shred; spread on orchard floor.
Orchard middles management Resident vegetation, disked or mowed to minimize competition with trees for water nutrients. Cover crops to suppress unwanted vegetation; increase soil tilth and water infiltration; adjust irrigation and other management practices to avoid competition with trees.
Habitat restoration & enhancement None Brush piles for bird habitat; owl and/or bat nesting boxes; annual or perennial insectary plantings on farm borders or waste areas.

Alternative pest management practices
Codling moth is the key insect pest of walnuts and as such, has been a major focus of the project’s efforts. Not only does codling moth damage have economic consequences for growers, but it also predisposes nuts to other types of damage that require further chemical treatment. The approach to managing codling moth was three-pronged:

1. use of alternatives to conventional insecticides, including pheromone mating disruption and releases of Trichogramma platneri and other codling moth parasitoids
2. intensive monitoring of orchards to determine pest thresholds and inform pest management decisions
3. use of non-disruptive insecticides as an alternative to organophosphate insecticides

Pheromone mating disruption
The BIFS project experimented with several types of pheromone mating disruption, making it the largest scale testing in walnuts to date of pheromone mating disruption products. Different technologies for codling moth mating disruption had different results (see below). Overall, all BIOS blocks showed consistently low numbers of codling moth during the three years of the project.

Previously, pheromone mating disruption for codling moth was not considered economically feasible in walnuts because of the high cost of pheromones and the large tree size and air volume needing to be permeated with pheromone for effective mating suppression. However, new products, such as Isomate C+, pheromone dispensers (puffers), and sprayable pheromone formulations, promise more success.

Low trap catches in pheromone mating disruption BIOS blocks indicated that mating was suppressed by all four mating disruption dispensing technologies, though they differed in longevity and in the amount of occasional “breakthrough” captures of male moths. Furthermore, low damage levels were reported. Results of dropped nut counts showed low levels of early season codling moth damage in all blocks. Overall, damage levels reported in growers’ commercial grade returns did not exceed the five percent threshold, which triggers a reduction in grade.

Ongoing research is needed to refine these technologies and to determine their long-term efficacy. As an outcome of this project, the California Walnut Marketing Board, Walnut Pest Management Alliance and others have expanded their research efforts aimed at evaluating sprayable and microsprayer pheromone formulations in walnuts. Also, the Center for Agricultural Partnerships (Ashville, NC) initiated a three-year privately funded mating disruption implementation project whose goal is to bring 25,000 acres of walnuts under mating disruption by 2004. The demonstration work from the BIOS project was a catalyst for these efforts. Taken together, they should help accelerate the development of this critical technology in walnuts.

Enhancement of natural enemies is an integral part of the BIOS approach. The field scout noted the presence of general predators during weekly monitoring visits. Seasonal compilation of these showed that predators were generally more prevalent in BIOS than conventional blocks (Table 2). Lady beetles and syrphid flies were significantly more abundant in one of the three project years. Lacewings, an effective general predator of mites and aphids, were more prevalent in BIOS blocks in all years.


Table 2. Seasonal average number of generalist predator observations in BIOS and conventional blocks*
(Modified from Table 16 in Walnut BIFS Final Report, March 2002)
1999
2000
2001
BIOS
28.3
37.5
25.6
Conv
18.7
26.9
15.9
P
0.003
0.001
0.002

*Only sites with paired BIOS and conventional blocks were used for comparison

Monitoring program
In order to reduce the number of applications of organophosphate insecticides, the management team, in collaboration with growers and other experts, developed a comprehensive monitoring program. A project field scout performed weekly monitoring of key pests in BIOS and conventionally managed comparison blocks from March through October of each year. The scout also made observations on other relevant aspects of orchard development during monitoring visits, including crop development, cover crop growth and beneficial insect activity. Each week, the field scout delivered the collected data to the growers or their PCAs and discussed alternative treatments based on the data. Growers’ pesticide use records for BIOS and conventional blocks show that their successes in managing key walnut pests in BIOS blocks were achieved while using few or no conventional pesticides (Table 3).


Table 3. Treatments applied for key pests in walnut BIOS and conventional blocks, 2001. Rates (pounds active ingredient per acre) follow chemical names. Block codes are identified in parentheses. (This table is modified from the original, which appears as Table 22 in Walnut BIFS Year End Report, Feb 2002)

Type of Block Codling moth Aphids
Dusky-veined or Walnut aphid 		mites
Two-spotted or European red 		Walnut Husk Fly
BIOS (A-L) Pheromone mating disruption
(J) phosmet 4.5 + chlorpyrifos 1.1

(B) chlorpyrifos 0.5; naled 0.94
(G) oxydemeton-methyl 0.5
(H) chlorpyrifos 0.5 		(B) clofentezine 0.072
(H) propargite 1.0
(J) fenbutatin-oxide 0.25
(K) propargite 2.25
(L) propargite 1.2		 (E) phosmet 0.4; chlorpyrifos 0.6
(F) phosmet 2.1
(I) chlorpyrifos 2.0
CONV. (A) diflubenzuron 0.50 + chlorpyrifos 2.0 + phosmet 3.5
(C) chlorpyrifos 3.5 + tebufenozide 0.25
(D) chlorpyrifos 2.0
(E) phosmet 0.6
(G) methyl parathion 2.0
(K) chlorpyrifos, 4.0
(L) phosmet 2.8		 B) esfenvalerate 0.02; naled, 0.94
(G) oxydemeton-methyl		 (A) propargite 1.5
(B) clofentezine 0.072
(C) propargite 1.5
(D) propargite 3.0
(G) propargite 2.5
(K) propargite 2.25
(L) propargite 1.2		 (E) phosmet 0.35

Cover crops, orchard floor and fertility management
Use of cover crops to improve soil structure, fertility, biological diversity and water penetration is a key component of the BIOS approach. Each orchard had unique site and cultural features, as well as management objectives that shaped growers’ choice of a cover crop. Most growers chose either a perennial grass and clover sod, a low-growing mix of annual legumes and grasses, or a more traditional “high biomass” mixture of legumes and grasses that is mowed or incorporated in spring. Growers reported a range of perceived benefits, including improved water penetration, reduced need for mowing, and increased abundance of generalist predators in their orchards.

To control weeds, growers traditionally use broadcast applications of herbicides based on calendar schedules. Conventional orchard floor management consists of using pre- and post-emergence herbicides to completely eliminate vegetation in eight to twelve foot bands along tree rows. For the BIOS project, growers were encouraged to use narrower herbicide-treated strips in BIOS blocks, replace nonselective pre-emergence materials with post-emergence herbicides, and use spot treatments where feasible.

By the third year of the project, most growers reported using narrower herbicide treated strips in tree rows in both BIOS and conventional blocks. During the project, one grower successfully transitioned to a program consisting entirely of narrow band post-emergence treatments, while another used only post-emergence materials in both BIOS and conventional blocks.

New tools for assessing fertilizer needs, such as leaf sampling and nitrogen budgeting, were emphasized in this project and data from application rates show a reduction in pounds of N applied from 1998 to 2001 (Table 4). In cases where leaf samples indicated that nitrogen levels were greater than considered sufficient for walnuts (2.6 percent), the project worked with growers to use a nitrogen budgeting approach and modify their nitrogen fertilizer applications accordingly. Year to year changes in nitrogen fertilizer rates and the results of leaf nitrogen analyses suggest that seven of the twelve growers attempted to manage tree nitrogen status in BIOS blocks by modulating their nitrogen fertilizer applications.

Table 4. Average nitrogen fertilizer use and leaf nitrogen concentration for BIOS and conventional blocks, 1998-2001 (Appears as Table 20 in the Walnut BIFS Final Report, March 2002)

 
Pounds fertilizer N applied
Leaf % N
 
1998
1999
2000
2001
1998
1999
2000
2001
BIOS
blocks
176
171
93
123
ND*
2.9
2.7
2.9

Conventional blocks
181
177
88
133
ND
3.0
2.6
2.9
P 0.36 0.18 0.35 0.35   0.84 0.12 0.90

*Leaf analyses not done in 1998. The project began in 1999.
P = probability of significant F ratio, based on one -way analyses of variance within project years using individual project sites as replications (n=6 to 8, depending on the year) and BIOS and conventional management as treatments. Averages from BIOS and conventional blocks are considered significantly different when P is less than or equal to 0.05.

Walnut Yields and Quality
Information on farming practices and yields was obtained from year-end questionnaires completed for BIOS and conventional blocks by all growers. Nut quality was evaluated using harvest samples collected when trees were shaken for commercial harvest. Yield and quality data were also obtained after harvest from growers’ grade results for loads delivered to commercial handlers from BIOS and conventional blocks. Over three years, yields were comparable in BIOS and conventionally managed comparison blocks (Table 5).

Table 5. Average harvest yield (dehydrated in-shell tons per acre) and nut quality for samples drawn from commercial deliveries from BIOS and conventional blocks 1, 2 (Appears as Table 10 in Walnut BIFS Final Report, March 2002)

  Block
Yield
% Insect
% Large sound
% Offgrade
% Edible yield
RLI3
1999 BIOS
2.2
0.7
76.1
5.7
45.2
53.1
Conv.
2.5
0.3
71.4
4.6
45.6
53.1
  P4
0.29
0.42
0.27
0.62
0.79
0.94
   
2000 BIOS
1.6
2.0
81.5
5.4
43.8
49.9
Conv.
1.6
1.0
77.3
4.4
44.1
50.2
  P
0.33
0.31
0.19
0.58
0.35
   
2001 BIOS
2.0
0.5
86.2
1.7
50.9
50.9
Conv.
1.9
0.3
83.7
1.9
48.7
51.6
  P
0.88
0.36
0.37
0.78
0.39
0.17

1. Only sites with paired BIOS and conventional blocks were used for comparison
2. Grading performed by Diamond Walnut Growers
3. Relative Light Index, a measure of kernel color; higher numbers mean lighter color.
4. In this and all tables, P = probability of significant F ratio, based one -way analyses of variance within project years using individual project sites as replications (n=6 to 8, depending on the year) and BIOS and conventional management as treatments. Averages are considered significantly different when P is less than or equal to 0.05.


Pesticide Use
Growers’ pesticide use records for BIOS and conventional blocks show that our successes in managing key walnut pests in BIOS blocks were achieved while using few conventional pesticides (Figure 1).

Figure 1. Number and type of annual pesticide treatments applied in BIOS and conventional blocks. (Only sites with paired BIOS and conventional blocks were used for comparison.) (Appears as Figure 3 in Walnut BIFS Final Report, March 2002)

Figure 2. Number and type of annual insecticide treatments for codling moth applied in BIOS and conventional blocks. (Only sites with paired BIOS and conventional blocks were used for comparison.) (Appears as Figure 4 in Walnut BIFS Final Report, March 2002)

Replacing codling moth insecticide sprays with mating disruption accounted for most of the differences between BIOS and conventional blocks (Figure 2).


Barriers to Adoption of Mating Disruption in Walnuts
The biggest current obstacle to promotion and broader use of the alternative codling moth strategies is the experimental nature of the pheromone mating disruption products. For example, the pheromone emulsion used in the project is not likely to be registered for use in California. We are committed to continued testing if the product remains available and has potential for eventual registration. Isomate C+®, though very effective at all project sites, has not been widely tested in walnuts, and the manufacturer has not aggressively pursued development opportunities in walnuts. The BIOS walnut project represents the largest scale testing to date in walnuts. Project coordinators remain in close contact with representatives of Pacific Biocontrol and have encouraged them to expand their research and development efforts in walnuts.


BIOS for Walnuts Outreach and Extension
The primary emphasis in the project’s outreach efforts has been on building project expertise and implementing the BIOS farming practices in project orchards. We have worked diligently throughout the three-year term of this project to foster a spirit of well-informed and proactive collaboration among project growers, PCAs, and implementation team members.

Three field workshops were conducted in 2000; a total of ten were held during the three-year term of the project. Typically, these workshops were designed to provide growers with technical information and assistance in implementing alternative management practices. Popular topics included pheromone mating disruption for codling moths in walnuts; pest and beneficial insect monitoring techniques; demonstrations of canopy damage assessment methods for in-season monitoring; nitrogen budgeting for determining fertilizer needs; cover cropping as an alternative soil building practice; proper tree planting techniques and new information on crown gall biology; chipping and shredding as an alternative to burning.

Flyers publicizing these events were sent to around 2,600 individuals on combined CAFF and UC Cooperative Extension mailing lists targeting Central San Joaquin Valley walnut growers. We are pleased at the large turnouts and interest these events have generated.

In response to an outreach team recommendation, we began holding periodic informal grower “breakfast” meetings this season. Project growers had expressed an interest in seeing other growers’ BIOS blocks and having opportunities to interact. Beginning in February, we held four such meetings this season, approximately on a monthly basis. Attendance has varied from four to seven growers and PCAs, and meetings have lasted from one to two hours depending on content and time constraints.

During the project, we collaborated with CAFF to publish a monthly BIOS Field Notes newsletter for growers and other clientele. News and information from our project were a regular feature of this newsletter, which was circulated to 250 growers, PCAs, and other readers in eight California counties. The newsletter was discontinued in 2000 due to budget constraints at CAFF. In 2001, we collaborated with CAFF in the publication of a joint newsletter, Walnut BIOS Notes (see Attachment C). Four issues were published and mailed to 360 walnut growers and allied agribusiness clientele. Most of this circulation was in the northern San Joaquin Valley.

Project Evaluation
In Fall 1999 and again in 2001, we asked project growers to complete written surveys to evaluate various aspects of the project, including usefulness of technical support they received from the implementation team, farm management plans, and orchard visits, the value and utility of monitoring information supplied by the field scout, and impacts of their involvement in the project on management of blocks other than those enrolled in the project. Growers reported many benefits of participating in the BIOS program: a reduction of fertilizer use; finding better ways of dealing with insect pests; increased knowledge of beneficial insects and trap counts; reductions in spraying costs; better community relations because of urban proximity; better working conditions for employees because of less organophosphate use; good opportunities for comparison to conventional practices. All growers surveyed reported that they would recommend the BIOS program to other farmers or PCAs.


MODIFIED EXCERPTS FROM:
PRUNE BIFS—FINAL REPORT 1999-2001, MARCH 1, 2002


Principal Investigator: Gary L. Obenauf
Consultant to the California Dried Plum Board
Agricultural Research Consulting
PMB# 345
7084 Cedar Ave.
Fresno, CA 93720
Phone: (559) 322-2181 FAX: (559) 322-2186
E-mail: gobenauf@agresearch.nu


Introduction
The California Dried Plum Board is a State Marketing Order that represents the 1,400 growers and 21 packers of California prunes. California produces about 200,000 dried tons annually on 81,000 bearing acres. California prune production represents 99 percent of the US total and about 70 percent of the world total. The annual crop value is approximately $200 million.

Economics and regulations are creating change in the way prunes are farmed. The cost of farming is going up and the industry is experiencing problems with over-production. Federal acts, such as the Federal Clean Air Act, Federal Food Quality Protection Act and California’s Proposition 65 and 204 dealing with water quality, establish expiration dates and/or threaten the continued use of many pesticides. Regulations established by California Department of Pesticide Regulation (DPR) have created new requirements and certification for application of pesticides. Misuse of natural resources is becoming a common environmental concern.

To adjust to current economics and regulations, alternative low environmental risk practices need to be researched and results demonstrated and implemented. Economic thresholds and monitoring techniques need to be discovered so that pesticide use can be safely reduced, or at least used in a timely fashion when needed. Improved uses of water and other inputs that do not interfere with prune production also need to be researched and demonstrated. The Integrated Prune Farming Practices/BIFS project was established to address these concerns.


IPFP/BIFS project objectives include:

Project Infrastructure
The IPFP/BIFS project was conducted on up to 33 prune farms in Tulare, Madera, Fresno, Yolo, Sutter, Yuba, Butte, Glenn and Tehama counties. These sites were chosen to best represent the prune industry in California. In most of these orchards, the project conducted comparisons between a conventional and a “reduced-risk” system. In nine orchards, the comparison was not feasible because participating growers had converted the entire project acreage to reduced-risk practices. Monitoring at these sites was conducted by project field scouts. In addition to grower sites there were also eight sites monitored by PCAs who used management protocols developed specifically for PCAs. Throughout the project, growers provided feedback and made suggestions on how to improve the program. PCAs and UC researchers provided guidance and input, as well as helped to validate protocols.

Comparison of conventional and BIFS alternative practices
To ensure that growers make well informed, consistent treatment decisions, the project focused on developing protocols for economic thresholds and reliable monitoring techniques (Table 1).

Table 1. Comparison of conventional and BIFS alternative practices (Extracted from the narrative in the IPFP/BIFS Final Report, March 2002)

Conventional Practice Used BIFS Alternative Practice Demonstrated
Annual dormant insecticide treatment Dormant spray decision guide, spring prune aphid monitoring/ reduced risk oil treatment
Annual dormant; annual worm spray Pheromone trap monitoring for San Jose Scale and Parasitoids
Annual in-season sulfur spray Prune rust monitoring
Prophylactic mite spray, spray based on visible damage or calendar date Monitoring for presence/absence of mites/predators, 5-minute search for mites
Prophylactic brown rot spray Brown rot predictive model
Irrigation timing based on soil moisture measurements, timing of other orchard practices,
or calendar schedule		 Tree water status to schedule irrigation
Fertilizer needs estimated without leaf and water analysis Leaf and water analysis to determine fertilization needs

 

Goal I. Develop economic thresholds, monitoring techniques and alternative pest control strategies to reduce the use of conventional biocides.

Dormant treatment decision guide
Prior to introducing the BIFS approach, prune growers had no way of knowing if they needed to apply a dormant insecticide and oil spray. Traditionally, they applied an annual dormant spray because they have been taught that dormant sprays kill a number of pests (including San Jose Scale (SJS), peach twig borer, European Red Mite (ERM), mealy plum aphid and leaf curl plum aphid), and that it is less harmful to beneficial insects than conventional in-season treatments.

Many prune growers also apply a dormant spray because there is no reliable reduced-risk alternative for controlling high populations of prune aphids. However, recently the dormant spray has been implicated in environmental pollution. These findings suggested that the dormant insecticide spray is being overused. To address this problem, the IPFP/BIFS team developed a monitoring technique to help growers decide to apply a dormant insecticide treatment only when pest and beneficial populations warrant it.

The dormant treatment decision guide developed in 2001 accurately predicted whether or not an orchard needed to be treated for Mealy Plum Aphid (MPA), Leaf Curl Plum Aphid (LCPA), SJS and/or EFL. By using this guide in 2001, we found that:

As the distribution of project orchards was intended to represent the California prune industry, we can speculate that not treating 60.78 percent of the bearing prune orchards with a dormant insecticide and oil spray would result in a reduction of 156,812 lbs. a.i. of pesticide (based on all bearing acreage receiving a dormant spray of diazinon at the recommended label rate). Clearly a “Dormant Treatment Decision Guide” such as the one developed by the IPFP team is very useful in making dormant treatment decisions.

Pheromone Traps to Aid with Treatment Decisions
Pheromone traps have long been available but are generally underutilized by prune growers making treatment decisions. Most commonly, they are used to help determine treatment timing. In some cases, they are also used to assess the presence of beneficial insects. Rarely have they been shown to be useful or have they been used to help determine whether or not a treatment is needed. Information of this type could be useful to prune growers who may need to treat against Peach twig borer, Oblique Banded Leaf Roller or San Jose Scale.

a. San Jose Scale (SJS)
The results showed that SJS traps are good indicators of scale and scale parasite presence in the orchard. The traps showed that beneficial SJS parasitoids were more abundant in reduced-risk and check plots where dormant insecticides had not been applied for three or more years. By comparison, dormant insecticide with oil treatments in conventional plots reduced the populations of SJS parasitoids. The traps also showed that the reduced risk approach against SJS is viable.

b. Peach twig borer (PTB)
The results show that fruit monitoring based on a PTB biofix using pheromone traps was a useful tool in determining treatment necessity and timing in 2001. However, more research on this method will need to be conducted.

c. Oblique Banded Leaf Roller (OBLR)
Fruit monitoring based on an OBLR biofix, using pheromone traps can be a useful tool in determining treatment necessity and timing. However, more research on this method will need to be conducted.


Spring Prune Aphid Monitoring
With a reduced reliance on dormant insecticide and oil treatments, there is an increased need for in-season monitoring of aphid populations to determine if treatments are needed.

The protocol developed by the IPFP team (Protocol #6 “sequential sampling technique for aphids”) was as accurate as and quicker than the more traditional monitoring approach. Using this new sequential sampling technique for presence of aphids gave a good indication of when, and if, a treatment was needed. Of all orchards not receiving a dormant spray, only 8.7 percent needed an in-season insecticide treatment for aphids in 2001, compared to 42 percent of the orchards in 2000 and 45 percent in 1999. According to this information, applying an in-season aphid spray, as opposed to the traditional annual dormant spray, would have resulted in 235,554 lbs. a.i. less pesticide being applied (based on applying diazinon at the recommended label rate to all bearing prune acreage) in 2001.


Prune Rust Monitoring and Treatment Timing Recommendations
Rust is the most common pest treated during the growing season. Prior to the project, growers had no way to monitor prune rust. Most growers simply apply one or more protective wettable sulfur treatments in May, June and/or July following rain.

The prune rust monitoring protocol developed by the project is simple and takes one person less than 30 minutes to evaluate an orchard. Results from this technique suggest that rust monitoring and rust treatments can be eliminated four to six weeks before harvest. The project estimates that had all prune growers followed this rust monitoring program in 2001, they would have saved 1,565,200 pounds of pesticide applied (based on all bearing prune acreage receiving one sulfur application for rust at 20 lbs./acre).


Presence-absence sequential sampling for web-spinning mites
Prunes are occasionally infested by web-spinning mites and require an in-season treatment. There are no established treatment thresholds for web-spinning mites in prunes. Pest control advisors often use subjective or unclear criteria when determining need for mite treatment. When growers make their own treatment decisions it is generally based on visible damage or on calendar date. This is often too late, too early, or unneeded. A presence-absence web-spinning mite monitoring technique originally developed for almonds was tested and modified for use on prunes.

The IPFP/BIFS team is refining the protocol based on the presence-absence sequential sampling of mites for prunes. Further evaluation of the treatment threshold is still needed and the time it takes to monitor also needs to be shortened to accommodate the needs of PCAs. Nevertheless, preliminary results already show that this monitoring technique is a useful method of determining the need for treatment and will reduce the likelihood of treating without justification.

Five-Minute Search for Web spinning Mites Technique
Few PCAs will use the presence-absence technique because it is too time consuming. A “5-minute search” monitoring technique, similar to what PCAs already use, was evaluated in 2001 and results compared with presence-absence technique to determine if any correlation between the two could be made. No treatment decisions were made based on the new technique this past year.

It was determined that the “5-minute search” monitoring technique could be an accurate time saving monitoring technique to determine whether or not a treatment is needed for web spinning mites. The “5-minute search” requires more training and experience than presence-absence. One reason the correlation is not better was human judgment. One person’s “low” could be considered another person’s moderate. In order to reduce this variability, guidelines will be needed to define what exactly low, moderate, etc., are. Training people in the techniques of scouting orchards will be more extensive next year.


Fruit Brown Rot Predictive Model (ONFIT)
There is currently no way of knowing if fruit brown rot will occur. Consequently, growers have been spraying pre-harvest for fruit brown rot based on a suspicion that it will occur. UC Plant Pathologist Themis Michalaides has created a technique to determine presence of fruit brown rot from latent infections that needs to be validated. The technique is called Over Night Freezing/Incubation Technique (ONFIT).

The ONFIT technique needs to be evaluated under more severe conditions before it can be relied upon. This monitoring technique could provide valuable guidance about the need for a fruit brown rot spray. More research and evaluation of the ONFIT during years of higher brown rot will need to be conducted before any definite conclusions can be made.


Goal II. More Effective Use of Fertilizers and Natural Resources


Using tissue analysis and water samples
Although tissue analysis has been recommended for many years it is an underutilized tool in determining fertilization needs. Water analyses are also valuable; some wells have nitrate nitrogen in their water. Knowledge of nitrogen (N) content of the water could be used by growers to supplement conventional N fertilizer programs. To promote the adoption of these valuable monitoring tools, IPFP/BIFS sought to demonstrate their utility to growers.

Based on UC-established critical mid-summer leaf tissue levels, almost half of the sites in 2001 were deficient in N and a few sites had zinc levels below the recommended level. Nitrogen levels had declined since 1999. In 1999, 20 percent of the sites were N deficient, in 2000 five percent of the sites were N deficient and in 2001 48.5 percent of the sites were N deficient. The advisors involved at these sites will work with their cooperators to determine fertilizer strategies based on these data.

Water samples did indicate several wells with significant levels of nitrate nitrogen. The high nitrate levels were considered when making fertilizer recommendations in the reduced risk plots. These tissue and water analysis have provided useful information and are proving to be valuable tools.


Early leaf analysis to forecast the need of a Potassium (K) fertilizer application
Established guidelines for adequate leaf K levels in prunes are available using July leaf tissue samples. However, if a deficiency is present at that time, detrimental effects to production of the crop may have already occurred. Limited research has been done on using early leaf tissue samples to predict the need for potassium applications. This year (2001), the early leaf tissue sampling for K was compared to the July leaf sample in all of the research and implementation orchards.

Based on the early leaf tissue samples taken in May, no fertilizer applications were recommended and no sites were found deficient in leaf K in July. Also, no sites showed any visual symptoms of K deficiency in June. However, two sites in July and eleven sites in August had visual symptoms of K deficiency.


Irrigation management
Previous research has determined that reducing irrigation (typically 40 percent) in mid-season, and allowing mild stress to occur has no negative economic effect on production or quality. Reducing irrigation saves money and water, reduces pesticide runoff and results in a lower dry away ratio. In order to achieve the goal of reduced irrigation and maximum economic productivity, the project utilized a monitoring technique that determines tree-water status (midday stem water potential or SWP) and evaluates stress using a “pump up” pressure chamber.

Most growers who began with comparison plots of reduced risk and conventional irrigation have adopted the reduced risk irrigation monitoring strategy on their conventional blocks, indicating they have recognized benefits of this approach to irrigation scheduling. Other growers reported unanticipated horticultural benefits of this practice, for instance the suppression of an undesirable and often chlorotic flush of shoot growth in the fall, presumably the result of over-irrigation. The fact that many growers have matched the reduced risk target SWP over the season indicates that the reduced risk monitoring technique is practical and achievable over a range of soil and orchard conditions.

This part of the project has become increasingly popular with growers because using the pressure chamber to schedule irrigations can potentially save them money by applying less water.


Yield and quality at harvest
Based on data obtained from the 1999 and 2000 P-1 grade sheets (Table 2), as well as 2001 Dried Fruit Association quality data, no adverse effects were seen in the reduced-risk program as compared to the conventional program.

Table 2. 1999 and 2000 Yields and quality of prunes in the IPFP reduced risk plots as compared to the conventionally managed plots. (Modified from Table 20 and 21 in Prune BIFS Final Report, March 2002.)

Year Farming System Yielf (lbs/acre) Average Count Per Pound Dry Away % ABC Screen %ABC Offgrade Screen
2000 Reduced Risk
4903.07
57.50
3.22
91.60
1.54
2000 Conventional
5139.39
58.80
2.99
91.52
1.26
1999 Reduced Risk
4705
52.5 b
2.8
91.4
2.2
1999 Conventional
4387
54.8 a
2.8
90.1
1.1

For each year, no significant difference at the 95 percent level of confidence according to Duncan’s Multiple Range Test for Mean Separation.


Cover Crop and Hedgerow Program
This project developed a robust cover crop, filter strip, hedgerow, and wildlife friendly program statewide with additional funds for three years from the USDA Environmental Quality Incentives Program (EQIP). These environmental practices were the primary feature at 28 meetings sponsored or cosponsored by the California Dried Plum Board. These meetings drew in excess of 1,000 farmers, landowners, agencies, and reporters. In addition to the meetings, there was television coverage by Channel 12 News, multiple press releases announcing the meetings, 14 follow up articles in regional and statewide newspapers and magazines, including the front-page story by California Farmer, Jan. 2000.


Cover Crop/Buffer Strip Program
A third of the IPFP growers use cover crops on their IPFP orchards as part of a normal floor management program. Their reasons include: improving water infiltration, nitrogen fixation, beneficial insect habitat, weed suppression, and establishing a durable floor for orchard operations. In spite of low price received for their crop, as a farm group, approximately 10 percent of the prune growers in the state have a perennial or annual cover crop as a normal orchard floor practice.

Eight project farmers established 10 different demonstration cover crops in their prune orchards which were then used as the focus of a number of meetings. The following cover crops were demonstrated, with the first being planted outside the orchard and then the next four non-tillage types being planted in order (Table 3). The last five were covers that required disking and incorporation. By allowing us to plant these 10 covers, each participating grower had a mixture in their orchard that was difficult to manage and mow, and their contribution to the project is commendable.


Table 3. Cover crops planted in Prune BIFS orchards. (Appears as text in IPFP/BIFS Final Report, March 2002)

Hard Fescue Used as a filter strips and vegetated road
Benefical Blend A filter strip and insectary reservoir
N. Z. White Clover/Trefoil A nitrogen fixing sod/insectary
Perennial Sod A durable, low maintenance orchard floor and water infiltration
NonTillage Clover A nitrogen fixing, mow able insectary floor
Plowdown Legumes A nitrogen fixing incorporated mixture of bell beans, peas and vetch
Max Organic Builder A soil improving incorporated mixture of oats, bell beans, peas and vetch
Juan Triticale A soil improving, weed suppressing grain
Common Barley A soil improving, weed suppressing grain
Resident Vegetation The comparison or check of what would be in the orchard

These efforts contributed to the establishment of a long-term cover crop trial at the CSU Chico Farm to serve as a regional demonstration. Forty perennial and 60 annual cover crops were planted in 2000 and again in 2001. These 5 by 30 foot demonstration plots have been marked and are an open walking tour for any group that wishes to view, cover crops, filter strips, California native grasses, insectaries, vetch, peas, annual clovers, fenoeugreek, brassicas, phacelia, erosion grasses, cereals, and mixtures. This planting has been the site of five walking tour meetings so far and was the site of a regional NRCS and RCD training workshop to be held April 25, 2002.


Insectary Hedgerows
The use of insectary hedgerows has been promoted by IPFP at meetings and a hedgerow project was implemented with the cover crop cooperators. Eight different prune ranches planted hedgerow habitat with signs for demonstration. Two particularly extensive plantings included a four times replicated planting at CSU, Chico prunes where permanent, laminated signs informed all of the visitors to the CSU Farm tours about the hedgerow species, insects attracted and pests controlled. The second planting at Billiou Ranches in Hamilton City is a 20 acre planting of hedgerow species; Coyote Brush, Coffee Berry, Yarrow, and Deergrass with the species placed in clumps in place of missing trees. Many groups have visited this innovative planting over the past four years as an insectary plantings interspersed in the orchard.


Wildlife Friendly Farming
The IPFP program has supported wildlife friendly farming through the cover crop and hedgerow plantings. Four of our hedgerow plantings were specifically planted next to waterways including Deer Creek and Gilsizer Slough to provide diversity, cover, and food for bird species. In addition to the field plantings and demonstrations, the project hosted along with our cosponsors, The Nature Conservancy and the Colusa County NRCS, three ‘Wildlife Workshops’ at the Colusa Farm and Equipment Show in 1999, 2000, and 2001. The attendance at the 2000 show exceeded 100 participants including; farmers, wildlife biologists, and Future Farmer of America students.


GOAL III. Encourage adoption of reduced risk practices through outreach and extension efforts.


Starting at petal fall, scouts and PCAs visit each orchard at least once a week until harvest. Orchard information such as insect counts and disease findings were reported to growers at least once per week. Ten newsletters were published and distributed to all 1,400 prune growers in California plus about 500 related industry members about the progress of the project. And finally, meetings to share information were numerous and well attended. 1065 people in 2001, over 1,154 in 2000 and over 787 in 1999 received information at meetings on the IPFP project. In addition, the Tehama County Farm Advisor provided insect day degree accumulation to clientele via e-mail on a regular basis. Advisors also wrote several newsletters.


Pest control Advisor involvement
Approximately 15 PCAs were asked to review and if possible try using monitoring techniques under evaluation during the 2000 and 2001 seasons. At meetings held in October 2000 and spring 2001, the PCAs and the project team met and discussed the monitoring techniques.

Overall, the PCAs were pleased to be involved in the project. The PCAs favor more subjective methods of monitoring. However, for this project, quantitative methods must be used in order to determine what treatment threshold and/or monitoring techniques are the most accurate. When the techniques and thresholds are finally presented to all involved in the prune industry, it is understood that many will use subjective techniques and shortcuts in order to save time and money.


Evaluation of Project Impacts


Pesticide Use reporting
One of the main goals of the project since its inception in 1998 was to reduce the amounts of organophosphate pesticides applied. Shown below, in Figures 1 and 2, are pounds of active ingredient applied per acre to prunes from 1998 to 2000 for all bearing prune acreage in California. Both Diazinon® and Supracide® have decreased since 1998, while Asana“ has remained almost the same. The amount of sulfur has decreased the most over the three years.

Figure 1. Pounds of active ingredient applied per bearing acre.
(Appears as Fig 19 in the IPFP/BIFS Final Report, March 2002)

Figure 2. Pounds of active ingredient applied per bearing acre (Appears as Fig. 20 in the IPFP/BIFS Final Report, March 2002)

 

MODIFIED EXCERPTS FROM:
APPLE BIFS—FINAL REPORT OCTOBER 26, 2001 AND PROGRESS REPORT, JULY 2002


Principal Investigator: Janet Caprile
UC Cooperative Extension, Contra Costa County
75 Santa Barbara Rd. 2nd Fl.
Pleasant Hill, CA 94523
Phone: (925) 646-6708
Email: jlcaprile@ucdavis.edu


Background
Agriculture-urban interface problems have led to an interest in adopting a reduced risk pest management program in Contra Costa County orchards. The use of pheromone mating disruption (MD) and other pheromone based “reduced risk” practices would allow apple growers to significantly reduce the use of controversial materials. However, the cost and risk of these practices have been prohibitive. The BIFS program was developed to offset these factors by providing a cost share for the pheromone products and monitoring assistance to help reduce the risk of failure.

The Reduced Risk Program
The primary goal of this project is to demonstrate and encourage the use of sustainable, reduced risk production practices for apple and pear growers. Pome fruit orchards currently have a fairly sustainable fertility and orchard floor management program. They are not high nitrogen users (0-50 lbs/A annually) and orchard floor management practices routinely include permanent or winter annual cover crops. Therefore the focus of this project has been on assisting growers to improve their pest management program. For the last two years the BIFS project has been run in conjunction with the Integrated Apple Production (IAP) project funded by DPR from 1999-2001. The IAP project was completed last season and the BIFS program continued on its own in 2002.

Codling moth (CM) is the primary pest in all pome fruit orchards. The BIFS orchards have employed mating disruption techniques as the foundation for their codling moth control program. These are non-toxic materials that are safe for people and animals and not disruptive to biological control. Mating disruption works best in large, uniform orchards with low codling moth populations. In the first few years, growers typically need to employ one to three supplemental codling moth sprays in addition to season long mating disruption. This is needed to reduce codling moth populations to very low levels so that mating disruption can become the primary control by the third or fourth years.

Mating disruption is a more expensive control program than conventional sprays, with the transitional years being especially costly due to the supplemental sprays. To offset these high costs during the transitional years, the BIFS (and IAP) program provided a 50 percent cost share for the mating disruption product for participating orchards. Growers pay all other pest management costs. During the first two seasons, BIFS/IAP growers averaged from $56/acre less to $63/acre more than the conventional comparison orchards due to the cost share program.

On Farm Demonstration of an Alternative Farming System
From 1999 to 2001, there were nine orchards (172 acres) that participated in the IAP program, and began the transition to “reduced risk” pest management practices based on mating disruption. In 2000, the BIFS program supported 11 additional orchards (311 acres) into a reduced risk pest management program. Ten of those orchards continued with the program in 2001 and three new orchards were added. Another 45-acre orchard adopted the BIFS management practices but was not an “official” member as funds were not available to include this last orchard. We provided monitoring assistance for this extra orchard as well as two other orchards that were in their fourth year of mating disruption and transitioning to organic production.


BIFS orchards demonstrated the use of:

1. Four different kinds of mating disruption products: Isomate“ dispensers; Checkmate XL-1000“ dispensers; Checkmate dispenser – experimental design; Suterra puffers

2. A new type of monitoring lure based on kairamones (plant volatile attractants) rather than pheromones. The BIFS and IAP orchards have cooperated in testing these lures (under test agreement with the USDA) over the past two years. They represent a tremendous improvement in our ability to track codling moth populations in mating disrupted orchards.

3. Three reduced risk sprays – Intrepid“, Assail“, Danitol“ - to supplement mating disruption. To date, there have not been very effective, reduced risk supplemental sprays. Both Assail“ and Intrepid“ are reduced risk, less disruptive materials that are reported to be fairly effective against codling moth. They are expected to get full California registration shortly and would be a great benefit if they prove effective.


Pesticide Use
The 2001 season showed a declining trend in the application of insect and disease management materials in comparison with the 2000 season. This trend reflects the continued poor apple market rather than a decrease in pest problems. The BIFS orchards had a slight (7 percent) increase in these materials while the IAP orchards showed a 70 percent decrease, the MD comparison orchards showed a 80 percent decrease and the conventional comparison orchards showed a 67 percent decrease in the use of these materials.

Although there was a trend for the total amount of pesticides to decrease, the percent of targeted
materials actually increased in 2001 in response to the increased pest pressure and the increased use of chemical thinning agents. Again, this is a result of the continued poor apple market. However, in comparison with 2001’s conventional orchards, the targeted materials were 33 percent lower in the BIFS orchards, 38 percent lower in the IAP orchards and 46 percent lower in the Mating Disruption (MD) comparison orchard.


Pest Damage
In 2001, codling moth damage in the BIFS orchards averaged 10.6 percent (range 0 to 35 percent), higher than 2000’s average of 7.3 percent damage (range 0-54 percent). The IAP orchards averaged 9.6 percent (range 0-20 percent), higher than 2000’s average of 3.1 percent damage (range 0-8 percent). The damage was higher than acceptable in 10 of the 21 program orchards. This can be attributed to the continued poor apple market (abandoned orchards, reduced inputs), high codling moth pressure and migration, trap indicator failures, and late mating disruption application coupled with supplemental spray problems (insecticide resistance, timing, materials).

There was additional pressure from secondary pests (scale, mite, leaf miner) in some orchards due to an increase in broad-spectrum sprays to control codling moth. Additional sprays went on to control these pests, averting damage in most cases. Some orchards also had disease problems due to the lack of an effective predictive model and efforts to reduce inputs and the number of preventative sprays.


Project Accomplishments and Challenges
There have been several notable successes to the IAP/BIFS program:

Despite successes, some challenges to the project remained:

Figure 1. Codling moth damage in the IAP/BIFS and comparison orchards (IAP, BIFS, and MD orchards all used mating disruption with supplemental sprays to control codling moth)
(Appears as Figure 5 in Apple BIFS Final Report, October 2001)

 

MODIFIED EXCERPTS FROM
CITRUS BIFS—ANNUAL REPORT, 2001-2002

Principal Investigator: C. Thomas Chao, PhD.
Assistant Extension Horticulturist
Department of Botany and Plant Sciences
University of California Riverside, Riverside, CA 92521
Phone: (909) 787-3441
Email: ctchao@citrus.ucr.edu.


The mission of the Citrus BIFS program was “To reduce risk associated with agricultural chemical use while maintaining yield, quality, and profitability through increasing the adoption of biologically integrated farming system for citrus growers.” The long-term goal was to enhance Fresno County citrus growers’ confidence in and adoption of a reduced input system that is economically viable. The short-term goal of the Citrus BIFS program was to develop and implement an extension program in five areas:

The Citrus BIFS ended after three years on June 30, 2002. We were able to demonstrate combinations of practices that can reduce pesticide input and reduce the use of pre-emergent herbicides, while demonstrating the benefits (or non-negative effect) of cover crops, a pest monitoring system, and a good irrigation monitoring system. We were able to promote these biological integrated systems to citrus growers in Fresno County and neighboring counties through grower days, seminars, and newsletters. The significant benefits of many of the Citrus BIFS practices can only be realized on a long-term basis (10 to 20 years). It is difficult to clearly demonstrate the direct benefit on such a short-term basis (2.5 years). Continuing efforts should be devoted to the BIFS approach in citrus in order to realize the greatest benefits.


On-farm demonstration of Citrus BIFS system
A comparison of alternative Citrus BIFS practices vs. the conventional citrus production practices is shown in Table 1. There are four demonstration sites for the cover crop trials. Table 2 shows the total acreage of participating growers in the Citrus BIFS program and the alternative practices growers used.


Table 1. Comparison of Citrus BIFS farming practices vs. conventional citrus farming practices. (Appears as Table 1 in Citrus BIFS Final Report, August 2002)

Parameters Conventional practices BIFS practices
CA Red Scale control OP’s, Carbamates application Aphytis release, IGRS, oil
Citricola scale control OP’s, Carbamates application Monitoring, OP’s only if needed
Thrips control Baythroid, Carzol, Dimethoate Agrimek, Success, Veretran,
Weed control Pre-emergents (Princep, Diuron) and Roundup Cover crops, Roundup, weed ID
Nematode control OP’s, Carbamates Monitoring and chemical only if necessary; cover crops
Phytophthora control Ridomil, Alliete Monitoring;
better irrigation management
Nitrogen fertilization One to two soil applications Leaf and water analyses; foliar sprays with better timing;
multiple soil applications
Other Pests Monitoring Monitoring
Irrigation Calendar based irrigation Scheduling based on ET, flow meters, tensiometers or electronic irrigation monitoring system, proper placement of irrigation microjet

Table 2. The acreage of the Citrus BIFS program and the BIFS practices used. (Appears as Table 2 in Citrus BIFS Final Report, August 2002)

Growers
Acres enrolled
BIFS acres
Citrus acres
Acres farmed
 BIFS practices used
A
17.4
8.9
600
640
 Insect monitor, cover crop, leaf & water sample
B-1
29
29
169
169
 Insect monitor, cover crop, erosion control, leaf & water sample
B-2
51
20.7
3000
>20,000
 Insect monitor, irrigation monitor, leaf & water sample
I
38
38
210
310
 Insect monitor, cover crop, leaf & water sample
M
24.2
9.6
50
690
 Insect monitor, pre-emergent/contact herbicide, leaf & water sample
S
40
40
40
40
 Insect monitor, leaf & water sample
T*
12
12
200
200
 Insect monitor, cover crop, leaf & water sample
H**
11
11
400
400
 Insect monitor, cover crops, irrigation monitor, leaf & water sample, Aphytis

*Growers enrolled since October 2000. There are two blocks of 6 acres at T’s site. Cover crops are used as main weed control practice and no pre-emergence herbicides were used at T’s site for the past four seasons.
**H farms over 400 acres of citrus. They use Aphytis release at all their citrus acreage. They also use native vegetative as cover crops to reduce the use of herbicide.

Accomplishments

Insect pest management
Regular pest monitoring is a critical component of the Citrus BIFS program. We continue to monitor the pest population at eight cooperating sites. A close monitoring of pest populations can reduce the use of pesticide and costs to the growers. We supplied the pest monitoring data during the spring and summer seasons to our cooperating growers on a monthly basis.

Temperature data collection at cover crop and non-cover crop demonstration sites
One of the major concerns for all citrus growers about using cover crops in citrus orchard floor management is the risk of lowering the temperature during a freeze. In theory, cover crops in the citrus orchard floor can lower the temperature as compared to orchards without any cover crops (bare ground). This belief is common among citrus growers. To promote the use of cover crops in citrus orchard, we installed environmental data loggers at four cover crop demonstration sites (Table 3).

Table 3. Cover crops planted at three BIFS Citrus orchards. (Appears as text, p. 7 in Citrus BIFS Final Report, August 2002)

Site Cover crop planted
A oats
I Sweet peas, oats, native grasses
T Crimson clover, sweet peas, oats

Two data loggers were installed at each location, one on the ground with cover crops and one on the ground without cover crops. There were very little differences in daily minimum low temperature between the cover crop site vs. the non-cover site at all three locations in the 2001-2002 season. Overall, there was no significant difference in temperature between the cover crop sites vs. the non-cover crop sites in the past two years (2000-2002). There was no damage to citrus trees in any of the cover crop sites. These results indicate that the use of cover crops combined with proper cover crop management such as late seeding should reduce potential frost damage to citrus trees.

Cover crops provide additional benefits. It was demonstrated that they have a significant effect in reducing soil erosion on hill sites. Cover crops also can reduce irrigation input and enhance population of beneficial insects.

Irrigation efficiency monitoring
Since July 2001, irrigation monitoring systems were installed at three sites. The systems can accurately monitor irrigation efficiency, timing of irrigation, and the depth of the wet zone. Growers were very satisfied with the information obtained from the monitoring systems. They were able to make proper adjustments in their irrigation management system that resulted in higher irrigation efficiency, lower cost, better tree health, and low chances of runoff. This system was also able to identify any problems in the irrigation practices and particular problem spots in the orchards. Overall, an efficient irrigation monitoring system is a critical component for successful integrated farming systems.

Nitrogen leaf analyses of participating grower sites
Leaf samples from all participating growers’ sites were collected in December 2001 for leaf analyses. Macro elements (N, P, K, Ca, Mg) and microelements (Zn, Mn, Fe, Cu, B, Na) were measured. In general, all orchards have normal level of nitrogen.

In 2000, the level of nitrogen was too high in most orchards. With advice from the Citrus BIFS team, all growers reduced their nitrogen input and the results were shown in 2001 analyses. Most of the other elements are in the normal ranges. Leaf nitrogen analyses, in combination with analyses of irrigation water, allowed growers to better monitor and predict the nutrient status of their trees and take corrective measures.

 


MODIFIED EXCERPTS FROM
DAIRY BIFS—INTEGRATING FORAGE PRODUCTION WITH DAIRY MANURE MANAGEMENT IN THE SAN JOAQUIN VALLEY—ANNUAL REPORT, SEPTEMBER 2001 AND SEMI-ANNUAL REPORT, MAY 2002

Principal Investigator: G. Stuart Pettygrove
Extension Specialist, Land Air and Water Resources, UC Davis
One Shields Avenue, Davis, CA, 95616
Phone: (530) 752-2533, FAX (530) 752-1552
gspettygrove@ucdavis.edu


Introduction
The Dairy BIFS project seeks to develop and demonstrate improved dairy manure management practices for reduction of nutrient related environmental problems. The focus is primarily on liquid manure water stored in on-site ponds or lagoons including all the manure, flush water from paved feed lanes, freestalls and milking parlors, and a portion of the storm runoff that is stored in lagoons. In California, this lagoon water is typically applied to cultivated fields via the flood irrigation system and in combination with commercial fertilizer application, is often associated with nutrient leaching. Excess nutrient application can be addressed through monitoring manure nutrient application and reducing commercial fertilizer application accordingly. The project implemented a nutrient monitoring and application system in 11 dairies throughout the San Joaquin Valley to improve the balance of nutrient application and removal in the dairy forage system. The project’s approach, based on flow measurement and nutrient analysis, makes it possible for dairies to accurately record and estimate nutrient application to fields.

Methods
Side-by-side comparisons of conventional and alternative practices serving as demonstrations were set up on farms. Contrasting conventional and improved BIFS practices are summarized in Table 1. Flow measurement of manure water onto fields is the main alternative practice, and it is being used to record nutrient application for non-BIFS project fields at some farms. Flow meters measure flow of dairy manure water. Nitrogen “quick tests” determine the exact amount of nutrients in the liquid manure. Flow rates of manure water into the irrigation are recorded as well as nutrient analysis, data on field area, and time required for an irrigation set. Nutrient application is then calculated from the collected data.


Table 1. Contrasted practices on Dairy BIFS fields (Appears as Table 2 in Final Report)

Dairy Conventional Practices Improved Practices
D1 - Apply manure as in past for disposal purposes - Use torpedoes in furrows to reduce total irrigation water use
- Reduce manure application by eliminating one or more manure water irrigations
D2 - Apply manure as in past for disposal purposes - Reduce manure application by eliminating one or more manure water irrigations
D3 - Apply manure water to ryegrass in spring only - Apply manure water as pre-irrigation on ryegrass, and in spring, monitoring to ensure proper amounts applied
D5 - Use commercial fertilizer only for silage corn production - Use manure water as only nutrient source for silage corn
D6 - Commercial fertilizer and manure water to supply corn nutrient needs - Manure water only to supply corn nutrient needs*
D7 - Apply manure water to fields, assuming that 25% of organic N is available - Apply manure water to fields, assuming that 75% of organic N is available
D8 - Use commercial fertilizer only for silage corn production - Use manure water as only nutrient source for silage corn
D9 - Avoid using manure on alfalfa - Apply manure water to alfalfa at carefully monitored rates
D10 - Apply manure water during high water volume irrigation - Apply manure water during low volume irrigation (reducing total nutrient load)
D11 - Apply manure water, assuming that 70% of organic N is available - Same as conventional, but adjust rates to account for soil NO3- in spring

* At this site, commercial fertilizer was applied to the improved portion of the field due to a lack of communication between the owner and the field equipment operator. Therefore, the conventional and improved treatments reported ended up being Conventional = more manure and Improved = less manure.

Other alternative practices include the use of soil and tissue samples for decision making on commercial fertilizer and lagoon water application. Soil samples were used to assess available N, P, and K levels, following which decisions were made to reduce or eliminate P and K application, and reduce N application (in manure and/or commercial fertilizer). Tissue samples were used to evaluate the crop for potential deficiencies, and when those deficiencies were found, manure and/or commercial fertilizer was applied to meet the crop needs.

Alternative practices on alfalfa forage involved diluting manure water to reduce concern about organic matter in the manure water competing with the alfalfa crop for oxygen. Manure application rate was low enough that all nutrients applied in the manure water were removed in the alfalfa crop. Overseeding with berseem clover was used to increase nutrient uptake and crop biomass, especially in the early spring when alfalfa growth is minimal.

Results

Manure nutrient application
Manure water nutrient application was tracked on each BIFS dairy with N, P2O-5, and K2O applications reaching up to 828, 425, and 1044 lbs./acre, respectively, on the summer 2000 corn silage crop. Manure water nutrient application on the alfalfa crop at Dairy 9 totaled 77, 36, and 143 lbs./acre of N, P2O-5, and K2O, respectively.

Once nutrient application could be tracked using flow meters and manure water analysis, on-farm decision-making at participating dairies consisted of two general approaches. Those following the first approach examined data collected from an irrigation and then made decisions about subsequent manure water or commercial fertilizer applications on the field. This was especially common where flow monitoring was relatively new, and growers were mostly interested in finding out what typical applications included. Some very high applications of manure water nutrients in a single irrigation resulted (up to 550 lbs.of N/acre at one location), but these growers decided to eliminate the manure water in all or some subsequent irrigations, even though this was not their normal practice. Most growers using this method that ended up with excess nutrient application have decided to reduce flow rates as well as total applications of manure water in the coming growing season.

If the manure management system had not been tested with different irrigation and forage production practices, it might have been assumed that all dairy producers in the state (or at least all confinement dairies in the Central Valley) would be able to adopt this improved system with as much ease as some producers in Merced County. Rather, we have found other limiting factors to play a role, and discovered that major changes to pipelines, water supply, and manure storage systems will be the norm for many California dairies wishing to implement improved manure nutrient management.

Reduction of fertilizer use and cost savings
Total commercial fertilizer use on improved BIFS fields was reduced compared to conventional practice. For example, an average of 103 lbs/acre of commercial N fertilizer was saved by implementation of the improved practices (Table 2), which was estimated to result in a $55/acre savings for participating growers. Dairies 7 and 11 are not included in the calculation of the average fertilizer savings, as they used little to no fertilizer on all BIFS land, and instead reduced manure water application for the improved treatment. Dairies 6 and 10 used the same amount of commercial fertilizer on each treatment, but reduced manure water application on the improved side. They both planned to reduce commercial fertilizer application in 2001 in order to better utilize manure water nutrients.

Table 2. Fertilizer use on silage corn at BIFS dairies, 2000 (Appears as Table 11 in Dairy BIFS Annual Report, September 2001)

 
Conventional
Reduced
Fertilizer Savings
Dairy
N (lbs/acre)
P (lbs P2O5/acre)
K (lbs K2O/acre
N (lbs/acre)
P (lbs P2O5/acre)
K (lbs K2O/acre)
N (lbs/acre)
P (lbs P2O5/acre)
K (lbs K2O/acre)
1
100
0
0
0
0
0
100
0
0
2
80
25
25
0
0
0
80
25
25
4
90
0
0
0
0
0
90
0
0
5
153
10
10
3
10
10
150
0
0
6
200
0
0
200
0
0
0
0
0
7
0
0
0
0
0
0
0
0
0
8
379
208
142
79
208
95
300
0
47
10
175
0
0
175
0
0
0
0
0
11
0
0
0
0
0
0
0
0
0
Average (not including Dairies 7 and 11)
103
4
10

 

Changes to the current improved management practices may be needed at some dairies. For example, most calculations of nutrient application have focused on N application, mainly due to the threat of nitrate pollution in the groundwater. However, for a couple of the dairies, K is out of balance compared to N due to high K content in the manure water. These locations also tend toward extremely high available K levels in the soil. Therefore, management of manure nutrients may need to focus on setting K application rates, supplementing with commercial N fertilizer. Additionally, the dairy producers may be able to reduce K levels in manure by adjusting feed rations.

Crop yield and quality
One very important factor for growers when considering changing management practices is whether or not the new practices will affect yield and quality. Yield of silage corn (at 70 percent moisture) ranged from 20 to 35 tons/acre with no significant difference between conventional and improved treatments (Figure 1). Nutrient content (percent N, P, and K) of harvested corn silage also showed no significant differences due to treatment (data not shown).

Reduction in fertilizer or manure application did not affect nutrient removal from the field in the harvested material, which averaged 211, 96, and 305 lbs/acre of N, P2O-5, and K2O, respectively. Up to 279, 142, and 420 lbs/acre of N, P2O-5, and K2O, respectively, were harvested at specific dairies. Therefore, it is important to have a good estimate of potential nutrient utilization at each location, instead of relying on book values that don’t take yield and concentration differences into account.

Winter forage, from pure wheat to oats to various forage mixtures, was all harvested for silage, and ranged in yield (70 percent moisture) from 13 to 27 tons/acre (data not shown). Nutrient removal during harvest ranged from 149 to 288 lbs N/acre, from 74 to 129 lbs P2O5/acre, and from 319 to 555 lbs K2O/acre.

Figure 1. Silage corn yield at BIFS dairies, comparing conventional and improved manure management practices, 2000

The experiment testing berseem clover overseeding and manure water application to alfalfa at Dairy 9 took place on two different fields in 2000 and in 2001. Manure application had no significant effect on yield in either year. Neither treatment affected quality, as measured by total digestible N (TDN), which averaged 52.8 and 55.3 percent i