* Data regarding the use of these practices were taken from field reports, n=5

Table 12. BIFS practices in weed IPM, percent of sites incorporating these practices (n=10), and the number of years in use. From Table 7, West Side BIFS Final Report, page 62 and Table 4, West Side BIFS 1998 Annual Report, page 29.

Insect Management

The use of cowpea buffer strips was fully demonstrated in 1998 in six BIFS fields. This approach increases the biological intensity of cotton pest management by providing an alternate host for Lygus, reducing the area requiring broad-spectrum insecticides, and conserving natural enemies. Six fields were planted with California black-eye bean strips 40 feet wide on the upwind side of the cotton field. The on-farm plots demonstrated the concept was feasible and performed adequately (Figure 4, West Side BIFS 1998 Annual Report, page 27), but did not live up to all expectations. Lygus migration occurred across a wide front and was not limited to the upwind border. Timing of the migration, stage of bean development, and irrigation timing are all crucial for maximum attractiveness. The BIFS growers feel that the concept has merit but is not very effective in its current form.

In 1998, four releases of green lacewing (Beneficial Insectary, 14751 Oak Run Rd, Oak Run CA 96009) were made at a rate of about 10,000 eggs per release. Releases were made according to insectary guidelines and placed in or near the buffer strips. These releases were made during July and August.

Weed management practices demonstrated include variable rates of Treflan®, introduction of a new "smart sprayer," and physical control of weeds, such as burning and cultivation, or burial. Variable rate layby application of Treflan® involves replacing nozzles in the incorporator close to the tomato row with nozzles of less gallonage, resulting in less material applied close to the plant. The bed shoulder receives the highest concentration and there is less herbicide needed at the tomato row because the tomato is a rapidly growing crop after layby and it quickly shades weeds close to the crop row. Treflan® use can be reduced 40 percent to 60 percent depending on how the incorporator is set up. Reducing the amount of Treflan® saves the farmer money and decreases the residual amount in the soil which reduces the chance of injury to a grass cover crop that a grower may want to use following tomatoes.

Another weed management practice used is the light-activated sprayer to apply post- emergence materials. The Patchen sprayer was introduced and demonstrated in the BIFS community. It uses sensor-activated nozzles that apply herbicide only when green plants are detected. It can replace broadcast applications that apply much of the product on bare ground. The current use is in cotton for control of bermuda grass and field bindweed. The herbicide used is Roundup® for either weed or Prism® for bermuda grass. Reduction in herbicides is estimated at 40 percent to 80 percent. Ron Jones of J & J Farms and the manager at Borba Farms both feel they have reduced their use of herbicides by 60 percent to 80 percent with this technology.

PIGGYBACK RESEARCH

A wide range of adjunct projects totaling $208,000 is either underway or being proposed for the West Side BIFS projects. These include: Effects of Organic Compost on Cotton Nitrogen and Soil Physical Properties, Sustainable Methods to Control Soilborne Diseases of Tomatoes, Integrated Management of Soilborne Diseases and Aphid Transmitted Viruses in California Vegetable Crops--An On-Farm Demonstration, Using Buffer Crops to Protect Cotton from Lygus, Survey of Arthropod Fauna in San Joaquin Valley Cotton, Planting Date Evaluations of Prospective Late Summer Cover Crops for the San Joaquin Valley Row Crop Systems, Nitrogen Mineralization from Organic Amendments, Use of Cover Crop Mulches in Tomato Production Systems, and Applying Variable Rates of Treflan® at Layby in Tomatoes.

DOCUMENTATION AND EVALUATION

This section (as required in Section 597 of AB 3383) provides "an analysis of the monitoring activities, a summary and assessment of pesticide and fertilizer use data, and an analysis of the success of each project in meeting the standards for integrated farming systems." This section is based on summarizing the West Side BIFS project’s own impact assessment activities and the second annual review by the program advisory review board, UC SAREP Director and staff. In addition, it includes an evaluation of the West Side BIFS Final Report by the UC SAREP Director and staff.

This project was very successful at monitoring the side-by-side comparisons of conventionally managed and biologically integrated production systems. Intensive monitoring of soil chemical, physical, and biological factors was performed each year in these plots.

Soil Quality Monitoring

A number of soil properties and sampling times have been selected for monitoring changes in soil quality. Soil samples were taken from the alternative and conventional fields of each participating farm in the spring and fall of each project year. Soil physical properties monitored included: bulk density, water stable aggregates, water-holding capacity, water infiltration rate, particle size distribution, and penetration resistance. Soil chemical properties monitored included: pH, electrical conductivity, cation exchange capacity, extractable Na, Ca, Mg, K, and P, total soil carbon and nitrogen, inorganic N (NH₄⁺, NO₃^-), sodium adsorption ratio (SAR), and percent organic matter. Key soil biological properties included dehydrogenase activity, potentially mineralizable N, earthworms, microbial activity and cloth strip decomposition, microbial biomass carbon and nitrogen, and phospholipid fatty acid analysis. Pages 30-40 in the West Side BIFS Final Report provide further details on soil quality sampling and analysis.

Initial samples taken in 1996 revealed no significant difference (p<0.05) between the conventional and alternatively managed plots in their initial values for soil pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic matter (SOM) and total N values in each agricultural system. This result suggests that the alternative and conventional systems were allocated to homogeneous fields. However, samples taken in 1998, almost three years into the project, revealed some significant differences (p<0.05) among the soil quality indicators. Those soil quality measures that showed the most consistent increases in alternatively managed sites included total soil carbon, microbial biomass carbon and nitrogen, exchangeable potassium and organic matter (Figures 7, 8, and 9). After almost three years of alternative management, all sites showed significant differences in at least one soil quality indicator. The West Side BIFS project coordinator also compared the impacts of conventional soil management to those of a nine-year organically managed soil and found significant differences in eleven of twelve soil quality indicators. The improvements in the organically managed soil, after nine years of certified organic production, indicate that changes in soil quality occur over time and may not be initially apparent.

Figure 7. Percent soil organic matter from individual BIFS sites (conventional and alternative practices), and from three farms with multiple alternative management practices. From page 31, West Side BIFS Final Report.

 

Figure 8. Microbial biomass carbon from individual BIFS sites (conventional and alternative practices), and from three farms with multiple alternative management practices. From page 32, West Side BIFS Final Report.

Figure 9. Microbial biomass nitrogen from individual BIFS sites (conventional and alternative practices), and from three farms with multiple alternative management practices. From page 31, West Side BIFS Final Report.

The extensive soil quality indicator property monitoring that has been conducted through the West Side BIFS Project and the UC Davis campus-based Sustainable Agriculture Farming Systems (SAFS) Project, provides outstanding datasets that are currently being used to develop a soil quality index. The goal of this project is to subject a Principal Component Analysis-identified subset of the BIFS and SAFS datasets to scoring functions that will create a ranked list. The ranking will also take into consideration the specific soil management goals of Central Valley farmers in order to generate a soil quality index. This will provide growers with a tool to conduct a semi-quantitative assessment of the quality of their soils relative to specific management goals, such as productivity or environmental conservation.

Compost and Manure Sampling and Crop Stand Establishment after Cover Crops

Representative compost samples were supplied by the BIFS participants and submitted to the DANR Analytical Service Laboratory for total content of C, K, Na, P, Ca, Mg, organic carbon and nitrogen, and total N (see Appendix 2, West Side BIFS Final Report). Based on the total compost N, and the soil P and K values, a guideline was prepared by the technical team and given to each grower for possible adjustments in their fertility programs. Crop plant stand counts were performed each year after the cover crop treatments to evaluate the impact of these organic matter amendments on seedling health and stand establishment.

Soil amendments, including plant-wastes, manure, and combinations of the two, varied among type in their net N mineralization rate. Plant wastes mineralized 4 percent or less of the total N present, mixtures of plant waste and manure mineralized 5-10 percent, and aged manures 10 percent. These results showed much slower N mineralization rates than many cited references show, but are consistent with growers’ experiences suggesting that organic soil amendments have more significant long term effects than was previously presented in the literature.

Productivity and Product Quality Measures

After three years of side-by-side treatments, the 1998 cotton yield estimates show some interesting results (Figure 10). Since location and individual production practices might affect data, results are expressed as standardized percentages of the BIFS divided by conventional. The bar at 100 percent represents equivalent yield. Yield estimates from hand-picked 1/1000^th-acre samples indicated that two of five farmers had slightly greater cotton yield in the BIFS plots than in conventional, and at three sites BIFS plots slightly under-yielded conventional. Care must be taken in interpreting these differences as a result of only BIFS practices. However, it should be noted that the more biological approach did not result in a general yield decline.

Figure 10.  BIFS cotton yields contrasted to conventional yields in 5 fields in the West Side. Results expressed as a percent of conventional. Adapted from Figure 6a, West Side BIFS 1998 Annual Report, page 32.

Determinations of postharvest crop residues in West Side BIFS rotations

Crop residue biomass collected throughout the West Side region from 1996 to 1998 ranged from 9,560 lb. per acre for corn following grain harvest to 570 lb. per acre for onions (West Side BIFS 1997 Annual Report, page 22). This data point to a very large range of organic matter recycling that results from various intensive cropping strategies in the West Side region and may be useful in determining optimal rotation schemes.

Though rotation decisions ultimately depend on economic factors, judicious crop rotations may be a means for sustaining soil organic matter, in addition to the deliberate use of amendments such as compost, manure and cover crops.

A 1998 survey of BIFS farmers indicated that pre-plant tillage costs average about 22 percent of the total cost of producing a crop in the West Side. While there are variations depending on the preceding crop, soil type and subsequent crop, typical tillage and land preparation practices for processing tomatoes and cotton result in approximately 12 different tillage operations across fields (Table 1, West Side BIFS Final Report, page 20).

Reducing tillage in West Side cropping systems is generally seen as a desirable goal, however, information is not available on how best to implement a conservation tillage (CT) program. Two informational meetings were held by the BIFS project during 1998 to initiate dialogue and provide pertinent background information on this topic, and to develop on-farm evaluations of CT practices.

IPM Activities

Starting in 1997 and continuing in 1998 the BIFS cotton fields were sampled weekly for major insect pest and beneficial species. This information was faxed to the grower and PCAs as well as sent out weekly as a newsletter entitled Out Standing in Your Fields (West Side BIFS 1997 Annual Report, attachment 4). In addition, during the 3 years of the project, populations of tomato, onion and garlic insect pests were also monitored using UC sampling guidelines. This data was collected on the side-by-side plots to investigate if the organic soil amendments had any impact on pest species. In cotton, monitoring of Lygus and other insects was also done on the cowpea strip crops to evaluate the impact of this management strategy on pest numbers (West Side BIFS Final Report, Figure 22, page 60).

Summary and Assessment of Pesticide and Fertilizer Use

Pesticide Use

Pesticide use data was obtained for pre-project years (1992-1996) from the County Agricultural Commissioner. The project looked at pesticide use in three ways: as acres treated divided by planted acres (treatment acres), as pounds active ingredient applied per acre (ai/acre), and as number of pesticide applications. In 1993, before the BIFS project, acreage treated by BIFS growers did not differ greatly from county-wide patterns (see West Side BIFS 1997 Annual Report, Figure 4, page 33).

From annual farm management plans, the project collected data on the number of applications of insecticides/miticides made by BIFS growers in 1997 and 1998. In 1997 these growers used a total of 13 applications on the conventional side and 12 on the BIFS. In 1998, pesticide use doubled for both farming systems; BIFS plots received 26 applications and the conventional received 29. In 1997 insecticide applications, the amount of ai/acre was similar among BIFS and conventional sites, although one grower used half as much insecticide on BIFS acreage (Figure 11). In 1998, however, three of five BIFS sites received less ai/acre than their conventional comparisons (Figure 12). While number of insecticide applications was similar, by 1998 BIFS sites received less pesticide than the paired conventional sites.

Figure 11. Pounds active ingredient of insecticides applied per acre of treated cotton sites in 1997. (From West Side BIFS Final Report, Figure 23b, page 64). Individual farms are represented as anonymous letter codes.

 

Figure 12. Pounds active ingredient of insecticides applied per acre of treated cotton sites in 1998. (From West Side BIFS Final Report, Figure 23c, page 64). Individual farms are represented as anonymous letter codes.

 

Reducing pesticide use alone may not have a positive impact on the environment or human health. The project provided a preliminary look at reducing risk through comparing the toxicity ratings of pesticides used. During 1997, Category I materials were used in 54 percent of applications on BIFS plots, and 52 percent of conventional plots. In 1998, 35 percent of BIFS treatments were with Category I materials, and 38 percent for conventional plots. Figure 13 presents the toxicity categories of insecticides used by 4 growers on their BIFS and conventional plots. BIFS sites received three fewer insecticide treatments than the conventional sites. This reduction is directly attributable to the BIFS practice of not using systemic insecticides such as Thimet (phorate) and Temik (aldicarb), Category I materials (signal word "Poison and Danger").

Figure 13. Insecticide use of four BIFS participants categorized by EPA Signal Words, adapted from Figure 5 of the West Side BIFS 1998 Annual Report, page 30.

 

This kind of analysis should be done for all the BIFS growers on their alternative and conventional plots. And, for comparison purposes more recent insecticide/miticide or herbicide data from the California Department of Pesticide Regulation and the San Joaquin County agricultural commissioner's office should be obtained and presented for this project. The project coordinators have been informed several times that a more complete analysis of pesticide use should have been included in the Final Report.

Treflan®, a pre-emergence herbicide, was applied to nearly all tomato acreage in Fresno County in 1995. The use of Treflan® at a variable rate can reduce the use of the chemical by 40 to 60 percent. Among BIFS growers, four adopted variable rate applications and eight avoided Treflan® applications in fields with low weed pressure. From 1995 to 1997, the amount of Treflan® used in BIFS tomato fields decreased by 20 percent (West Side BIFS Final Report, pages 55-58). Reducing the rate of Treflan® did not affect weed densities until only 40 percent of the normal rate was applied, and no differences in yield were seen.

West Side BIFS farmers were asked in a survey in 1997 to characterize their highest pesticide use period from 1981 to the present. The majority responded that 1991-1996 was the highest use period for insecticides and herbicides. The majority of farmers did not use fungicides or nematicides for cotton production. The portion of the cost of cotton production due to pesticides during the period 1991-1996 was seen as increasing for both insecticides (12 farmers) but less so for herbicides (7 farmers). The mean increase in cost was estimated to be $56/acre for insecticides and $23/acre for herbicides.

Fertilizer Use

Records of soil fertility inputs for 1997 and 1998 are provided in the West Side BIFS Final Report, Table 5, pages 46-47. Depending on the crop that was produced in a given year at a given site, most N fertilizer inputs ranged from 120 lbs/acre to 250 lbs/acre. In general, West Side BIFS participants considered the addition of organic amendments as a means for adding organic matter (carbon) to the soil during these early years of this project and did not, therefore, adjust the amounts of mineral fertilizer they applied in their BIFS fields relative to their alternative fields. This is due to concerns about possible yield reductions that may occur if nutrient inputs are reduced. However, in 1997 and 1998 six BIFS sites either reduced or eliminated a synthetic fertilizer application.

Experiences of BIFS mentor farmers Tim O’Neill and John Diener suggest that soil fertility building via organic materials generally takes more than three years. There is also experimental evidence presented and discussed during a BIFS meeting on May 1, 1998 by Dr. Tim Hartz, UC Davis, working with BIFS compost materials, that a relatively low percent of nitrogen is typically mineralized during the year following application.

Opportunities for optimizing tomato nitrogen fertilizer management and for reducing potential fertilizer leaching were also evaluated in 1998 in six BIFS project-related on-farm N-strip trials. In these studies, participating farmers evaluated the response of 0, 50, 100, 150, 200, 250 and 300 lb. per acre nitrogen applications on processing tomato yield and quality and also contributed to the development of a data base that is being developed to predict nitrogen needs based on pre-sidedress soil nitrogen pools. Preliminary data from this study (West Side BIFS 1998 Annual Report, Figure 2, page 23) present the average yield resulting from various total N inputs at six BIFS sites. It can be inferred from the fact that these fertilizer response curves are quite flat that there may be substantial means for reducing and optimizing N fertilizer inputs into West Side processing tomato production systems.

The potential for reducing mineral nitrogen fertilizer applications in cotton was evaluated in 1998 through an on-farm trial combining compost applications (10 and 20 tons/acre) with synthetic nitrogen applications. Similar yields produced between treatments indicate a potential to reduce nitrogen applications without yield loss (West Side BIFS Final Report, page 43-44).

Evaluation of the Project in Meeting Integrated Farming Systems Standards

Impact assessment survey for West Side BIFS management team

In a survey of project contributors, including UCCE, private, and public agency management team members, respondents evaluated the extent to which the Project met its five major objectives as follows, where 1 = very successfully, 2 = moderately successfully, 3 = slightly successfully and 4 = not successfully. Nine of the twelve questionnaires that were distributed have been returned and compiled.

 Over the three years of the study, all 16 BIFS demonstration plots received either compost or grew a cover crop, and 75 percent of BIFS sites incorporated an alternative soil management practice in each project year. For many of the plots, this was the first time that organic material was added other than from crop residue. When project participants were surveyed, a majority felt that they have increased their knowledge about soil quality management and that they intend to use this knowledge to a greater extent in the future. Seventy percent of respondents said their knowledge of functions of cover crops, selection of cover crops for particular planting windows, and management strategies for using cover crops has increased either greatly or moderately as a result of the project. Six of ten respondents indicated that their use of cover crops will increase over the next five years with four of ten indicating that their use will stay about the same. Nine of ten respondents indicated that their use of postharvest residue information will increase over the next five years when designing crop rotations.

The West Side farmers were asked to rate their overall approach to cotton IPM on a scale from 1 to 10, with 1 being conventional and 10 being biologically integrated. Overall, participants rated themselves in the middle and slightly to the conventional side of the range (mean rating = 5.04) when responding to their current approach but indicated a desire to move toward a more biologically integrated approach in the future (mean rating = 6.92). When participants rate their use of IPM in each of the four pest areas on a four point scale with 1 being no use to 4 being a lot of use, disease, insect, and weed management were all rated moderate use with means of 3.0-3.4. Highest IPM use was reported for insects and weeds; 8 and 6 farmers respectively rated their use "a lot." When asked how well informed they felt they were about IPM, all but one responded they were "fairly well informed" or "well informed." When asked if their knowledge of IPM is greater now than five years ago, all of those responding indicated their knowledge had increased but only three reported "moderately more" to "a lot more now."

Based on 1998 survey results, the majority of farmers agreed that the information provided by field inspections and through the weekly updates in Out Standing in Your Fields helped them to better understand pest situations in their fields, learn new concepts, and make better decisions. The weekly data helped them develop a better understanding of the pest situation in the larger surrounding area by providing another insect population estimation in their fields, by providing additional information about natural enemies in their fields, and in providing more information about cotton growth and development.

Summary of the Annual Review

The following list summarizes conclusions from the November 1997 annual review meeting and subsequent analysis by UC SAREP of the West Side BIFS project based on their final report:

• The monitoring program for soil quality continues to generate excellent data. This program has involved collecting baseline and end-of-each-season data on key soil physical, chemical, and biological properties. Summary data for two and a half project years indicate some significant changes in biological and chemical properties in the BIFS sites as compared to conventional sites. Data of the last half of year three is still being analyzed and has not yet been presented. The soil quality monitoring data will be used to develop a Soil Quality Index that will provide growers with a tool to guide their soil management practices, and is expected to be completed in the fall of 1999.

• The monitoring program for pest management has increased in intensity during the three years of the project. During the first year, monitoring of pests and natural enemies was hardly done, and the project lacked a planned demonstration of an alternative pest management system. Only four of the sixteen sites were monitored and only for a limited number of plant and pest parameters. The project coordinator was told at the end of the first year that this component of the project must be improved in subsequent years. Renewed funding of this project was made contingent on development and submission of a monitoring program by March 31, 1997. In the 1997 and 1998 seasons, an intensive monitoring program for pest and beneficial species was developed on cotton, and a weekly newsletter with detailed information on organism populations and cotton growth stages was shared with BIFS growers.

• Trap cropping strips were used to supplement intensive in-field monitoring to aid in the control of Lygus hesperus in the BIFS demonstration plots. As reported by the project, the trap cropping performed only marginally and not as well as expected. However, improvements in the implementation of the trap cropping methods may lead, in part, to greater "trapping" capacity of the planted strips. The selection of a determinate variety of black-eyed peas for use as the trap crop likely limited the effectiveness of the practice. As the plants go out of flower, the trap crop becomes less attractive to pests, and consequently the target crop becomes more attractive. Use of indeterminant cowpea varieties such as Chinese Red, Iron Clay or Red Ripper and inclusion of multiple varieties and other plant species in the trap crop would have been better approaches and are supported by the scientific literature (Flesischer, Bugg et al, Hokkanen, Stern). Farmers’ experience with Lygus migration patterns, and their desire to balance pest control costs with loss in yield due to reduced cotton acreage, guided the planting of trap crops only along the upwind margin of a field. However, there is no published experimentally derived evidence that supports the planting of trap crops only along this border in the hope that the trap crop will protect an entire crop field. Problems associated with the specific methods implemented in these demonstrations affected the in-field success of trap crop use.

• Baseline and end-of-season data on the previous years fertilizer and pesticide use were not presented in the 1996 annual report. The project supervisor was informed that he needed to collect and analyze these data and to submit them to UC SAREP by June 30, 1997. Some data on baseline pesticide use was submitted in the Final Report and 1997 Annual Report, and the farm plans which include pesticide and fertilizer data were submitted, however this data needed to be summarized and analyzed more completely. The project supervisor was informed that for the 1998 report this kind of data summary and analysis was required. The number of insecticide applications the BIFS growers used on their conventional and alternative plots was presented in 1997 and 1998; this is a good start. In addition, information was presented on the use of the pre-emergence herbicide Treflan®, both as total pounds used countywide, and as average pounds applied/acre for both BIFS sites and the county as a whole. However, the number of applications, acres treated, and pounds applied for all BIFS growers and for other agricultural chemicals should be presented. For example, post-emergence herbicide data was not presented. In addition, the presentation of the pesticide use data based on toxicity rating should be provided for all the BIFS growers (and not just 4) for their side-by-side plots and for all pesticides used (not just the insecticides). Comparisons of the number of applications, acres treated, and pounds applied between BIFS growers and the county averages during the three years of the project could also be presented.

• In the 1998 report, interesting data was presented from a BIFS piggy-back research project on tomato yield responses to different nitrogen rates from 0 to 300 lbs. per acre. While the data is preliminary, it may demonstrate a lack of response to nitrogen at the higher rates, indicating that some other nutrient or input is limiting, and providing some data on what the optimum rate should be for tomatoes in the area.

• Good data were collected on tomato, garlic and cotton yields and quality for each season, and show no difference in yields between the two farming systems.