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Table 1. Effects of short-term fallowing and fumigation on subsequent performance of peach trees used to replant a cleared peach orchard site in 1998; Parlier, CA; data from Trout and Ajwa

 

 

Trunk diameter (mm)d

Marketable yield (kg/tree) d

Pre-plant treatmenta

11/98

12/99

11/00

11/01

10/02

8/00

8/01

8/02

0-year fallow, non-fumigated

22 c

40 c

63 c

81 c

104 c

6.7 b

17.1 a

32.8 a

1-year fallow, non-fumigated

27 bc

50 b

74 bc

88 bc

113 bc

7.2 b

18.4 a

35.5 a

1-year fallow, Telone + Vapamb

29 b

53 b

80 ab

97 ab

116 ab

9.1 a

20.4 a

38.2 a

0-year fallow, methyl bromide c

37 a

63 a

89 a

104 a

126 a

9.9 a

18.8 a

38.2 a

 

aFor the fallow treatments, trees were removed in fall, either 0 year (4 mo) or 1 year (16 mo) before replanting. After tree removal, fallow plots were ripped to 76 cm depth and planted to Merced rye, which was mowed in spring. All treatments were planted simultaneously in February 1998.

b35 gal/A Telone II EC (310 lb/A 1,3-D) was applied by sub-drip in 100 mm water in fall 1997 with Vapam (26 gal/A) microsprayed on the soil surface.

cMethyl bromide (350 lb/A) was shank-injected in fall 1997, under HDPE plastic.

dMeans within a column and with letters in common are not significantly different (P=0.05).

 

 

 

Table 2. Effects of short-term fallowing and fumigation on subsequent performance of peach trees used to replant an old peach orchard site in 1999; Parlier, CA; data from Trout and Ajwa

 

 

Trunk diameter (mm)d

Marketable yield,7/02 (kg/tree) d

Pre-plant treatmenta

12/99

11/00

11/01

10/02

0-year fallow, non-fumigated

17 c

42 c

61 b

88 c

22.6 c

1-year fallow, non-fumigated

19 b

49 b

69 b

94 bc

26.2 bc

1-year fallow, Inline + Vapamb

22 a

58 a

80 a

106 a

32.8 a

0-year fallow, methyl bromide c

23 a

58 a

79 a

104 ab

30.1 ab

 

aFor the fallow treatments, trees were removed in fall, either 0 year (4 mo) or 1 year (16 mo) before replanting. After tree removal, fallow plots were ripped to 76 cm depth and planted to Merced rye, which was mowed in spring. All treatments were planted simultaneously in February 1998. b35 gal/A Inline (Telone C-35 EC) (320 lb/A 1,3-D+130 lb/A chloropicrin) was applied by sub drip in 76 mm water in fall 1998 with Vapam (13 gal/A) microsprayed on the soil surface.

cMethyl bromide (350 lb/A) was shank-injected fall 1998, covered with HDPE plastic.

dMeans within a column and with letters in common are not significantly different (P=0.05).

 

 


Table 3. Effects of short- to long-term pre-plant fallowing and pre-plant fumigation on performance of plum trees used to replant an old plum orchard site in 2000; Parlier, CA; after Trout and Ajwa

 

 

Trunk diameter (mm)d

 

Pre-plant treatmenta

10/00

11/01

10/02

Marketable yield (kg/tree) d

0-year fallow, non-fumigated

25 c

52 c

92 b

4.7 b

1-year fallow, non-fumigated

29 b

64 b

108 a

5.9 ab

1-year fallow, non-fumigated, herbicide treatment of stumps b

28 bc

63 b

109 a

6.4 ab

2-year fallow, non-fumigated

30 ab

67 ab

111 a

8.3 ab

3-year fallow, non-fumigated

34 a

71 a

115 a

12.7 a

0-year fallow, methyl bromide c

34 a

71 a

115 a

11.8 a

 

aFor the fallow treatments, trees were removed in fall, either 0, 1, 2, or 3 year before replanting. After old tree removal, fallow plots were ripped to 76 cm depth and planted to Merced rye, which was mowed in spring. All plots were planted on the same day in February 2000.

bStumps of old trees treated with Roundup (50 ml/tree) immediately after cutting off tops in September, 16 mo before replanting.

cMethyl bromide (350 lb/A) was shank-injected fall 1999, covered with HDPE plastic.

dMeans within a column and with letters in common are not significantly different (P=0.05).

 

 

 

Table 4. Effects of short- to long-term pre-plant fallows and pre-plant fumigation on subsequent performance of peach trees used to replant an old peach orchard site in 2000; Parlier, CA; after Trout and Ajwa

 

 

Trunk diameter (mm)c

 

Pre-plant treatmenta

11/00

10/01

10/02

Marketable yield (kg/tree) c

0-year fallow, non-fumigated

20 b

42 d

62 c

8.0 d

1-year fallow, non-fumigated

20 b

44 cd

72 b

10.4 cd

2-year fallow, non-fumigated

22 b

48 bc

76 b

14.0 bc

3-year fallow, non-fumigated

23 b

50 b

80 b

16.0 b

0-year fallow, methyl bromide b

29 a

58 a

90 a

18.2 a

 

aFor the fallow treatments, trees were removed in fall, either 0, 1, 2, or 3 year before replanting. After old tree removal, fallow plots were ripped to 76 cm depth and planted to Merced rye, which was mowed in spring. All treatments & plots were planted on the same day in February 2000.

bMethyl bromide (350 lb/A) was shank-injected fall 1999, covered with HDPE plastic.

cMeans within a column and with letters in common are not significantly different (P=0.05).

 

 


Table 5. Effects of pre-plant cover crop and fumigation treatments on subsequent growth of peach seedlings in soil collected from an old peach orchard site near Parlier, CA

Pre-plant soil treatmentsa

 

Performance of Nemaguard peach seedlingsb

 

Fumigation status

 

Cover crop / fallow conditions

Cover crop residue incorporated per 2-liter pot (range, g)

Top fresh weight (g)

Root fresh weight (g)

Percentage of discolored rootsc

Non-fumigated

Bare fallow, moist soil

0

115

75

46

Non-fumigated

Bare fallow, dry soil

0

118

98

46

Bucket-fumigatedd

Bare fallow, moist soil

0

113

82

26

Field-fumigatede

Bare fallow, dry soil

0

92

66

36

Non-fumigated

Castor bean, Ricinus communis

233-306

130

111

48

Non-fumigated

Crotolaria

107-141

117

78

52

Non-fumigated

Sesbania, Sesbania exaltata

88-131

107

76

52

Non-fumigated

Sudangrass, Sorghum sudanensis

134-182

117

80

42

Non-fumigated

Sudex, Sorghum bicolor x sudanese

124-206

122

94

41

Non-fumigated

Sword bean, Canavalia ensiformis

87-95

115

70

40

Non-fumigated

Velvetbean, Mucuna pruriens var. utilis

102-135

120

97

44

Non-fumigated

Vetch, Vicia sativa

3-26

110

75

44

Non-fumigated

Wheat, Triticum aestivum, cv. ÔDawsÕ

118-124

110

85

41

Non-fumigated

Wheat, Triticum aestivum, cv. ÔSpragueÕ

148-151

122

92

47

L.S.Df:

 

 

NS

NS

14

 

aSoil was collected in summer 1999 from replicate MBr-fumigated and non-fumigated plots near Parlier, screened through a 1-cm mesh screen, placed in 2-liter pots in a greenhouse, and subjected to the cover crop / fallow treatments. The cover crops were allowed to grow 4 months, uprooted, chopped with a shredder, weighed, incorporated into the soil, and allowed to decompose for 2 months.

bAfter the decomposition period, three Nemaguard peach seedlings were planted per 2-liter pot (May 2000). Three months after transplanting, total top and root fresh weight was determined for the peach seedlings in each pot, and the roots were washed free from the soil and inspected for symptoms of disease. There were four replicate pots per treatment combination.

cVisual estimate of the percentage of total root length with brown-discolored cortex tissue or decay extending through the root cortex.

dFumigated 3 weeks before transplanting with peach seedlings (MBr : chloropicrin 67:33, 0.8 g per liter soil; in a sealed 19-liter bucket).

eFumigated fall 1998, approx. 9 mo before collection of soil (MBr, 350 lb/A, shank injected in the field under HDPE plastic).

fLeast significant difference among means, based on 95% confidence intervals; NS indicates no significant difference.



Table 6. Effects of pre-plant cover crop and fumigation treatments on subsequent growth of peach seedlings in soil collected from an old plum orchard site near Parlier, CA

Pre-plant soil treatmentsa

 

Performance of Nemaguard peach seedlingsb

 

Fumigation status

 

Cover crop / fallow conditions

Cover crop residue incorporated per 2-liter pot (range, g)a

Top fresh weight (g)

Root fresh weight (g)

Percentage of discolored rootsc

Non-fumigated

Bare fallow, moist soil

0

113

55

42

Non-fumigated

Bare fallow, dry soil

0

106

64

44

Bucket-fumigatedd

Bare fallow, moist soil

0

81

64

30

Non-fumigated

Castor bean, Ricinus communis

233-306

127

63

36

Non-fumigated

Crotolaria

107-141

108

54

48

Non-fumigated

Sesbania, Sesbania exaltata

88-131

111

60

44

Non-fumigated

Sudan grass, Sorghum sudanensis

134-182

123

84

39

Non-fumigated

Sudex, Sorghum bicolor x sudanese

124-206

121

84

42

Non-fumigated

Sword bean, Canavalia ensiformis

87-95

114

63

43

Non-fumigated

Velvetbean, Mucuna pruriens var. utilis

102-135

116

61

47

Non-fumigated

Vetch, Vicia sativa

3-26

111

48

42

Non-fumigated

Wheat, Triticum aestivum, cv. ÔDawsÕ

118-124

129

75

39

Non-fumigated

Wheat, Triticum aestivum, cv. ÔSpragueÕ

148-151

125

59

36

L.S.D.f:

 

 

NS

NS

NS

 

aSoil was collected in summer 1999 from replicate non-fumigated plots near Parlier, screened through a 1-cm mesh screen, placed in 2-liter pots in a greenhouse, and subjected to the cover crop / fallow treatments. The cover crops were allowed to grow 4 months, uprooted, chopped with a shredder, weighed, incorporated into the soil, and allowed to decompose for 2 months.

bAfter the decomposition period, three Nemaguard peach seedlings were planted per 2-liter pot (May 2000). Three months after transplanting, total top and root fresh weight was determined for the peach seedlings in each pot, and the roots were washed free from the soil and inspected for symptoms of disease. There were four replicate pots per treatment combination.

cVisual estimate of the percentage of total root length with brown-discolored cortex tissue or decay extending through the root cortex.

dFumigated 3 weeks before transplanting with peach seedlings (MBr : chloropicrin 67:33, 0.8 g per liter soil; in a sealed 19-liter bucket).

fLeast significant difference among means, based on 95% confidence intervals; NS indicates no significant difference.

Table 7. Effects of pre-plant cover crop and fumigation treatments on incidence of fungal genera associated with peach seedling roots grown in soil collected from an old peach orchard site near Parlier, CAa

 

Fumigation status

 

Cover crop / fallow conditions

Incidence of selected fungal genera on roots of Nemaguard peach seedlings (%)

Cylindrocarpon

Fusarium

Mortierella

Papulospora

Pythium

Rhizoctonia

Trichoderma

Non-fumigated

Bare fallow, moist soil

0

50

5

3

0

3

20

Non-fumigated

Bare fallow, dry soil

0

50

3

3

0

3

30

Bucket-fumigatedb

Bare fallow, moist soil

3

15

3

0

0

13

23

Field-fumigatedc