Figure 1
Fruit size of apples from three production systems. Differences between values in a year followed by different letters are significant at the 0.05 level (LSD).
Figure 2
Size distribution of apples in 1998 and 1999 from three production systems. The difference between the organic and conventional fruit size distributions resulted in an average 20% reduction in organic fruit value.
Figure 3
Trunk cross-sectional area (TCSA) of apple trees grown in three production systems. No differences in growth were detected in any year between treatments at the 0.05 level (LSD).
Figure 4
The study area of four replicate plots for each of the three apple production systems. Each plot contains four rows of approximately 80 trees per row trained on a two-wire trellis system. Trees were planted at a spacing of 1.4 m within rows and 3.2 m between rows for a density of 2240 trees per hectare. The soil on all 12 plots is a coarse-loamy, mixed, mesic Xerifluventic Haplocambid (FAO: Haplic Cambisol). We kept the size of the study area to 1.7 hectares to maintain uniformity of this one soil type. Extending the study area to the west or north would have included different soil types. Permanent pasture areas to the east and south belonged to a neighbor. Prior to installation of the experimental orchard the site had been in grass pasture which was tilled to a depth of 30 cm in January 1994. Soil samples were taken from each of the designated plots following the planting of trees but prior to implementation of management treatments. Analyses of pertinent soil morphological, physical, chemical, and biological properties revealed no significant differences between treatments at that time. Grass corridors (5 m wide) surround the study area and another one cuts through the middle of the study area. These grass corridors act as buffers from the conventional commercial orchards to the north and west and as passageways to beneficials from pastures to the south and east (Thies, C., Tscharntke, T., Landscape structure and biological control in agroecosystems, Science, 285, 893-895, 1999). As an additional buffer, the two treatments (conventional-1 and integrated-4) furthest to the west had an additional fifth row of trees. In these two plots, soil and plant samples were taken in the third and fourth rows from the western edge. With grass corridors, tree-row buffers, and sampling in middle rows only, the efficacy of pest control and fertilization for each treatment was not compromised by plot size. The 20 cm of average annual precipitation at the site is supplemented with an under-tree sprinkler irrigation system.
Table A1. Market grade of apples from three production systems. Prior to 1998 all fruit was sold for processing. Differences between values in a year followed by different letters are significant at the 0.05 level (LSD).
|
Grade |
Year |
Organic |
Conventional |
Integrated |
|
Washington Extra Fancy (%) |
1998 |
0.00 |
0.00 |
0.00 |
|
1999 |
73.24 a |
70.06 a |
74.18 a |
|
|
Washington Fancy (%) |
1998 |
26.62 a |
33.65 a |
28.97 a |
|
1999 |
0.00 |
0.00 |
0.00 |
|
|
Processed (%) |
1998 |
73.38 a |
66.35 a |
71.03 a |
|
1999 |
26.76 a |
29.94 a |
25.82 a |
Table A2. Leaf tissue nutrient analyses of three apple production systems. Differences between values in a year followed by different letters are significant at the 0.05 level (LSD).
|
Nutrient |
Year |
Organic |
Conventional |
Integrated |
|
Nitrogen (%) |
1995 |
2.57 a |
2.63 a |
2.64 a |
|
1996 |
2.41 a |
2.42 a |
2.66 b |
|
|
1997 |
2.86 a |
2.94 a |
2.92 a |
|
|
1998 |
2.25 a |
2.37 a |
2.34 a |
|
|
1999 |
2.23 a |
2.36 a |
2.38 a |
|
|
Phosphorus (%) |
1995 |
0.25 a |
0.24 a |
0.24 a |
|
1996 |
0.21 a |
0.18 b |
0.19 ab |
|
|
1997 |
0.18 a |
0.19 a |
0.20 a |
|
|
1998 |
0.16 a |
0.16 a |
0.16 a |
|
|
1999 |
0.21 a |
0.18 b |
0.17 ab |
|
|
Potassium (%) |
1995 |
1.95 a |
2.03 b |
1.95 a |
|
1996 |
2.23 a |
2.00 a |
2.08 a |
|
|
1997 |
1.25 a |
1.38 a |
1.58 b |
|
|
1998 |
1.40 a |
1.73 b |
1.75 b |
|
|
1999 |
1.83 a |
1.85 a |
1.90 a |
|
|
Sulphur (%) |
1995 |
0.21 a |
0.23 a |
0.24 a |
|
1996 |
0.19 a |
0.21 a |
0.20 a |
|
|
1997 |
0.17 a |
0.17 a |
0.16 a |
|
|
1998 |
0.11 a |
0.11 a |
0.12 a |
|
|
1999 |
0.15 a |
0.16 a |
0.14 a |
|
|
Calcium (%) |
1995 |
1.62 a |
1.71 a |
1.62 a |
|
1996 |
1.68 a |
1.84 b |
1.69 a |
|
|
1997 |
1.74 a |
1.73 a |
1.68 a |
|
|
1998 |
1.70 a |
2.09 a |
1.93 a |
|
|
1999 |
1.83 a |
1.86 a |
1.87 a |
|
|
Magnesium (%) |
1995 |
0.32 a |
0.35 b |
0.35 b |
|
1996 |
0.37 a |
0.38 a |
0.37 a |
|
|
1997 |
0.34 a |
0.31 b |
0.32 b |
|
|
1998 |
0.38 a |
0.41 a |
0.40 a |
|
|
1999 |
0.34 a |
0.31 a |
0.33 a |
|
|
Boron (ppm) |
1995 |
22.75 a |
24.50 ab |
25.25 b |
|
1996 |
21.50 a |
26.00 b |
22.25 a |
|
|
1997 |
27.75 a |
25.75 a |
26.25 a |
|
|
1998 |
20.50 a |
23.00 a |
20.50 a |
|
|
1999 |
18.75 a |
17.75 a |
17.50 a |
|
|
Zinc (ppm) |
1995 |
11.75 a |
13.25 ab |
14.50 b |
|
1996 |
15.75 a |
25.25 b |
14.50 a |
|
|
1997 |
10.75 a |
12.75 a |
12.00 a |
|
|
1998 |
10.75 a |
13.00 b |
12.50 b |
|
|
1999 |
14.25 a |
15.00 a |
14.75 a |
|
|
Manganese (ppm) |
1995 |
51.00 a |
59.25 a |
58.75 a |
|
1996 |
51.75 a |
58.75 b |
56.25 ab |
|
|
1997 |
61.75 a |
60.75 a |
58.75 a |
|
|
1998 |
61.50 a |
59.00 a |
63.75 a |
|
|
1999 |
47.75 a |
46.25 a |
50.25 a |
|
|
Copper (ppm) |
1995 |
9.00 a |
8.75 a |
8.75 a |
|
1996 |
9.50 a |
10.25 a |
9.25 a |
|
|
1997 |
8.50 a |
8.25 a |
8.00 a |
|
|
1998 |
8.50 a |
8.00 a |
8.25 a |
|
|
1999 |
8.50 a |
8.50 a |
9.00 a |
|
|
Iron (ppm) |
1995 |
188.00 a |
138.75 ab |
122.50 b |
|
1996 |
281.75 a |
354.75 a |
247.50 a |
|
|
1997 |
159.00 a |
135.75 ab |
116.25 b |
|
|
1998 |
190.75 a |
172.50 a |
188.75 a |
|
|
1999 |
315.50 a |
259.25 a |
296.50 a |
Table A3. Fruit tissue nutrient analyses of three apple production systems. Fruit was not analyzed for tissue content in 1996. Differences between values in a year followed by different letters are significant at the 0.05 level (LSD).
|
Nutrient |
Year |
Organic |
Conventional |
Integrated |
|
Nitrogen (%) |
1995 |
0.36 a |
0.40 a |
0.40 a |
|
1997 |
0.26 a |
0.32 ab |
0.35 b |
|
|
1998 |
0.40 a |
0.47 ab |
0.54 b |
|
|
1999 |
0.30 a |
0.40 b |
0.41 b |
|
|
Phosphorus (%) |
1995 |
0.135 a |
0.130 a |
0.140 a |
|
1997 |
0.070 a |
0.088 b |
0.075 ab |
|
|
1998 |
0.090 a |
0.100 a |
0.100 a |
|
|
1999 |
0.073 a |
0.080 b |
0.075 ab |
|
|
Potassium (%) |
1995 |
0.97 a |
0.95 a |
1.00 a |
|
1997 |
0.72 a |
0.85 b |
0.80 ab |
|
|
1998 |
0.83 a |
0.90 a |
0.85 a |
|
|
1999 |
0.80 a |
0.88 a |
0.88 a |
|
|
Calcium (%) |
1995 |
0.04 a |
0.03 a |
0.03 a |
|
1997 |
0.04 a |
0.04 a |
0.05 a |
|
|
1998 |
0.06 a |
0.07 a |
0.06 a |
|
|
1999 |
0.10 a |
0.10 a |
0.09 a |
|
|
Magnesium (%) |
1995 |
0.05 a |
0.04 b |
0.05 ab |
|
1997 |
0.04 a |
0.04 a |
0.04 a |
|
|
1998 |
0.05 a |
0.05 a |
0.05 a |
|
|
1999 |
0.05 a |
0.05 a |
0.05 a |
|
|
Boron (ppm) |
1995 |
7.75 a |
7.75 a |
9.75 b |
|
1997 |
6.75 a |
15.50 b |
13.75 b |
|
|
1998 |
5.00 a |
7.00 ab |
7.25 b |
|
|
1999 |
7.75 a |
11.50 b |
7.50 a |
|
|
Zinc (ppm) |
1995 |
3.75 a |
2.00 b |
3.00 a |
|
1997 |
4.25 a |
5.00 a |
4.50 a |
|
|
1998 |
4.50 a |
5.25 a |
4.50 a |
|
|
1999 |
4.25 a |
6.75 a |
5.00 a |
Table A4. Fruit maturity analyses of apples from three production systems (a) at harvest, (b) following 3 months controlled atmosphere storage, and (c) following 6 months controlled atmosphere storage. Analyses were not carried out prior to 1998. Differences between values in a year followed by different letters are significant at the 0.05 level (LSD).
|
Fruit Maturity |
Year |
Organic |
Conventional |
Integrated |
|
|
(a) At Harvest |
|||||
|
Firmness (N) |
1998 |
58.03 a |
52.84 b |
50.44 b |
|
|
1999 |
66.91 a |
65.53 ab |
64.82 b |
||
|
Soluble Solids (Brix) |
1998 |
15.32 a |
15.53 a |
14.58 b |
|
|
1999 |
14.61 a |
14.05 b |
14.59 a |
||
|
Titratable acidity (%) |
1998 |
0.77 a |
0.83 ab |
0.85 b |
|
|
1999 |
0.71 a |
0.74 b |
0.75 b |
||
|
Ratio of soluble solids to titratable acidity |
1998 |
19.81 a |
18.81 ab |
17.10 b |
|
|
1999 |
20.71 a |
19.15 b |
19.44 b |
||
|
(b) 3 Months Storage |
|||||
|
Firmness (N) |
1998 |
57.11 a |
56.15 a |
56.09 a |
|
|
1999 |
58.00 a |
57.01 b |
57.34 ab |
||
|
Soluble Solids (Brix) |
1998 |
14.77 a |
14.42 a |
13.77 a |
|
|
1999 |
15.59 a |
14.96 b |
15.24 ab |
||
|
Titratable acidity (%) |
1998 |
0.63 a |
0.66 ab |
0.71 b |
|
|
1999 |
0.59 a |
0.62 b |
0.61 b |
||
|
Ratio of soluble solids to titratable acidity |
1998 |
23.53 a |
21.88 a |
19.46 b |
|
|
1999 |
26.81 a |
24.19 b |
24.87 b |
||
|
(c) 6 Months Storage |
|||||
|
Firmness (N) |
1998 |
56.22 a |
57.84 a |
58.24 a |
|
|
1999 |
56.37 a |
53.40 b |
54.66 ab |
||
|
Soluble Solids (Brix) |
1998 |
14.27 a |
15.01 a |
14.34 a |
|
|
1999 |
15.61 a |
14.90 b |
15.56 a |
||
|
Titratable acidity (%) |
1998 |
0.56 a |
0.61 ab |
0.64 b |
|
|
1999 |
0.42 a |
0.43 ab |
0.44 b |
||
|
Ratio of soluble solids to titratable acidity |
1998 |
25.87 a |
24.88 ab |
22.56 b |
|
|
1999 |
36.90 a |
34.55 b |
35.21 b |
||
Table A5. Consumer taste preferences of apples from three production systems (a) at harvest and (b) following 6 months controlled atmosphere storage. Preference tests were conducted only in 1999. Differences between values in a test category followed by different letters are significant at the 0.05 level (LSD).
|
Taste Parameter |
Organic |
Conventional |
Integrated |
|
(a) At Harvest |
|||
|
Overall Acceptance (1 = Dislike extremely; 9 = Like extremely) |
6.3 a |
6.8 a |
6.2 a |
|
Texture (1 = Dislike extremely; 9 = Like extremely) |
6.6a |
7.1 a |
6.7 a |
|
Flavor (1 = Dislike extremely; 9 = Like extremely) |
6.3 a |
6.6 a |
6.1 a |
|
Firmness (1 = Very Soft; 9 = Very hard) |
6.3 a |
6.3 a |
6.1 a |
|
Sweetness (1 = Not at all sweet; 9 = Extremely sweet) |
5.5 a |
5.3 a |
5.0 a |
|
Tartness (1 = Not at all tart; 9 = Extremely tart) |
4.6 a |
5.6 b |
5.5 b |
|
(b) 6 Months Storage |
|||
|
Overall Acceptance (1 = Dislike extremely; 9 = Like extremely) |
6.1 a |
6.0 a |
6.5 a |
|
Texture (1 = Dislike extremely; 9 = Like extremely) |
6.1 a |
5.9 a |
5.9 a |
|
Flavor (1 = Dislike extremely; 9 = Like extremely) |
6.0 a |
5.9 a |
6.7 b |
|
Firmness (1 = Very Soft; 9 = Very hard) |
5.5 a |
5.3 a |
5.1 a |
|
Sweetness (1 = Not at all sweet; 9 = Extremely sweet) |
5.6 a |
5.0 b |
5.6 a |
|
Tartness (1 = Not at all tart; 9 = Extremely tart) |
3.6 a |
4.7 b |
4.8 b |
Table A6. Cumulative environmental impact ratings of four apple production systems from 1994 to 1999. Total points = A X B X C. In some cases, the total points may appear not to equal the product of A X B X C due to rounding errors.
|
(A) |
(B) |
(C) |
||||||||
|
Treatment |
Product name |
Chemical name |
No. of applications |
Rate (amount application-1 ha-1) |
Points per unit amount |
Total points
|
||||
|
Organic |
Dipel |
Bt |
5 |
2.2 |
kg |
7.28 |
81.5 |
|||
|
Isomate C |
Pheromone |
4 |
988.0 |
ties |
0.02 |
59.3 |
||||
|
Microthiol |
Sulfur |
11 |
11.2 |
kg |
2.32 |
285.3 |
||||
|
Superior Oil |
Oil |
5 |
18.7 |
liters |
0.42 |
39.5 |
||||
|
Total |
465.6 |
|||||||||
|
Conventional |
Captan |
Captan |
1 |
14.0 |
liters |
4.02 |
56.3 |
|||
|
Dipel |
Bt |
4 |
2.2 |
kg |
7.28 |
65.2 |
||||
|
Ethrel |
Ethephon |
7 |
2.1 |
liters |
2.33 |
34.2 |
||||
|
Guthion |
Azinphos methyl |
16 |
2.2 |
kg |
17.64 |
632.3 |
||||
|
Isomate C |
Pheromone |
4 |
988.0 |
ties |
0.015 |
59.2 |
||||
|
Lorsban |
Chlorpyrifos |
7 |
1.2 |
liters |
10.57 |
86.5 |
||||
|
Microthiol |
Sulfur |
9 |
11.2 |
kg |
2.35 |
244.5 |
||||
|
Provado |
Imidacloprid |
3 |
0.1 |
liters |
274.84 |
57.8 |
||||
|
Procure |
Triflumizole |
4 |
0.6 |
kg |
18.70 |
41.9 |
||||
|
Rally |
Myclobutanil |
7 |
0.4 |
liters |
131.92 |
323.7 |
||||
|
Roundup |
Glyphosate |
23 |
4.7 |
liters |
9.51 |
1022.6 |
||||
|
Rubigan |
Fenarimol |
1 |
0.4 |
liters |
83.52 |
33.4 |
||||
|
Simazine |
Simazine |
3 |
2.3 |
liters |
8.25 |
57.8 |
||||
|
Sevin |
Carbaryl |
2 |
1.8 |
liters |
13.53 |
47.4 |
||||
|
Solicam |
Norflurazon |
3 |
2.2 |
kg |
10.81 |
90.8 |
||||
|
Superior Oil |
Oil |
5 |
18.7 |
liters |
0.42 |
39.5 |
||||
|
Total |
2,893.2 |
|||||||||
|
Integrated |
Captan |
Captan |
1 |
14.0 |
liters |
4.02 |
56.3 |
|||
|
Dipel |
Bt |
4 |
2.2 |
kg |
7.28 |
65.2 |
||||
|
Ethrel |
Ethephon |
7 |
2.1 |
liters |
2.33 |
34.2 |
||||
|
Guthion |
Azinphos methyl |
16 |
2.2 |
kg |
17.64 |
632.3 |
||||
|
Isomate C |
Pheromone |
4 |
988.0 |
ties |
0.015 |
59.2 |
||||
|
Lorsban |
Chlorpyrifos |
7 |
1.2 |
liters |
10.57 |
86.5 |
||||
|
Microthiol |
Sulfur |
9 |
11.2 |
kg |
2.32 |
244.5 |
||||
|
Provado |
Imidacloprid |
3 |
0.1 |
liters |
274.84 |
57.8 |
||||
|
Procure |
Triflumizole |
4 |
0.6 |
kg |
18.70 |
41.9 |
||||
|
Rally |
Myclobutanil |
7 |
0.4 |
liters |
131.92 |
323.7 |
||||
|
Roundup |
Glyphosate |
11 |
4.7 |
liters |
9.30 |
480.8 |
||||
|
Rubigan |
Fenarimol |
1 |
0.4 |
liters |
83.52 |
33.4 |
||||
|
Sevin |
Carbaryl |
2 |
1.8 |
liters |
13.53 |
47.4 |
||||
|
Superior Oil |
Oil |
5 |
18.7 |
liters |
0.42 |
39.5 |
||||
|
Total |
2,211.1 |
|||||||||
|
Non-PMD Conventional |
Guthion |
Azinphos Methyl |
14 |
2.2 |
kg |
17.64 |
553.3 |
|||
|
Dipel |
Bt |
8 |
2.2 |
kg |
7.28 |
130.4 |
||||
|
Carbaryl |
Carbaryl |
6 |
2.1 |
liters |
13.5 |
170.7 |
||||
|
Lorsban |
Chlorpyrifos |
4 |
4.7 |
liters |
10.6 |
197.6 |
||||
|
Ethrel |
Ethephon |
3 |
2.1 |
liters |
2.33 |
14.7 |
||||
|
Rubigan |
Fenarimol |
6 |
0.3 |
liters |
114.38 |
200.4 |
||||
|
Roundup |
Glyphosate |
8 |
4.7 |
liters |
9.51 |
355.7 |
||||
|
Provado |
Imidacloprid |
5 |
0.1 |
liters |
274.8 |
96.3 |
||||
|
Lime Sulfur |
Lime Sulfur |
11 |
37.4 |
liters |
2.11 |
869.4 |
||||
|
Supracide |
Methidathion |
1 |
0.6 |
liters |
9.85 |
5.8 |
||||
|
Rally |
Myclobutanil |
5 |
0.4 |
liters |
131.9 |
231.2 |
||||
|
NAA 200 |
NAA |
3 |
0.2 |
liters |
76.1 |
34.7 |
<||||