Oakes Irrigation Research
Site
Carrington Research Extension Center * North Dakota State University
P.O. Box 531, Oakes, ND 58474-0531, Voice: (701) 742-2189, FAX: (701)
742-2700, email: rgreenla@ndsuext.nodak.edu
CABBAGE COVER CROP STUDY
Richard G Greenland
Planting a cover crop helps reduce wind erosion and may help conserve soil organic matter and control weeds. If let grow too tall it also competes with the cabbage and reduces yield and quality. In this study we investigated how tall we could let a barley living mulch grow before killing it and still not reduce cabbage yield or quality.
| Soil: | Maddock sandy loam; pH=7.8; 2.3% organic matter; soil-P and soil-K were very high; soil-S was medium. |
| Previous crops: | 1998 - field corn. 1997 - onion; 1996 - potato. |
| Seedbed
preparation: |
Disked 4 November 1998. Disked April 12. Field cultivated twice on April 12 to incorporate fertilizer and herbicide. |
| Planting: | Direct seeded cabbage on April 13 with a Stanhay vegetable planter modified to drill barley (1 bu/acre, 6-inch rows) between and parallel to the cabbage rows. Cabbage seeds were spaced about 7 inches apart in 16-inch rows. Plants were later thinned to 15 inches apart (about 26,000 plants/acre). Seeds were placed ¼ to ¾ inches deep into a flat, fine seedbed. |
| Plots: | Each plot was 6 ft (4 rows plus tractor tire) wide by 17 ft. long with a two-foot alleyway between plots. The study had 4 reps. |
| Fertilizer: | On April 7, broadcast 15 lbs N/acre and 75 lbs P2O5/acre as 10-50-0, 18 lbs N/acre and 20 lbs S/acre as 21-0-0-24, and 99 lbs K20/acre as 0-0-60. Sprayed 40 lbs N/acre as 28-0-0 on April 12 and 50 lbs N/acre as 28-0-0 on June 24. |
| Irrigation: | Overhead sprinkler irrigation as needed. |
| Pest
Control: |
Weeds were controlled using Treflan (1 pt/acre applied preplant incorporated on April 12), Lentagran (2 lb/acre on June 1 and June 23), Poast plus Dash (3 pt + 2 qt/acre on June 11), and by hand weeding. Sprayed Asana (8 oz/acre on June 29 and Aug 13) and Agree (1 lb/acre on June 16, July 7, July 16, July 26, Aug 2, and Aug 9) to control cabbage looper and cabbage worm. |
| Harvest: | Ten feet of the center two rows of each plot were hand harvested on September 28. |
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Table 47. Time of Fusilade application to kill the barley cover crop, and the response of cabbage and barley plants in measurements taken on July 1.
| Application timing† | Measurements taken on July 1, 1999 |
Cabbage heads harvested |
Cabbage yield |
Cabbage head size |
||||
|---|---|---|---|---|---|---|---|---|
| date sprayed | barley height | cabbage height | barley plant height | cabbage plant width | cabbage plant height | |||
| inches | inches | 1000s/acre | tons/acre | lbs/head | ||||
| May 18 | 6 | 2 | 1.5 a‡ | 17.5 a | 9.5 | 24.5 | 38.7 a | 3.2 a |
| May 25 | 8 | 2.5 | 3.8 a | 16.0 ab | 8.3 | 26.5 | 34.6 ab | 2.6 ab |
| June 7 | 17 | 6 | 18.3 b | 13.3 c | 8.5 | 27.4 | 27.8 b | 2.0 b |
| June 11 | 21 | 6 | 18.5 b | 14.0 bc | 8.5 | 27.4 | 25.7 b | 1.9 b |
| C.V. (%) | 14 | 11 | 10 | 8 | 19 | 20 | ||
| Probability | 0.0001 | 0.02 | 0.26 | 0.23 | 0.04 | 0.014 | ||
†Date, height of barley, and height of cabbage when plots were sprayed with Fusilade.
‡Values in the same column followed by the same letter are not significantly different at the 0.05 level. If no letters in a column, there are no significant differences between values in that column.
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Cabbage yield and head size were reduced, but number of cabbage heads harvested was not reduced, when the barley living mulch was allowed to grow more than 8 inches tall before spraying it with Fusilade. When barley was allowed to grow taller, the width of the cabbage plant was reduced but cabbage height was not. This created a skinny plant that did not form a good head. The longer the barley was allowed to grow, the more barley cover remained as of July 1 to protect the cabbage and soil, but the greater the competition with the cabbage.
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Go to Oakes Irrigation Research Site Cover Crop Study page
Go to Oakes Irrigation Research Site 1999 annual report