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No-tillage cotton planted in a killed vetch winter cover crop (1989-92) indicated that the average vetch dry matter biomass yield was 2115 lb/ac with an N content equivalent to 104 lb N/ac. First planting cotton stand failures in no-tillage (1989-91) may have been due to soil compaction caused by the planter cast iron seed-slit closing wheels and the soil's surface being wetter under the vetch mulch (no-tillage). Changing the seed-slit closing wheels to small inverted disks and flat press wheel resulted in good first planting stands in 1992. Plant mapping data indicated that no-tillage + no N and no-tillage + 80 lb N/ac produced more harvestable bolls and nodes/plants than conventional tillage (no vetch) + 80 lb N/ac. Plant population, first fruiting branch nodes and % bolls in first and second position were not affected by tillage and N rate. Seedcotton yield varied from year to year, but no-tillage + no N produced yield equal to the conventional tillage + 80 lb N/ac all four years. The no-tillage cotton + 80 lb N/ac, four year average, was not different from no-tillage + no N but was higher than conventional tillage + 80 lb N/ac. Conventional tillage cotton showed no yield difference for N rate and 40 to 80 lb N/acre was sufficient for maximum yield. |
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©National Cotton Council, Memphis TN |
Document last modified Sunday, Dec 6 1998
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