ABSTRACT:
Winter annual legumes double-cropped with grain sorghum (Sorghum bicolor L. Moench) can potentially provide nitrogen (N) for the sorghum and enhance long-term sustainability. A 4-year experiment was conducted near College Station, Texas, to evaluate conventional disk tillage, no-till, and green manuring for their potential in grain sorghum production. Annual clovers were used in combination with both no-till and green manure methods, which were compared to conventional disk tillage without clover. Fertilizer rates of 0 and 60 kg N ha−1 (54 pounds/acre) were used on all treatments. The green manure treatment with no added N produced higher grain yields than the similar conventional disk tillage treatment in 3 of 4 years and was statistically equal to conventional disk tillage receiving 60 kg N ha−1 (54 pounds/acre) in 3 of 4 years. Yields from no-till treatments without N fertilizer never matched those from conventional disk tillage treatments with fertilizer. Green manuring of clover prior to sorghum planting apparently better approximated clover N mineralization to sorghum demand, resulting in greater grain production. Grain sorghum no-till planted into clover surface mulch cannot be recommended because N availability was not synchronous with plant demand.
Footnotes
R. G. Lemon was a graduate research assistant, F. M. Hons is an associate professor of soils, and V. A. Saladino is an agricultural research technician, Soil and Crop Sciences Department, Texas A&M University, College Station, 77843. Lemon currently is an extension associate, Texas Agricultural Extension Service, Texas A&M University. This article is a contribution from the Texas Agricultural Experiment Station, Texas A&M University.
- Copyright 1990 by the Soil and Water Conservation Society
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