Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/1999
Publication Date: N/A
Technical Abstract: The objective of this study was to find how nitrogen (N) provided by no- till crimson clover (Trifolium incarnatum L.) was used to support pearl millet (Pennisetum glaucom L.) in either a hayed or steer grazed system. Two instrumented watersheds, (P1) 2.71 ha and (P2) 1.30 ha, were used in this study. Crimson clover was no-till planted in autumn of each of three years and pearl millet no-till planted in the following spring. Hay was harvested from both watersheds in the first year. Steers grazed P2 for 6 weeks during years 2 and 3. Soil samples at various depths to 300 cm were used to estimate ammonium and nitrate N. In situ fecal collections were used to estimate N returned to the soil. Rainfall and runoff were measured to account for N loss. Results indicated that 67 to 77 % of available N was harvested as millet hay on P1. Only 3-4 % of available N was removed as steer gain with 9-14 % of N redistributed as feces. Very little N was lost as runoff. Vectors of N loss in grazing systems were largely unexplained.