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Texas A&M University (1996)

Sorghum production under reduced tillage in a semiarid environment

Sow, Abdoul Abdoulaye

Titre : Sorghum production under reduced tillage in a semiarid environment

Auteur : Sow, Abdoul Abdoulaye

Université de soutenance : Texas A&M University

Grade : Doctor of Philosophy (PhD) 1996

Résumé
Water deficits limit crop yields in the Texas Northern High Plains. Cultural and management practices are needed to reduce runoff and capture rainwater to increase yields of sorghum (Sorghum biclolor (L.) Moench). Furrow diking (FD) and no-tillage with residues (NT+) treatments were more effective than conventional tillage (CT) and no-tillage without residues (NT$-$) treatments for improving precipitation storage as soil water by reducing and even preventing runoff. Average yield with the FD treatment was 4840 kg ha$\sp-1,$ which was about 800 kg ha$\sp-1$ more that with the CT and NT$-$ treatments. Grain yield with the NT+ treatment was 15% greater than with CT and 17% greater than with NT$-$ treaments. The greater rooting depth, at all growth stages, that occurred under FD and NT+ treatments was associated with higher soil moisture contents throughout the soil profile and particularly in the surface layers. Forrow diking resulted in greater $(P<0.05)$ soil NO$\sb3$-N at the 30- to 60-cm depth at half bloom. No significant differences for soil NO$\sb3$-N were observed at the 0- to 7.5-cm depth in FD, CT, and NT+ plots. Concertrations of N in leaf, stover, and grain were greater in plants with FD that with other treatments. Available soil water, soil NO$\sb3$-N, sorghum leaf N composition, and grain and stover yield were noticeably responsive to tillage and wheat residue management. In water deficit areas, like the Texas Northern High Plains, the water conserved with FD and NT+ systems can result in greater crop yields ; thus increasing financial returns for the region. In any effort to encourage rooting depth of crops in the Northern High Plains of Texas, consideration must be given to the possible influence of tillage and residue management on root growth and water extraction and consequently plant growth and yield. In the semi-arid environment of the U.S. Southern Great Plains, either the FD or the NT+ treatment is most suitable for grain sorghum production in a wheat-sorghum-fallow (WSF) system where all the crops are grown on unfertilized fields.

Mots clés : Agronomy, furrow diking, sorghum bicolor, Biological sciences

Accès au document : Proquest Dissertations & Theses

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