Author
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Unger, Paul |
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Submitted to: Conservaton and Production Research Laboratory Report
Publication Type: Other Publication Acceptance Date: 7/28/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Soil water storage increases with increases the amount of crop residues kept on the soil surface, but dryland crops often do not produce residue (straw or stover). This study was conducted to determine if different winter wheats and grain sorghums (five of each crop) grown in a rotation would cause residues to accumulate on the soil surface. By 'cross planting' 'sorghum on previous wheat plots and vice versa, 25 wheat and sorghum combinations were achieved. Amounts of surface residues and soil water contents at crop planting and harvesting, yields, and sorghum growth and grain quality factors were determined. Amounts of residue were different at few samplings and no consistent differences occurred. The total amount of residues on an area where wheat was planted as the third crop was 4550 kg/ha; it was 5180 kg/ha where sorghum was planted as the third crop. The amounts were not affected by any wheat and sorghum combinations. Soil water contents and crop yields also did not differ. Some sorghum growth and quality factors were different because of hybrids used, but not due to any wheat and sorghum combination. The wheats and sorghums used did not affect the amounts of residues carried over from one crop to the next. The study was conducted when precipitation was very low during some periods. More 'normal' precipitation could have caused different results. Also, wheats and sorghums containing different amounts of lignin and other plant constituents would possibly have residues that decompose slower. Using such cultivars could possibly increase their accumulation on the soil surface, soil water accumulation, and dryland crop yields. Technical Abstract: Soil water storage increases with increases in amounts of crop residues retained on the soil surface, but dryland crops often produce only small amounts of residue (straw or stover). This study was conducted to determine if winter wheat and grain sorghum cultivars existed that would increase crop residue accumulation on the soil surface. Five wheats and five sorghums were grown in a rotation to evaluate the potential. By 'cross planting' sorghum on previous wheat plots and vice versa, 25 wheat and sorghum combinations were achieved. Amounts of surface residues and soil water contents at crop planting and harvesting, crop yields, and crop growth and grain quality factors (for sorghum) were determined. Amounts of residue types differed at few samplings and no consistent differences occurred. The mean total amount of residues where wheat was planted as the third crop was 4550 kg/ha; it was 5180 kg/ha where sorghum was planted as the third crop. The totals were not affected by the wheat and sorghum cultivar combinations. Soil water contents and crop yields also did not differ. Some sorghum growth and quality factors differed due to hybrids per se and not to any cultivar combination. Cultivars used had no effect on amounts of residues carried over from one crop to the next. The study was conducted when precipitation was very low during some periods. More 'normal' precipitation may have resulted in different results. Also, analyzing wheat and sorghum cultivars to determine their contents of lignin and other plant constituents could possibly lead to identifying cultivars having residues that decompose slower. Using such cultivars could potentially increase their accumulation on the soil surface, soil water accumulation, and dryland crop yields. |
