Soil aggregation as a factor in yields following alfalfa
1944
Myers, H.E. | Myers, H.G.
Aggregate analyses were made of soil samples taken at successive intervals after plowing down of alfalfa and sweet clover in rotations of legume 2 years, row crop, oats, wheat and at corresponding times in a rotation of row crop, oats, wheat. Approximately 50% higher total aggregation was found in samples taken before row crop and before oats from the legume rotations than those taken from the nonlegume rotations. Differences in aggregation were not significant in samples removed from the wheat plots either in early spring or after harvest. This apparent break down of water-stable aggregates in the legume rotations coincides with small grain yields in these rotations. The legume rotations have increased oat yields an average of 6.7 bushels over the nonlegume rotation yields, but have increased wheat yields only 1.1 bushels. It appears that the favorable effects of the legume upon subsequent small grain yields under these conditions may be largely through its effect on soil structure rather than from its influence on soil nitrogen.
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