Soil Polysaccharides and Aggregation in Crop Sequences
1965
Webber, L. R.
Soil polysaccharides and aggregation (mean weight-diameter and aggregate stability) were determined in the corn plots from a rotation project where the preceding crops were corn, oats, alfalfa-brome, or winter wheat. The residues from these crops did not result in significant differences in the content of soil polysaccharides; only in a two-year crop sequence, corn and oats underseeded with red clover, were the polysaccharides increased by the addition of manure. Aggregate stability was greater in the rotations that included a grass-legume; manure improved aggregation over unmanured plots. In a multiple regression analysis, polysaccharides and organic matter together, accounted for 36% of the variation in mean weight-diameter and 27% of the variation in aggregate stability. The seasonal variation in the content of polysaccharides and aggregate stability showed a marked out-of-phase relationship except under oats, which were underseeded with a grass or legume.
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