Hello to all...
There are a number of longterm cropping system studies that have shown that
the inclusion of soybeans in a cropping system can result in loss of soil
organic matter... soybeans are clearly a valuable part of many crop
rotations in term of profitability, breaking of pest cycles, reduced
fertility needs, provision of N for subsequent crops... etc.. nevertheless,
studies clearly show that multiple years of soybeans combined with
intensive tillage often results in depletion of soil organic matter... Soil
organic matter depletion associated with soybeans seems to be related to
the low crop residue return by soybeans and the rapid rate of decomposition
of soybean residues.
If a crop contributes to the loss of total soil organic matter, than the
crop is causing the loss of soil N even if its "annual nitrogen budget"
shows a net gain.
Joel
Joel Gruver
Visiting Faculty
Principia College
Elsah, Illinois 62028
(618) 374 - 5289
jgruver@principia.edu
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