Overall, the aggregate stability of cultivated soils was more affected by the reducing conditions than that of uncultivated soils. This indicates that the management system plays an important role in the stability of aggregates.
The use of natural soils without addition of chemicals simulated a realistic field situation when aerobic upland soils remained saturated for several days and the oxygen level depleted to a minimum, causing reducing conditions. The authors believe that once the reducing reactions take place in the field and disaggregation has occurred, the process will not reverse itself because the natural drainage will carry away the released chemicals and the chemistry of the soil-water system will not return to the original state. The disintegrated aggregates may clog the soil pores and further degrade the soil structure.
However, reducing conditions only occur for short periods of time during the wet season in upland soils, whereas aggregation processes operate for several months causing re-aggregation of soil particles. The long-term irreversibility in soil disaggregation caused by the short-term reducing conditions remains an open question.
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| Contact: Sara Uttech suttech@soils.org 608-268-4948 Soil Science Society of America Source:Eurekalert |