Compost Applications Increase Water-Stable Aggregates in Conventional and No-Tillage Systems
2003
Whalen, Joann K. | Hu, Quancai | Liu, Aiguo
Agricultural practices that alter the soil organic matter (SOM) content are expected to cause changes in soil stability and aggregation. The objective of this study was to evaluate short-term (<2 yr) changes in water-stable aggregates (WSA) in a silt-loam soil under different management regimes. The interactive effects of tillage (no-till and conventional tillage), crop rotations (continuous corn, corn-soybean rotation) and composted cattle manure applications [0, 15, 30, and 45 Mg (wet weight) ha⁻¹] on WSA were assessed in a factorial (tillage × crop rotation) split plot (compost) experiment. The proportion of WSA >4 mm was greater in compost-amended than unamended soils within 1 yr, and the mean weight diameter (MWD) of aggregates increased with increasing compost application rates. By the second year of the study, no-till soils under continuous corn and the soybean phase of the corn-soybean rotation had more WSA >4 mm and a greater MWD than any crop rotation in conventionally tilled soils. Increasing the C input to soil increased the MWD of aggregates. The MWD of aggregates was related to the C content of soils under no-till, but not conventional tillage, suggesting more physical stabilization of organic matter (OM) in no-till than conventional tillage agroecosystems. Our findings indicate rapid improvements in aggregation of a silt-loam in the first 2 yr after compost application and the adoption of no-tillage practices.
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