Effects of field managements for soil organic matter stabilization on water-stable aggregate distribution and aggregate stability in three agricultural soils

The effect of different soil organic matter (SOM) managements on soil aggregate stability was evaluated in three agricultural sites in Italy. The field plots were treated with traditional deep tillage, minimum tillage, green manuring, mature compost, and iron-porphyrin as a biomimetic catalyst. Although the original soil texture exerted a strong influence on the overall soil physical quality, after 3 years of field experiments, the soil additions with humified compost, under maize cropping, improved both, the yield of water stable macroaggregates and the soil aggregate stability, with a pronounced effect on the aggregate distribution of the coarse textured soil. Soil treatments with the biomimetic catalyst, under wheat cropping, promoted an initial stable incorporation of finer particle-sizes in water-stable macro-aggregates. This effect was progressively lost with increasing experimental time due to either loss or inactivation of the catalyst. Innovative management practices for SOM stabilization based on soil amendment of either humified mature compost or a water-soluble catalyst to promote in-situ photopolymerization of humic molecules, were found to improve distribution and stability of soil water stable aggregates, as compared to the conventional methods of SOM management. (c) 2012 Elsevier B.V. All rights reserved.