Nutrient Sources and Harvest Frequencies Impact Water Stable Soil Macro-Aggregates

Abstract

We evaluated the effects of nutrient sources [cattle manure, poultry litter, urea, chemical fertilizers [nitrogen (N), phosphorus (P) and potassium (K)], inter-seeded crimson clover (Trifolium incarnatum L.), and a control], and harvest frequency (single and twice) on water stable soil macro-aggregates through wet sieving. The experiment was performed in a split-plot design with four replications. In most cases, single harvest resulted in more water stable soil aggregates than twice harvest. This could be due to less soil disturbance and uninterrupted root exudate supplies for soil microbes. Application of cattle manure and poultry litter significantly increased the percent of water stable soil macro-aggregates to the extent of 47% compared with chemical (NPK) fertilizer application. These results demonstrated that vigilant recycling of these animal wastes could improve soil aggregate formation. However, long-term monitoring of this practice is needed to evaluate system sustainability and profitability.