Soil Organic Matter and Carbohydrate Contents of a Dystric Leptosol Under Organic Waste Management and Their Role in Structural Stability of Soil Aggregates

摘要

The structural stability of soils has an impact on a wide range of processes that influence crop growth. This study evaluated the role of soil organic matter (SOM) and carbohydrate pools of soil organic matter (cold water, hot water and dilute acid soluble) on the structural stability of organic waste amended dystric leptosol in Abakaliki area southeastern Nigeria. The wastes used for soil amendment were Poultry Droppings (PD), Cow Dung (CD), Sewage Sludge (SS) and Swine Waste (SW) applied at 0, 10 and 20 Mg ha^-1 concurrently for two years. The results of the study showed that SOM was significantly higher in waste amended plots than in the control by 122-179 and 166-226% in the first and second cropping seasons, respectively. Observed mean increase in soil carbohydrate content was 169 mg kg^-1 (cold water soluble), 476 mg kg^-1 (hot water soluble) and 593 mg kg^-1 (dilute acid soluble) in the first cropping season. In the second cropping season 193% (cold water soluble), 86% (hot water soluble) and 93% (dilute acid soluble) increase were observed relative to the control in the second cropping season. Aggregate stability correlated positively (r = 0.68*) with SOM and poorly with soil carbohydrate (cold water, hot water and dilute acid soluble) content. The results from this study showed that SOM contributes to soil aggregate stability whereas the soil carbohydrate pool was not effective in aggregation of the soil studied.