SOIL AGGREGATE STABILITY AND CHEMICAL PROPERTIES: EFFECTS OF DIFFERENT SIZE FRACTIONS OF BLACK SOLDIER FLY DERIVED COMPOST

Abstract

An incubation experiment was carried out to observe the effects of black soldier fly larvae derived compost (BSC) on aggregate stability with respect to mean weight diameter (MWD) and the changes in soil organic matter (OM), exchangeable calcium (Ca) and magnesium (Mg) contents. To achieve the goal, sandy loam surface was incubated with BSC having two different size fractions (e.g., <125 µm and 250–500 µm) at the rates of 1% and 2% (w/w) on the dry weight basis. The MWD of soil aggregates was measured by wet sieving method. The results of the experiment revealed that the MWD potentially improved with the application of BSC, especially at higher application rates and with finer particle sizes. When compared to the control, the soil OM content was found significantly (p<0.05) higher in all BSC treatments, with finer fraction (<125 µm) showing the maximum increases. The contents of exchangeable Ca and Mg were also found to be higher in BSC treated soils with better response at higher rates of incorporation and fine manure fraction. Multiple linear regression revealed that the MWD was positively associated with OM, Ca and Mg, though the effect was significant as for Ca and Mg (p<0.05). Besides, soil OM was positively related with the concentrations of exchangeable Ca and Mg with significant (p<0.05) effect as for exchangeable Ca only. Overall, this research highlights the potential of BSC as an amendment to improve stability of soil aggregates as well as the availability of nutrients for sustainable crop production.