Effectiveness of compost and biochar in improving water retention characteristics and aggregation of a sandy clay loam soil under wind erosion

The profitability of a sandy clay loam (SCL) soil is well known to be constrained due to poor aggregation and aggregate stability, rapid infiltration and drainage of water, as well as low capability of retaining water and nutrients, and thereby culminating in decreased water and fertilizer use efficiency, which in turn decrease agricultural production. Thus, organic materials have long been reported as a promising avenue for addressing the aforementioned difficulties in different soil types. In this regard, the aims of this study were to determine the effect of applying Oleaster tree pruning residues (OPR) in two the different forms (compost and biochar) as an organic material on improving aggregation and water retention characteristic of a SCL soil. Biochar was obtained from OPR through pyrolysis process at 450°C, while compost was obtained from composting of the OPR through windrow composting process. Compost and biochar were individually applied to a SCL soil at a rate of 0, 1, 2 and 4% (wt/wt) with four replications and thoroughly mixed with the soil, then moistened to field capacity (FC) equated to 0.29 g g-1 and subsequently incubated for the period of two months. At the end of incubation period, obtained experimental results indicated that applied compost and biochar significantly improved aggregation and water retention characteristics of a SCL soil and improvements were proportional to application rates. We concluded that both applied forms of the OPR (compost and biochar) could be considered leading soil amendments for improving aggregation and water retention capacity of a SCL, and thereby enhancing agricultural production.