Assessment of the role of agricultural wastes in aggregate formation and their stability.

The purpose of this study was to evaluate the effects of three agricultural processing wastes (APWs) on aggregate formation and aggregate stability in a sandy loam textured soil (Typic Xerofluvent) in Antalya, Turkey. The effects of APW applications on aggregate formation and aggregate stability were observed for different aggregate size groups (>4; 4-2; 2-1; 1-0.5; 0.5-0.25; 0.25-0.050 and <0.050 mm). Sugar Beet Pulp (SBP), Apple Pomace (AP) and Cotton Gin Waste (CGW) were applied to soil as fresh material (dry weight basis 0, 10, 20 and 40 t ha(-1)), and a greenhouse pot experiment was conducted using a completely randomized design with five replicates of each treatment. The study consisted of two periods. The first period (P1) consisted of a six-month incubation period (1st sample period). The second period (P2) is a six-month period and includes an eight-week green bean (Phaseolus vulgaris L.) growing process (2nd sample period). At the end of the first six months and fourteen months in total, aggregate formation and aggregate stability were determined and their correlation to different C sources was explained. At the end of the experiment, formation of aggregates was increased with increase in the application level of organic wastes in particular intermediate aggregates. Increase in the incubation time significantly enhanced the formation of particular macroaggregates. Soil aggregate stability of all aggregate sizes generally increased with the increasing in the level of implementation. In addition, incubation time effects on aggregate stability for macroaggregates were not significant, but significant for macro and microaggregates.