The Effect of Organic Waste Applications on Soil Aggregation and Soil Organic Carbon Fractions

In this study, organic wastes obtained from different sources (Olive Oil Solid Waste-OSW, vermicompost-VC, farmyard manure- FYM) were applied in different doses (0, 1, 2, 3%) and the aggregation status of the soils and soil organic carbon (SOC) fractions (organic carbon-OC, activated carbon-AC, microbial biomass carbon-MBC) were investigated. In this study, unlike other studies, the contribution of organic materials to SOC fractions and which of these fractions have a significant relationship on aggregation have been revealed. In the study, the aggregate stability (AS) and mean weight diameter (MWD) properties of the soils increased by 12% and 8% compared to the control with 3% organic waste application. It was determined that OSW and FYM were more effective than VC on aggregate development of soils. In addition, statistically significant differences were found with organic material application on SOC fractions. The highest increase was detected in the microbial biomass carbon content (69%) compared to the control. While a high positive correlation was determined between aggregate stability and carbon fractions, the relationship between C fractions and AS was listed as organic carbon > microbial biomass carbon > activated carbon (r: 0.96, 0.94, 0.68; p < .05). The effects of organic wastes applied at 2 and 3% dose levels, the obtained AS, MWD, and OC contents showed significant variability depending on the differences in the wastes. As a result of the study, it was evaluated that organic waste application was effective in the aggregate development of soils. In addition, it was determined that the most effective SOC fraction in increasing the aggregate stability of soils was OC. On the other hand, it was determined that the more unstable activated carbon contributed to the increase of AS at lower levels.