Temporal variations in soil aggregation following olive pomace and vineyard pruning waste compost applications on...

This study was aimed to determine the temporal effects of olive pomace (OPC) and vineyard pruning waste (VPC) composts on soil aggregation of three different textured soils. Both OPC and VPC are the most common agricultural wastes in the Mediterranean Region. The application of these composts to soils with different textures (clay, loam, and sandy loam) at different rates and knowing how long after the application the aggregate stability (AS) reaches the maximum (for different compost, texture, and rate) increases the novelty value of this study. Composts were prepared in automatic temperature and aeration-controlled reactors. The experiment consisted of three different soil textures (clay, loam, and sandy loam), five different treatments (control, 3% and 6% OPC, 3% and 6% VPC), 10 different incubation times, and four replications. The highest AS values were obtained with 6% VPC application on the 210th day of incubation for clay and loam soils while it was the highest for 6%OPC on the 120th day of incubation for sandy loam soil. Soil carbon (TC) was the strongest and positively correlated with AS 90 days after VPC and OPC applications in all soils. Final TC stocks increased by 131% and 417% in clay, 72% and 251% in loam, and 21 to 257% in sandy loam soil, compared to 15 days of incubation. OPC and VPC amendments to clay, loam, and sandy loam soils increased AS while reducing the mean weight diameter (MWD) of aggregates. It took a shorter time (90 days) for the VPC application to increase the amount of TC in soils.