Effect of vineyard pruning residue application on soil aggregate formation, aggregate stability and carbon content in different aggregate sizes

Abstract

In this research, the effects of amendments of vineyard (Vitis vinifera) pruning residue (VPR) into soil (Typic Xerofluvent) by two different soil tillage (disk harrow and rotary tiller) on aggregate formation (AgF), aggregate stability (AgS) and organic carbon (OC) content of macro– and micro–aggregate sizes were investigated. For this purpose, an experiment was conducted during 2011 to 2012 in the Batı Akdeniz Agricultural Research Institute station in Turkey. VPR was incubated for two years in soil after having been chopped by the power take off (PTO) driven pruning residue chopper. At the end of the incubation period, the effects of VPR on soil AgF, AgS, and OC content in different aggregate scales (0.05–0.25 mm, 1–2 mm) were determined by using soil samples taken at the depths of 0–10 cm and 10–20 cm. After pruning in every two years, VPR were applied to soil at the amendment rate of 7233 kg ha−1 based on the dry matter. The amount of macro–aggregate in all sizes, except for >4 mm, at both soil depths increased in the second year comparing to first year by the VPR amendment with rotary tiller. There were significant differences for AgS between 2011 and 2012. AgS decreased in some micro–aggregates and in most macro–aggregates in pruning amendments with rotary tiller at 0–10 cm soil depth. It was also determined that OC content of micro (0.05–0.25 mm) and macro (1–2 mm) soil aggregates decreased after the amendment of VPR in the second year. The results of this study suggest that the use of VPR may offer benefits for soil structural development and soil conservation, whereas the soil tillage could have a negative effect on carbon conservation.