Soil Water Capacity, Pore Size Distribution, and CO₂ Emission in Different Soil Tillage Systems and Straw Retention

The long-term implementation of crop rotation and tillage has an impact on the soil environment through inputs and soil disturbance, which in turn has an impact on soil quality. Tillage has a long-term impact on the agroecosystems. Since 1999, a long-term field experiment has been carried out at the Experimental Station of Vytautas Magnus University. The aim of this experiment is to investigate the effects of long-term various-intensity tillage and straw retention systems on soil physical properties. The results were obtained in 2013 and 2019 (spring rape was growing). According to the latest edition of the International Soil Classification System, the soil in the experimental field was classified as Endocalcaric Stagnosol (Aric, Drainic, Ruptic, and Amphisiltic). The treatments were arranged using a split-plot design. In a two-factor field experiment, the straw was removed from one part of the experimental field, and the entire straw yield was chopped and spread at harvest in the other part of the field (Factor A). There were three different tillage systems as a subplot (conventional deep ploughing, cover cropping with following shallow termination, and no-tillage) (Factor B). There were four replications. The long-term application of reduced tillage significantly increased soil water retention and improved the pore structure and CO₂ emissions. Irrespective of the incorporation of straw, it was found that as the amount of water available to plants increases, CO₂ emissions from the soil increase to some extent and then start to decrease. Simplified tillage and no-tillage in uncultivated soil reduce CO₂ emissions by increasing the amount of water available to plants from 0.151 to 0.233 m³·m^-3.