Implementation of observed changes in soils under no-till and conventional management in selected crop models

In recent years, there has been an increasing emphasis on reducing greenhouse gas emissions in agriculture with no-till management (NT) instead of traditional conventional tillage (CT). The NT management has been adopted as a promising strategy to improve physical and organic pools in the soil profile and dynamics of agriculture. The CT leads due to the mixing of the soil, to higher disturbance of soil aggregates, faster decomposition of biomass, and thus increasing emission of carbon dioxide. Therefore, NT has been envisaged as the method for increasing soil organic carbon (SOC) content in the upper layers of soil. The accumulation of SOC in arable land would prevent the release of carbon from the soil into the atmosphere, and its added effect on global warming.

To assess the potential of NT for increase SOC we carried out a meta-analysis of 36 studies with 91 sites in a temperate climate. The main two parameters for comparison were the content of SOC and bulk density (BD) in the upper 30 cm of soil and when possible other soil parameters (e.g. total nitrogen). The study further assessed the NT vs. CT for different soil compositions and therefore five soil texture categories were established i.e. sand, sandy loam, silt loam, clay loam, and clay. The differences in soil parameter shift for each soil category when CT is replaced by NT have been determined.

In the next step of this study, two crop models HERMES and MONICA were tested for sensitivity to tillage practice. Although these models are based on the relationship between plants, soil, and atmosphere, when providing outputs with high quality, both models report only slight differences in the absence of plowing. The determined results from the meta-analysis were used for models calibration.