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Finding agricultural managements able to increase soil organic carbon without a reduction in crop yields is important to: decrease soil erosion, protect soil ecosystem services, increase soil health, help to curb net CO2 emissions toward the EU goal of carbon neutrality. Various studies have shown that catch crops, when managed in the proper way, may result in an increase in soil carbon stocks; however, recent studies have cast doubts on those findings, due to short study duration (3 years or less), few data points, and catch crops mismanagement. Model studies to estimate the potentials of catch crops for soil carbon sequestration shown mixed results; however, in these studies, only the direct effects of catch crops (i.e. the input of carbon from crop inclusion in the soil) was accounted for. Here, we show the result of a study to compare two crop managements: traditional against catch crop together with precision agriculture. We measured agricultural productivity, soil organic carbon, soil respiration, and soil conditions in two different sites in Italy for a period of 4+ years, then we modelled the field managements using a modified version of RothC model, to account for both direct and indirect catch crop effects on soil. The results show that catch crops and precision agriculture can result in an increase in soil organic carbon, with no effects, or, in some cases, an increase in crop production. [ABSTRACT FROM AUTHOR]

Mulching of agricultural soils has been identified as a viable solution to sequester carbon into the soil, increase soil health and fight desertification; as such, it is an interesting option for carbon farming in Mediterranean areas. Models are used to project the effects of agricultural practices on soil organic carbon in the future for various soil and climatic conditions, and to help policy makers and farmers assess the best way to implement carbon farming strategies. Here, we modify the widely used RothC model to include mulching practices and their direct and indirect effects on soil organic matter input, soil temperature changes, and soil hydraulic balance. We then calibrated and validated our modified RothC (RothC_MM) using the dataset collected in a field mulching experiment described in detail in a companying article, and used the validated RothC_MM to estimate the expected soil carbon sequestration by year 2050 due to mulching for the Valencian community (Spain). Our results show that RothC_MM improved the fit with experimental data with respect to basic RothC, and was able to predict SOC and CO2 observations taken in the field, and to model the effects of mulch on soil temperature and soil water content. [ABSTRACT FROM AUTHOR]

Biochar production and application as soil amendment is a promising carbon (C)-negative technology to increase soil C sequestration and mitigate climate change. However, there is a lack of knowledge about biochar degradation rate in soil and its effects on native soil organic carbon (SOC), mainly due to the absence of long-term experiments performed in field conditions. The aim of this work was to investigate the long-term degradation rate of biochar in an 8-year field experiment in a poplar short-rotation coppice plantation in Piedmont (Italy), and to modify the RothC model to assess and predict how biochar influences soil C dynamics. The RothC model was modified by including two biochar pools, labile (4 % of the total biochar mass) and recalcitrant (96 %), and the priming effect of biochar on SOC. The model was calibrated and validated using data from the field experiment. The results confirm that biochar degradation can be faster in field conditions in comparison to laboratory experiments; nevertheless, it can contribute to a substantial increase in the soil C stock in the long term. Moreover, this study shows that the modified RothC model was able to simulate the dynamics of biochar and SOC degradation in soils in field conditions in the long term, at least in the specific conditions examined. [ABSTRACT FROM AUTHOR]