Shoot and root residues decomposition from different cropping systems under semiarid Mediterranean conditions

Abstract Aims: Improving the management of crop residues is essential for water and soil conservation and for increasing soil C and N levels in dryland agroecosystems. The main objective of the study was to evaluate the decomposition dynamics and nutrient release from crop residues from different cropping systems in a semiarid Mediterranean agroecosystem. Methods: A litterbag experiment was conducted from July of 2020 to June of 2021 to examine the shoot and root decomposition dynamics of vetch, pea and barley residues in different cropping systems: a barley continuous monoculture, B(B), and the two phases of two crop rotations: barley in rotation with vetch, B(V) and V(V); barley in rotation with barley, B(P) and P(B). Results: From week 9 to 14, a general decay of residues was observed caused by the higher soil moisture and temperatures. After 48 weeks of decomposition, a 41% and 60% of mass remaining was found corresponding to vetch and pea surface residues respectively, whilst barley mass remaining ranged 87-76% depending on the cropping system. In root residues, the mass decay from legume residues (40-44%) was higher compared to barley residues (17-29%). Exponential decay and linear models explained the residues decomposition observed in our study conditions. The C to N ratio of residues and edaphoclimatic conditions played a major role controlling the decomposition and nutrient loss rates. Conclusion: According to our results, in Mediterranean semiarid agroecosystems, residue decomposition and nutrient release dynamics from different crop residues need to be considered for improving the sustainability of the cropping systems.