Grassland management and integration during crop rotation impact soil carbon changes and grass-crop production
Résumé
To investigate the impact of integrating ley grassland in crop rotations on soil C changes at depths of 0–30 and 0–60 cm, field data regarding C input, soil C and crop production were collected during 2005–2016 from a long-term experimental site in Lusignan, southwestern France. Root biomass C was sampled annually, and the stable C isotope signature (δ13C) was determined to quantify the amount of C input from the root biomass. The results showed that integrating ley grassland in crop rotations increased the C input in the 0–30 and 0–60 cm soil layers. Carbon stocks also increased in the 0–30 cm soil layer but not always in the 0–60 cm layer. However, during the first full rotation (2005–2013), treatments involving 3-year and 6-year grasslands showed 37.5% and 62.5% losses of their crop production, respectively. In crop rotations, integrating ley grassland together with high-nitrogen (N) or low-N fertilisation did not impact the C input, changes in soil C in either the 0–30 or 0–60 cm soil layer, or even crop production, while grass production decreased by 22.2–66.6% under low-N fertilisation. Compared with cropland, permanent grassland did not show a greater C input, whereas the latter showed a C stock increase of 0.6–1.4 Mg C ha−1 yr−1. The analysis of 2005–2013 crop rotation data suggested that both above- and belowground C inputs should be considered as a single total C input. An estimated baseline C input rate of 1.9 Mg C ha−1 yr−1 was suggested to maintain soil C stocks for some of the crop rotations at the site. Considering the balance of food production and soil C stocks, crop rotation in conjunction with 3 years of high-N-fertilised grassland is recommended.
Auteurs, date et publication :
Auteurs Teng Hu , Abad Chabbi
Publication : Agriculture, Ecosystems & Environment
Date : 2022
Volume : 324
Pages : 107703