CO(2) fixation in above-ground biomass of summer maize under different tillage and straw management treatments

This study was conducted to quantify the potential for CO(2) fixation in the above-ground biomass of summer maize (Zea mays L.) under different tillage and residue retention treatments. The treatments were paired and included conventional tillage with straw removed (CT(0)), conventional tillage with straw retained (CT(S)), no-till with straw removed (NT(0)), no-till with straw retention (NT(S)), subsoiling with straw removed (SS(0)), and subsoiling with straw retained (SS(S)). The results indicated that NT(S) and SS(S) can enhance translocation of photosynthates to grains during the post-anthesis stage. SS(S) showed the highest total production (average of 7.8 Mg ha(−1)), carbon absorption by crop (Cd) (average of 9.2 Mg C ha(−1)), and total C absorption (Ct) (average of 40.4 Mg C ha(−1)); and NT(S) showed the highest contribution of post-anthesis dry matter translocation to grain yield (average of 74%). Higher CO(2) emission intensity and CO(2) fixation efficiency (CFE) were observed for straw retention treatments. In comparison with CT(S), the mean CFE (%) over four years increased by 26.3, 19.0, 16.5, and 9.4 for NT(0), SS(0), NT(S), and SS(S), respectively. Thus, SS(S) and NT(S) systems offer the best options for removing CO(2) from the atmosphere while enhancing crop productivity of summer maize in the North China Plain.