Effects of green manure cultivation for aboveground carbon store and returning to the field to ameliorate soil quality in saline alkali soil

Abstract

The utilization of saline-alkali land together with the consideration of the productive value (improving soil productivity) and ecological value (increasing carbon store ability) has rarely been reported. We conducted a field experiment to investigate the impact of green manure cultivation for aboveground carbon (C) store and then returning this to field to improve soil quality in saline alkali soil. The biomass in Lolium multiflorum cultivation treatment was significantly (P < 0.05) higher than that of Medicago sativa and Brassica campestris cultivation. A similar tendency was observed in aboveground C store. Green manure cultivation resulted in largely different physicochemical properties at time of harvest. Returning the green manure to the field could significantly (P < 0.001) improve soil fertility. Moreover, the soil fertility index of Lolium multiflorum treatment was significantly (P < 0.05) enhanced by 55.56% and 33.33%, as compared with Medicago sativa and Brassica campestris treatments. Based on PLS-PM analysis, both fast-changing soil properties and biomass exhibited the greatest positive impacts (0.72 of the total effects) on soil fertility improvement after aboveground returning to the field. Our research provides evidence that Lolium multiflorum is the best potential variety to improve saline alkali soil fertility. Additionally, green manure cultivation in saline-alkali soil is an important way to store carbon in plants, then returning to the field is a feasible approach to improve saline alkali soil quality, which is beneficial for the green and sustainable development of saline-alkali agriculture.