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• Leguminous green manure increased SOC and TN stocks compared with summer fallow. • Coupling RothC and the correlation of SOC and TN can assess their future stocks. • Leguminous green manure will increase SOC and TN stocks by 107% and 158%. Estimating the dynamics and future sequestration potential of soil organic carbon stocks (SOCS) and total nitrogen stocks (TNS) is useful to determine whether cropping systems can promote sustainable production in terms of improving soil fertility. The Rothamsted Carbon (RothC) model and the correlations between SOCS and TNS were used to estimate the future SOCS and TNS of green manure-based wheat production systems on the Loess Plateau of China. The field study was a split-plot design with 4 main treatments (Huai bean, soybean and mung bean grown as green manure in summer, with a fallow treatment as the control) and 4 subtreatments (synthetic N rates of 0, 108, 135 and 162 kg ha−1 applied at wheat sowing). Leguminous green manure (LGM) treatments increased the amount of carbon and nitrogen returned to the field by 67–91% and 74–125%, respectively, compared with the fallow treatment (P < 0.05). These treatments also increased SOCS by 15–23% and TNS by 12–22% (P < 0.05) after 8 years in comparison with the fallow treatment. Coupling of the RothC model and the correlations between SOCS and TNS of the 3 LGM treatments generated acceptable simulations for the dynamics of SOCS and TNS. The projected SOCS for LGM and fallow treatments at the new equilibrium are 37.67–47.29 and 13.97–17.58 Mg ha−1, respectively. The corresponding TNS for LGM treatments are 5.42–6.79 Mg ha−1. The projection also indicates that under the LGM treatments, the SOCS and TNS at the new equilibrium will be 107% and 158% higher, respectively, than the values prior to the experiment. In conclusion, growing LGM to replace summer fallow would be a useful alternative to improve soil fertility and promote sustainable crop production. [ABSTRACT FROM AUTHOR]

A challenge for dryland crop production in China is closing the yield gap while propelling the sustainable development of agriculture when the natural resources are limited. A 4-year fixed field experiment was conducted to analyse the effect of introducing leguminous green manure (LGM) to different cropping systems on soil water, residual nitrate, soil quality and economic benefits to compare their sustainability using a comprehensive scoring system. The main treatments of the experiment were different cropping systems, leguminous green manure-winter wheat (LGM-WW) and leguminous green manure-spring maize-winter wheat (LGM-SM-WW) with summer fallow-winter wheat (SF-WW) as control. LGM late incorporation, early mulch and early incorporation were sub-treatments for LGM-WW while stalk mulch, incorporation and move-away were the sub-treatments for LGM-SM-WW to study the effects of different LGM managements. Compared with SF-WW, LGM-WW decreased average soil water storage before wheat seeding by 11% and increased residual nitrate storage after wheat harvest by 77% while they were not significantly changed for LGM-SM-WW. The soil organic carbon (SOC) content of LGM-WW and LGM-SM-WW in the 0–20-cm layer significantly increased when using legume as mulch. The economic benefits of LGM-SM-WW were 2 times greater than those of the other 2 cropping systems. The scoring system indicates that the total score of LGM-WW ranged from 11.85 to 12.78, which was even lower than that of SF-WW (13.07). On the contrary, the total score of LGM-SM-WW ranged from 16.46 to 18.49. In conclusion, the scoring system determined that the optimum cropping system for sustainable dryland agriculture is leguminous green manure-spring maize-winter wheat with legume stalk mulch. [ABSTRACT FROM AUTHOR]

The cultivation of leguminous green manure (LGM) crops in place of bare fallow in summer enhances soil fertility, which can positively impact soil life in the agroecosystem. An improvement in soil life, in turn, can promote soil fertility and agricultural sustainability. Based on an ongoing field trial in the Loess Plateau, China, we investigated the long-term effects of LGM crops and nitrogen (N) fertilization on soil mesofaunal community and analyzed the interrelationships among the various mesofaunal groups and soil fertility under dryland conditions. The results showed that the long-term growth of the LGM crops significantly increased the soil fertility and the abundance, richness, and diversity of the soil mesofaunal community compared to the fallow system. A total of 14 mesofaunal groups were identified only in the LGM system, mainly due to the high root biomass of the LGM crops. Among the three tested LGM crops, soybean and Huai bean performed better than mung bean in providing growth benefits and stable abiotic environments for the soil mesofaunal community. In addition, the long-term application of N fertilizer had an overall negative effect on the soil mesofaunal community under dryland conditions. Moreover, the abundance, richness, and diversity of the soil mesofaunal community were strongly correlated with soil fertility indicators. Hence, the analysis of the soil mesofaunal community can be used as a bioindicator of soil fertility in agroecosystems. The long-term growth of the LGM crops instead of bare fallow efficiently built a more sustainable and fertile soil in the agricultural ecosystem, thus providing a theoretical basis and guiding field management strategies for the development of sustainable agriculture in local and other similar dryland regions. [Display omitted] • Growth of LGMs promoted the mesofaunal community by enhancing soil fertility. • N fertilizer had overall negative effects on the soil mesofaunal community. • The mesofaunal community was strongly correlated with soil fertility in agroecosystems. [ABSTRACT FROM AUTHOR]