Grain protein content (GPC) often increases with nitrogen (N) fertilizer; however, low GPC is preferred for soft wheat (Triticum aestivum L.). The combined effects of decreasing N and increasing seed rate (SR) on soft wheat quality, economic benefits (Eb), apparent N recovery (ARN), and soil nitrate-N residual (SNR) are poorly understood. Field experiments were conducted with three SRs (SR135, SR180, and SR225) and two N levels (N235 and N290) in 2017-2018, and three N levels (N290, N235, and N180) with a control (N0) in 2018-19. The results showed that storage proteins, GMP, HMW-GS, and Zeleny sedimentation value significantly decreased with lower N levels and increased with higher SR. At the same SR, the significant difference for the parameters mentioned were greater at a low N rate than at a high rate. Furthermore, grain yield (GY), Eb, ARN, and SNR were significantly affected by N and SR. Increasing SR from 135 to 180 resulted in an average Eb increase of 13.32%, while increasing from 180 to 225 led to a decline of 3.75%. Compared to N290, N235 decreased SNR and GPC by 27.5% and 4.7%, respectively, but increased ARN by 18.3%. The highest Eb (13,914 CNY) and ARN value (57.5%) were observed with the treatment (N235SR180). Additionally, optimal combination for maximizing GY (90%), Eb (87.8%), and ARN (97%) was found at N235SR198, according to regression and spatial analysis. This study confirmed that optimizing N and SR can improve soft wheat quality and resource use efficiency without decreasing yield.

The economic benefits of rice-wheat (RW) and rice-oilseed rape (RO) rotation in China are low. By contrast, the rice-edible mushroom Stropharia rugosoannulata (RE) rotation yields significantly higher economic benefits than RW and RO rotations. Furthermore, RE rotation can avoid air pollution caused by rice straw burning and has been widely adopted in China. Nevertheless, it remains unclear how the rotation affects CH4 and N2O emissions and global warming potential. Herein, three rice-based rotations, including RW, RO and RE rotations, were conducted in central China. The RE rotation resulted in the lowest CH4 emission from the winter crop season as well as the lowest annual N2O emission from the rice seasons among the three rotations. Moreover, compared with the RW and RO rotations, the RE rotation significantly increased the soil organic carbon content by 30.2 % and 31.2 %, and the rice yield by 16.0 % and 17.0 %, respectively. Hence, the RE rotation significantly reduced the net global warming potential by 2008.4 % and 696.5 % compared with the RW and RO rotations, respectively. Furthermore, the RE rotation improved soil fertility compared with the other two rotations. Although the RE rotation required the highest agricultural input among the three rotations, it contributed to the highest net ecosystem economic profits owing to its highest agricultural income and lowest environmental damage cost. Thus, RE rotation is an effective rice-based rotation that can use rice straws to reduce the net global warming potential and increase economic benefits and soil fertility. Therefore, RE rotation may serve as an alternative strategy for achieving sustainable agricultural production in winter fallow areas of the rice-upland region in Yangtze River Basin, China.

Straw return and plastic film mulching are two critical management measures that not only maintain high and stable crop yields, but also have a significant impact on the ecological environment. However, there is still a lack of research on the comprehensive effects of straw return and different film mulching treatments on the ecological environment. Thus, a 2-year field experiment was conducted and six treatments, which included two main treatments, namely straw return (SR) and non-straw return (NR), and three sub-treatments, namely no film mulching (CK), plastic film mulching (PM) and fully biodegradable film mulching (BM), were applied in a garlic cropping system. Based on the life cycle assessment method, six endpoint damage categories, resource consumption, global warming potential, environmental acidification, eutrophication, human health, and ecotoxicity, were assessed. Furthermore, we also evaluated the costs and economic benefits of the six treatments and optimized the treatment of used mulch and straw off-farm. The results indicated that the environmental impacts of the six endpoint damages in the garlic cropping system were ranked as ecotoxicity, eutrophication, environmental acidification, global warming potential, human health, and resource consumption. The SR-BM treatment had the lowest life cycle environmental impact composite index at 27.68 per unit area, followed by SR-PM at 27.75. All six endpoint damage categories for the PM and BM treatments were lower than the CK treatment per t of yield, with the SR-BM treatment being the most economically efficient, yielding at 3691.03 CNYt-1 and exceeding that of the SR-CK treatment by 7.26%. Fertilizer inputs were the primary contributor to resource consumption, global warming potential, environmental acidification, eutrophication, and ecotoxicity, accounting for about 72.80% of these five environmental impacts. Crop protection significantly affected human health, and garlic mulching helped minimize pesticide use, thereby reducing potential health impacts. Compared to straw incineration and waste mulch power generation, straw power generation and waste mulch recycling granulation offered positive environmental benefits and were more effective offset strategies. In conclusion, straw return with biodegradable mulch is a synergistic cultivation measure that offers both environmental and economic benefits. For straw return with plastic film mulch, environmental impacts can be reduced by waste mulch recycling granulation.

China accounts for around 50 % of the global vegetable harvested area which is expected to increase continuously. Large cropland areas, including rice paddy, have been converted into vegetable cultivation to feed an increasingly affluent population and increase farmers' incomes. However, little information is available on the balance between economic benefits and environmental impacts upon rice paddy conversion into vegetable fields, especially during the initial conversion period. Herein, the life cycle assessment approach was applied to compare the differences in agricultural input costs, yield incomes, net economic benefits (NEB), carbon (C) and nitrogen (N) footprints and net ecosystem economic benefits (NEEB) between the double rice paddy (Rice) and newly vegetable field (Veg) converted from Rice based on a four-year field experiment. Results showed that yield incomes from Veg increased by 96-135 %, outweighing the increased agricultural input costs due to higher inputs of labor and pesticide, thus significantly increasing NEB by 80-137 %, as compared to Rice. Rice conversion into Veg largely increased C footprints by 2.3-10 folds and N footprints by 1.1-2.6 folds, consequently increasing the environmental damage costs (EDC) by 2.2 folds on average. The magnitudes of increases in C and N footprints and EDC due to conversion strongly declined over time. The NEEB, the trade-offs between NEB and EDC, decreased by 18 % in the first year, while increasing by 63 % in the second year and further to 135 % in the fourth year upon conversion. These results suggested that rice paddy conversion into vegetable cultivation could increase the NEB at the expense of enhanced EDC, particular during the initial conversion years. Overall, these findings highlight the importance of introducing interventions to mitigate C and N footprints from newly converted vegetable field, so as to maximize NEEB and realize the green and sustainable vegetable production.

With the development of the economy, the contradiction between population, resources, and the environment has become more and more prominent. How to make full use of limited cultivated land resources to increase food production while reducing damage to the environment is an important issue facing agricultural production. Maize plays an essential role in ensuring global food security. Furthermore, planting density is a key agronomic factor affecting maize yield. Although soil organic matter (SOM) is an important indicator of soil fertility. Whether there are different agronomic optimal planting densities of maize under varying SOM contents remains unknown. Furthermore, there is limited understanding on whether optimizing maize planting density based on SOM further improves grain yield and resource use efficiency. Therefore, this study investigates the influence of SOM and planting density on maize grain yield. We also determine the relationship between SOM and agronomic optimal planting density (AOPD) and compare the grain yield, economic benefits, and resource use efficiency of sowing under uniform conventional planting density (SUD) versus optimized planting density based on SOM (SOD). The results showed that AOPD and its corresponding yield increased linearly with the increase in SOM. Compared with SUD, the yield of the two experimental sites under SOD increased by 2.3 % and 5.5 %, respectively, and the economic benefits increased by 0.5 % and 4.9 %, respectively. The average energy use efficiency, energy mass productivity, and energy economic productivity of the two experimental sites under SOD were all higher than those of SUD. These results demonstrate that it is theoretically feasible to optimize maize planting density based on the spatial heterogeneity of SOM. SOD is a potentially sustainable maize production method that can fully utilize the resources of cultivated land to increase grain yield and economic benefits.