| Rapeseed-rice rotation and wheat-rice rotation are the most important rice cropping modes in China,and because the traditional wheat and rapeseed planting requires a large number of chemical fertilizers and pesticides,and the treatment of rice straw needs to be solved urgently,which in turn affects the economic benefits of rice fields and restricts the sustainable development of the rice cultivation system.After the rice harvest in autumn and winter,the new rice mushroom model of using rice straw to cultivate mushrooms has been popularized and applied in many provinces in the Yangtze River Basin because its annual production income increased by 23.60%-32.70%compared with the traditional rice cropping mode.However,the economic and ecological benefits of the rice mushroom model are not yet clear,so this study conducted a field experiment in Meijiadun Village,Tuanfeng County,Huanggang City,Hubei Province,from 2019 to 2021.In this experiment,four models were set up,namely rice-wheat(RW),rice-rapeseed(RO),rice-morchella esculenta(RME)and rice-stropharia rugoso-annulata(RSR),to explore the effects of different rice cropping patterns on crop yield,soil fertility,greenhouse gas emissions,carbon and nitrogen water footprint and economic benefits.The main findings are as follows:1.Among the different rice cultivation modes,the rice-mushroom model effectively improved soil fertility,among which the medium rice-stropharia rugoso-annulata model had the best soil fertilization effect.Compared with the RW model,the contents of soil NH4+-N,NO3--N,available phosphorus,available potassium,dissolved organic carbon,and total organic carbon in the winter maturity stage of the RSR model increased significantly by 382.13%-545.26%,13.11%-34.15%,6.06%-10.89%,14.11%-18.37%,54.14%-64.44%,25.15%-27.71%,respectively,and the soil available phosphorus in the RME model.The available potassium content was significantly increased by 15.26%44.12%and 19.65%-29.97%,respectively,and the contents of NO3--N,available potassium,dissolved organic carbon and total organic carbon in RSR mode were significantly increased by 13.97%-14.75%,18.95%-22.24%,73.70%-88.35%,25.86%30.22%,and the soil available phosphorus and available potassium content in the RME mode were significantly increased by 22.53%-44.16%、21.29%-31.18%.Compared with the RO model,the contents of NH4+-N,NO3--N,available phosphorus,available potassium,dissolved organic carbon,and total organic carbon in the winter maturity stage of the RSR model were significantly increased by 362.77%-568.30%,23.50%-31.80%,2.94%-9.70%,5.16%-10.29%,27.98%-30.68%,24.78%-30.16%,respectively,and the soil available phosphorus in the RME mode.The available potassium content increased significantly by 11.87%-42.56%and 15.46%-15.64%;after rice harvest,the content of NO3--N,available potassium,dissolved organic carbon and total organic carbon in RSR mode increased significantly by 15.32%-19.88%,15.76%-17.63%,77.70%-77.82%,27.02%-31.23%,and the soil available phosphorus and available potassium content in the RME mode were significantly increased by 19.33%-42.37%、18.04%-26.23%.2.Rice cropping patterns significantly affect greenhouse gas emissions.Among the different rice farming modes,the greenhouse gas emission reduction effect of the ricefungus model is significantly better than that of the traditional rice-rapeseed and rice-wheat mode,and the RME mode has the best greenhouse gas emission reduction effect,followed by the RSR mode.Compared with the RW model,the cumulative emissions of CH4,N2O cumulative emissions and global warming potential in the non-rice season of RME mode were significantly reduced by 96.30%-97.62%,42.54%-62.50%,61.36%-80.03%,the cumulative emissions of CH4 in RSR mode were significantly reduced by 61.90%-67.59%,and the cumulative emissions of N2O and the global warming potential were significantly increased by 49.45%-165.91%and 8.36%-51.32%.Compared with the RW model,the cumulative emissions of CH4,N2O and global warming potential in the RME mode were significantly reduced by 24.31%-40.08%,-4.76%-59.39%,18.23%-47.29%,respectively,the cumulative emissions of N2O in the RSR mode were significantly reduced by 23.81%55.15%,and the cumulative emissions of CH4 and the global warming potential were significantly increased by 69.38%-114.02%and 49.66%-51.18%.Compared with the RO model,the cumulative emissions of CH4,N2O and global warming potential in the non-rice season of the RME model were significantly reduced by 96.00%-97.77%,71.94%-90.62%,76.64%-92.09%,respectively,and the cumulative emissions of CH4,N2O cumulative emissions and global warming potential of RSR mode were significantly reduced by 64.38%-65.03%,27.10%-33.52%and 34.50%-40.09%.Compared with the RO model,the cumulative CH4 emissions,N2O cumulative emissions and global warming potential of the RME model were significantly reduced by 64.94%76.79%,21.43%-42.24%,58.77%-72.03%,respectively,while the cumulative CH4 emissions,N2O cumulative emissions and global warming potential of the RSR mode were significantly reduced by 17.10%-21.55%,36.21%-42.86%and 19.76%-24.53%.3.In In different rice cropping modes,the RSR and RME models are not conducive to carbon footprint reduction per unit area,and are conducive to nitrogen footprint reduction per unit area,the RSR is not conducive to water footprint reduction,and the RME mode is conducive to water footprint reduction.In terms of carbon footprint per unit area,compared with the RW and the RO models,the RME model increased by 213.69%231.32%,137.64%-208.16%,respectively,and the RSR model increased by 205.87%216.31%,126.87%-200.47%,of which the largest contribution of the carbon footprint per unit area of the RW and the RO models was CH4 and diesel combustion,accounting for 26.42%-28.56%,36.09%-41.13%and 14.30%-23.10%,10.25%-22.70%respectively,the RME and the RSR models and carbon footprint per unit area contributed the most to agricultural film and lime,accounting for 56.31%-57.10%,33.23%-34.44%and 20.51%20.80%,21.04%-21.79%respectively.In terms of nitrogen footprint per unit area,the RME model was reduced by 27.38%27.42%,25.26%-25.32%compared with the RW and RO models,and the RSR mode was reduced by 30.08%-30.36%,28.06%-28.33%compared with the RW and RO models.The largest contributions of nitrogen footprint per unit area of the RW and the RO models were NH3 and N2O,accounting for 93.73%-94.12%,90.40%-90.75%,2.50%-2.56%,6.19%6.29%respectively,while the largest contributions of nitrogen footprint per unit area of the RME and the RSR models were NH3 and agricultural film,accounting for 73.16%73.51%,76.29%-76.31%and 18.98%-19.07%,11.32%-11.33%.In terms of water footprint per unit area,compared with the RW and the RO models,the RSR model increased by 3.49%-6.29%and 3.58%-14.00%,respectively,while the RME model decreased by 6.60%-11.12%and 6.52%-4.67%,respectively.Among them,from the perspective of blue water footprint,it is found that the RSR model is 10.38%21.46%,5.76%-14.07%,and the RME is 14.15%-21.37%,7.23%-16.29%compared with the RW and the RO models;from the perspective of the green water footprint,the RSR mode is 1.32%and 15.10%higher than the RW and the RO models,and the RME mode is 11.23%-23.60%higher than the RW and the RO models.9.50%-13.21%;From the perspective of grey water footprint,it is found that the RME and the RSR modes are reduced by 26.62%and 27.76%respectively compared with the RW and the RO modes.4.Different rice cropping patterns significantly affected rice yield and annual economic benefits.The yield of rice in the RSR and the RME modes was significantly higher than that in the RW and the RO modes,and the highest yield was in the RSR mode,reaching 8834.63 kg·hm-2-9254.60 kg·hm-2,which was significantly increased by 15.39%16.64%and 14.85%-19.03%compared with the RW and the RO modes,followed by the RME mode,reaching 8417.42 kg·hm-2-8151.03 kg·hm-2,which was higher than that of the RW mode.The RO model significantly increased production by 2.73%-9.94%and 4.58%9.43%.The annual economic benefits and costs of the RSR and the RME models are significantly higher than those of the RW and the RO models.The annual cost of each model is 22,600 yuan·hm-2-295,600 yuan·hm-2,of which the RSR model is 7.66 times9.79 times and 6.96 times-11.02 times higher than the RW and the RO models,respectively,and the RME model is 5.74 times-6.41 times and 6.41 times and 6.02 times-7.26 times higher than the RW and the RO models,respectively;the annual economic benefits of each model are 0.33 million yuan·hm-2-68.72 million yuan·hm-2,of which,together with the RW,Compared with the RO model,the annual economic benefits of the RSR model were increased by 100.51 times to 154.64 times and 39.12 times to 53.73 times,and the annual economic benefits of the RME model were increased by 39.27 times to 207.24 times and 20.72 times to 52.69 times,respectively.In summary,compared with the traditional rice-oil and rice-wheat models,the rice mushroom model effectively improves soil fertility,reduces greenhouse gas and carbon and nitrogen footprint emissions,and improves rice yield and annual economic benefits.Among them,the rice-stropharia rugoso-annulata pattern works best. |
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