| Global warming caused by greenhouse gases has become increasingly an important issue,since farmland ecosystem is an important source of greenhouse gas emissions,the control of it is essential to mitigating the greenhouse effect.However,as a special type of ecosystem,the farmland ecosystem should give equal emphasis to reducing soil carbon emissions in agricultural production,the stable of the system as well as the increase of production.Because of high production of intercropping,it is often used in dried area of agricultural production,but the lack of intercropping high production model of carbon reduction theory and technical support in the production practice,and no-tillage as carbon abatement technology has been confirmed,so put forward an agronomic measures of take no-till and close planting in the intercropping system,and provide theoretical basis of reduce carbon emissions of farmland system.The study was carried out in Hexi Oasis,Gansu Province in2016,and analyzing the effects of different tillage measures combined with maize density treatment(Low density:45000 plant/hm2;medium density:60000 plant/hm2;high density:75000 plant/hm2)on carbon accumulation,carbon emission and its key influencing factors,the system carbon balance and production benefit evaluate models of the maize intercropping system and under the comprehensive different manages,exploring the carbon balance characteristics and ecological sustainability of maize intercropping peas under different tillage methods combined with maize close planting.These results will provide theoretical basis for optimizing the low carbon,high efficiency and sustainable development measures in Hexi Oasis irrigation district.The main conclusions are as following:1.No-tillwith maize close planting can significantly reduce the total amount of soil carbon emissions in maize intercropping pea system,and contribute to the increase of crop carbon accumulation in the maize intercropping pea system,thereby increasing the net ecosystem productivity of maize intercropping peas and enhancing the carbon sequestration potential of the system.Intercropping more than monocropping can reduce the total soil carbon emissions 37.60%.The total soil carbon emission in the intercropping system was 15.29% ~41.36% lower than that of the convention tillage.There was no significant difference in total soil carbon emissions under no-tillage at three densities.The intercropping had the advantage of intercropping with the monocropping,and the carbon equivalent ratio of the intercropping group was between 1.08 and 1.15.Compared with the convention tillage,the carbon accumulation of intercropping system was 2.24% ~ 5.04% under three kinds of densities,Compared with low density,medium density and high density could significantly increase the crop carbon accumulation in the intercropping no-tillage by 6.28% and 5.73%.Compared with the conventiontillage,no-tillage could increase the net ecosystem productivity of the intercropping system was7.10% ~ 8.19%,increase the carbon sequestration potential of the system 18.75% ~ 31.35%.Compared with lowand high density,medium density of maize can increase the net ecosystem productivity of intercropping system by 1.05% ~ 6.90%。2.The total amount of soil carbon was linear correlation to crop dry matter accumulation,and the total amount of soil carbon was index correlation with soil temperature.No-tillage treatment can reduce the dry matter accumulation of maize in maize intercropping pea system during pea harvest,no-tillwith maize close planting can reduce soil temperature during crop growth period,which in turn helps to reduce the total amount of soil carbon released from maize intercropping pea.Compared with the convention tillage,no-tillage could average reduce the dry matter accumulation of 33.07%.Compared with the convention tillage,the no-tillage in high-density treatment can significantly reduce the average soil temperature of the crop during the whole growth period by 1.71%.3.The combination of no-till and reasonable density planting has the potential to increase the yield and ultimately enhance the intercropping system production efficiency and ecological sustainability.The ratio of land equivalents of maize to pea is greater than 1,which shows the yield advantage.Compared with the convention tillage,the no-tillage could increase the yield of maize intercropped pea by 5.23% ~11.13%,.Compared with no-tillage low-density and high-density treatments,no-tillage medium density could increase grain yield by 9.50% and 6.29%.The ecological sustainability index of maize intercropping was increased by 26.50% ~ 33.91% compared with the convention tillage under no-tillage condition.Compared with no-tillage low-density and high-density treatments,no-tillage medium density could significantly increased by 11.84% and 6.60%.Significant increase in system sustainability compared to the corresponding monocropping maize.Therefore,no-tillage medium density with maize intercropping pea is the most suitable low-carbon and efficient agronomic measures for the sustainable development of oasis irrigation. |
