| The loess dryland agricultural area is one of the most key grain production areas in China.In order to meet the demand of the population on the quantity and quality of grain,the resource-grabbing fertilization and tillage production mode has been implemented blindly for a long time.As a result,the phenomenon of soil erosion and degradation is increasingly aggravated.In addition,affected by the fluctuation of rainfall,the stress of water and fertilizer in agricultural production continues to deteriorate,which seriously affects its food,ecological and economical safety.Besides,how to allocate fertilization and tillage production modes in a scientific and coordinated way,so as to increasing the crop yield,saving cost,and promoting soil fertility is always the significance of agricultural study.Thus,this research based on the Han Yuan area of Weibei arid-land in the south of the Loess Plateau,has yet to be completed in 12 years locating winter wheat fertilization-conservation tillage experiment.In recommended fertilizer(RF),ease fertilizer(EF),and traditional fertilizer(CF)main mode and match no-till/subsoiling(NS),subsoiling/plowing(SP)and plowing/no-tillage(PN)three rounds of conservation tillage rotations and continuous no-tillage(NT),subsoiling(ST)and plowing(PT)tillage measures,a total of 18-kind of fertilization-conservation tillage production modes.Based on analysis of rainfall pattern and study cycle process perspective,to analysis and evaluation of different production modes of storage and water use efficiency;soil nutrient promotion,water-stable aggregates structural improvement,and its sustainable potential production,then further to assure the advantage of the winter-wheat production(fertilization-conservation tillage)mode and its theoretical mechanism eventurally.The main results are as follows:(1)Under the wet rainfall pattern,the soil water storage and water use efficiency of the wheat-land are the best,and with the huge production potential of increasing yield and profit.Conservation tillage rotation(PN or NS)based on plowing or no-tillage is helpful to improve the fallow water efficiency,and the water storage in the fallow end(0-200 cm).The NS and SP rotation under different rainfall and fertilizer levels were can maintain a higher water use efficiency,and mainly improve the soil water storage of 160-200 cm in seedling stage,and display the characteristics of water trans-utilization(0-100 cm water replenishment and 120-180 cm water consumption)under the wet rainfall conditions.(2)After the end of the first cycle(6 years),the content of water-stable aggregates with particle size of > 2 mm in the wheat field increased in different fertilizer-conservation tillage production modes compared to the pre-experiment.As the study progresses,each fertilizer-conservation tillage system promoted the content of water-stable macroaggregates with >5 and 5-2 mm particle sizes,even in 0-20 cm depth,the size of >2 and 1-0.5 mm of the water-stable aggregates synergtic change is obviously.The content of water-stable macroaggregates(>0.25 mm)was higher in the recommended fertilizer-plowing/no-tillage(RF-PN)mode(cycle 1 and 2),and the water-stable aggregate stability in the conventional fertilizer-no-tillage/subsoiling mode(CF-NS)(cycle 1),and the ease fertilizer with subsoiling/plowing(EF-SP)mode(cycle 2)is optimized,respectively.(3)The contents of soil total nitrogen,phosphorus,and organic matter in the 0-20 and 20-40 cm soil depth of the wheat-land in recommended fertilization mode(RF)were relatively high.The conservation rotations were beneficial to the increase of soil nutrients(TN,TP and SOM),and the best effects of fertilize promotion were obtained by the rotation tillage methods of no-tillage/subsoiling(NS)and plowing/no-tillage(PN).(4)Recommend fertilizer(RF)has a good potential of steady yield and sustainable production,and match with the no-tillage/subsoiling(NS)rotation was used to optimize the economic profits,yield stability and sustainability potential of winter wheat production. |
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