| In order to ensure the sustainability of winter wheat production in the dryland region of southeast loess Plateau under the background of complex climate change,it is necessary to clarify the green cultivation measures of drought-resistant,high-yield and high-efficiency wheat in dryland.Therefore,field experiments were carried out in Wenxi in Dryland Wheat Experimental demonstration Base of Shanxi Agricultural to study the effects of three tillage methods of deep ploughing（DP）,deep subsoiling（SS）and no-tillage（NT）on winter wheat yield and soil water storage during fallow period of different precipitation years,and to build an early yield prediction model.To study the effects of soil water storage,wheat growth,and development,plant nitrogen accumulation,and transport,yield quality formation,and soil respiration characteristics on the interaction between two sowing methods,furrow sowing,and drill sowing and five fertilization methods,i.e.,farmer fertilization,optimizing fertilization,optimizing nitrogen reduction,optimizing phosphorus reduction,and optimizing potassium reduction.To study the effects of nitrogen rates of 150 kg ha–1,180 kg ha–1 and 210 kg ha–1 on growth,and development,photosynthetic characteristics,yield quality formation,and soil respiration characteristics of wheat with farmer fertilization,optimizing fertilization,optimizing nitrogen reduction.APSIM model was used to simulate the effects of optimized cultivation measures on wheat yield,and economic benefit in dryland under different precipitation,and to clarify the cultivation methods in response to climate change,providing theoretical,and technical support for stable yield,increase of income and green production in dryland wheat.The main results are as follows:1.Both precipitation year type and fallow tillage had significant effects on wheat yield,and components in dryland.Compared to no-tillage,fallow tillage significantly increased yield,and soil water storage,but there were differences in different precipitation years.Based on the standard precipitation evapotranspiration index during the fallow period,ten experimental years from 2010 to 2019 were classified into different precipitation year types,and the classification method was consistent with the climatic background in dryland wheat the southeast of the Loess Plateau.In drought years,subsoiling significantly increased the yield,up to 4775.44 kg ha–1.In non-drought years,the yield of deep ploughing in fallow period was 5149.10 kg ha–1.In this study,controllable soil water storage factors and uncontrollable meteorological factors were introduced to construct a random forest prediction model.The average prediction errors of the model for wheat yield,ear number and grain number per spike were 6.36%,6.96%,and 7.07%,respectively.The prediction results were reliable.2.Under the condition of deep tiller in fallow period,the effective tiller number,nitrogen accumulation in each organ at anthesis stage,nitrogen transport before anthesis and grain contribution rate were significantly increased by furrow sowing.The number of spike,grain per spike,and 1000-grains weight were increased by 3.5%,2.5% and 5% respectively,and the yield was increased by 7%.The protein content,starch content and flour processing quality were improved.Improved soil respiration rate.The yield of wheat was better,and the partial productivity of nitrogen fertilizer was increased by 146%,partial productivity of potassium fertilizer was increased by 67%,water use efficiency was increased by 2.9%,soil carbon emission was decreased and carbon emission efficiency was increased by 14.5%.Considering the three factors of yield,carbon emission,and return on investment,it was concluded that furrow sowing to optimized fertilization was effective cultivation measure to ensure stable yield,and increase income of winter wheat and realize energy conservation and emission reduction.3.The nitrogen rate of 210 kg ha–1 increased the plant height,secondary rooting and tiller number of winter wheat at different growth stages compared to other sowing rates under the condition of deep ploughing and furrow tillage during fallow period.The SPAD value,net photosynthetic rate,transpiration rate and stomatal conductance of flag leaves after anthesis were increased.Increase spike number by 3.1%-7.4%,grain number per spike by 4.6%-6.0%,and yield by 1.7%-3.7%.The grain protein content,total starch content and flour processing quality were improved and enhanced soil respiration.Compared to 210 kg ha–1,the sowing amount of 180 kg ha–1 decreased the yield by 0.5%-1.0%,but there was no significant difference.Optimal fertilization significantly increased the interception amount of photosynthetic radiation in the canopy at jointing,anthesis and maturity stages compared to farmer fertilization.Increasing soil water storage by 5.3%,and 1000-grain weight by 5%-11% at mature stage.Combined to 180 kg ha–1,the soil respiration rate was significantly reduced by 1.5-15.0%,and soil carbon emission was significantly reduced during the whole growth period.Considering economic benefits,ecological benefits and return on investment,the optimal fertilization with sowing amount of 180 kg ha–1 can not only ensure stable winter wheat yield and increase income,but also realize the development of agricultural production emission reduction.4.APSIM simulation of wheat yield in dryland under different cultivation in the southeast of loess Plateau was consistent with the field experiment results.However,considering the ecological,and environmental benefits of farmland,the cultivation was carried out by deep ploughing in non-drought years（subsoiling in drought years）,matching sowing amount of 180 kg ha–1 and optimized fertilization.It can realize the win-win of economic,and ecological benefits of wheat in dryland of southeast loess Plateau.Under this cultivation mode,if the actual precipitation in the future was 10% higher than the average precipitation in the growth period,the yield of winter wheat increased by 14.99-1418.26 kg ha–1,and the income increased by 36-3404 CNY ha–1.The winter wheat yield will decrease by 16.12-1340.01 kg ha–1,and the economic loss will be 39-3216 CNY ha–1.In conclusion,the cultivation technology that integrates fallow tillage with furrow sowing,sowing amount of 180 kg ha–1 and fertilization optimization in dryland wheat region of southeast loess Plateau was beneficial to soil moisture storage,improve photosynthetic capacity of flag leaves,and partial fertilizer productivity,promote nutrient accumulation,and transport between plant organs,and reduce CO2 emissions from farmland.So that the output and quality can be synchronized to improve,realize fertilizer saving,emission reduction,increase production,increases income. |
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