Integrated Optimization And Application Effect Of Rice-wheat Dual Cropping Technology In Yellow River Rice Region

With the continuous advancement of China's green development concept,straw returning to the field has become an important measure to improve soil fertility and reduce farmland ecological pollution,and has received increasing attention.Since the 13 th Five-Year Plan,China has determined to build environmentally-friendly agriculture.How to promote the efficient and sustainable use of crop straw has become an important development direction for fertilizing soil and storing grain in the field.The Yellow River Rice Region is located in the transition zone between the northern mature rice area and the southern rice-wheat two-crop rice area.The farming system(mainly including tillage,rotary tillage and beating)and planting patterns(mainly include: rice and wheat,spring rice,winter rice,etc.)diversified,resulting in poor soil structure in paddy fields and backward farming and paddy cultivation techniques.Therefore,this experiment adopts the field planting mode,and designs three experiments of optimization of cultivation techniques,optimization of cultivation techniques and organic-inorganic combined fertilization techniques.Then it is to screen suitable soil fertigation and cultivation techniques in the Yellow River rice area,combined with optimization of water and fertilizer management measures.This paper analyzes the bottlenecks in the production and application of paddy soil fertility and tillage techniques in the Yellow River rice region,and provides a theoretical basis for the establishment of a suitable soil fertility and tillage system for the paddy field in the Yellow River rice region.The results of the study show that:1.Optimization of tillage techniques for returning full amount of straw under rice and wheat double cropping conditionsIn the Yellow River rice area,the change of tillage mode has no effect on the 1000-grain weight of crops under the condition of full return of rice and wheat.FT4(when no-till live in the wheat season,tillage + rotary tillage in the rice season)and FF5(wheat-density reduction and nitrogen reduction + deep rotation tillage,rice season dense nitrogen reduction + tillage)can increase the effective panicle number of crops,resulted in significantly increasing yields of rice and wheat,ranging from 8.17% to 24.27%.while conventional tillage did not significantly increase the yields of wheat and rice,and there was a reduction of yield.Conventional tillage does not promote the dry matter accumulation,leaf area index(LAI),post-anthesis population growth and nutrient accumulation of the plants.In this experiment,the FT4 and FT5 treatments can significantly increase the population quality indexes of wheat and rice,and nutrient absorption and utilization efficiency,promote nitrogen agronomic efficiency and nitrogen bias productivity,thus improve crop growth.Straw returning to the field can significantly increase the soil organic matter content.Straw returning to the field can promote the increase of total nitrogen content in the 20-40 cm soil in the Yellow River rice field.Soil organic matter and total nitrogen content under the FT4 and FT5 treatments were higher than that under the other treatments of straw returning fields.Although the benefits of FT4 and FT5 treatments are basically the same in terms of yield,plant population quality index,nutrient uptake,and soil nutrient,the economic benefit of FT5 treatment is more than 0.27-0.29 million yuan per hectare of FT4.Therefore,tillage treatment with wheat season dense nitrogen reduction + deep rotation tillage,rice season dense nitrogen reduction + tillage(FT5)is more suitable for the rice and wheat double cropping straw returning in the Yellow River rice area,and should be promoted.2.Optimization of cultivation techniques of returning straw to the field under the condition of rice and wheat double croppingThe cultivation method was changed under the condition that the rice and wheat double-crop straws were returned to the field in the Yellow River rice area.Although the comprehensive yield of wheat and rice was significantly increased compared with the no-nitrogen treatment,there was no difference between different cultivation treatments.The effect on the yield of seasonal crops is different.Compared with the conventional cultivation measures(CT2),the conventional water and fertilizer treatment(CT3)increases the yield of wheat season,by 19.78%,and the yield components are better than other treatments.The crop yield and its components of the rice season in the rice season and the conventional water and fertilizer treatment(CT5)and pre-conventional water treatment(CT6).Were better than other treatments Compared with the conventional tillage(CT2)treatment,there are no significant difference of the aboveground dry matter accumulation,leaf area index,post-anthesis population growth,plant nutrient utilization,nitrogen agronomic efficiency,and nitrogen bias productivity,and soil total nitrogen and organic matter under CT4(rice and wheat double-season conventional nitrogen reduction density)and CT(rice-wheat double-season nitrogen-increasing conventional density)treatment.The effects of densification conventional water and fertilizer treatment(CT3)on wheat season crop population quality indicators,plant nutrient uptake,soil nutrients,etc.are better than other treatments,And the effect of densification and nitrogen reduction treatment(CT5)and conventional water and fertilizer pre-water treatment(CT6)on the rice season is better than other treatments.In terms of economic benefits,CT5 in 2017 and CT6 in 2018 showed the highest economic benefits in the two-year phase of the trial.Therefore,in the Yellow River rice region,under the rice and wheat double-crop straws method,the cultivation method of increasing the planting density and conventional water and fertilizer management are more suitable for wheat season.the cultivation method of densification and nitrogen reduction treatment or conventional water and fertilizer treatment is more suitable for rice season..However,this experiment did not design the rice-wheat two-pronged treatment method of the dominant cultivation,so the cultivation method suitable for the straw-returning rice-wheat two-ripening water-crop rotation in the Yellow River rice area remains to be further determined.3.Study on organic and inorganic fertilization technology in paddy field under rice and wheat double cropping conditionsIn the Yellow River rice area,the ratio of organic fertilizer to inorganic fertilizer was changed under the condition of rice and wheat double-crop straws method.With the higher application rate of organic fertilizer,the increase of the effective panicle number of rice was more significant.Both can increase rice yield,and 50% organic fertilizer application(OT4)and 100% organic fertilizer application(OT5)increased by 28.47% yield,exhibited the highest.The soil nutrient also increased with the application rate of organic fertilizer.The soil total nitrogen and organic matter showed a trend of increasing in different soil layers The dry matter quality,leaf area index,plant nutrient absorption and utilization,economic benefits,etc also showed a gradual increasing trend,and were significantly higher than that under the conventional fertilizer application treatment,and the treatment OT4 was the best.Therefore,in the Yellow River rice region,application with 50% organic fertilizer + 50% chemical fertilizer is more suitable for the organic-inorganic application of rice and wheat.