Effects Of Fertilization Coupled With Drip Irrigation With Straw Returning On Yield Formation,Water And Nitrogen Utilization Efficiency In Maize

Using nitrogen fertilizer reasonably and scientifically,an important to measure to improve maize yield,nitrogen use efficiency,reduce the waste of resources and low cost,serve for environmental friendly production of maize.The method of straw returning and nitrogen fertilizer application significantly improve the crop yield and nitrogen use efficiency.The drip irrigation system was used to irrigate the crops and fertilization coupled with drip irrigation.It maintains the high water content and nutrient content in the root zone,reduces the leaching and nutrient loss also improves the utilization efficiency of water and nutrients.However,the effects of drip fertilization and straw returning on maize yield formation,the distribution regulars of water and nitrogen in soil,and its utilization efficiency are still not systematically studied well.Therefore,the field experiment was conducted during 2016-2017 in the medium and low production fields of Xinxiang County,Henan Province,which was the main production area of maize in Huang Huai Hai.The maize hybrid Zheng Dan-958 was used in this study,the spatial distribution of soil water and nitrogen,the dry matter and nitrogen accumulation and yield of maize under different nitrogen application levels and straw treatment methods were studied.The effect of nitrogen utilization efficiency,and their regulation mechanism of the yield formation of summer maize,the distribution law of soil water and nitrogen,and its utilization efficiency were analyzed.The main results are as follows:1.Drip fertigation and straw returning significantly increased summer maize yield and the utilization efficiency of water and nitrogen.Under the application of equal amount of nitrogen fertilizer,the yield of maize was significantly increased 10.0%-28.0% of drip fertilization and straw returning treatment to the field,which was higher to compare with other treatment.The drip irrigation and straw returning at the 375kg/hm2 level was the highest yield,which was 11.4 t/hm2,compared with flooding irrigation treatment,the yield increased by 28%.The yield increase of drip fertigation and straw returning was mainly achieved by increasing grain number per panicle and 1000 grain weight,which was increased by 24.8% and 4.6% respectively compared to flooding irrigation.The water use efficiency,the nitrogen agricultural efficiency,nitrogen partial productivity,and the nitrogen apparent utilization rate were significantly increased 75.8%,4.1%,5.6% and 62.1% of drip fertilization and straw returning treatment to the field,Which was higher to compare with flooding treatment.2.The interaction between drip fertigation and straw returning significantly increased the dry matter accumulation of maize during the whole growth period,especially the dry matter accumulation after anthesis.The treatment of drip fertilization and straw returning to the field is mainly by increasing the leaf area index of the whole period of maize,and reducing the decline rate of the leaf area index,increasing the chlorophyll content of the leaves of each layer,keeping the leaf highly photosynthesized,assimilating more photosynthetic materials,increasing the accumulation of dry matter and increasing the accumulation of dry matter in grain.3.Drip fertigation and straw returning significantly increased the absorption and accumulation of nitrogen in different growth stages of maize,which increased by 36.3% in mature stage compared with the flooding irrigation treatment.The fastest stage of nitrogen accumulation in plant was from V12 stage to flowering stage,and the nitrogen accumulation rate was 38 mg plant-1d-1,followed by the stage from flowering to milk ripening period,and nitrogen accumulation rate was 35 mg plant-1d-1.Drip irrigation and straw returning significantly increased the nitrogen accumulation rate from the ripening stage to the mature stage,which increased by 14.1% compared with the flooding treatment.Under drip irrigation and straw returning treatment,the treatment of drip irrigation and straw returning in the nitrogen distribution in different stages of maize,the nitrogen accumulation in grain in mature stage was the largest,which was 141.7 Kg/hm2 and increased by 6.0%-14.0%.4.Drip irrigation and straw returning treatment maintained higher water content of 0-60 cm soil layer in each period of maize growth than other treatments,and increased 22.0%-217.0% on average.In 60-100 cm soil layer,drip irrigation and straw returning treatment significantly reduced soil water content and reduced water leakage loss to deep soil.The total nitrogen content in soil 20-40 cm soil layer significantly increased 5.0%-63.0%,by drip irrigation and straw returning and the total nitrogen content in root area was maintained.At the same time,it also increased the content of organic matter and available potassium in 20-40 cm soil layer,increasing by 48.0%-168.1% and 23.2%-98.0% respectively.Therefore,the improving of soil nitrogen distribution,increasing soil water and nitrogen contents,organic matter and available potassium in the shallow root zone,maintaining the sufficient nitrogen supply in the late growing period of maize,and promoting the increase of nitrogen accumulation in the plant,drip fertilization and straw returning can improve the leaf area index and the dry matter accumulation,thus improving the yield of maize and the utilization efficiency of water and nitrogen.