Effect Of Combined Organic And Inorganic Application On Nitrogen Reduction And Efficiency Enhancement Of Summer Maize In Fluvo-Aquic Soil

It is knowing that nitrogen(N)is an important kind of nutrients for high and stable yield on summer maize.In China,nitrogen as a fertilizer is being on excessive and inefficient application,meanwhile residues of the nitrogen fertilizer leave behind and endanger the ecological environment.Henan province is the major summer maize producing areas in China and has the same set of questions in nitrogen fertilizer application.Therefore,an appropriate technology leading to the reducing nitrogen rate should be adopted to promote the nitrogen efficiency and green development in ecological zone based on summer maize cultivating.For obtaining the suitable content and rate of nitrogen fertilization in different ecological zones.From years of 2019 to2021,under conditions of fluvo-aquic soil in northern Henan province,field experiments were taken out on annually substituting manure for chemical nitrogen fertilizer and reducing the content of the chemical one at in-and pre-season summer maize.Through the crop growth periods,the maize yield,soil nutrient contents and nitrogen efficiency were picked up and analyzed.The main results present as:1.In summer maize reduction,organic substitution of 20%-40% could increase summer maize yield by 3.63%-8.68% at Xuchang and Xunxian,and 2.80%-9.57% at Yuanyang and Qingfeng.The effect of 20% organic reduction was the best for Xuchang and Jun county,the effect of 40% organic replacement reduction on summer maize at Yuanyang and Qingfeng was the best.In northern Henan,the rate of nitrogen reduction was 0.00% to 20.75%,and the highest average yield of summer maize was 10936.06kg/hm2.The organic replacement ratio was 0.00%-42.84%,and the theoretical maximum average yield of summer maize was 11,1288.93 kg/hm2,with an average increase of 3.13%.2.Summer maize annual substitution medium(previous crop),The yield of Yuanyang winter wheat decreased significantly when the ratio of organic replacement reduction reached 60%.The yield of winter wheat was the best at Xuchang when the ratio of organic replacement reached 40%.Summer maize yield was the highest in Yuanyang organic fertilizer nitrogen replaced by 40% fertilizer nitrogen and the yield of summer maize was the best when organic fertilizer was applied alone at Xuchang.For Summer corn anniversary substitution,40% organic replacement is recommended for winter wheat and conventional fertilization for summer maize.We can achieve the highest yield in winter wheat period at Xuchang and in summer corn period at Yuanyang.3.In the replacement reduction of summer maize,nitrogen agronomic efficiency,nitrogen harvest index and partial nitrogen productivity of summer maize were increased by 20% organic replacement reduction and 40% organic replacement reduction compared with chemical fertilizer at Xuchang and Xunxian,Qingfeng and Yuanyang.The soil nutrient content of summer maize in the four experimental sites was increased by 20% organic replacement and 40% organic replacement compared with the single fertilizer application.4.In summer maize annual replacement(previous stubble),the 40% organic replacement treatment winter wheat increased N harvest index,but decreased N partial productivity and N grain productivity at Yuanyang;Nitrogen use efficiency was improved by 40% organic substitution treatment in winter wheat at Xuchang.There was no significant difference between 40% organic replacement treatment and single fertilizer treatment on soil available nutrient content and soil urease activity at mature stage of winter wheat at Xuchang.The soil available potassium content and soil urease activity of 40% organic replacement treatment were significantly increased in winter wheat mature stage compared with that of chemical fertilizer alone,but there was no significant difference between the two treatments in summer maize mature stage.In conclusion,When organic replacement occurs in the summer corn season,20%organic replacement was recommended for the farmland with high fertility at Xuchang and Junxian on the tidal soil region of northern Henan province,and 40% organic replacement was recommended for the farmland with low fertility at Qingfeng and Yuanyang on the tidal soil region of northern Henan province.The reduction rate of nitrogen fertilizer was 0.00%-20.75%,and the replacement rate of organic fertilizer was0.00%-42.84%.In the annual replacement of summer maize(prestubble),40% organic replacement was recommended for the previous wheat season and fertilization was recommended for the maize season in the tidal soil region of northern Henan province.