Effects Of Combined Application Of Organic And Inorganic Fertilizers On Yield In Summer Maize And On Soil Environment

This experiment was carried out in fluvo-aquic soil of the North China Plain.We took summer maize, a main crop in local area as the experimental materials.Whole experiment setted four nitrogen rates,and under every nitrogen application rate we established four different combined rates. Through the experiment,we have studied the effects of nitrogen fertilizer rate and combined application of organic and inorganic fertilizers on soil physical-chemical properties, environment,apparent fertilizer balance,summer maize yield and grain quality of maize.It was the best match of crops yield and environment carrying capacity that we focused on,our experiment also tried to offer help to solve the problem,such as environmental pollution result from fertilizers abusing and realize agricultural sustainable development. The results showed that:Summer maize yield and crude protein content in corn grain are mainly effected by nitrogen fertilizer rate ,but the effect of combined application of organic and inorganic fertilizers on them is not conspicuous .Fertilization can improve the content of soil organic matter, total nitrogen, total phosphorus, and the content of soil organic matter, total nitrogen and total phosphorus increase following the rate of fertilizetion;Under the same level of nitrogen fertilizer rate , the content of organic matter, total nitrogen and total phosphorus is expressed as:100%M>75%M+25%N>50%M+50%N>100%N.Application of organic manure can increase the C/N ratio of soils,but inorganic fertilizers has a tendency lower the ratio.In the upper soil layer, the C/N ratio of soils more vulnerable to the impact of fertilizer application and environmental conditions; Under the same level of nitrogen fertilizer rate,the laws for the C/N ratio of soil is:100%M>75%M+25%N>50%M+50%N>100%N. Single organic fertilizer or high nitrogen fertilizer level can easily be trapped in a "nitrogen hunger" situation.The effet of fertilization on ammonium nitrogen is less,the content of ammonium nitrogen unchanged basically.The content of ammonium nitrogen in all soil layer is less than 4mg/kg,and when recommending nitrogen or evaluating the pollution caused by nitrogen, the factor can be ignored.The effet of fertilization on soil NO3--N is significant,and the contentof soil NO3--N increases following the rate of nitrogen fertilizer;The co-ntent of NO3--N in upper layer aff ect greater by rate of fertilizer,but inlower layer,the effct is smaller. Under the same level of nitrogen fertilizer rate, the effct of combined application of organic and inorganic fertilizers on the content of soil NO3--N is obvious,and the specific l-aws is:100%N>50%M+50%N>75%M+25%N>100%M;Single applicationof inorganic fertilizers or high level of nitrogen fertilizer rate can increase the risk of soil NO3--N leaching. Fertilization can increase soil available phosphorus content; more applicating of organic manure can increase the content of soil available phosphorus,but if the quantity of organic manure is excessive,the risk of phosphorus leaching is great.The impact of N application rate on the directions of nitrogen fertilizers is great.The more of N application rate,the number of the apparent residue rate, leaching loss and gaseous loss all are increaser. When nitrogen fertilizer rate under the level of 200kg/hm2, the apparent utilization shows increase,while under the level of 200kg/hm2, the apparent utilization shows decline. the ratio of organic fertilizer is greater. the rate of apparent utilization and rate of leaching loss is lower, but the apparent residual rate is higher; the rate of gaseous loss is lowest under the condition of combined application of organic and inorganic fertilizers.The main loss of nitrogen fertilizer is leaching loss and gaseous loss.Generally take the summer maize yield, soil physical and chemical properties ,the apparent nitrogen balance and other factors into consideration, When nitrogen fertilizer rate is 200kg/hm2,the more appropriate fertilization model in our study area is that 75% of the nitrogen provided by the organic manure, and 25% of the nitrogen provided by the inorganic fertilizers.