Study On Influences Of Nitrogen And Phosphate Application On Yield And Environmental Effects Of Wheat-maize Rotation

Hebei province is one of the important countrywide bases of grain production. Withthe increase of population and grain demand, Hebei area should pay attention to the foodproblems. Fertilizers play an important role in high yield and high quality of food. Themajor problems of grain crops growing were blindly excessive fertilization, low fertilizeruse efficiency, unbalanced soil nutrient, shortage of fertilizer supply and so on, whichrestricted the high yield and high quality of food. Therefore, the rational fertilization andscientific management are the only way for agricultural sustainable development in thefuture.Taking wheat-corn crop rotation system as example, based on fertilizer response, thefield experiment was conducted to comprehensively analyze the variation characteristics ofsystem including crop, soil and fertilizer for achieving fertilizer threshold which combineda higher output and a friendly environment in Baoding area of Hebei province.This paper designed a nitrogen fertilizer experiment of six nitrogen fertilizationlevels(0,180,240,300,360and480kg/hm2during wheat,0,135,180,225,270and360kg/hm2during maize) and a phosphate fertilizer trial of four phosphate fertilizer levels(0,120,240and480kg/hm2). Analyzing the impacts on growth and yield of wheat and maizeby nitrogen and phosphorus, use efficiency of nitrogen and phosphorus and the impacts onsoil environment by nitrogen and phosphorus, this paper got some results.(1) The proper quantity of nitrogen fertilizer played a positive role in promotingbiological characteristics of wheat and maize. The impact of wheat height by N fertilizerwas mainly showed during earlier stage, while the impact of maize height by N fertilizerwas average during the whole growth period. Phosphate fertilizer had little effect onbiological characteristics of wheat and maize.(2) With the increase of nitrogen application and phosphorus application, nutrientcontent of most of the organs of wheat and maize would increase in various degrees, whilethe higher amount of nitrogen and phosphorus fertilizer would lower the NPK content ofdifferent organs. With the increase of nitrogen fertilizer, grain crude protein of wheat andmaize would increase firstly and then decrease, and with the increase of phosphate fertilizer, it would increase. The impact of wheat was higher than maize.(3) Compared with no fertilization, the increase of nitrogen fertilizer and phosphatefertilizer could increase the yield of wheat and maize. With the300kg/hm2nitrogenfertilizer, the yield of wheat got the highest value which increased by46.80%compared tothe control, while with the180kg/hm2nitrogen fertilizer, the yield of maize got the highestvalue which was11500.38kg/hm2. With the240kg/hm2phosohate fertilizer, the yield ofwheat gets the highest value which increased by32.44%compared to the control, whilewith the120kg/hm2phosohate fertilizer, the yield of rotation got the highest value whichwas17620.69kg/hm2。(4) With the impacts of nitrogen fertilizer and phosphate fertilizer within certain limits,nutrient uptake efficiency (UE), partial factor productivity from fertilizer (PFP), apparentrecovery efficiency of fertilizer (RE) and agronomic efficiency of fertilizer (AE) couldachieve the highest values. NPK uptake efficiency of N2deal (240kg/hm2during wheat,180kg/hm2during maize) got the highest values, while optimum phosphate fertilizerdemanded by nutrient uptake was different. Within all the deals, nitrogen fertilizer criticalvalue demanded by wheat and rotation PEP was N3(300kg/hm2during wheat,525kg/hm2during rotation), while phosphate fertilizer critical value demanded by wheat NK PEP wasP2(240kg/hm2). REPcould be improved significantly by maize. This needed to considerevery index to find a balanced fertilizer application.(5) The increase of nitrogen fertilizer and planting years could add the nitrate-Nconcentration and nitrate-N accumulation, and the increase of phosphate fertilizer couldreduce that. The proper quantity of nitrogen fertilizer could effectively reduce the residueof rapid available phosphorus in surface soil, while it had a little effect on the whole profile.Within certain limits, the increase of nitrogen fertilizer would reduce rapidly availablepotassium content in surface soil, and the increase of phosphate fertilizer will increase that.(6) The nitrogen application of wheat240kg/hm2(WN2), nitrogen application180kg/hm2(MN2) of maize and120kg/hm2(P1) phosphate application of rotation were theoptimum, which could achieve the goals of high yield of wheat and maize andenvironmental sustainability.