Effects Of Long-Term Application Of Chemical Fertilizer And Organic Manure On Nitrogen Flow And Water Use Efficiency In Winter Wheat Field

The experiment was conducted at the Maize Technological Innovation Center of the north China plain(NCP)and State Key Laboratory of Crop Biology of Shandong Agricultural University in 2013~2015,based on the 5-year long-term same location test.The winter wheat(Triticum aestivum L.)variety was Shimai15,the source of organic nitrogen was cow manure,and the fertilizer was applied as four different treatments: no N fertilizer application(CK),single application of urea(U),single application of cow manure(M),and combined application of urea and cow manure(U+M).The aim of our study is to study the effect of chemical fertilizers combined application on nitrogen flow,mineral nitrogen balance,water use characteristics and yield in winter wheat field.The aim is to find out reasonable fertilization ways to reduce N losses,non-point source pollution and amount of chemical fertilizers in agricultural production,at the same time to solve the contradiction between water shortage and water use efficiency.Then provide guidance and reference for realizing the synergetic and efficient use of water and nitrogen and agricultural sustainable development.The main findings are as follows: 1.Effect of chemical fertilizer and organic manure application on nitrogen flow of winter wheatMost of the fertilizer nitrogen applied to the soil is absorbed by the plant,accounting for 31.7%~45.6%.Some are lost to the environment in various forms,Total N total losses were 18.9~39.8 kg ha-1,amounting to 10.5%~22.1% of N applied at a rate of 180 kg ha N.Ammonia volatilization(AV)was the main loss pathway(12.71~32.62 kg ha-1),accounting for 67.5%~82.0% of total losses.Leaching losses were lower(2.13~4.64 kg ha-1).Losses through cumulative denitrification were the lowest(1.7~2.5 kg ha-1),accounting for 0.5%~1.0% of total applied N.Total N losses were 18.3%~25.9% of applied urea N,but were lower following U+M treatment(12.7%~17.1%).a large part remains in the soil,accounting for 20.8%~44.4%.Hence,the combined application of urea and manure was advantageous for reducing N loss.Under the combined application of organic and inorganic fertilizers,the nitrogen fertilizer flow is divided into the following parts:(1)the proportion of nitrogen uptake by plant was 45.6%,which was 6.6% and 13.9% higher than that of single application of chemical fertilizers and organic manure respectively,and the ratio of nitrogen distribution of grain was 4.4% higher than that of single application;(2)the amount of nitrogen applied to the environment by ammonia volatilization,leaching,denitrification and so on is about 10.9% of the total amount of nitrogen fertilizer,which is 6.5% lower than that of single chemical fertilizer treatment,which is 4.4% higher than that of single chemical fertilizer treatment;and(3)20.8% of the nitrogen fertilizer in the form of mineral nitrogen residues in the soil,compared with single fertilizer and single application of organic fertilizer were reduced by 2.5% and 23.6%.It can be concluded that the combination of organic and inorganic fertilizers can optimize the flow of nitrogen fertilizer,increase the nitrogen absorption and utilization of plants while reducing nitrogen loss and nitrogen residue,and reduce the potential pollution of the environment.2.Effect of chemical fertilizer and organic manure application on mineral nitrogen balance and nitrogen use efficiency of winter wheatAmong the four treatments,applying nitrogen fertilizer was conducive to maintain a surplus nitrogen balance.Under U+M,the nitrogen cycle showed low input and high output,the low input was namely the lowest initial mineral nitrogen,and the total input was 3.0%–3.8% lower than that of the chemical fertilizer alone.High output included: the total loss of nitrogen loss and nitrogen loss ratio decreased significantly.The total amount of nitrogen loss was 44.5%–47.9% lower than that of U,and the amount of crop uptake was the highest(1.05 times than that of U),and the content of soil mineral nitrogen was lower.So that the nitrogen surplus and surplus rate of U+M was the lowest,15.1%–19.8% and 13.8%–19.3% less than that of U,respectively,this reduced the risk of environmental pollution caused by nitrogen loss.In addition,compared with M and U,the available N use efficiency and N recovery rate of U+M was significantly increased by 10.5%,24.7% and 18.9%,48.6%,respectively.3.Effect of chemical fertilizer and organic manure application on water use characteristicsof winter wheatThe types of fertilizer and fertilization way were obviously influenced on the water consumption characteristics and water use efficiency of winter wheat.The crop water consumption of U+M was higher,reaching 548.5–556.7 mm and had no significant difference with U in two growing seasons.In all growth stages,the water consumption,water consumption model of coefficient of U+M was the highest in the stage of flowering to maturity,the water consumption that allocated to the flowering to maturity accounted for 33.6%–42.4% of the total water consumption.The mixed application of urea and manure increased the consumption of soil water,especially the deep water storage.Soil water storage consumption of U treatment was the highest,but that of U+M treatment was distributed more on grouting phase.The leaching of treatment U+M was the lowest,which was 66.8%,52.5% and 37.6% lower than other treatments.U+M treatment had the highest dry matter accumulation in the two growing seasons,which 11.9% and 22.3% higher than those in the U and M treatments,respectively.U+M was obvesioudly increased water use efficiency of winter wheat.The water use efficiency(WUE)and dry matter water use efficiency(WUE)of U+M were the highest in the two growing seasons,which was 44.7%?10.4%?9.5% and 79.4%?11.2%?19.6% higher than U and M.4.Effect of chemical fertilizer and organic manure application on grain yield and dry matter accumulation and distribution of winter wheatFertilizer combined with organic manure significantly increased the yield of winter wheat.The yield of different fertilization treatments showed a trend of U+M>U>M>CK.Compared with the control treatment,the yield of U,M and U+M increased by 61.2%,58.1% and 72.1%,respectively.As far as yield components,the U+M treatment mainly increased the number of spike per hectare and the number of grains per spike,and the one thousand grain weight was between single organic manure and single chemical fertilizer.Nitrogen application significantly increased winter wheat dry matter accumulation.The dry matter accumulation of U+M was the highest in different N-applied trentmens,which was 9.8% and 21.0% higher than that of U and M,respectively.The proportion of grain and spike axis + glume of the total dry matter increased under U+M,which was accounted for 45.0%,while that of single fertilizer and organic manure was only 39.6% and 41.8%,respectively.The combined application of chemical fertilizers and organic manure increased the dry matter accumulation capacity of winter wheat and increased the distribution of photosynthate to grain.