| It is a great significance to improve the crop yield and resources use efficiency for food security and environmental sustainability.Drip irrigation under film mulching is the new agricultural technology that can achieve high yield and high use efficiency.However,its potential in the current production has not been totally realized.Our objective was to understand the limited factors in present film mulching system of maize that based on the yield gap between filed practice and potential,as well as to prove the high yield and high efficiency maize system by means of model simulation and field experiment.Meanwhile,we investigated the impact of nutrient management?rate and frequency of fertilizer?on biomass and nutrient accumulation.The main results were as below:?1?Yield gap between farmers' practice and potential was defined by farm survey and Hybrid-Maize model in the maize of Northeast China Plain.The results showed that averaged maize yield was 10.8Mg ha-1,which amount to 71%of the yield potential.?2?The optimized nitrogen?N?management that based on the target yield and the pattern of N requirement in high production maize was lower 70 kg N ha 1 than FP(350 kg N ha-1).However,compared with FP,the yield and partial N fertilizer production?PFPN?were increased from 11.7 to 13.8 Mg ha-1 and from 33.3 to 51.0 kg kg-1,respectively,and the apparent N losses was decreased from 171.5 to 64.5 kg ha-1.The results suggested that optimized N management in maize production was available.?3?Phosphorus?P?application could enhance the maize yield significantly by increasing kernels per spike and thousand seed weight.The greatest yield was 13.3 Mg ha-1 that found in the application of 100 kg P2O5 ha-1.More P application showed no effects on yield improvement,but the decline of P use efficiency reflected by the P recovery efficiency that decreased from 11.7 to 7.2%in one season,agronomy efficiency of P decreased from 18.9 to 12.0 kg kg-1,as well the partial P fertilizer production?PPFP?declined from 129 to 96 kg kg-1.?4?Potassium?K?also could significantly increase yield by 6.4-17.1%in the two years experiments.The greatest yield was found in the rate of 90 kg K20 ha-1.The highest K accumulation in aboveground was at filling stage and decreased later on.?5?Split applications could significantly improve the maize yield,nutrient transfer and fertilizer use efficiency compared to single application.The maize yield of five times topdressing had no loss comparable to the six times topdressing,and was greater than four times topdressing.?6?A designed system that based on optimized crops and resource management in Qianan County,Jilin Province.The yield of experiment gained 14.5 Mg ha-1 which amount to 92%of the yield potential.On the one hand,designed system has elevated the crop production and economic benefits significantly compared to farmers practice?FP?,on the other hand,it also has enhanced the nutrient and water use efficiency compared to high production system?HP?. |
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