Variation Of Nitrogen And Phosphorus Use Efficiency And Optimal Fertilizer Inputs Among Different Wheat Varieties

Breeding fertilizer saving wheat varieties is an effective way to reduce fertilizer input in agro-ecosystems.A large number of studies have shown that there are significant differences in nitrogen(N)and phosphorus(P)use efficiency among different wheat varieties.However,N and P use efficiency of different wheat varieties may vary among planting areas.N and P efficient wheat varieties selected from different wheat populations may be inconsistent.Thus,particularity of planting area should be considered during the screening process of N and P efficient wheat varieties.In our study,we firstly analyzed the differences of N and P use efficiency of 15 wheat cultivars which are suitable for planting in Weibei dryland,and then,the relationship between yield and fertilization input of different wheat cultivars was analyzed by establishing fertilizer input models.Optimal N and P fertilizer application rates were calculated based on the models,and fertilizer saving wheat varieties which may be suitable for planting in the dry land of Shaanxi province were screened.The main results are as follows: 1.By studying N use efficiency of different wheat varieties,the results indicated that N absorption and recovery efficiency of Yanzhan 4110 and Changhan 58 were higher than the other wheat varieties,and these two wheat varieties were N uptake efficient varieties;N partial productivity,N agronomic efficiency,grain N utilization efficiency,and shoot N utilization efficiency of Weimai 8,Yannong 19,Yaomai16 and Longping 203 were higher than the other varities,and these four wheat varieties were N utilization efficient varieties.2.By analyzing P use efficiency of different wheat varieties,the results indicated that P uptake and recovery efficiency of Wanmai 68 were higher than the other varities,and these two varities were P uptake efficient varieties;the partial productivity of P fertilizer,P agronomic efficiency,grain P utilization efficiency and shoot P utilization efficiency of Yaomai 16,Longping 203 and Changhan 58 were higher than the other wheat varities,and these three wheat varieties were P utilization efficient varieties.3.Nuptake and utilization efficient wheat varieties often had higher N uptake or utilization parameters under various N application rates,and similar results were also found for the P uptake and utilization efficient wheat varieties.4.Among the 15 wheat varieties,the relationship between N application and yield of 8 wheat varieties,such as Chuanmai 104,fitted the linear plateau model;while the relationship between nitrogen application and yield of 7 wheat varieties,such as Xinong 3517,did not fit the linear platform model or quadratic function model.The relationship between N application rate and economic benefit of 7 wheat cultivars such as Chuanmai 104 fitted the linear platform model;while 8 wheat cultivars such as Jinmai 90 did not fit the linear plateau model or quadratic function model.The relationship between phosphorus application rate and yield or economic benefit of 15 wheat varieties did not fit the linear plateau model or quadratic function model.5.To obtain the highest grain yield,the input of N fertilizer for the wheat varieties Yaomai 16,Changhan 58,and Yannong 19 was 113.8 kg/ha,96.7 kg/ha and 125.1 kg/ha,respectively,and was lower than the other varieties;to obtain the highest economic benefits,the input of N fertilizer for the wheat varieties was 105.1 kg/ha,83.4 kg/ha,and 112.8 kg/ha,respectively,and was lower than the other varieties.Overall,there were obvious differences in N and P use efficiency among different wheat varieties,and efficient wheat varieties were still efficient under different N and P fertilization rates.From the point of view of optimum yield and economic benefit,three wheat varieties,Yaomai 16,Changhan 58 and Yannong 19,were fertilizer-saving varieties,which have great potential in using in wheat production.