Study On Optimum Rates Of Nitrogen, Phosphorus And Potassium For Wheat And Maize In Xian County

Xian County is a major agricultural county for grain production. For a very long time, the lack ofefficient fertilization technology has brought about unscientific fertilization and behavior in pursuitinghigh yielding production. Seriously blind fertilization has led to lower benefit although sometimes yieldwas observed to be increased a little bit. Winter wheat and summer maize experiments were conductedunder different soil fertility levels to study grain yield, nutrient uptake and nutrient use efficiency, so asto put forward to the reasonable fertilizer N, P and K applciuation rates for wheat and maize for Xiancounty. The findings from this study help provide the classification guidance for farmers to fertilizereasonably, so as to promote optimized fertilization management for wheta and maize. The mainachievements are as follows:1. For the soils with relatively high fertility level, fertilizer application rate should be controlled ina certain range. For summer maize, the appropriate rates of N, P2O5and K2O respectively were10.8kg/mu,5.5kg/mu and6.5kg/mu; for winter wheat, the appropriate rates of N, P2O5and K2O respectivelywere11.3kg/mu,10kg/mu and8.7kg/mu. With this fertilizer recommendation, it is supposed to notonly get high yield, but also save fertilizer input with improving benefit.2. For the soils with relatively medium fertility level, the recommended fertilizer application ratesof N, P2O5and K2O for summer maize were12.4kg/mu,6.6kg/mu and8.1kg/mu, respectively,those for winter wheat were13.8kg/mu,11.2kg/mu and10.2kg/mu, respectively.3. For the soils with relatively low fertility level, fertilizer application rates should be increased tobuild up the soils. For summer maize, the appropriate rates of N, P2O5and K2O were14.6kg/mu,9.3kg/mu and11.4kg/mu respectively; for winter wheat, the appropriate rates of N, P2O5and K2O were15.9kg/mu,12.9kg/mu and11.8kg/mu respectively. In this way, it can get not only high yield, butalso improve the soil nutrient content to achieve the maximum economic benefit.4. Under different fertility soils, with fertilizer application rate increased, the agronomic efficiencydecreased gradually. The lower soil fertility was, the higher agronomic efficiency would be. With theincrease of soil fertility, the agronomic efficiency decreased. For summer maize, in the same plots,potassium agronomy efficiency was higher than that of nitrogen and phosphorous. For winter wheat, inthe same plots, phosphorous agronomy efficiency was higher than that of nitrogen and potassium.5．The higher soil fertility, the more nutrients soil can supply; the lower fertilizer applied, thehigher fertilizer use efficiency is, and visa versa. In the same plots, potassium use efficiency was thehigheset and phosphorous efficiency was the lowest.