Study On The Optimum Rate Of Nitrogen, Phosphorus And Otassium In Sweet Potato In Daxing District, Beijing

In recent years, there has been little study on nutrient uptake of sweet potato, and thusfarmers areshortage of scientific guidance on fertilization of sweet potato. Field experiments were conducted tostudy effect of different N, P and K fertilizer application rate on grain yield, nutrient uptake andnutrient use efficiency parameters in sweet potato to put forward to reasonable N, P and K applicationrate for sweet potato. The outcome of this study would provide scientific basis for sweet potatoproduction in Daxing District, Beijing. The main achievements are as follows:1, The yield of balanced fertilization is the highest in three types of soils, the results showed thatexcessive fertilization will cause the reduction of output. The effect is obvious in the soil that have agood soil nutrient supply capacity, is not obvious in the soil that have a poor soil nutrient supplycapacity.2, Great attention should be paid to N and K application in the low fertility soils with sandy loamtexture, and the appropriate dosage of N, P2O5and K2O for the maximum yield is9.8kg/mu,4.8kg/mu and11.7kg/mu, respectively;The low fertility soils with sandy texture has the features of fertilizerleakage, so the N, P and K affected yield significantly. The appropriate dosage of N, P2O5and K2Ofor the maximum yield is19.3kg/mu,10.4kg/mu and23.7kg/mu, separately. For medium fertilitysoils with sandy loam, more attention should be paid attention to potassium application, since bothpotassium deficiency and excess could also cause more serious consequences of reduction of output,and the appropriate dosage N, P2O5and K2O for the maximum yield is6.9kg/mu,10.3kg/mu and10.7kg/mu, respectively.3, In the low fertility soils with sandy loam texture, low fertility soils with sandy texture andmedium fertility soils with sandy loam as fertilizer inputs increase partial factor productivity of N, P andK decline, there was a high negative correlation between the two. In three kinds of soils, the partialfactor productivity from high to low are P, N and K. Balanced fertilization can ensure better agronomicuse efficiency in the low fertility soils with sandy loam texture and low fertility soils with sandy texture,excessive fertilization can reduce agronomic use efficiency of N, P and K in three types of soils. Inbalanced fertilization, nutrient recovery efficiency of N, P and K are highest, the nutrient recoveryefficiency of N is highest, the second is P, K is minimum.4, Nitrogen and potassium in the nutrient absorption has a great effect on the tuberous roots ofsweet potato, the nutrient absorption of the tuberous roots of sweet potato as rate of fertilizer increasesoccurrence increases first and then decreases. In the different P fertilizer application rates, the nutrientabsorption had no obvious change rule. Balanced fertilization can ensure better nutrient recoveryefficiency.