Effects of N,  P and K fertilization on spring maize yield and fertilizer use efficiency in Weibei rainfed highland

The purpose of this research was to study the fertilization effect on spring maize, and to investigate the effect of fertilizer application rate and fertility level on yield, profit, fertilizer contribution rate(FCR) and agronomy efficiency(AE) in Weibei rainfed highland under present conditions based on 184 3414 field experiments conducted during 2006 to 2009. The results indicate that the yields of spring maize are increased by 2177, 1157 and 656 kg/ha respectively by applying nitrogen(N), phosphorus(P2O5) and potassium(K2O) fertilizers and the yield increase rates are 34.0%, 15.2% and 7.9% respectively. The average profits are increased by 2901, 1517 and 733 Yuan/ha, corresponding to 23.0%, 12.6% and 7.0% of FCRs, and 9.4, 10.5 and 9.5 kg/kg of AEs respectively. The increased yields, profits and contribution rates of fertilizers are in order N＞P2O5＞K2O, and the AEs of fertilizers are P2O5＞K2O＞N. The yield could be improved significantly by fertilization. Compared with rational fertilization, excessive fertilization does not increase the yield significantly, but decreases the profit and fertilizer use efficiency. In medium and low fertility soils, fertilization means high fertilizer use efficiency and high profit. Compared with 1980s, the use efficiency of N is decreased, and those of P2O5 and K2O are increased.