Effects of long-term nitrogen,phosphorus and potassium fertilizer applications on maize yield and soil fertility

A study on crop yield and soil fertility with different fertilization systems were carried out based on a 13-year fertilizer experiment in Drab Fluvoaquic soil in Beijing.At this site,13 different treatments were established in 1990.Seven treatments were chosen for this study: CK(no fertilizer application),N,NK,NP,PK,NPK and NPKM(NPK with farm yard manure).The amount of chemical fertilizer per year was N 150 kg/ha,P2O5 75 kg/ha,K2O 45 kg/ha and manure 22.5 t/ha.The results indicted that crop yields of NPK and NPKM treatments were greater than other treatments.Soil organic matter,total N and P,available N,P and K and microelement contents were increased in NPK and NPKM treatments.On the contrary,total N and P were exhausted in the treatments without N and P fertilizers.Available P and K had the same variation trend in the treatments without P and K fertilizers.The phosphorus fertilizer and farmyard manure had the best effects on maize yield in Drab Fluvo-aquic soil.