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Field experiments were carried out to study the effects of nitrogen ( N ) application rate on rapeseed yield and N fertilizer use efficiency in Hubei Province during 2007 to 2008. Compared to no N application, the yield of N treatments ( as 75, 150 and 225kg/hm²) increased 41.9%, 70.3% and 66.2% respectively. N content increased 9.1%, 14.2% and 13.1%, and total N absorbed by above ground parts increased 59.6%, 111.6% and 108.0% respectively. The results demonstrated that N application significant promoted growth, yield and N accumulation. With increased N application rate, N requirement for 100kg -seeds was increased, while N agronomic use efficiency (AUE), partial factor productivity (PFP) and apparent recovery efficiency (ARE) of rapeseed decreased significantly. Based on rapeseed yield and N use efficiency, the optimum N fertilizer application rate was 150kg/hm² in Hubei Province. [ABSTRACT FROM AUTHOR]

Field experiments were carried out to study the effects of phosphorus (P) application rate on rapeseed yield and P fertilizer use efficiency in Hubei Province during 2007 -2008. Compared to the control with zero P application, the yield of P2O5 treatments (as 37. 5, 75. 0 and 112. 5kg/hm2, respectively) increased 24. 2% 42.9% and 43. 2% ,as well as the P content increased 10. 5%, 16. 7% and 27.1%, and total P absorbed by aboveground parts increased 36. 1% , 59.1% and 78.7% , respectively. The results indicated significant promotion of P application to growth, yield and P accumulation. With the increase of P application rate, the P required for 100kg seeds was increased, while the P agronomic use efficiency (AUE) , partial factor productivity (PFP) , apparent recovery efficiency (ARE) and physiological use efficiency (PUE) of rapeseed were decreased significantly. 75.0kg/hm2 of P fertilizer was the optimum to both yield and P use efficiency. [ABSTRACT FROM AUTHOR]

Eleven field experiments were carried out to study the effects of potassium (K)application rate on rape seed yield, nutrient concentration, nutrient accumulation and fertilizer-K use efficiency in Hubei province during 2007-2008. Compared to no K treatment, the average yield of the treatment with K2O rates 60,1 20 and 180kg/hm² increased by 16.9%, 21.6% and 19.8%, with average K content increased by 2.7%,9.0% and 7.8%,total K up take by the above ground parts of rapeseed average increased by 42.9%, 63.0% and 82.2%, respectively. The results illustrated that K application increased the yield, K concentration and accumulation of rape seed significantly. With K application rate increase, K agronomic use efficiency (AUE), partial factor productivity(PFP), apparent recovery efficiency (ARE) and physiological use efficiency (PUE) of rape seed were decreased significantly. However, K requirement for 100kg seeds of rape seed was increased with K application rate increase. Based on rape seed yield and K use efficiency, the optimum fertilizer application was 60∼120kg/hm² of K2O in Hubei province. [ABSTRACT FROM AUTHOR]