Historical comparison on the response curves of rice yield-nitrogen application rate in Tai Lake Region

The rice yield-nitrogen (N) application rate response curve obtained from the network of field experiments conducted in 2004-2006 is compared with that conducted in 1982-1985. Results show that in comparison with the response curve obtained in 1982-1985, the response curve obtained in 2004-2006 is at a markedly higher position at the Y-axis, the agronomic efficiency and the apparent plant recovery of fertilizer N are improved considerably. Presumably, these are primarily, in addition to the improvement in the application technique, resulted from the current use of rice cultivars with high yield potential and high uptake efficiency. The findings reveal that the breeding of new varieties with even higher yield potential and higher N uptake efficiency and higher response to N, combined with the improvement in cultivation technique (including N fertilizer application technique) are the basic approaches for the sustainable development of rice production in the region.