108 Min Huang, Xuefeng Zhou, Xiaobing Xie et al.
Figure 1. Soil organic matter content (a), total N content (b), available N content (c),
and ratio of available N to total N (d) in a long-term rice-oilseed rape rotation paddy
field in 2004 and 2015.
They determined the N response of hybrid rice cultivar Liangyoupeijiu
over a wide range of N rates (60–410 kg ha–^1 ) and reported that this cultivar
required a minimum N rate of 120–150 kg ha–^1 to produce maxium grain yield
of about 9.0 t ha–^1. The difference in soil fertility was partly responsible for the
different N repsopnses of Liangyoupeijiu between our study and the study of
Huang et al. (2008).