%A LIU Li-Jun,WANG Kang-Jun,BIAN Jin-Long,XIONG Yi-Wei,CHEN Lu,WANG Zhi-Qin,YANG Jian-Chang %T Differences in Yield Response to Nitrogen Fertilizer among Rice Cultivars and Their Relationship with Root Morphology and Physiology %0 Journal Article %D 2014 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2014.01999 %P 1999-2007 %V 40 %N 11 %U {https://zwxb.chinacrops.org/CN/abstract/article_5767.shtml} %8 2014-11-12 %X

Yield responses to nitrogen (N) rates in indica rice cultivars Tianyouhuazhan, Liangyoupeijiu and japonica rice cultivars Lingxiangyou 18 and Ningjing 1 were investigated and showed significant differences among them. The optimal N rates in Tianyouhuazhan and Lingxiangyou 18 were only 242.5–255.5 kg ha-1, significantly lower than those in Liangyoupeijiu and Ningjing 1 (327.3–328.0 kg ha-1), when the maximum grain yield (10.1–10.3 t ha-1) reached. The agronomic use efficiency and partial factor productivity of N fertilizer were much higher in Tianyouhuazhan and Lingxiangyou 18 than in Liangyoupeijiu and Ningjing 1, indicating that the yield is much more sensitive to N rate in the former two cultivars than in the latter two rice cultivars. Under high-yielding (10.5–10.9 t ha-1) conditions, root dry weight, root length and total root absorbing area at main growth stages were lower, but the root active absorbing area and its ratio to total root absorbing area, root bleeding sap and root activity were higher in Tianyouhuazhan and Lingxiangyou 18 than in Liangyoupeijiu and Ningjing 1. These results suggested that increasing root active absorbing area, root bleeding sap and root activity through the regulation of cultivation or breeding will be much more beneficial to decreasing N rate and increasing grain yield and N use efficiency in rice.