Acta Agriculturae Zhejiangensis ›› 2021, Vol. 33 ›› Issue (6): 984-992.DOI: 10.3969/j.issn.1004-1524.2021.06.03

• Crop Science • Previous Articles     Next Articles

Effects of reduced nitrogen application on yield and nitrogen agronomic efficiency of Yongyou indica-japonica hybrid rice

WANG Feng1(), SHEN Jianghua1, CHEN Ruoxia1,*(), SHI Jun1, REN Shaopeng1, JIN Shuquan1, YAO Hongyan1, ZHU Defeng2, DAI Yaolu1   

  1. 1. Institute of Eco-Environmental Sciences, Ningbo Academy of Agricultural Sciences, Ningbo 315040, China
    2. China National Rice Research Institute, Hangzhou 310006, China
  • Received:2020-12-25 Online:2021-06-25 Published:2021-06-25
  • Contact: CHEN Ruoxia

Abstract:

A field experiment was carried out in two sites (Xiangshan and Yinzhou),which represented different soil type of single-season rice area in east Zhejiang from 2017 to 2019, with four Yongyou indica-japonica hybrid rice cultivars (YY1540, YY7850, YY12 and YY538) and two conventional japonica rice cultivars (N84 and XS134) as materials. Four treatments were set with varying levels of N application rates: HN (N: 240 kg·hm-2 for hybrid rice and 200 kg·hm-2 for conventional rice); MN (N reduction of 17% compared with HN), LN (N reduction of 34% compared with HN), N0 (control without N). It was shown that the grain yield (GY) decreased with the reduction of nitrogen application rate in both sites. The yield of Yongyou hybrid rice under MN treatment in Xiangshan and Yinzhou was 10.8 t·hm-2 and 9.9 t·hm-2, respectively, which was only 1.2% and 2.6% lower than that under HN, with no significant difference. N reduction (MN and LN) decreased effective panicle (EP) in both sites, but increased seed setting rate (SSR) and 1 000-grain weight (GW) in Xiangshan. Correlation analysis showed that the GY of Yongyou indica-japonica hybrid rice was significantly (P<0.05) positively correlated with EP, number of spikelets per panicle (NSP) and maximum number of tillers and stems (MNTS) in Xiangshan, and was significantly (P<0.05) positively correlated with EP, SSR and panicle-bearing tiller rate (PBTR) in Yinzhou. N agronomic efficiency (NAE) of Yongyou indica-japonica hybrid rice was not significantly affected by N application rate, but increased rapidly with the trial age in Xiangshan, indicating that long-term reduction of N input without other technical assistance had a potential risk. For Yongyou indica-japonica hybrid rice under the conventional practice in the coastal region of east Zhejiang, nitrogen application rate could be reduced by 17% with no significant reduction of the grain yield. But, for the long-term run, comprehensive effects of soil fertility, rice varieties and fertilizer utilization should be well considered.

Key words: Yongyou indica-japonica hybrid rice, yield, nitrogen

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