Pedosphere 26(1): 85--97, 2016
ISSN 1002-0160/CN 32-1315/P
©2016 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Relationships between yield, quality, and nitrogen uptake and utilization of organically grown rice varieties
HUANG Li-Fen1,2,3, YU Jun1,2,3, YANG Jie1,2,3, ZHANG Rong1,2,3, BAI Yan-Chao4, SUN Cheng-Ming1,2,3 and ZHUANG Heng-Yang1,2,3
1Jiangsu Key laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009 (China)
2Co-Innovation Center for Moden Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009 (China)
3College of Agronomy, Yangzhou University,Yangzhou 225009 (China)
4College of Environmental Science and Engineering, Yangzhou University, Yangzhou 225009 (China)
ABSTRACT
      Due to the relatively late start of organic rice (Oryza sativa L.) research in China, there is a still lack of systematic research on rice varieties, organic fertilizer management practices, and especially the mechanisms of nitrogen (N) uptake and utilization. Three rice varieties, Nanjing 5055, Nanjing 9108, and Nanjing 46, were grown at organic farming (OF) with three organic fertilizer levels (103.2, 160.8, and 218.4 kg N ha-1) and conventional farming (CF) with regular chemical fertilizers. Rice grain yields, yield components, and quality, dry matter accumulation, and plant N were measured at different growth stages during the 2012 and 2013 growing seasons. Compared with CF, OF had a significantly reduced yield. Nanjing 9108 showed significant reductions in number of panicles per unit area and the percentage of filled grains, and had the lowest yield. The effects of fertilizer type and application rate on dry matter accumulation during the main growth periods were significant for all varieties. The N content and uptake of organically grown rice were lower compared with that of rice under CF. The N recovery efficiency and N agronomic efficiency were significantly lower, whereas N physiological efficiency and N partial factor productivity were greater under OF than under CF. Under OF, the processing quality showed a slight but insignificant decline, protein content and gel consistency increased, and amylose content decreased compared with those under CF. Correlation analysis showed that under OF, grain yield was significantly correlated with N uptake. The medium organic fertilizer level (160.8 kg N ha-1) was found to be the optimum fertilizer treatment, and Nanjing 46 appeared to be the best variety for organic rice cultivation. To increase rice grain yields and reduce the potential risk of non-point source pollution in organic agriculture, further research is needed to improve the N use efficiency in organic rice cultivation.
Key Words:  conventional farming, grain quality, grain yield, N use efficiency, organic farming, organic fertilizer
Citation: Huang, L. F., Yu, J., Yang, J., Zhang, R., Bai, Y. C., Sun, C. M. and Zhuang, H. Y. 2016. Relationships between yield, quality, and nitrogen uptake and utilization of organically grown rice varieties. Pedosphere. 26(1): 85-97.
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