Pedosphere 27(6): 1092--1104, 2017
ISSN 1002-0160/CN 32-1315/P
©2017 Soil Science Society of China
Published by Elsevier B.V. and Science Press
Nitrogen Use Efficiency of Rice Under Cadmium Contamination:Influence of Rice Cultivar Versus Soil Type
ZHOU Yanli1,2, SUN Bo1
1State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China)
2Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201 (China)
ABSTRACT
      There is a need for rice cultivars with high yields and nitrogen (N) use efficiency (NUE), but with low cadmium (Cd) accumulation in Cd-contaminated paddy soils. To determine the relative effects of rice genotype, soil type, and Cd addition on rice grain yield and NUE, a pot experiment consisting of nine rice cultivars was conducted in two types of paddy soils, red soil (RS) and yellow soil (YS), without or with Cd spiked at 0.6 mg kg-1. The N supply was from both soil organic N pools and N fertilizers; thus, NUE was defined as the grain yield per unit of total crop-available N in the soil. Cd addition decreased grain yield and NUE in most rice cultivars, which was mainly related to reduced N uptake efficiency (NpUE, defined as the percentage of N taken up by the crop per unit of soil available N). However, Cd addition enhanced N assimilation efficiency (NtUE, defined as the grain yield per unit of N taken up by the crop) by 21.9% on average in all rice cultivars. The NpUE was mainly affected by soil type, whereas NtUE was affected by rice cultivar. Hybrid cultivars had higher NUEs than the japonica and indica cultivars because of their greater biomass and higher tolerance to Cd contamination. Reduction of NUE after Cd addition was stronger in RS than in YS, which was related to the lower absorption capacity for Cd in RS. Canonical correspondence analysis-based variation partitioning showed that cultivar type had the largest effect (34.4%) on NUE, followed by Cd addition (15.2%) and soil type (10.0%).
Key Words:  crop-available N, grain yield, N uptake efficiency, N assimilation efficiency, soil available N
Citation: Zhou, Y. and Sun, B. 2017. Nitrogen Use Efficiency of Rice Under Cadmium Contamination:Influence of Rice Cultivar Versus Soil Type. Pedosphere. 27(6): 1092-1104.
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