Pedosphere 22(3): 294--303, 2012
ISSN 1002-0160/CN 32-1315/P
©2012 Soil Science Society of China
Published by Elsevier B.V. and Science Press
In-season root-zone nitrogen management strategies for improving nitrogen use efficiency in high-yielding maize production in China
MENG Qing-Feng1, CHEN Xin-Ping1, ZHANG Fu-Suo1, CAO Ming-Hui1, CUI Zhen-Ling1,2, BAI Jin-Shun1, YUE Shan-Chao1, CHEN Su-Yi2 and T. MÜLLER2
1 Center for Resources, Environment and Food Security, China Agricultural University, Beijing 100193 (China)
2 Fertilization with Soil Chemistry (340i), Institute of Crop Science, Universität Hohenheim, Stuttgart 70593 (Germany)
ABSTRACT
      Many recently developed N management strategies have been extremely successful in improving N use efficiency. How-ever, attempts to further increase grain yields have had limited success. Field experiments were conducted in 2007 and 2008 at four sites to evaluate the effect of an in-season root-zone N management strategy on maize (Zea mays L.). According to the in-season root-zone N management, the optimal N rate (ONR) was determined by subtracting measured soil mineral N (NH4+-N and NO3--N) in the root zone from N target values. Other treatments included a control without N fertilization, 70% of ONR, 130% of ONR, and recommended N rate (RNR) by agronomists in China that have been shown to approach maize yield potentials. Although apparent N recovery for the ONR treatment was significantly higher than that under RNR in 2007, grain yield declined from 13.3 to 11.0 Mg ha-1 because of an underestimation of N uptake. In 2008, N target values were adjusted to match crop uptake, and N fertilization rates were reduced from 450 kg N ha-1 for RNR to 225 to 265 kg N ha-1 for ONR. High maize yields were maintained at 12.6 to 13.5 Mg ha-1, which were twice the yield from typical farmers' practice. As a result, apparent N recovery increased from 29% to 66%, and estimated N losses decreased significantly for the ONR treatment compared to the RNR treatment. In conclusion, the in-season root-zone N management approach was able to achieve high yields, high NUE and low N losses.
Key Words:  apparent N recovery, environmental pollution, N losses, optimal N rate, soil N supply
Citation: Meng, Q. F., Chen, X. P., Zhang, F. S., Cao, M. H., Cui, Z. L., Bai, J. S., Yue, S. C., Chen, S. Y. and MÜller, T. 2012. In-season root-zone nitrogen management strategies for improving nitrogen use efficiency in high-yielding maize production in China. Pedosphere. 22(3): 294-303.
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