Optimizing Soil Nitrogen Supply in the Root Zone to Improve Maize Management
- X. P. Chenab,
- F. S. Zhanga,
- Z. L. Cui *a,
- F. Liac and
- J. L. Lid
- a College of Resources and Environmental Sciences, China Agricultural Univ. 100094 Beijing, China
b State Key Lab. of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Water and Soil Conservation, Chinese Academy of Sciences, 712100 Yangling, China
c College of Ecology and Environmental Science, Inner Mongolia Agricultural Univ., 010019 Hohhot, China
d College of Resources and Environmental Sciences, Qingdao Agricultural Univ., 266023 Qingdao, China
Developing agronomically sound, environmentally appropriate N management strategies are critical for the sustainability of agricultural production. Our objective was to evaluate agronomic performance and potential environmental impacts of in-season N management (INM) against increased or reduced N fertilization on a calcareous alluvial soil for maize (Zea mays L.) in China. Optimal N rates (ONR) were determined for INM by deducting measured soil NO3–N content in root layers from the N target value during three maize growth periods: from planting to three-leaf stage, three- to 10-leaf stage, and 10-leaf stage to harvest. Other treatments included a 0 N control, below ONR (70% ONR, 50% ONR, or ONR − 30 kg N ha−1), above ONR (130% ONR, 150% ONR, or ONR + 30 kg N ha−1), and farmers' N practice (FNP). Across all 14 sites from 2003 to 2006, when N treatment was less than ONR (average 141 kg N ha−1), grain yield was significantly reduced from 8.5 to 7.7 Mg ha−1 while maintaining similar residual soil NO3–N content and N losses. When extra N fertilizer was applied, no yield gain was achieved, but N losses were significantly increased from 50 to 81 kg N ha−1 The FNP treatment had the lowest N recovery (22%) and greatest residual soil NO3–N of 158 kg ha−1 and N loss of 87 kg ha−1 The INM is an extremely practical strategy for effectively utilizing soil N supply, synchronizing N demand and N supply, and addressing site-specific N management needs.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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