| Autor: |
Liwei Shi, Zhenling Cui, Fusuo Zhang, Jun-Liang Li, Jiu-Fei Xu, Xinping Chen |
| Rok vydání: |
2006 |
| Předmět: |
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| Zdroj: |
Pedosphere. 16:806-812 |
| ISSN: |
1002-0160 |
| DOI: |
10.1016/s1002-0160(06)60117-3 |
| Popis: |
Excessive nitrogen (N) fertilizer application to winter wheat is a common problem on the North China Plain. To determine the optimum fertilizer N rate for winter wheat production while minimizing N losses, field experiments were conducted for two growing seasons at eight sites, in Huimin County, Shandong Province, from 2001 to 2003. The optimum N rate for maximum grain yield was inversely related to the initial soil mineral N content (Nmin) in the top 90 cm of the soil profile before sowing. There was no yield response to the applied N at the three sites with high initial soil mineral N levels (average 212 kg N ha−1). The average optimum N rate was 96 kg N ha−1 for the five sites with low initial soil Nmin (average 155 kg N ha−1) before sowing. Residual nitrate N in the top 90 cm of the soil profile after harvest increased with increasing fertilizer N application rate. The apparent N losses during the wheat-growing season also increased with increasing N application rate. The average apparent N losses with the optimum N rates were less than 15 kg N ha−1, whereas the farmers' conventional N application rate resulted in losses of more than 100 kg N ha−1. Therefore, optimizing N use for winter wheat considerably reduced N losses to the environment without compromising crop yields. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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