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| Nitrogen reduction technique systemfor sustaining high yield of paddy fields |
| Received:November 15, 2015 |
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| KeyWord:chemical N fertilizer reduction;theoretical N rate;N split ratio;real-time diagnosis of growth status;yield;soil fertility |
| Author Name | Affiliation | | XUE Li-hong | Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China | | LI Gang-hua | Nanjing Agricultural University, Nanjing 210095, China | | HOU Peng-fu | Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China | | FAN Li-hui | Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China
Nanjing Agricultural University, Nanjing 210095, China | | YANG Lin-zhang | Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China |
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| Abstract: |
| A nitrogen reduction technique system was put forward based on the previous research results including the 15N isotope trace, different split ratios of basal, tiller and panicle N fertilizer experiments. The N reduction technique system included the determination of theoretical N rate, the suitable split ratio of basal, tiller N fertilizer, and the real-time adjustment of panicle topdressing N rate based on the rice growth status. The theoretical N rate should be calculated based on the target yield and N requirement per unit grain. Then, the split ratios of N fertilizer at different growth stages should be optimized according to the soil fertility. Nitrogen rate reduction should be emphasized on basal and tiller N. At the same N rate, the suitable basal and tiller N ratio decrease with increasing soil fertility level, and should be 60%, 50% and 40% for low, medium and high soil fertility, respectively. Under low soil fertility, a certain amount of basal N rate should be applied and the ratio of basal to tillering should be kept at 3:7 to ensure the high yield and N use efficiency. However, no obvious influences was observed for different split ratios of basal to tiller N under high soil fertility. Finally, in order to ensure a high yield, the panicle topdressing N should be adjusted based on the crop growth and target yield using the leaf color or canopy reflectance spectra as the non-destructive diagnostic tool. |
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