| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1992: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1991: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Research Abstract |
By using 16 containers (1/5,000 a), the influence of nine factors on Nitrous Oxide emission from soils was measured. The effects of the conditions of temperature (10ﾟC or 20ﾟC), soil water (saturated or unsaturated), kind of fertilizer curea or ammonium nitrate), quantity of fertilizer (5kgN/10a or 10kgN/10a), kind of soil (clayloam or Kuroboku soil), amount of each irrigation (5mm/day or 10mm/day), irrigation interval (3days or 6days), plant (transplanting of rice or none) and method of fertilization (incorporation or broadcast) were investigated. These nine factors were arrenged by the method of experimental design. The containers were set in the steady temperature room after stuffing with soil about 12cm height. After the fertilization, young rice plants were transplanted and distillled water was irrigated. Nitruns Oxide was collected into 16 rubber bags everydays by using a handy pump after putting a funnel on the containers, and the concentration was measured by a ECD type gas chromatograph.
1. The result of the analysis of variance for the mass of nitrous oxide emission per 10a during 24 days indicated the significant relation of five factors of soil water (unsaturated>saturated), temperature (20ﾟC>10ﾟC), quantity of fertilizer (10kgN/10a>5kgN/10a), irrigation interval (6days>3days) and method of fertilization (incorporation>broadcast).
2. When the condition of kind of fertilizer was changed into coating fertilizer or urea, the result of the analysis of variance for the mass of nitrous oxide emission per 10a during 48 days showed the significance of three factors of soil water (unsaturated>saturated), temperature (20ﾟC>10ﾟC) and kind of fertilizer (urea>coating fertilizer).
3. To reduce the mass of nitrous oxide emission, it is necessary to consider for saturated condition of soil water, low input of nitrogen, broadcasting fertilization, frequent irrigation and the use of coating fertilizer.
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