| Budget Amount *help |
¥7,600,000 (Direct Cost: ¥7,600,000)
Fiscal Year 2005: ¥2,600,000 (Direct Cost: ¥2,600,000)
Fiscal Year 2004: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Research Abstract |
The research was carried out in Nong Ngu Lauem village, Nakorn Pathom province, Thailand. In this village, farmers concentrated on export-oriented asparagus cultivation, particulary to Japan. This village produces about a half of the annual export of asparagus from Thailand to Japan.
We have surveyed nitrogen and phosphorus budget in the cropping system. The asparagus farming needs 840 kg nitrogen per ha per year, but only 4.7% of the nitrogen is taken away in the product and more than 95% of the nitrogen remained in the soils. Vertical distribution of nitrogen in the soils revealed that nitrate concentrations of the soil layers are higher than those under sugarcane cultivation. This suggest that excessive nitrogen leach downward the soil. This was confirmed by analyzing nitrate concentrations in the underground waters which have been taken from 16 wells in the village for more than 4 years. The highest value of 50ppm was recorded, and the concentrations fluctuated. The highest concentrations in the rainy season and the lowest at the dry season, which suggests that nitrate moves downward in the soil layers by water movement.
To decrease the nitrogen stress on the environment, we have tried to use slow-releasing fertilizers and single-component nitrogen fertilizers, such as urea, 46-0-0. During 2 years of the research, farmers have started to pay more attention to their environment.
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