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Soil Nitrate as a Source of Nitrogen for Rainfed and Deep-Flooded Rice |
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| รหัสดีโอไอ | |
| Creator | Manoch Kongchum |
| Title | Soil Nitrate as a Source of Nitrogen for Rainfed and Deep-Flooded Rice |
| Contributor | Wuti Niponkit, R. J. Buresh, D. W. Puckridge |
| Publisher | Department of Agriculture |
| Publication Year | 2542 |
| Journal Title | Thai Agricultural Research Journal |
| Journal Vol. | 17 |
| Journal No. | 2 |
| Page no. | 174-184 |
| Keyword | soil nitrate-N, deepwater rice |
| URL Website | https://at.doa.go.th/journal |
| Website title | Thai Agricultural Research Journal |
| ISSN | 0125-8389 |
| Abstract | Deepwater rice (DWR) is grown under rainfed upland conditions for 2-4 months, followed by deep flooding for 1-5 months. Nitrogen is important for the pre-flood growth of the crop, particularly to promote growth and development before the stress of deep flooding. Nitrate accumulated during transition from the dry to the wet season is a ptential source of nitrogen. We measured soil nitrate before and during flooding in the Central Plain of Thailand on two different soil types, a Thio-gypsic Tropaquept and a Sulfic Tropaquept. Soil samples were collected from depth intervals of 0-20, 20-40 and 40-60 cm from plots without N fertilizer, and extracted with 2M KCI for analysis of N by a cadmium reduction technique. Plant samples were dried and analyses for nitrogen content by Kjedahl analysis. Soil nitrate-N levels were less than 15 kg ha-1, and appear to have contributed little to crop N uptake. Nitrogen was lost from the crop at the beginning of flooding, but subsequently uptake of N contimued, apparently from sources other than the pre-flood N transformations in the soil. |
