Fate of fertilizer nitrogen (15N-labelled) in wetland rice soil in Thailand
1984
Chanthana Siriphaibun | Pathum Sanitwong Na Ayutthaya | Phonphimon Chaiwannakhup (Department of Agriculture, Bangkok (Thailand). Agricultural Chemistry Div.)
Field experiment was conducted using 15N-labelled ammonium sulphate, urea, supergranule, sulphur coated urea and ammonium chloride to study the fate of fertilizer nitrogen in Rangsit acid sulphate soil at the Klong Luang Rice Experimental Station in Wet Season 1980. Nitrogen recoveries in plant and soil were measured and the nitrogen loss was indirectly determined from the 15N balance in the plants and soil. Fertilizer rate did not significantly influence nitrogen recovery in plant and soil. The recovery in plants was 50 % for supergranules, 38.7 % for sulphur coated urea but only 26 % for the other fertilizer sources. Significant quantities of 15N-labelled fertilizer were immobilized in the 0-30 cm. soil layer. Recoverable amount in this layer was 38 % for supergranule and from 48 to 55 % for the other four nitrogen sources. The average total 15N recoveries by fertilizer source showed 88 % for supergranule, 80 % for ammonium sulphate, 78 % for sulphure coated urea and ammonium chloride and 77 % for urea. The losses averaged 12, 20, 22 and 23 % respectively.
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