Leaching losses of urea-N applied to permeable soils under lowland rice |
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Authors: | Bijay-Singh Yadvinder-Singh C. S. Khind O. P. Meelu |
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Affiliation: | (1) Department of Soils, Punjab Agricultural University, 141 004 Ludhiana, India |
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Abstract: | Application of 120 kg urea-N ha–1 to lowland rice grown in a highly percolating soil in 10 equal split doses at weekly intervals rather than in 3 equal split doses at 7, 21 and 42 days after transplanting did not significantly increase rice grain yield and N uptake. Results suggest that leaching losses of N were not substantial. In lysimeters planted with rice, leaching losses of N as urea, NH4+, and NO3- beyond 30 cm depth of a sandy loam soil for 60 days were about 6% of the total urea-N and 3% of the total ammonium sulphate-N applied in three equal split doses. Application of urea even in a single dose at transplanting did not result in more N leaching losses (13%) compared to those observed from potassium nitrate (38%) applied in three split doses. Nitrogen contained in potassium nitrate was readily leached during the first week of its application. More N was lost from the first dose of N applied at transplanting than from the second or third dose. Data pertaining to yield, N uptake and per cent N recovery by rice revealed that the performance of different fertilizer treatments was inversely related to susceptibility of N to leaching. |
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Keywords: | Ammonium sulphate leaching nitrogen potassium nitrate urea lowland rice |
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