Research Articles
Biochar Based Slow-Release Urea Fertilizer: Production and Assessing the Effects on Growth of Lowland Rice and Nitrogen Dynamics in an Alfisol
Authors:
M. K. N. W. Jayarathna,
University of Peradeniya, Peradeniya, LK
About M. K. N. W.
Department of Soil Science, Faculty of Agriculture
R. S. Dharmakeerthi ,
University of Peradeniya, Peradeniya, LK
About R. S.
Department of Soil Science, Faculty of Agriculture
W. M. U. K. Rathnayaka
Rice Research and Development Institute, Bathalegoda, LK
Abstract
Use efficiency of N fertilizers in lowland rice cultivation is very low. Biochar can be used to modify the N releasing rates of fertilizers and increase their efficiency. Maximum amount of urea that can be intercalated into biochar (BC) and the effects of biochar based slow-release urea fertilizer (SRF) on soil solution N contents and growth of rice (Oryza sativa) were investigated. Two feedstock materials (sawdust and tea waste) were slow pyrolysed at 500°C to produce BC and N were intercalated into BC using urea solutions with seven concentrations (U1=0% <U2<U3<U4<U5<U6<U7=100% w/v). The maximum intercalated N contents in sawdust BC and tea waste BC were 28% and 22%, respectively. Five treatments: two SRFs at 17.25 mg N kg–1 soil (75% recommended N) and three urea levels (0, 75, and 100% N) were applied to rice plants (Bg 251) in a pot experiment. Application of SRF significantly improved the greenness and growth of rice plants when compared with 0% N control and were comparable with 100% urea-N treatment. The apparent recovery of N (ARN) was significantly (p<0.05) improved in SRFs (60-71%) compared to urea only treatments (38-52%). Nitrate-N contents in soil solution were not significantly different (p<0.05) among treatments while NH4+-N content in 100% urea treatment was significantly (p<0.05) higher throughout. Based on urea intercalation efficiency and the ARN, we concluded that SRF made using sawdust biochar is having a higher potential than SRF made using tea waste biochar to improve the efficiency of urea in lowland rice cultivation.
How to Cite:
Jayarathna, M.K.N.W., Dharmakeerthi, R.S. and Rathnayaka, W.M.U.K., 2021. Biochar Based Slow-Release Urea Fertilizer: Production and Assessing the Effects on Growth of Lowland Rice and Nitrogen Dynamics in an Alfisol. Tropical Agricultural Research, 32(2), pp.168–178. DOI: http://doi.org/10.4038/tar.v32i2.8464
Published on
01 Apr 2021.
Peer Reviewed
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