Mitigating Rapid Release of Nitrate from Rejected Sago Starch-coated Urea and Uncoated Urea


Citation

Kavitha Rajan, . and Latifah Omar, . and Ahmed, Osumanu Haruna and Charles, Primus Walter and Susilawati Kasim, . (2024) Mitigating Rapid Release of Nitrate from Rejected Sago Starch-coated Urea and Uncoated Urea. Malaysian Journal of Soil Science (MJSS) (Malaysia), 28. pp. 117-133. ISSN 1394-7990

Abstract

Urea is the most widely used nitrogen (N) fertilizer as it has a high N content (46%), is inexpensive, easily available, and can be conveniently stored. However, the high water-solubility and rapid hydrolysis of urea in the soil leads to much N loss. Rejected sago starch (RSS) was used to coat urea to prevent rapid release of N. A soil leaching experiment was conducted over 30 days to determine the effectiveness of RSS-coated urea in retaining soil N availability in the form of exchangeable NH₄⁺ and available NO₃ˉ compared with uncoated urea. The soil used in the leaching experiment was Bekenu Series (Sandy loam, Typic Paleudults). This study compared seven different treatments: soil alone (S), 5 g of uncoated urea (U), 5 g of 2% RSS-coated urea (CU1), 5 g of 3% RSS-coated urea (CU2), 5 g of 4% RSS-coated urea (CU3), 5 g of 5% RSS-coated urea (CU4), and 5 g of 6% RSS-coated urea (CU5). The RSS-coated urea (CU1, CU2, CU3, and CU4) significantly reduced N leaching due to the coating on the urea that serves as a barrier which slows down the conversion of N into NH₄⁺ and NO₃ˉ. Gradual released of N helps in retaining more soil exchangeable NH₄⁺ in all RSS-coated urea than uncoated urea. Optimize use of RSS-coated urea in CU1 (2% of RSS) did not only mitigates NO₃ˉ leaching, but it is also increasing soil TOM, TOC, total N, soil exchangeable NH₄⁺, and available NO₃ˉ although all the RSS-coated urea has minimal effects on soil pH.


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Abstract

Urea is the most widely used nitrogen (N) fertilizer as it has a high N content (46%), is inexpensive, easily available, and can be conveniently stored. However, the high water-solubility and rapid hydrolysis of urea in the soil leads to much N loss. Rejected sago starch (RSS) was used to coat urea to prevent rapid release of N. A soil leaching experiment was conducted over 30 days to determine the effectiveness of RSS-coated urea in retaining soil N availability in the form of exchangeable NH₄⁺ and available NO₃ˉ compared with uncoated urea. The soil used in the leaching experiment was Bekenu Series (Sandy loam, Typic Paleudults). This study compared seven different treatments: soil alone (S), 5 g of uncoated urea (U), 5 g of 2% RSS-coated urea (CU1), 5 g of 3% RSS-coated urea (CU2), 5 g of 4% RSS-coated urea (CU3), 5 g of 5% RSS-coated urea (CU4), and 5 g of 6% RSS-coated urea (CU5). The RSS-coated urea (CU1, CU2, CU3, and CU4) significantly reduced N leaching due to the coating on the urea that serves as a barrier which slows down the conversion of N into NH₄⁺ and NO₃ˉ. Gradual released of N helps in retaining more soil exchangeable NH₄⁺ in all RSS-coated urea than uncoated urea. Optimize use of RSS-coated urea in CU1 (2% of RSS) did not only mitigates NO₃ˉ leaching, but it is also increasing soil TOM, TOC, total N, soil exchangeable NH₄⁺, and available NO₃ˉ although all the RSS-coated urea has minimal effects on soil pH.

Additional Metadata

[error in script]
Item Type: Article
AGROVOC Term: urea
AGROVOC Term: nitrogen fertilizers
AGROVOC Term: leaching
AGROVOC Term: soil analysis
AGROVOC Term: nitrogen retention
AGROVOC Term: soil organic matter
Geographical Term: Malaysia
Depositing User: Mr. Khoirul Asrimi Md Nor
Date Deposited: 22 May 2025 03:40
Last Modified: 22 May 2025 03:40
URI: http://webagris.upm.edu.my/id/eprint/2815

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