Nitrogen budgets for Boro rice (Oryza sativa L.) fields in Bangladesh

A - Papers appearing in refereed journals

Hossain, M. F., Elahi, S. F., White, S. K., Alam, Q. K., Rother, J. A. and Gaunt, J. L. 2012. Nitrogen budgets for Boro rice (Oryza sativa L.) fields in Bangladesh. Field Crops Research. 131, pp. 97-109.

AuthorsHossain, M. F., Elahi, S. F., White, S. K., Alam, Q. K., Rother, J. A. and Gaunt, J. L.

Nitrogen (N) budgets are a valuable tool for improving N efficiency because they assess the size and interactions of various N pools, as well as their gains from the atmosphere and losses to the environment. To understand the impact of changes in management practice upon a farming system, it is necessary to increase the complexity of the N budgets to include N flows. Therefore, a project was undertaken in lowland irrigated systems of Bangladesh to study the N budgets of Boro rice grown under ecological and conventional farming systems in four locations (Dhamrai, Daulatpur, Gabtali and Shibgonj) in Bangladesh in 2007 and 2008. The N budget focuses on the total-N inputs and losses of the entire system. The budgets were negative for both farming systems in both years. Overall, ecological farming system produced a less negative balance in both years (−6 to −36kgNha−1 in 2007 and −76 to −160kgNha−1 in 2008) than the conventional farming system (−28 to −80kgNha−1 in 2007 and −91 to −157kgNha−1 in 2008). Nitrogen balance studies highlighted losses of mineral N (26–53kgNha−1) which accumulated prior to irrigation and also losses due to N removal (13–28kgNha−1) by weeds. Beneficial impacts of ecological farming on N balances were observed due to the elimination of fertiliser N loss (30–133kgNha−1). The difference between conventional and ecological management reflects the high losses of fertiliser N under conventional management. These fertiliser N losses reflect the low agronomic efficiency of N fertiliser. An understanding of various N losses and their consequences is important to provide a basis for developing efficient N management strategies in boro rice. These N budgets can be used to improve or design new technologies that tackle soil fertility management problems and also can help improve the financial performance of the farmers. Soil N budgets will continue to challenge agricultural scientists by slowly revealing fundamental principles. By understanding these principles and the factors influencing them, basic and applied scientists will have a stronger foundation for improving N use efficiency and concurrently reducing N losses to the environment.

Keywordsnitrogen budgets; Rice; Lowland systems; Ecological and conventional farming; Bangladesh
Year of Publication2012
JournalField Crops Research
Journal citation131, pp. 97-109
Digital Object Identifier (DOI)
Open accessPublished as non-open access
Elsevier Science Bv

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