Dourado-Neto, D. and Powlson, D. and Bakar, R.A. and Bacchi, O.O.S. and Basanta, M.V. and Cong, P.T. and Keerthisinghe, G. and Ismaili, M. and Rahman, S.M. and Reichardt, K. and Safwat, M.S.A. and Sangakkara, R. and Timm, L.C. and Wang, J.Y. and Zagal, E. and Van Kessel, C. (2010) Multiseason recoveries of organic and inorganic nitrogen-15 in tropical cropping systems. Soil Science Society of America Journal, 74 (1). pp. 139-152.

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In tropical agroecosystems, limited N availability remains a major impediment to increasing yield. A 15N-recovery experiment was conducted in 13 diverse tropical agroecosystems. The objectives were to determine the total recovery of one single 15N application of inorganic or organic N during three to six growing seasons and to establish whether the losses of N are governed by universal principles. Between 7 and 58 (average of 21) of crop N uptake duringthe first growing season was derived from fertilizer. On average, 79 of crop N was derived from the soil. When 15N-labeled residues were applied, in the first growing season 4 of crop N was derived from the residues. Average recoveries of 15N- labeled fertilizer and residue in crops after the first growing season were 33 and 7, respectively. Corresponding recoveries in the soil were 38 and 71 . An additional 6 of the fertilizer and 9.1 of the residue was recovered by crops during subsequent growing seasons. There were no significant differences in total 15N recovery (average 54) between N from fertilizer and N from residue. After five growing seasons, more residue N (40) than fertilizer N (18) was recovered in the soil, better sustaining the soil organic matter N content. Long-term total recoveries of 15N-labeled fertilizer or residue in the crop and soil were similar. Soil N remained the primary source of N for crops. As higher rainfall and temperature tend to cause higher N losses, management practices to improve N use efficiency and reduce losses in wet tropical regions will remain a challenge. © Soil Science Society of America.

Item Type: Article
Uncontrolled Keywords: Agro-ecosystems; Average recovery; Cropping systems; Fertilizer use; Growing season; Inorganic nitrogen; Management practices; N availability; N content; N use efficiency; Nitrogen-use efficiency; Primary sources; Soil organic matters; Total recovery; Tropical regions, Biogeochemistry; Biological materials; Crops; Ecosystems; Nitrogen; Organic compounds; Recovery; Soils; Strength of materials; Tropics, Nitrogen fertilizers, agricultural ecosystem; crop residue; fertilizer application; growing season; inorganic nitrogen; management practice; nitrogen isotope; nutrient use efficiency; organic nitrogen; soil organic matter; tropical region
Subjects: Agricultural and Biological Sciences
Divisions: SCIENTIFIC PRODUCTION > Agricultural and Biological Sciences
Depositing User: Administrateur Eprints Administrateur Eprints
Last Modified: 31 Jan 2020 15:44

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