In:
Soil Science Society of America Journal, Wiley, Vol. 74, No. 1 ( 2010-01), p. 139-152
Kurzfassung:
In tropical agroecosystems, limited N availability remains a major impediment to increasing yield. A 15 N‐recovery experiment was conducted in 13 diverse tropical agroecosystems. The objectives were to determine the total recovery of one single 15 N 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 during the first growing season was derived from fertilizer. On average, 79% of crop N was derived from the soil. When 15 N‐labeled residues were applied, in the first growing season 4% of crop N was derived from the residues. Average recoveries of 15 N‐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 15 N 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 15 N‐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 15 N losses, management practices to improve N use efficiency and reduce losses in wet tropical regions will remain a challenge.
Materialart:
Online-Ressource
ISSN:
0361-5995
,
1435-0661
DOI:
10.2136/sssaj2009.0192
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2010
ZDB Id:
241415-6
ZDB Id:
2239747-4
ZDB Id:
196788-5
ZDB Id:
1481691-X
SSG:
13
SSG:
21
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