ISSN:
1573-0867
Keywords:
agronomic N use efficiency
;
direct seeding
;
grain yield
;
leaf N content
;
N uptake
;
partial factor productivity
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Broadcast wet-seeding is gradually replacing transplanting in irrigated rice systems of Southeast Asia. Previous studies reported higher fertilizer-N use efficiency for broadcast-seeded than transplanted rice despite similar grain yields in treatments that received N fertilizer. To re-examine this issue, we compared crop performance and the recovery efficiency (εr, Δ N uptake per unit N applied), agronomic efficiency (εa, Δ grain yield per unit N applied), and partial factor productivity from applied N (PFP, grain yield per unit N applied) in broadcast-seeded and transplanted rice across a wide range of N fertilizer rates at research stations and in farmers' fields. Rice crop established by broadcasting had more rapid leaf area development, dry matter accumulation, and N uptake than transplanting during vegetative growth stages, but slower growth rates and N uptake after panicle initiation, particularly during the grain filling period. Without applied N, grain yield and N accumulation at maturity were significantly lower in broadcast-seeded than transplanted rice, whereas yields and N uptake were comparable for both planting methods with equivalent rates of applied N. Although both εr and εa were higher for broadcast-seeded than transplanted rice, this advantage was an artifact of lower yields and reduced N uptake by broadcasting without applied N rather than improved performance with applied N. In contrast, PFP values were similar for broadcast-seeded and transplanted rice at comparable fertilizer-N rates and in the absence of lodging. We conclude that the PFP from applied N provides a more relevant measure of N use efficiency of different crop establishment methods, and that the system-level N use efficiency of broadcast-seeded rice was not greater than that of transplanted rice.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00790662
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