ISSN:
1573-5036
Keywords:
common bean
;
foliar N
;
nitrogen fixation
;
N fertilizer
;
15N isotope
;
Rhizobium
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract Common bean (Phaseolus vulgaris L.) is able to fix 20–60 kg N ha−1 under tropical environments in Brazil, but these amounts are inadequate to meet the N requirement for economically attractive seed yields. When the plant is supplemented with N fertilizer, N2 fixation by Rhizobium can be suppressed even at low rates of N. Using the 15N enriched method, two field experiments were conducted to compare the effect of foliar and soil applications of N-urea on N2 fixation traits and seed yield. All treatments received a similar fertilization including 10 kg N ha−1 at sowing. Increasing rates of N (10, 30 and 50 kg N ha−1) were applied for both methods. Foliar application significantly enhanced nodulation, N2 fixation (acetylene reduction activity) and yield at low N level (10 kg N ha−1). Foliar nitrogen was less suppressive to nodulation, even at higher N levels, than soil N treatments. In the site where established Rhizobium was in low numbers, inoculation contributed substantially to increased N2 fixation traits and yield. Both foliar and soil methods inhibited nodulation at high N rates and did not significantly increase bean yield, when comparing low (10 kg N ha−1) and high (50 kg N ha−1) rates applied after emergence. In both experiments, up to 30 kg N ha−1 of biologically fixed N2 were obtained when low rates of N were applied onto the leaves.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00016341
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