ISSN:
1572-9680
Keywords:
green manure
;
mulch
;
pruning
;
woody legumes
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Abstract A microplot study was conducted with Leucaena leucocephala and Gliricidia sepium to determine the effect of pruning the trees and applying the prunings to the soil (as either surface mulch or soil-incorporated green manure) on N2 fixation by the trees. N2 fixation was estimated by the 15N dilution method, and the non-N2-fixing species Senna siamea was used as a reference species. Number and dry weight of nodules were reduced with applications of prunings in Leucaena, and increased in Gliricidia. For both species, the lowest rate of N2 fixation (47%) occurred under green manure incorporation after pruning, and the highest (66%) with mulching and no-pruning. Incorporation of green manure into soil significantly depressed N2 fixation by 19.1% in Gliricidia and 20.6% in Leucaena compared to no-pruning treatment. The deleterious effect of incorporation of prunings into soil also affected the amount of N2 fixed. During the nine months following pruning, green manure incorporation steadily decreased the percentage of N2 fixed, whereas with no-pruning, pruning only and pruning with mulching, N2 fixation increased with time. Reduction of N2 fixation in pruned plants could imply that they would compete for N with interplanted food crops, causing lower N use efficiency by the latter. Despite lower dry-matter and N yields of Leucaena as compared with Gliricidia, its biological N2 fixation amounted to 73% of its N requirement as opposed to the corresponding figures of 50% for Gliricidia.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1005957206624
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