EVALUATION OF<i>GLIRICIDIA SEPIUM</i>PROVENANCES FOR THE LOW COUNTRY HUMID ZONE OF SRI LANKA

Liyanage, M. De S.; Jayasundara, H.P.S.; Liyanage, L.V.K.

doi:10.1080/01435698.1991.9752905

Cited by 3 publications

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“…Many published reports have suggested that the ~SN methods are more reliable for measuring N2 fixation in trees (Dohoux and Dommergues, 1985;Sanginga et al, 1989;Zaharah et al, 1986), and would thus be very useful for quantifying differences among genotypes. In a preliminary study, Liyanage et al (1991) found high variability in growth and biomass production among a collection of G. sepium provenances from the Oxford Forestry Institute and a local landrace. The present study is a follow-up of that study, aimed at examining in addition, to growth, any differences in Nz-fixing potentials.…”

Section: Introductionmentioning

confidence: 96%

Biological nitrogen fixation in four Gliricidia sepium genotypes

1994

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A field experiment was conducted at the Coconut Research Institute in Sri Lanka to examine the biological nitrogen fixation potential of three Gliricidia sepium provenances (OFI 14/84, 17/84, 12/86) and a local landrace (designated LL), using the 15N isotope dilution method. There was marked variation in dry matter, total N, nodulation and 15N enrichment among the Gliricidia genotypes (= 0.001), and the dry matter yield of Cassia siamea (syn. Senna siamea), the non-N2 fixing reference plant was higher than for G. sepium. In all cases, highest biomass and total N were aboveground, with roots on average accounting for < 20 % of total dry matter or the total N in plants. Atom % 15N excess was highest in C. siamea, and lowest in OFI 14/84. Although atom % 15N excess was lower in Gliricidia leaves than in the other organs (all of which had similar 15N enrichments), values of % N derived from atmospheric N2 fixation ( % Ndfa) calculated for any individual organ or for the whole plant were similar. This was because the relative distribution of 15N in the different parts of the fixing plant followed the same trend as in the reference plant. There were significant differences (p = 0. 01) in N2 fixation between the Gliricidia genotypes.The values ranged from 17.8 g N tree -I (equivalent to 86 kg N ha -l at 5000 trees ha -1) in OFI 12/86 to 61.7g N tree -~ (equivalent to 309 kg N ha -1) in OFI 14/84. Although most of this variability was due to differences in both % Ndfa and total N in plant, amount of N fixed was more correlated with total N in plant (r = 0.935) than with % Ndfa (r = 0.707). On average, % Ndfa in all three G. sepium provenances and LL was about 55 % or 34.6 g N tree-l (equivalent to some 166 kg N ha-l) in the 9 months within which N2 fixation was measured. This represents a substantial contribution of N into the soil-plant system. SamplingPlants were separated into roots, stem, branches and leaves, which were chopped into 1-5 cm pieces, and then weighed fresh. A 300 g sub-sample was taken for drying at 70°C to constant weight in a forced-draft

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Section: Introductionmentioning

confidence: 96%

Biological nitrogen fixation in four Gliricidia sepium genotypes

1994

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“…For instance, creeping legumes (Pueraria javanica, Centrosema pubescens, Calopogonium mucunoides, etc.) are often recommended with coconut to maintain soil nitrogen fertility [5], or tree legumes such as Leucaena leucocephala or Acacia mangium, which also supply firewood [19,29,31]. Vanuatu is also worth mentioning as a specific case: its smallholders combine immature coconut palms with food crops (cassava, taro, yam, groundnut), and subsequently with livestock rearing.…”

Section: Introductionmentioning

confidence: 99%