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  • 1
    Electronic Resource
    Electronic Resource
    Indigenous agroforestry of Pohnpei (1991)
    Springer
    Agroforestry systems 16 (1991), S. 159-165 
    Details
    ISSN: 1572-9680
    Keywords: Pacific islands ; Micronesia ; agroforestry ; traditional agriculture ; low-input agriculture ; spatial pattern ; succession
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A vegetation survey of 54 randomly-selected Pohnpeian land holdings quantified agroforest vegetation patterns in terms of horizontal distribution in the landscape and changes over time. Spatial distribution of species, expressed as distance from the main household, varied greatly with successional stages to produce the characteristic pattern of the Pohnpeian agroforest. Food crops, bananas, and Piper methysticum were planted around the house compound first, then gradually planted further away over time. Upland forest and secondary successional trees were removed by girdling, and gradually replaced by annual and perennial crops and breadfruit and other trees. A fallow or reduced management stage was discerned, characterized by low densities of early successional crops and higher densities of weedy secondary successional species; this stage resulted from a reduction in management intensity, mainly due to a variety of socioeconomic factors. Although the indigenous Pohnpeian agroforestry system is permanent and thought to be sustainable, it is dynamic in space and time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00129746
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Indigenous agroforestry of Pohnpei (1991)
    Springer
    Agroforestry systems 16 (1991), S. 139-157 
    Details
    ISSN: 1572-9680
    Keywords: Pacific islands ; Micronesia ; agroforestry ; species diversity ; cultivars ; indigenous agriculture ; low-input agriculture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Plant species and cultivars of the indigenous agroforestry system of Pohnpei were surveyed in transects through 54 randomly-selected farms. The agroforestry system was characterized by extensive cultivation of yams (Dioscorea), aroids (Alocasia), and Piper methysticum under a permanent overstory of breadfruit, coconut, and forest remnant trees and a middle canopy of Hibiscus tiliaceus, Musa spp., and Morinda citrifolia. In the 10 ha of survey plots, 161 species were found, of which 102 were trees, shrubs, and crops and 59 were uncultivated herbaceous plants. Numbers of tree, shrub, and crop species per farm ranged from 16 to 37 with an average of 26. Twenty-eight breadfruit and 38 yam cultivars were found in the survey plots, showing that cultivar diversity is an important component of the biological diversity maintained and utilized in Pohnpeian agroforests.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00129745
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Nitrogen mineralization patterns of leaf-twig mixtures from tropical leguminous trees (1993)
    Springer
    Agroforestry systems 24 (1993), S. 223-231 
    Details
    ISSN: 1572-9680
    Keywords: alley cropping ; Calliandra calothyrsus ; Gliricidia sepium ; green manure ; incubations ; nitrogen mineralization ; multipurpose tree
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Green manure applications in alley cropping systems often include twigs despite their potential to absorb (immobilize) nitrogen (N). To assess the impact of twigs on net N mineralization or immobilization from hedge row cuttings, we separated cuttings fromCalliandra calothyrsus andGliricidia sepium into leaf-only, twig-only, and mixed (leaf + twig) fractions and incubated them with moist soil in the laboratory. Soil extractable inorganic N did no differ among treatments after two weeks, but after four and eight weeks was greatest in leaf-only, and least in twig-only treatments. After two weeks, extractable N from the leaf-only treatment rose steadily, while that from the twig-only and mixed treatments was variable due to periods of net mineralization and net immobilization. The pattern of variation in mixed treatments paralleled that of twig-only, indicating that net immobilization in the mixture was largely caused by the presence of twigs. Extractable N from the mixture was somewhat lower than that predicted from the sum of leaf-only and twig-only treatments. We conclude that twigs in green manure reduce short-term N availability to associated crops in agroforestry systems.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00705623
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  • 4
    Electronic Resource
    Electronic Resource
    Alley cropping of maize with nine leguminous trees (1992)
    Springer
    Agroforestry systems 17 (1992), S. 159-168 
    Details
    ISSN: 1572-9680
    Keywords: alley cropping ; maize ; nitrogen fixing trees ; soil degradation ; traditional farming
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A maize-leguminous tree alley cropping system was studied on N-deficient soils in Hawaii to determine mulch effects on maize yields. Calliandra calothyrsus, Cajanus cajan, Cassia siamea, Gliciridia sepium, KX1 — Leucaena hybrid (L. pallida X L. diversifolia), L. leucocephala, L. pallida, L. salvadorensis, and Sesbania sesban were evaluated for green manure and yield of intercropped maize. S. sesban, G. sepium, L. pallida, and KX1 produced between 5 and 12 dry t/ha/yr green manure with nitrogen yields between 140 and 275 kg N/ha in 4 prunings. Maize yields responded linearly to nitrogen applied as green manure. Maize yield increased 12 kg for each kg of nitrogen applied. Additions of prunings from hedge rows were able to support maize grain yields at about 1800 kg/ha for two consecutive cropping seasons, while control plot yields averaged less than 600 kg/ha. Maize yields reflected the amount of nitrogen applied as green manure, regardless of tree species from which the nitrogen was derived. In March, maize yields decreased 34% in the row spaced 40 cm from the hedge, relative to the one spaced 110 cm away. In July, increasing the distance away from the hedge to 60 cm and coppicing the hedge earlier in maize growth, significantly improved grain yield. Grain yields decreased only 10% in the row closest to the trees.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00053120
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Effects of chemical composition on nitrogen mineralization from green manures of seven tropical leguminous trees (1992)
    Springer
    Plant and soil 143 (1992), S. 127-132 
    Details
    ISSN: 1573-5036
    Keywords: alley-cropping ; incubations ; lignin ; N-fixing trees ; N mineralization ; polyphenols ; tropical agroecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Green manures from seven tropical leguminous trees were incubated with soil to determine the rates and controls of net nitrogen release. Fresh green manure (leaves and succulent twigs) was mixed with moist soil and incubated in polyethylene bags. Net N mineralization from green manures was estimated by the accumulation of extractable ammonium and nitrate minus the accumulation in soil alone. Patterns of N mineralization were complex, differed among species, and at 12 weeks ranged from 10 to 65 percent of original green-manure N. Cumulative net N mineralization was negatively correlated with initial soluble polyphenol content in the early phases of decomposition (1 through 8 weeks) and with initial lignin content in later phases (4 through 12 weeks). Neither initial percent N nor lignin: N ratio were strongly correlated with N mineralization. The best chemical index of N release was the initial polyphenol: N ratio. This study confirms previous findings that N mineralization from tropical legumes is controlled more by soluble polyphenols than by lignin or N content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00009137
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    Paper (German National Licenses)
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in nodule and root biomass of Sesbania sesban and Leucaena leucocephala following coppicing (1991)
    Springer
    Plant and soil 138 (1991), S. 9-16 
    Details
    ISSN: 1573-5036
    Keywords: below-ground biomass ; growth efficiency ; Leucaena leucocephala ; pot study ; Sesbania sesban ; tropical trees
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A pot study was conducted to measure the extent of and determine the factors controlling fine root and nodule shedding following coppicing of Sesbania sesban and Leucaena leucocephala. Fine (〈2 mm) root biomass decreased below pre-cutting values, but the decreases were not statistically significant in either species. Living (white) nodule biomass decreased and dead (brown) nodule biomass increased significantly two weeks after cutting in both species. These changes were relatively greater in Sesbania than in Leucaena. In the uncut treatments of both species, fine root and nodule biomass were correlated with leaf biomass, and in the cut treatments, root and nodule biomass returned to near this apparent equilibrium by two weeks after cutting. Stem growth rate per unit leaf area was not different between cut and uncut treatments, nor was it correlated with root:leaf ratios in either species. Leucaena allocated a greater fraction of its total biomass below-ground, and a greater fraction of its below-ground biomass to coarse (〉2 mm) roots than Sesbania. These results are consistent with the hypothesis that relatively lower allocation to below-ground storage tissue is the cause for Sesbania's relatively greater sensitivity to cutting.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00011802
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