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Decomposition and nutrient release from leaves,twigs and roots of three alley-cropped tree legumes in central Togo 总被引：2，自引：0，他引：2
The decomposition of leaves, twigs and roots of two diameter classes (<1.5 mm, 1.5–5 mm) were examined in an alley cropping experiment withGliricidia sepium, Calliandra calothyrsus andSenna sianea in the subhumid savanna of Central Togo using the litterbag technique. The effect of the application of leaves and twigs as mulch or green manure was examined.
Gliricidia showed the most rapid mass loss. For all species, leaves decomposed faster than roots. Twigs had the lowest decomposition rate except forCalliandra. The two diameter classes of roots decomposed differently in the three species:Gliricidia fine roots decomposed faster than its coarser root fraction, the coarse roots ofSenna decomposed faster than the fine roots.Termites influenced the mass loss of twigs and roots to varying extents for the different species. In the case of twigs this was markedly influenced by the mode of application: green manure showed more termite frass than mulch.Nutrient release resembled the mass loss patterns of the prunings except for K, which was leached independently from mass loss. The release of the different nutrients was in the order CaGliricidia andSenna seemed to be best for mulch and green manure production at our site. 相似文献
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Agroforestry opportunities for the United States of America 总被引：4，自引：0，他引：4
Agriculture in the United States makes intensive use of large portions, of the nation's arable landscape. This landscape is dominated by large fields of annual crops with few perennial buffering communities within them. Agroforestry systems such as riparian buffers, alleycropping, windbreaks, tree/pasture systems, and forest farming provide buffering opportunities within these landscapes. Riparian buffers and alleycropping systems provide two unique opportunities toward sustainable production by reducing nonpoint source pollution while increasing ecological diversity. The major impediment to agroforestry in the United States is a lack of identity. Agroforestry as a practice is not officially recognized by federal and most state agencies and thus does not qualify for cost-share support or funding for research and establishment of demonstrations. A recent white paper, prepared by representatives from government agencies, academic institutions, and nongovernment organizations, identified eight major actions that could provide the support, for making agroforestry an acceptable alternative to nonsustainable agriculture. Ames, Iowa. Project No. 3209.Journal paper no. J-16071 of the Iowa Agriculture and Home Economics Experiement Station, Ames, Iowa. Project No. 3209. 相似文献
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Data on curculio-caused nut mortality have been collected since 1985 to assess the impact of this nut predator on black walnut trees grown in a plantation environment. These data have been analyzed to investigate spatial and temporal patterns of curculio damage. Curculio damage was independent of nut cluster height or cardinal direction within the crowns of young, nut-bearing black walnut trees, and was greater in parts of a walnut planting that bordered a stand of native hardwoods than in a part remote from the stand. Nut losses caused by the curculio were consistently higher in an upland versus a bottomland planting, although the differences were not significant during most years of the study. Nut mortality caused by the curculio differed among years of the study and was negatively correlated with annual nut abundance.Contribution from the Missouri Agricultural Experiment Station, Journal Series No 12, 156. 相似文献
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