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Journal and Journal Articles: Recent submissions
Now showing items 1421-1440 of 5273
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Leucaena + maize alley cropping in Malawi; part 2: residual P and leaf management effects on maize nutrition and soil properties
(1996)Agroforestry systems involving leaf removal for animal fodder may result in rapid depletion of soil fertility. The purpose of this research was to determine if the effects of leaf removal on soil fertility parameters and maize yield in aLeucaena leucocephalaalley cropping system could be reversed. Three leaf management strategies in aLeucaenaalley cropping trial that had been in effect from 1987 to 1991 were investigated: 1) leaves returned, 2) leaves removed, and 3) leaves removed, with 100 kg ... -
Seasonal and habitat variability in the fungal pathogens, neozygites cf. floridana and Hirsutella thompsonii, associated with cassava mites in Benin
(1996)A survey of the pathogenic fungi associated with mites on cassava in Benin, West Africa, revealed both geographical and seasonal variation in the presence of Neozygites cf. floridana (Weiser and Muma) and Hirsutella thompsonii Fisher on Mononychellus tanajoa (Bondar) and Oligonychus gossypii (Zacher). Few dead and infected mites were found during the dry season, regardless of vegetation zone. In three of 30 surveyed sites, N. floridana was found infecting 1% of the dead M. tanajoa and 2% of the ... -
Soil litter dynamics and N use in a leucaena (Leucaena leucocephalaLam. (de Witt)) alley cropping system in southwestern Nigeria
(1996)The recovery of a single application of leucaena (Leucaena leucocephala) leaf N (78 kg N ha−1) in a maize crop, the hedgerow and the top 10 cm soil of a leucaena alley cropping system was measured for 236 d through the use of 15N labeled residues. The leucaena-derived-N (LDN) was followed in the surface litter and the soil-litter — separated by a flotation method on water — during the same period.At 45 and 129 d after the residue application (DAA), only 4.2 and 10.0% of the added leucaena N was ... -
System dynamics and the defintion of research domains for the northern Guinea Savanna of West Africa
(1996)The northern Guinea savanna in Africa (NGS) with a season length of 151–180 days and an altitude below 800 m has long been recognized as highly suitable for crop production and animal husbandry. At present, land use intensity and farming as well as livestock systems vary widely across the zone. Subsistence farming and traditional pastoralism are present as well as intensive, market-oriented production of cash crops and highly integrated crop-livestock systems. This article presents an approach for ... -
A simplified Shaw's wet-combustion technique for determination of carbon in plant materials
(1996)A simplified Shaw's wet‐combustion technique for carbon (C) determination in plant materials is described which requires less reagent and operation time. The simplified technique gave high recovery (99.4%) of the C in analytical pure grade sucrose and citric acid, and high reproducibility of C measured in 18 different plant materials. -
Capabilities of Landsat 5 Thermatic Mapper data in regional mapping and characterization of inland valley agroecosystems in West Africa
(1996)This study demonstrated the capabilities of Landsat-5 Thematic Mapper (TM) data in regional mapping and characterization of inland valley (valley bottoms plus valley slopes or fringes) agroecosystems. A methodology was developed involving image enhancement, display and digitizing, as well as image and Geographical Information System (GIS) manipulation techniques for rapid studies of inland valley characteristics over large areas. A case study was conducted using Landsat-5 TM data over the regions ... -
Ruminant assay for rapidly estimating plant residue decomposability in the field
(1996)Field litterbag decomposition study, through widely accepted for examining decomposition of plant residues, is time consuming, as it requires several months to complete. An experiment was conducted to explore the possibility to introduce ruminant nylonbag assay which only takes 3-4 days, to plant residue decomposition studies for agricultural purpose. Results showed decomposability of plant residues, measured using the ruminant nylon bag significantly correlated with those using the litterbags, ... -
Identification of okra mosaic virus from Indigofera spicata in Nigeria
(1996)Okra mosaic virus (OMV, tymovirus group) was isolated from Indigofera spicata plants growing at the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria. Its identity was established on the basis of particle morphology, analysis of viral coat protein and nucleic acid and Indigofera spicata. In reciprocal agar gel diffusion tests, the virus isolate from I. spicata and an OMV isolate from okra in Ibadan (OMV-Ibadan isolate) were found to be serologically identical. However, ... -
Carbon-13 assignments and revision of the stereostructures of the Cadinanes 2-Hydroxy-8α-angeloyloxycalamenene and 2-Hydroxy-8α-hydroxycalamenene
(1996)The two known cadinanes 2-hydroxy-8α-hydroxycalamenene and 2-hydroxy-8α-angeloyloxycalamenene were isolated from a Louisiana population of Heterotheca subaxillaris. Their 13C NMR spectra were fully assigned by the application of HETCOR, COLOC, COSY, NOESY and DEPT experiments. It was shown on the basis of NOESY experiments that both cadinanes require revision at the stereogenic centre C-7.
