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Agroforestry Systems (agroforestry + system)
Selected AbstractsThe inherent ,safety-net' of an Acrisol: measuring and modelling retarded leaching of mineral nitrogenEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 2 2002D. Suprayogo Summary The inherent features of Acrisols with their increasing clay content with depth are conducive to reducing nutrient losses by nutrient adsorption on the matrix soil surfaces. Ammonium (NH4+) and nitrate (NO3,) adsorption by a Plinthic Acrisol from Lampung, Indonesia was studied in column experiments. The peak of the H218O breakthrough occurred at 1 pore volume, whereas the median pore volumes for NH4+ and NO3, ranged from 6.4 to 6.9 and 1.1 to 1.6, respectively. The adsorption coefficients (Ka in cm3 g,1) measured were 1.81, 1.51, 1.64 and 1.47 for NH4+ and 0.03, 0.09, 0.10 and 0.17 for NO3,, respectively, in the 0,0.2, 0.2,0.4, 0.4,0.6 and 0.6,0.8 m soil depth layers. The NH4+ and NO3, adsorption coefficients derived from this study were put in to the Water, Nutrient and Light Capture in Agroforestry Systems (WaNuLCAS) model to evaluate their effect on leaching in the context of several cropping systems in the humid tropics. The resulting simulations indicate that the inherent ,safety-net' (retardation mechanism) of a shallow (0.8,1 m) Plinthic Acrisol can reduce the leaching of mineral N by between 5 and 33% (or up to 2.1 g m,2), mainly due to the NH4+ retardation factor, and that the effectiveness in reducing N leaching increases with increasing depth. However, the inherent ,safety-net' is useful only if deep-rooted plants can recover the N subsequently. [source] Biodiversity in tropical agroforests and the ecological role of ants and ant diversity in predatory functionECOLOGICAL ENTOMOLOGY, Issue 4 2006STACY M. PHILPOTT Abstract 1.,Intensive agricultural practices drive biodiversity loss with potentially drastic consequences for ecosystem services. To advance conservation and production goals, agricultural practices should be compatible with biodiversity. Traditional or less intensive systems (i.e. with fewer agrochemicals, less mechanisation, more crop species) such as shaded coffee and cacao agroforests are highlighted for their ability to provide a refuge for biodiversity and may also enhance certain ecosystem functions (i.e. predation). 2.,Ants are an important predator group in tropical agroforestry systems. Generally, ant biodiversity declines with coffee and cacao intensification yet the literature lacks a summary of the known mechanisms for ant declines and how this diversity loss may affect the role of ants as predators. 3.,Here, how shaded coffee and cacao agroforestry systems protect biodiversity and may preserve related ecosystem functions is discussed in the context of ants as predators. Specifically, the relationships between biodiversity and predation, links between agriculture and conservation, patterns and mechanisms for ant diversity loss with agricultural intensification, importance of ants as control agents of pests and fungal diseases, and whether ant diversity may influence the functional role of ants as predators are addressed. Furthermore, because of the importance of homopteran-tending by ants in the ecological and agricultural literature, as well as to the success of ants as predators, the costs and benefits of promoting ants in agroforests are discussed. 4.,Especially where the diversity of ants and other predators is high, as in traditional agroforestry systems, both agroecosystem function and conservation goals will be advanced by biodiversity protection. [source] Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestryJOURNAL OF ANIMAL ECOLOGY, Issue 2 2006ALEXANDRA-MARIA KLEIN Summary 1Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0,1415 m), light intensity (37·5,899·6 W/m,2) and number of vascular plant species (7,40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3A total of 13 617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey. [source] Isolation and characterization of new microsatellite markers in shea tree (Vitellaria paradoxa C. F. Gaertn)MOLECULAR ECOLOGY RESOURCES, Issue 4 2008FRANÇOIS ALLAL Abstract Vitellaria paradoxa is one of the major components of African parkland agroforestry systems. In order to assess the genetic diversity and population structure of this species, we isolated and characterized 14 polymorphic nuclear microsatellite loci. Primers developed to amplify these loci were used to analyse 200 individuals of a shea tree population in Mali. Loci have shown a high number of alleles ranging from four to 26, and display an observed level of heterozygosity between 0.37 and 0.85. These new very polymorphic microsatellite markers will be useful for genetic and ecological studies of V. paradoxa. [source] Identification and characterisation of traditional chestnut varieties of southern Spain using morphological and simple sequence repeat (SSRs) markersANNALS OF APPLIED BIOLOGY, Issue 3 2009M.A. Martin Abstract The maintenance of plant genetic resources requires the identification of places and agroforestry systems that support high levels of genetic diversity. The aim of this work was to clarify the number and names of chestnut (Castanea sativa) cultivars in the south of Spain. Accordingly, 100 grafted chestnut trees corresponding to 34 traditional names were evaluated using 10 qualitative morphological traits and seven simple sequence repeat (SSRs) markers. We identified 38 varieties, 12 in the Huelva region and 26 in Malaga, and synonymies and homonymies were discussed. This work demonstrated that the joint use of morphological traits and SSR markers is an efficient method to evaluate the agrobiodiversity of chestnut in this region. It was also stated that chestnut production in the south of Spain is a traditional system using varieties developed ,in situ'. This constitutes a genuine system of on-farm conservation, which is now threatened. Consequently, adopting strategies for its safeguarding are urgently recommended. [source] | ||||||||||