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ParikesitEmail author K.?Takeuchi A.?Tsunekawa O.?S.?Abdoellah 《Agroforestry Systems》2005,63(2):171-182
A comprehensive study was carried out on a typical indigenous agroforestry system, called kebon tatangkalan, in the changing agricultural landscape of the Upper Citarum Watershed, West Java, Indonesia. The main objectives of the study are to elucidate the structural patterns, multidimensional functions, and dynamics of this multi-layered agroforest. The study has identified 12 groups of different plant assemblages indicating that this type of agroforest contributes considerably to the heterogeneity of the agricultural landscape in the study area. Multivariate analysis suggests that elevation and slope are the biophysical factors that correlate most significantly with the distribution of plant species in kebon tatangkalan. The presence of this man-made vegetation is currently declining from the landscape due to population growth and rapid regional economic development. Serious effort to revitalize this traditional agroforest is needed to prevent its disappearance. Introduction of highly productive species and establishment of integrated policies in regional land-use planning and management are measures that should be taken into account in preserving this traditional agroforestry system. 相似文献
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Zerihun Nigussie Atsushi Tsunekawa Nigussie Haregeweyn Enyew Adgo Makoto Nohmi Mitsuru Tsubo Dagnachew Aklog Derege Tsegaye Meshesha Steffen Abele 《Small-Scale Forestry》2017,16(2):219-233
The development of woodlots as an additional source of livelihood and as a land management option for small-scale farmers is a challenging issue in the cereal-based subsistence farming systems of north-western Ethiopia. There is a need to understand why and which factors determine the decisions of small-scale farmers to grow short-rotation woodlots on their land. Data used in this study were collected from a survey of 200 randomly selected households in the region. A Tobit regression model was used to determine predictor variables for farmers’ decisions to allocate land to planting Acacia decurrens (J.C. Wendl.) Willd. and at what density trees are planted on the respective plots. The most important motivations for planting A. decurrens were income, soil fertility management, and soil and water conservation. Having a male head of household, long distance to markets and plots being on marginal land, among other factors, increased the allocation of land to A. decurrens woodlots. Having a male head of household, access to credit and plots being on marginal land, among other factors, increased tree planting density. Age had a negative effect on both allocation of land to woodlots and tree density, whereas farm size had an inverted U-shaped relationship with both decisions. These results suggest that wider expansion of A. decurrens-based plantation systems could be achieved through improving extension, credit access and road infrastructure to connect small-scale farmers to markets and finance. 相似文献
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Nigussie Haregeweyn Bekure Melesse Atsushi Tsunekawa Mitsuru Tsubo Derege Meshesha Bedru Babulo Balana 《Journal of Soils and Sediments》2012,12(2):291-305
Purpose
The Angereb dam in northwestern Ethiopia was commissioned in 1997 to serve as a domestic water supply for 25 years. However, its sustainability is being threatened by rapid sedimentation. The overall objective of this study was to understand reservoir sedimentation in this tropical highland watershed and to propose its mitigating strategies that would contribute to the improved planning and management of reservoirs in similar regions. 相似文献4.
Mekuriaw Shigdaf Tsunekawa Atsushi Ichinohe Toshiyoshi Tegegne Firew Haregeweyn Nigussie Nobuyuki Kobayashi Tassew Asaminew Mekuriaw Yeshambel Walie Misganaw Tsubo Mitsuru Okuro Toshiya 《Tropical animal health and production》2020,52(3):1287-1298
Tropical Animal Health and Production - Browse species are important sources of forage for livestock in Ethiopia, especially during the dry season, when the quality and quantity of green herbage is... 相似文献
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The Central Rift Valley (CRV) is one of the most environmentally vulnerable areas of Ethiopia. Most of the lowland in the CRV is arid or semiarid, and droughts occur frequently. We studied the dynamics of land use and cover and land degradation by analyzing Landsat data from 1973, 1985, and 2006 using Geographic Information Systems and remote sensing techniques. The analysis revealed that in the last 30 years, water bodies, forest, and woodland decreased by 15·3, 66·3, and 69·2 per cent, respectively; intensive cultivation, mixed cultivation/woodland, and degraded land increased by 34·5, 79·7, and 200·7 per cent. The major causes of land use and cover change (LUCC) and land degradation in the area were population and livestock growth in regions of limited resources, unsustainable farming techniques, the Ethiopian land tenure system and poverty. Lake level and area decline, and accelerated land degradation are the major environmental impacts of LUCC observed in the CRV. The environmental and socio‐economic consequences of LUCC and land degradation are far‐reaching. As a result of the expansion of land degradation over time, agricultural productivity has decreased and worsened food insecurity (shortages) and poverty in the Ethiopian CRV. In addition, if current trends in LUCC continue, Lake Abiyata will dry up by 2021. A detailed study of the degradation amount in relation to soil erosion, sediment yield to the lakes and catchment characteristics should be made using adaptable models; so as to guide the implementation of comprehensive and sustainable land use management by giving more attention to erosion prone areas. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
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Tenma Hinako Tsunekawa Koki Fujiyoshi Riho Takai Hajime Hirose Masae Masai Nanami Sumi Kosuke Takihana Yuta Yanagisawa Sogen Tsuchida Kota Ohara Kenichi Jo Toshiaki Takagi Masaki Ota Akiko Iwata Hiroyoshi Yaoi Yuichi Minamoto Toshifumi 《Fisheries Science》2021,87(3):321-330
Outbreaks of bacterial cold-water disease (BCWD), caused by Flavobacterium psychrophilum, are widespread in Japan, especially among ayu Plecoglossus altivelis. There are few investigations of F. psychrophilum in river water, and its seasonal distribution has not been clarified. We aimed to identify the spatiotemporal dynamics of F. psychrophilum and ayu to provide information that is useful for establishing a countermeasure for BCWD. Quantitative analysis of environmental DNA (eDNA) was used to clarify the year-round dynamics of ayu and F. psychrophilum. We sampled river water from the Nagara and Ibi rivers in Japan, and conducted monthly water sampling and eDNA quantification. Changes in the eDNA concentration of ayu were consistent with the known life histories of the fish. There was a strong negative correlation between the eDNA concentration of F. psychrophilum and water temperature, suggesting a strong dependence of F. psychrophilum dynamics in the river on water temperature. Furthermore, relatively high eDNA concentrations were recorded for both organisms in early summer and fall, suggesting that ayu is infected with F. psychrophilum during these seasons when experiencing up- and downmigration, respectively.
相似文献8.
Xiangwei Han Atsushi Tsunekawa Mitsuru Tsubo Shiqing Li 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(2):112-121
Abstract The fragile ecosystem of China's Loess Plateau is being exposed to increasing atmospheric nitrogen deposition but little information about the response of the region's natural vegetation is currently available. We studied the responses of aboveground biomass (AGB) to simulated nitrogen deposition in a field experiment conducted on natural grassland on sunny and shady slopes. Three levels of simulated nitrogen deposition were applied, and two treatments with phosphorus were included to test for secondary phosphorus limitation. For the same level of nitrogen deposition, grass generally grew better on the shady slope than on the sunny slope. Compared to a control treatment with no additional nitrogen, we found: (1) the 2.5 g N m?2 yr?1 treatment significantly increased biomass only on the sunny slope; (2) the total AGB increased significantly in the 5 g N m?2 yr?1 treatment on both the shady slope (by 31%) and the sunny slope (by 25%); and (3) for 10 g N m?2 yr?1, AGB was also significantly increased, however, phosphorus limitation became more apparent, and soil nitrate N levels increased significantly, suggesting nitrogen saturation and the potential for nitrate pollution. The AGB of Stipa bungeana (the dominant grass) was significantly increased by nitrogen, but not by phosphorus. The biomass of the second dominant species Lespedeza davurica Schindl., was not affected by increased nitrogen but addition of phosphorus had some positive impact. Therefore, nitrogen deposition was proven to have effects on plant growth in our study area on the Loess Plateau of China, but high level of nitrogen deposition would result in P limitation. Furthermore, increasing nitrogen deposition is likely to induce diversity change. 相似文献
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Shigdaf Mekuriaw Firew Tegegne Atsushi Tsunekawa Toshiyoshi Ichinohe 《Tropical animal health and production》2018,50(5):965-972
The objective of this experiment was to determine effects of substituting concentrate mixture (CM) with water hyacinth (Eichhornia crassipes) leaves (WHL) at different inclusion levels of feed and nutrient intake, digestibility, and growth performance of Washera sheep. Twenty yearlings intact male sheep with initial body weight of 24.1?±?1.68 kg (mean?±?SD) were used in both 90 days of feeding and 7 days of digestibility trials. The experimental animals were arranged into four blocks of five animals based on their initial body weight. The dietary treatments used in the experiment were 100% concentrate mix (0WHL-T1), 50% WHL and 50% CM (50WHL–T2), 75% WHL and 25% concentrate mix (75WHL-T3), and 100% WHL (100WHL-T4). Rice straw was given ad libitum. The crude protein (CP) content of water hyacinth leaf is 14.4%. Dry matter digestibility was greater (p?<?0.001) for 0WHL and 50WHL followed by 75WHL. The average daily weight gain was higher for 100% concentrate mix followed by 50 and 75% water hyacinth leave supplemented sheep. Therefore, wilted water hyacinth leave can safely substitute concentrate mix up to 75% and result in the optimum growth of Washera sheep from the feeding regime employed in this study. 相似文献