• 제목/요약/키워드: Arid-Areas

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Crop-Animal Production Systems in Tropical Regions - Review -

  • Devendra, C.
    • Asian-Australasian Journal of Animal Sciences
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    • 제13권2호
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    • pp.265-276
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    • 2000
  • Crop-animal systems which form the backbone of agriculture in the tropics are discussed with reference to their characteristics, economic importance of animals, genesis and types of crop-animal systems, relevance and potential importance, and priorities for research and development. These production systems are found across all agroecological zones: rain-fed temperate and highland systems, semi-arid and arid tropics, and sub-humid and humid tropics: the last four are priority areas in Asia. The potential importance of these systems in Asia is reflected in their advantages, synergism and complimentarity, economic benefits and contribution to sustainability. Illustrative case studies are cited which are appropriate to the two broad types of mixed farming systems: systems combining animals and annual cropping, and systems combining animals with perennial cropping with reference to Indonesia, Philippines, Malaysia, Sri Lanka, China and Nigeria. Priorities for research and development should address more complete use of the animal genetic resources, intensive utilisation of the feed resources, development-oriented utilisation of research results, minimizing animal diseases, and implementation of appropriate institutional and policy issues.

한국의 식생에 있어서$C_3, C_4 $ 및 CAM 식물의 분류, 생산력 및 분포에 관한 연구 3. $C_3 와 C_4$ 형 식물의 식생분포와 종분포 (Studies on the Classification, Productivity, and Distribution of $C_3,;C_4 $ and CAM Plants in Vegetations of KoreaIII. The Distribution of $C_3 and C_4$Type Plants)

  • Chang, Nam-Kee;Sung-Kyu Lee
    • The Korean Journal of Ecology
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    • 제6권2호
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    • pp.128-141
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    • 1983
  • The districbution of $C_3; and; C_4$ type plants in Korea were studied. In the standpoint of photosynthetic types, plant distribution in Korea is classified as $C_3; and; C_4$ type plant zones. The forest destroyed by man interference, cultivating areas, and seashore areas are characterized by the dominant of $C_4$ type plants.(Figs. 2, 3, 4, 5) According to the results of this study, $C_3; and; C_4$ type plant distribution in Korea has a great relation to the habitat of plant vegetation (Table 1). The arid areas were in high proportion of C4 flora percenntages, while the well-developed woody forests or the vegetation of humid areas were in lower proportion(Fig.8).

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Native Hawaiian Collection Systems in Lava Tubes(Caves) and Fault Cracks: Puna - Ka'u Districts, Hawaii

  • Martin, James F.
    • 동굴
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    • 제4호
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    • pp.41-50
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    • 1996
  • The coastal plains of the Puna and Ka' u Districts of the island of Hawaii are a contradiction to the popular view that the island of Hawaii is a tropical rain forest or a vegetated landscape with abundant water sour This section of the island lies in the rain shadow of Mauna Loa a Kilauea Volcanoes and receives less than 30 inches of annual precipita When rain does come. it is in the form of sudden down pours. givi residents of the area little time to collect and conserve water. Due to porous nature of the rock. there is no standing surface water. In spite of these harsh climatic conditions. archeological evidence indic that an extensive agriculture complex existed not only along the coast. into the most remote parts of what is called the Ka'u Desert. Pass through these agricultural areas are historic and pre - historic t systems. These trail systems apparently played a significant suppor role for exchange between the ahupua's (classic land divisions of Haw and the geopolitical districts. The question arises as to how could vast agricultural complexes a heavy foot travel over miles of arid land exist without dependable wa sources\ulcorner While planting - pits and mounds were designed to make most efficient use of available water and conserve moisture(Carter 19 9). people involved in planting also needed potable water for surv Most publications and research papers dealing with the early population this area make only oblique reference to springs and wells which t populations depended upon. The Federal Cave Resource Protection Act(1988) has served as imprtus for the National Park Service to look closer at the lava tu caves and fault cracks within Hawaii Volcanoes National Park. P visitors to these underground areas found large volumes of standing wa in fault cracks. and abundant drip areas with the lava tubes. Re observes noted that in most cases. where the cracks and caves we located in the arid sections of the park. there has been extens modifiacation or utilization of these water sources by the early Hawaii and others. The variety of western containers used for collection indica that these water sources were used during historic times. William E described similar water sources in his narrative of his trip around island in 1823(Eills 1979), This report is directed at documenting recent observations and a stimulating further research into early Hawaiian water collection syst It also explores the implications that power and political influence of e chiefs in the arid portions of Hawaii could have been linked to the con of the water resources.

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Characteristics of a Radial Flux Type Slotless Brushless DC Motor for No Cogging Torque

  • Hong, Sun-Ki
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제4B권1호
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    • pp.20-23
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    • 2004
  • BLDCMs are widely used in many industries. In certain specialized areas, they need to have high efficiency, high power rate and produce a low volume of noise, etc. In this study, a new type of slotless BLDCM is proposed that has no cogging torque, low iron loss and low volume as compared to commonly used BLDCMs. With a high performance magnet and coreless compact winding structure similar to those employed in linear synchronous motors, motor volume is reduced. The proposed motor has been put been through various experiments arid has demonstrated acceptable results for industry applications.

Different Climate Regimes Over the Coastal Regions of the Eastern Antarctic Ice Sheet

  • Cunde, Xiao;Dahe, Qin;Zhongqin, Li;Jiawen, Ren;Allison, Ian
    • Ocean and Polar Research
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    • 제24권3호
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    • pp.227-236
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    • 2002
  • For ten firn cores, from both the eastern and the western side of Lambert Glacier basin (LGB), snow accumulation rate and isotopic temperature were measured far the recent 50 years. Results show that snow accumulation for five cores over the eastern side of LGB (GC30, GD03, GD15, DT001, and DT085) at Wilks Land and Princess Elizabeth Land increases, whereas it decreases at the western side (Core E, DML05, W200, LGB 16, and MGA) at Dronning Maud Land, Mizuho Plateau and Kamp Land. For the past decades, the increasing rate was $0.34-2.36kg\;m^{-2}a^{-1}$ at the eastern side and the decreasing rate was $-0.01\;-\;-2.36kg\;m^{-2}\;a^{-1}$ at the western side. Temperatures at the eastern LGB were also increased with the rate of $0.02%o\;a^{-l}$. At the western LGB it was difficult to see clear trends, which were confirmed by Instrumental temperature records at coastal stations. Although statistic analysis and modeling results display that both surface temperature and accumulation rate has increased trends in Antarctic ice sheet during 1950-2000, the regional distributions were much more different for different geographic areas. We believe that ice-core records at Wilks Land and Princess Elizabeth Land reflect the real variations of SST and moisture change in the southern India Ocean. For the Kamp Land and Dronning Maud Land, however circulation pattern was different, by which the climate was more complicated. The International Trans-Antarctic Scientific Expedition (ITASE) aimed to reveal an overall spatial pattern of climate change over Antarctic ice sheet for the past 200 years. This study points the importance of continental to regional circulation to annual-decadal scale climate change in Antarctica.

Establishment of the Chickpea Wilt Pathogen Fusarium oxysporum f. sp. ciceris in the Soil through Seed Transmission

  • Pande S.;Rao, J. Narayana;Sharma M.
    • The Plant Pathology Journal
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    • 제23권1호
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    • pp.3-6
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    • 2007
  • Chickpea wilt caused by Fusarium oxysporum f. sp. ciceris(FOC) is the most destructive disease in India. It is seed-borne as well as soil-borne pathogen. The role of seed-borne FOC in introducing and establishing wilt in FOC free soils is unknown. Using seeds of FOC infected chickpea cultivar K 850, we provided an evidence of establishing wilt disease in the FOC free soils within three crop cycles or seasons. In the first cycle, typical wilt symptoms were observed in 24 pots in 41 days after sowing. These 24 pots were used for second and third cycles without changing the soil. These 24 pots were sown with seeds collected from healthy plants of a susceptible cultivar JG 62, one seed per pot and development of wilt symptom was recorded. Wilt symptoms appeared in all the pots 26 days after sowing in second cycle and in 16 days after sowing in third cycle. On selective medium, all of the wilted plants yielded FOC in all the three cycles indicating that the mortality was due to wilt. FOC propagules on selective medium were 172, 1197, and 2280 $g^{-1}$ soil at the end of the first, second, and third cycles, respectively. These studies indicated that Fusarium wilt of chickpea is seed-borne and seeds harvested from wilted plants when mixed with healthy seeds can carry the wilt fungus to new areas and can establish the disease in the soil to economic threshold levels within three seasons.

VALUE OF BARLEY GRAIN AND COTTONSEED CAKE AS SUPPLEMENTS TO FOURWING SALTBUSH, AND THE LIVE WEIGHT GAINS AND WATER CONSUMPTION OF SHEEP FED THE DIETS

  • Rehman, Atiq-ur;Thompson, E.F.;Rafique, S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제9권6호
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    • pp.647-650
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    • 1996
  • Fifteen sheep were used in a trial which compared the feeding value of whole barley gain and cottonseed cake as supplements to a basal diet of leaves of fourwing saltbush (Atriplex canescens). Diet SB contained 700 g (air-dry matter) of saltbush alone, diet SB + BG contained 700 g SB with 400 g whole barley grain and diet SB + CS contained 700 g SB with 400 g cottonseed cake. The digestibility of the dry matter of diets SB (69%) and SB + CS (70%) were lower (p < 0.001) than of diet SB + BG (76%). Sheep offered SB alone daily lost 80g whereas those fed the other diets gained 11 g (SB + CS) or 17 g (SB + BG) per day. Daily water consumption of the sheep offered the three diets was similar (p > 0.05), but their water consumption was higher (p < 0.001) than that of sheep offered daily 700 g wheat straw and 200 g barley grain. The results indicate that, at the levels of feeding used, barley grain and cottonseed cake had similar value as supplements to fourwing saltbush harvested in summer. The addition of the supplement allowed the sheep to gain some live weight. However, the presence of saltbush leaves in the diet resulted in higher water intakes by the sheep.

Characterization of Sclerospora graminicola Isolates from Pearl Millet for Virulence and Genetic Diversity

  • Pushpavathi B.;Thakur R. P.;Rao K. Chandrashekara;Rao V. P.
    • The Plant Pathology Journal
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    • 제22권1호
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    • pp.28-35
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    • 2006
  • Virulence and genetic diversity were studied using 21 isolates of Sclerospora graminicola, the pearl millet downy mildew pathogen collected from major pearl millet growing areas of India. Variability for virulence was determined by inoculating a set of 10 differential hosts with the S. graminicola isolates in a greenhouse. The isolates varied for latent period (6.4 to 11 days), disease incidence (0 to $98\%$), virulence index (0 to 18.7) and oospore-production potential (1 to 4). Among the 21 isolates, Sg 139 (Rajasthan) was the most virulent and Sg 110 (Tamil Nadu) the least virulent. Based on virulence index (disease incidence$\time$slatent $period^{-1}$), the 21 isolates were classified into eight virulence groups. Genetic diversity among isolates was studied using AFLP markers. Based on similarity index of banding pattern, the 21 isolates were clustered into eight genotypic groups. The AFLP groupings, however, did not match with that of the virulence groupings, and these two were found independent. The isolate Sg 139 that remained distinct in both pathogenic and genetic groupings indicated its highly virulent nature. Implications of these results in downy mildew resistance breeding are discussed.

Potential soil loss evaluation using the RUSLE/RUSLE-runoff models in Wadi Saida watershed (N-W Algeria)

  • Cherif, Kessar;Yahia, Nasrallah;Bilal, Bilssag
    • Advances in environmental research
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    • 제9권4호
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    • pp.251-273
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    • 2020
  • Soil degradation has become a major worldwide environmental problem, particularly in arid and semi-arid climate zones due to irregular rainfall and the intensity of storms that frequently generate heavy flooding. The main objective of this study is the use of geographic information system and remote sensing techniques to quantify and to map the soil losses in the Wadi Saida watershed (624 ㎢) through the revised universal soil loss equation model and a proposed model based on the surface erosive runoff. The results Analysis revealed that the Wadi Saida watershed showed moderate to moderately high soil loss, between 0 and 1000 t/㎢/year. In the northern part of the basin in the region of Sidi Boubkeur and the mountains of Daia; which are characterized by steep slopes, values can reach up to 3000 t/㎢/year. The two models in comparison showed a good correlation with R = 0.95 and RMSE = 0.43; the use of the erosive surface runoff parameter is effective to estimate the rate of soil loss in the watersheds. The problem of soil erosion requires serious interventions, particularly in basins with disturbances and aggressive climatic parameters. Good agricultural practices and forest preservation areas play an important role in soil conservation.

Effects of Water Restriction on the Growth Performance, Carcass Characteristics and Organ Weights of Naked Neck and Ovambo Chickens of Southern Africa

  • Chikumba, N.;Chimonyo, M.
    • Asian-Australasian Journal of Animal Sciences
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    • 제27권7호
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    • pp.974-980
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    • 2014
  • In semi-arid areas of Southern Africa, dehydration can compromise the performance and welfare of local chickens, particularly during the growing period when confinement is curtailed and birds are left to scavenge for feed and water. The effect of water restriction on the growth performance was compared in Naked Neck (NNK) and Ovambo (OVB) chickens that are predominant in Southern Africa. A total of 54 eight-wk-old pullets each of NNK and OVB chickens with an initial average weight of $641{\pm}10g/bird$ were randomly assigned to three water intake treatments, each having six birds for 8 wk. The water restriction treatments were ad libitum, 70% of ad libitum and 40% of ad libitum intake. Nine experimental pens with a floor space of $3.3m^2$ per strain were used. The pens were housed in an open-sided house with cement floor deep littered with a 20 cm layer of untreated wood shavings. Feed was provided ad libitum. Average daily water intake (ADWI), BW at 16 weeks of age (FBW), ADG, ADFI, feed conversion ratio (FCR) and water to feed ratios (WFR) were determined. Ovambo chickens had superior (p<0.05) FBW, ADG and ADWI than NNK chickens. Body weight of birds at 16 weeks of age, ADG, ADFI, ADWI, and WFR declined progressively (p<0.05) with increasing severity of water restriction while FCR values increased (p<0.05) as the severity of water restriction increased. Naked Neck chickens had better FCR at the 40% of ad libitum water intake level than Ovambo chickens. The dressing percentage per bird was higher in water restricted birds than those on ad libitum water consumption, irrespective of strain. Heart weight was significantly lower in birds on 40% of ad libitum water intake than those on ad libitum and 70% of ad libitum water intake, respectively. In conclusion, NNK chickens performed better than OVB chickens under conditions of water restriction and would be ideal to raise for meat and egg production in locations where water shortages are a major challenge.