نتایج جستجو برای: arid and humid tropics
تعداد نتایج: 16832179 فیلتر نتایج به سال:
Dioscorea cayenensis and Dioscorea rotundata are among the most important yam species for the humid and sub-humid tropics. We isolated nine polymorphic microsatellite markers using a microsatellite-enriched genomic library technique. The nine primer pairs were validated in 22 D. cayenensis accessions, and were tested for transferability in 26 D. rotundata accessions. The number of bands ranged ...
Agriculture is the human enterprise that is most vulnerable to climate change. Tropical agriculture, particularly subsistence agriculture is particularly vulnerable, as smallholder farmers do not have adequate resources to adapt to climate change. While agroforestry may play a significant role in mitigating the atmospheric accumulation of greenhouse gases (GHG), it also has a role to play in he...
Rainfall erosivity force as on important factor in soil erosion and sediment yield has been introduced in different indexes. The objective of this study was to determine suitable rainfall erosivity indices for two climates of semi-arid in Maravetape and very humid in Sangdeh, both in Khazar watershed, by correlation between rainfall erosivity indices and sediment outflow from erosion plots. F...
Cassava (Manihot esculenta, Crantz) is emerging as a dominant staple of primary or secondary importance in many developing countries of the humid and sub-humid tropics in Africa and elsewhere. Since it can withstand drought, it is sometimes a nutritionally strategic famine reserve crop in areas of unreliable rainfall. This paper reviews reasons for the spread of, and increasing interest in, cas...
Some plants are more able than others to grow on soils with low pH. This interesting ability was not well recognized until the past 20 years or so, and it still is not fully understood. Crop tolerance of low soil pH has become extremely important in the agricultural development of the humid tropics because so many of those soils have low pH (Kamprath and Foy 1985, Salinas and Sanchez 1981, Mara...
Analysis of stacked Permo-Pennsylvanian palaeosols from north-central Texas documents the influence of palaeolandscape position on pedogenesis in aggradational depositional settings. Palaeosols of the Eastern shelf of the Midland basin exhibit stratigraphic trends in the distribution of soil horizons, structure, rooting density, clay mineralogy and colour that record long-term changes in soil-f...
Global climate change has a significant effect on extreme environments and a profound influence on species survival. However, little is known of the genome-wide pattern of livestock adaptations to extreme environments over a short time frame following domestication. Sheep (Ovis aries) have become well adapted to a diverse range of agroecological zones, including certain extreme environments (e....
Alluvial fans develop at the base of drainages where feeder channels release their solid load (Blair and McPherson, 2009; Leeder et al., 1998; Harvey et al., 2005). A classic fan-shape forms where there is a well-defined topographic apex. Multiple feeder channels, however, often blur the fan-shape resulting in a merged bajada. Alluvial fans can be found in almost all terrestrial settings. These...
Chromolaena odorata L (Asteraceae) is a bad invasive plant, found in the humid tropics and sub-tropics worldwide. It is used against dysentery, diarrhea, malaria, wound healing, headache and toothache in traditional medicine. In the present study, we investigated the antibacterial activities of different leaves extracts of Chromolaena odorata L. (cyclohexane, dichloromethane, ethyl acetate and ...
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