0 one of the two imaginary lines around the earth at approximately 23.5 degrees north and 23.5 degrees south of the equator -- 回归线
In some highly fragile environments, found most often in the tropics, soils may be highly vulnerable to rapid and irreversible degradation with inappropriate agricultural practices.
Although the focus of this proposition is the developing world tropics, problems with agricultural development in semi-arid regions are not confined to the developing world.
Elsewhere, and especially in the semi-arid tropics where climate is much harsher, more ®ckle and more extreme, life has always been far tougher.
Genetic improvement of selected vegetables for the tropics and subtropics.
All a re below 200 m i n elevation, a nd temperatures a re typical of the lowland tropics.
Emerging paradigms of tree phenology in dry tropics.
Shading improved dry-season survival while competition for moisture had significant effects on seedling performance compared with tree seedlings in the humid tropics.
Successful establishment of seedlings in the dry tropics is dependent mainly upon moisture availability.
