ABSTRACT
This chapter is concerned mainly with ecological adaptation and nutrient requirements of some Stylosanthes species that are considered promising for tropical pastures. Stylosanthes contains approximately 39 species which are widely distributed within the latitudes 40 °N and 40° S. This broad zone includes different climatic regions such as the humid tropics, seasonal rainforests, seasonal rain subtropics, piedmonts, savannas, deciduous forests and dry tropics. However, most Stylosanthes species are distributed in seasonal tropical and subtropical environments. In general, determination of minerals that are deficient or toxic for leguminous pastures can be made by soil analysis, plant tissue analysis, and by observing foliar symptoms of mineral disorders. Many tropical forage legumes have been identified as tolerant to acid soil constraints, and many of these have their center of origin in acid soil regions. This suggests that adaptation to soil constraints is part of the evolutionary process.
