The dynamics of deforestation in the Brazilian Amazon are complex. A growing debate considers the extent to which deforestation is a result of the expansion of the Brazilian soy industry. Most recent analyses suggest that deforestation is driven by the expansion of cattle ranching, rather than soy. Soy seems to be replacing previously deforested land and/or land previously under pasture.

Tropical savannas constitute one of the most predominant ecosystems in South America with an overall extension of almost 250 millions ha. The role that these grasslands play over the environment is a key factor to understand its functioning and the response to changes induced by humankind.

Describes the geology, relief, climate, major soil types, vegetation zones and land use patterns of the subhumid zone of Nigeria. Presents results of studies on natural forage productivity & composition and forage production constraints.

Drought stress was imposed on 2 cassava cv. (M Col 22 and M Mex 59) at Santander de Quilichao (Colombia), by withholding rainfall from field plots (plastic covers were placed over the soil surface) for 10 wk, commencing when crops were 12 wk old. The plants were then allowed to recuperate until the expt was terminated at 10 mo. Harvests were taken at intervals through the growth cycle and were supplemented with measurements of fine root distribution, leaf production and senescence, soil and plant water status, and stomatal response. As a result of the stress, the late-developing cv.