摘要：South American countries still possess considerable land reserves for agricultural development. Huge areas of virgin lands and natural pastures have been converted to agricultural crops and suffer increasing pressure. Growing demand for food in the world and attractiveness for capital investment drive this colonization further deep into the regions that cannot be converted to commercial agriculture without serious negative environmental consequences. Agricultural development in these areas neither can be considered economically sustainable, as high production costs sometimes surpass revenues from the harvest. Most of the recently colonized regions in South America are those under savanna landscapes, where low nutrient availability in the soil restricts agricultural use. Understanding the problem of sustainability of agricultural development in savannas is impossible without geographical analysis. Spatial approach at different scales enables precise vision of weak points of recently established agricultural systems and helps to draw solutions to diminish their instability. The objective of this paper was to develop, with GIS tools, a geographically based analysis that could identify the spatial variation and magnitude of soil potassium, potassium uptake, potassium fertilization, and potassium balance in order to improve the efficiency of mineral fertilizers use.
关键词：sustainable development of agriculture;mineral fertilizers;savannas;cerrado;South America;Brazil
