02210naa a2200253 a 450000100080000000500110000800800410001902000220006010000190008224500990010126000090020030000160020952014100022565000200163565000230165565000270167865000260170565000170173165000280174865000270177665000090180370000170181277301270182919594052025-10-22       2013    bl uuuu     u00u1 u    #d  a978-0-8138-1989-11 aFAGERIA, N. K.  aWater- and nutrient-use efficiency in food production in South America.h[electronic resource]  c2013  ap. 275-296.  aIntroduction; Major soil groups in South America; Cropping systems in South America; Water-use efficiency; Nutrient uptake by crop plants; Nutrient-use efficiency in crop plants. Food production in sufficient amount and quality is essential to maintain the health of people and animals as well as world security. To achieve these objectives, it is necessary to increase yield of food crops per unit area as well as incorporate new agricultural lands in the cropping systems. In addition, food production can be increased with the adoption of multiple cropping systems. South America is a large continent comprising 13 countries and offers all these alternatives of producing food and fiber (Fageria & Baligar 2008). Globally, South America has the largest area of unused agricultural land. In addition, climatic conditions (precipitation and temperature) are favorable for crop production throughout the year. This may allow producing at least two crops per year with appropriate resource management without degrading the environment. For example, Brazil has 12% of the potable world water. Figure 16.1 shows the distribution of water in different regions of Brazil. Most of the Brazilian water is in the Amazon region (80%), and this region is densely populated (7%). Although South America has a vast water potential, the irrigated area in South America is less than 4% of the world total (Howell 2001).  aFood production  aWater conservation  aConservação da água  aDeficiência hídrica  aFertilizante  aProdução de alimentos  aRelação água-planta  aSolo1 aSTONE, L. F.  tIn: RENGEL, Z. (Ed.). Improving water and nutrient-use efficiency in food production systems. Ames: Wiley-Blackwell, 2013.