Improvement of low fertility soils (oxisols) for high productivity and sustainability of crop-livestock systems in tropical savannas of Colombia

♦ SAVANNAS OF COLOMBIA • The Latin America savannas occupy about 250 million ha (50% of the world’s savanna areas). • The Eastern Plains of Colombia cover an area of about 17 million hectares. • The Altillanura (flat savannas) occupies 3.5 million hectares. • The soils are mostly acid, with high aluminum saturation, dominated by kaolinite (1:1), have very low cation exchange capacity and very low base saturation. ♦ MAJOR SOIL CONSTRAINTS FOR CROP PRODUCTION For agricultural production these soils have the following limitations: • Are very shallow, A horizon is of 10 to 20 cm thickness • Have low rates of water infiltration (Photo 1) • Are susceptible to the erosion and prone to surface sealing (Photo 2) • They are hard and not easily penetrated by roots • Have low aeration capacity • Are very infertile