EASTERN COLOMBIA — CRIST AND GUHL V 395 



and if animal fertilizer, phosphates, nitrates, lime, and trace elements 

 are used wherever necessary. 



Usually just beyond the front ranges or foothills there is a zone 

 of predominantly light-textured alluvial soils, with occasional belts 

 or strips of heavy-textured soils, and the vegetation grades from low 

 rain forest to bunch grass interspersed with scattered brush and small 

 trees. These soils are generally of dark color to a depth of a foot or 

 more, and the water table seldom falls to more than 3 feet below the 

 surface even in the dry season ; they are cleared and prepared for cul- 

 tivation with relative ease. With good crop adaptation and manage- 

 ment these moderately fertile soils would be very productive. At 

 present, yuca, corn, and plantains are generally very successful on the 

 better types of this soil. Much of the rice cultivation around Villavi- 

 cencio is on the deep soils of this type, and any substantial expansion 

 of rice production will probably be brought about through mechani- 

 zation and the introduction of chemical fertilizer on this same type. 

 Peanuts would probably do very well on the better drained soils of 

 this type. Those phases of this soil type that are light in texture and 

 poorly drained have been largely used for pasture on a rather empirical 

 basis. If attention were paid to improving both pastures and live- 

 stock, production per unit area would surely be greatly increased. 

 Sugarcane is grown, mainly for local use. Yields are fair and replant- 

 ing is usually done after three or four years of ratooning. The use of 

 a soil-building crop, adjusted to this climate, in a crop rotation would 

 certainly increase productivity of many of the crops now being grown 

 on these soils. Between Villavicencio and Puerto Lopez the extensive 

 treeless sectors of claypan soils, underlain by an impermeable layer, 

 would seem to be ideal for the large-scale production of paddy rice if 

 abundant chemical fertilizer were used. 



The deep, well-drained, medium-textured, fertile, alluvial soils in 

 heavy rain forest are well adapted to the production of plantains, 

 corn, yuca, vegetables, citrus fruits, and improved pasture for cattle. 

 These soils of sandy loam have a pH content of 6.0 to 7.0 to a depth 

 of 3 feet or so. At present, one of the limiting factors in developing 

 this kind of land for large-scale commercial agriculture would be the 

 expense involved in clearing. However, the labor and time of the 

 pioneer with a machete are his own, so he does not count the cost. 

 With reasonably good soil management this kind of land is extremely 

 favorable for cultivated crops for a period of years ; even without the 

 use of fertilizers it will not deteriorate rapidly. 



The soft shales and limestones in the vicinity of Caqueza, on the 

 Bogota- Villavicencio highway, make an excellent soil, on which live 

 in dispersed settlements a dense population. This area was originally 

 peopled by settlers from mountain slopes higher up and still receives 

 recruits from there in spite of the fact that this sector in turn, owing 



