uncontrollable weed growth. Thus there is a great need 

 to define which lands should and should not be 

 developed, and to develop crop and livestock production 

 technology well suited to the generally difficult 

 stresses common to these areas. 



There is little doubt of the need to increase 

 agricultural production on existing tropical lands. 

 Although it is questionable whether certain tropical 

 soils should be cleared and developed for agriculture 

 or preserved as forest or conservation lands, these 

 questions are frequently moot because decisions to 

 develop are made by land-hungry farmers or worried 

 governments without regard to land suitability or 

 potential. 



FAO has estimated that from 1979 to 1985 over 10 

 million hectares per year will be newly developed 

 worldwide, with development proceeding at a faster rate 

 thereafter, mostly in the humid tropics. Unless 

 carefully planned and orchestrated, this process, which 

 will involve major population shifts, may well lead to 

 disappointment or even disaster. 



Some tropical soils are not suited for cultivation 

 with the production systems now available. Many are 

 highly weathered, arid, low in fertility, and suffer 

 from aluminum and manganese toxicity and phosphorus 

 deficiency. Their generally low capacity to hold water 

 makes them subject to frequent droughts. When these 

 soils are cleared mechanically, nutrient deficiencies 

 can be aggravated and erosion hazards are created. 

 Notwithstanding these problems, it has been 

 demonstrated experimentally that good production is 

 possible, perhaps even exceeding that in similar soils 

 in the United States because of the opportunity for 

 more than one crop per year. 



with current technology, it is possible to devise 

 successful management packages for sustained 

 productivity for some tropical soils. There are, 

 however, numerous opportunities for strengthening the 

 knowledge base and developing better, more appropriate, 

 and less costly techniques for managing these soils. A 

 partial list would include: plant breeding for 

 aluminum or drought tolerance, evaluation of sources of 

 rock phosphate to make phosphorus more readily 

 available at lower cost, site-specific recommendations 

 for minor element fertilization, microbiological 

 amendments to fix nitrogen or extract phosphorus, and 

 better placement of lime and/or fertilizers to improve 

 response. Fertilizer storage, handling, and 

 application techniques must be improved, and various 

 cropping sequences evaluated to optimize total 

 production. Experimentation is needed with 

 combinations and sequences of new and old plants, 

 soils, water use, cultivation practices, and soil 



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