Tropical shifting cultivation

Negligible quantities of wood may be removed when tropical forests are cut for shifting cultivation or pasture conversion. In contrast to the temperate coniferous forests of the Northwest USA, only small quantities of wood are usually exported as a result of timber operations in tropical evergreen forests. In... 

Much of the surface soil erosion and hence nutrient loss occurs when deforestation and biomass burning removes and/or consumes the organic materials that protect the soil surface. Significant losses may occur by dry ravel or overland water erosion associated with precipitation events. Under a shifting cultivation system in a tropical deciduous forest ecosystem in Mexico, Maass et al. 61) reported first year losses of N, P, K, and Ca were 187, 27, 31, and 378 kg ha" respectively. In contrast, losses in adjacent undisturbed forests were less than 0.1 kg ha for all nutrients except Ca (losses were 0.1-0.5 kg ha for Ca). 

Sanchez, P. A. 1976. "Soil management in shifting cultivation areas." In Properties and Management of soils in the tropic, ed. P. A. Sanchez (John Wiley Sons, New York), pp. 347-412. 

Shang, C., and H. Tiessen. 1997. Organic matter lability In a tropical Oxisol evidence from shifting cultivation, chemical oxidation, particle size, density, and magnetic fractionations. Soil Science. 162 795-807. 

Douglas I (1996) The impact of land-use changes, especially logging, shifting cultivation, mining and urbanization on sediment yields in tropical Southeast... 

Shifting cultivation was primitive man s method of eking out an existence on many of the tropical areas, and that practice still prevails in many regions. What is meant by shifting cultivation It varies from place to place but the principles involved are similar... 

The system of shifting cultivation, practiced in many parts of the Tropics, prevents erosion in much the same manner as do forests, except that much of the litter is eliminated by burning. The main protection is from the trees and bushes that occupy the area more than 90% of the time. Under tropical conditions vegetation grows so rapidly that no cleared area remains barren for more than a few days or weeks. 

In this section we derive some rough estimates of the quantities of biomass that are burned in the tropics through various activities, such as forest clearing for permanent use for agriculture and ranching, shifting cultivation, removal of dry... 

Andriesse, J. P. Momtorir ject of Nutrient Cycling in Soils Usedfin Shifting Cultivation under Various Climatic Conations in Asia. Knal Report Part I Royal Tropical Institute Amsterdam, The Netherlands, 1987 141 p. 

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