The effects of land use on physical and chemical properties on tropical soils, Costa Rica.

摘要

It is well documented that changes in land use result in changes in soil properties. Costa Rica offers one of the most unique settings for studying soils and land use changes in the tropics. Once almost completely covered in forest, the country now bears the scars of colonization and development. However, Costa Rica is currently a working model of ecological protection and home to a successful eco-tourism industry. By setting aside large tracts of land for conservation, Costa Rica is a perfect location to compare changes in soil properties with changes in land use.;The soils at the Texas Christian University San Ramon Tropical Research Station in Costa Rica, a private facility dedicated to conservation and research, have never been studied. In order to understand how land use changes have affected them, soil quality analyses were conducted. Soil pits in primary growth forest, secondary growth forest, and deforested land once used for cattle grazing were be dug in order to carry out a suite of soil tests. The results indicate that while bulk density will increase following deforestation and cattle trampling, soil porosity will return with forest succession. Cation exchange capacity results on the other hand indicate that soil fertility increases with the introduction of grasses in deforested areas. Cations also show a return to pre-disturbance levels with forest succession, which in this case is lower than post-disturbance levels.