Comparison of soil properties of native forests, Pinus patula plantations and adjacent pastures in the Andean highlands of southern Ecuador: land use history or recent vegetation effects?
Article first published online: 31 JUL 2009
© 2009 The Authors. Journal compilation © 2009 British Society of Soil Science
Soil Use and Management
Volume 25, Issue 4, pages 427–433, December 2009
How to Cite
Chacón, G., Gagnon, D. and Paré, D. (2009), Comparison of soil properties of native forests, Pinus patula plantations and adjacent pastures in the Andean highlands of southern Ecuador: land use history or recent vegetation effects?. Soil Use and Management, 25: 427–433. doi: 10.1111/j.1475-2743.2009.00233.x
- Issue published online: 19 NOV 2009
- Article first published online: 31 JUL 2009
- Received October 2007; accepted after revision June 2009
- Ecuadorian Andes;
- volcanic soils;
- exotic tree plantations;
- land use impacts;
- historical patterns
In the high Andes of Ecuador scarcity of farmland has led to accelerated deforestation, in particular over the last 40 years. Soil mis-management has caused the rapid decline of soil fertility and most farmland has been irreversibly transformed into grassland or tree plantations. The present study assessed whether pastures and particularly pine plantations were associated with less soil nutrients. The soils from six sites each of native forests and Pinus patula plantations, and their adjacent pastures were sampled in a geographically large area in the Paute watershed, south Ecuador. Soil analyses showed statistically significant differences for soil cations and effective cation exchange capacity (ECEC) only. ECEC was highest in soils from native forests and their adjacent pastures (6.4 cmol/kg) compared to pine plantations and their pastures (4.2 cmol/kg). Mean soil organic matter and pH were similar in native forests/pastures (39% SOM; pH 5.4) and in plantations/pastures (40% SOM; pH 5). As pasture soils had ECEC concentrations statistically similar to those of their adjacent forest or plantation, they do not form a single homogeneous land use type based on soil nutrients. Therefore, this study cannot conclude that the presence of pines alone has caused soil degradation, but instead that the soil at the site was already degraded before pines were planted. This study proposes the scenario that pine plantations are established in pastures as a last resort, when the soils are already strongly degraded, and more profitable land uses are not available. Farmers are reluctant to use fertile land for tree plantations, and only the planting of well-known species, such as pines, is officially encouraged.