Relationship of soil characteristics to vegetation successions on a sequence of degraded and rehabilitated soils in Honduras

Land degradation and rehabilitation on hillsides are some of the most urgen t natural resources management challenges in tropical and subtropical agric ulture. Shifting cultivation is widespread in developing countries and afte r losing soil fertility the land is abandoned and a succession of different natural vegetation stages can be observed on the degraded soil. These succ essions can be used as autochthonous indicators of the degree of soil degra dation as well as its recovery stage in the rehabilitation process. This st udy was carried out in the small La Lima watershed in Central Honduras on a bandoned degraded hillside soils belonging to the Entisols order. Vegetatio n stages were classified by farmers and basic physical and chemical soil pa rameters were measured. Factor analysis of the data enabled the identificat ion of three soil fertility indices, an Index of Soil Acidity and Aluminium Toxicity, an Index of Soil Protection and Macronutrient Availability, and an Index of Organic Reserve and Nutrient Retention, which along with other soil characteristics changed significantly with vegetation stages. Cause-ef fect relations between the fertility indices and other soil parameters were established and tested. Cluster analysis was used to group study plots by soil characteristics with similar vegetation associations, and the farmers' classification of vegetation stages were shown to be reasonable autochthon ous indicators of soil degradation and rehabilitation. It was concluded tha t factors influencing organic matter content, nutrient supply, soil vegetat ion cover and soil compaction are critical for soil degradation and they mu st be managed appropriately for soil rehabilitation. (C) 1999 Elsevier Scie nce B.V. All rights reserved.