Evaluation on Agro-forestry System in Salt Affected and Non-salt Affected Areas

Abstract

Low economical return is the main constraint that makes farmers not grow more trees in salt affected areas. So, the research interest was paid to the applicable agro-forestry system combining advantages of trees and crops for rehabilitating salt affected soils and increasing local farmers’ income. Accordingly, existing agro-forestry systems in salt affected and non-salt affected areas in Khon Kaen province were investigated and evaluated. For the evaluation, the plant profile of each system was described in the investigation plot at 20m x 20m. In addition, Simpson and Shannon indexes were used to evaluate plant diversity of each investigation plot. Agro-forestry systems on salt affected areas could be categorized into five types: patch forests in farmlands, trees on paddy bunds, tree plantations associated with animal husbandry, home gardens, and trees in vegetable gardens. On the other hand, agro-forestry systems in non-salt affected areas could be categorized into seven types: trees in farm boundaries, trees on paddy bunds, tree plantations associated with animal husbandry, trees in home gardens, trees in vegetable gardens, trees in fruit orchards, and trees and aquaculture. The results of the two indexes revealed that the diversity of plants in agro-forestry systems in non-salt affected areas was higher than that in salt affected areas, except in the systems of tree plantations associated with animal husbandry and of trees in home gardens. It was considered that as the plant diversity in salt affected areas was lower than that in non-salt affected areas due to soil salinity; local people in salt affected areas kept higher plant diversity in the systems of tree plantations associated with animal husbandry and of trees in home gardens for their livelihoods.