A. Maintains or increases site productivity through nutrient recycling and soil protection, at low capital and labour costs
B. Increase the value of output on a given area of land through spatial or inter temporal intercropping of tree and other species
C. Both (a) & (b)
D. None of these
The correct answer to the question: "The principal of positive economic features and the underlying hypotheses about agroforestry are:" is "Both (a) & (b) ".