EFFECTS OF TREE LEAF LITTER ON SOIL SOLUTION PHOSPHORUS, NUTRIENT UPTAKE AND YIELD OF RICE ON ROI - ET SOIL

Abstract

Nutrient cycling and organic matter contribution through litter fall from trees are main benefits of trees in agroforestry for sustainable land use. The system has been adopted by farmers in the Northeast of Thailand since early agricultural development more than a hundred years ago. However, short-term effects of litter fall on agricultural crop production is still unclear. A glasshouse experiment was conducted to elucidate shortterm roles of leaf litter from raintree (Samanea saman), mango (Mangifera indica), Dipterocarpus tuberculatus, Irvingia malayana and Eucalyptus camaldulesis on availability of nutrients, nutrient uptake, growth of rice variety RD 23 and yields on Roi-et soil. The results indicated that all leaf litters could promote nutrient availability, but unproportionately to their nutrient contents. Eventhough they could similarly improve rice yield, yield components of RD 23 rice vary according to, probably, both of their nutrient contents and contribution to nutrient availability in the soil. The difference might be induced by their biochemical properties. The findings would lead to implications on nutrient management of agroforestry system for correction, or awareness of possibility, of nutrient imbalance. Besides, it was clear that nutrient contents in litter fall are unreliable on prediction of their benefits on soil fertility and productivity in agroforestry system.