PRIORITIZATION OF TREE SPECIES BASED ON GREEN LEAF NUTRIENT LEACHING: AN APPROACH FOR SUSTAINABLE AGROFORESTRY PRACTICES

Abstract

Nutrients leaching from litter (leaves, bark, needles and twigs) have a major contribution to the supply and cycling of nutrients to crops. Among the litter parts, leaves are the main and quick source of organic matter to the soil whereas, green leaves return more nutrients than other forms of leaves. The return potentiality of K, P and N through leaching from green leaves of the major agroforest tree species: Zizyphus jujuba, Melia azadirachta, Albizia saman, Dalbergia sissoo and Azadirachta indica are presented on this study. Green leaves of the studied tree species were collected and then leached in water (deionized). Nutrient release through a leaching experiment was conducted for 192 hours. Percentage (%) of green leaf mass loss and Total Dissolved Solid with Electrical Conductivity of the collected leaching water showed a curvilinear relationship with time significantly (p < 0.05). NH4, PO4 and K concentration of the collected leaching water of the individual cropland agroforest tree species was significantly (p < 0.05) increased for 72 hours in the initial stage but at the later stage remained constant. Individual tree species showed the same nutrient release (K > NH4 > PO4) pattern. The highest concentration of 5121 ppm NH4 and potassium (13357 ppm) was found for Melia azadirachta and the lowest concentration of 1424 ppm NH4 and potassium (4410 ppm) was observed for Albizia saman. Results from the study highlighted that M. azadirachta was the best among the studied tree species in terms of nutrient return followed by A. indica and D. sissoo.