Role of tree stands in soil fertility restoration of degraded land of east coastal tract in Tamilnadu

摘要

Studies were undertaken in ten and twenty year old pure stands of Acacia auriculiformis, along with twenty year old mixed stand dominted by Enterolobium cyclocarpum raised in the degraded lands of coastal tract in Auroville, South Arcot District, Tamilnadu. The efficacy of these plantations in restoring fertility of the degraded site was compared as a prelude to expanding the afforestation efforts. Litter fall and precipitation of components jointly added major nutrient elements to soil, viz., N, P, K, Ca and Mg amounting to 156-277, 2.5-9.7, 82-102, 56-74 and 18-39 kg/ha/year, respectively. On the contrary, for the barren soil, the only source of nutrient was incident rainfall with 4 kg of N, 5 Kg of K, 11 Kg of Ca and 5 Kg of Mg per ha per year.In the precipitation components the concentration of P was trace. Considering the semi-arid condition of the study sites, fertility enhancement via litterfall and precipitation components under tree stands is gratifying, compared to open land wherein the only source was precipitation with least concentration of various nutrients.