Tree Growth, Organic Carbon and Nutrient Content of Soil under Various Multipurpose Tree Species

摘要

The effect of pure stands of seven tree species was studied on soil organic carbon (OC) and macronutrient (N, P and K) content of soil in Punjab. Tree plantations of 13-year-old Eucalyptus tereticornis (eucalyptus), Azadiractita indica (neem), Melia azedaracti (dek), Dalbergia sissoo (shisham), Albizia lebbeck (siris), Leucaena leucoceptiala (subabul) and Acacia nilotica (kikar) spaced at 6 x 3 m and adjoining open (control) area were selected for this study. Depthwise (&-15,15-30, 30-45 and 45-60 cm) soil samples were taken randomly from each plantation as well as control and analysed for soil OC and available macronutrients (N, P and K). After 13 years of growth, eucalyptus, subabul and siris recorded higher diameter at breast height and height than the other tree species. The effects of litterfall addition were significantly higher in the surface layer (0-15 cm) than the lower soil depths. The soil OC and nutrient content decreased with increase in depth irrespective of the tree species. In thesurface soil depth, the OC increased by 90.4% under siris followed by kikar (84.6%), shisham (82.2%) and subabul (80.9%) over control (8.53 Mg/ha). The OC content in the 0-60 cm soil profile under the tree species varied from 30.0 Mg/ha under eucalyptusto 39.2 Mg/ha under kikar. The available nitrogen was higher under leguminous tree species subabul, siris, shisham and kikar (N: 167.6, 162.2, 158.6 and 155.9 kg/ha, respectively in surface layer) than the other tree species and control (120.1 kg/ha).