Comparative soil nutrient status of agroforestry block plantations in semi-arid Telangana

Abstract

Trees species wise agroforestry block plantations were studied for soil properties. The tree species under block plantations were tamarind, malabar neem, teak, eucalyptus, simarouba, neem and pongamia planted in the year 2009 at AICRP on Agroforestry research blocks, Professor Jayashankar Telangana Agricultural University, Hyderabad, Telangana, India. The soils of all the tree based land use systems are slightly acidic in reaction (pH 6.03 - 6.8) and the electrical conductivity ranged from 0.21 dS m-1- 0.38 dS m-1, which is normal in range. Significantly higher soil organic carbon was recorded under tamarind (5.04 g kg-1) and lower soil organic carbon was recorded under teak block plantation (2.83 g kg-1). Significantly higher values of soil available N and P2O5 were recorded in pongamia block plantation (201 kg ha-1, 36 kg ha-1, respectively) and lower soil available N recorded under teak and melia block plantations (175 kg ha-1, 30 kg ha-1, respectively). Significantly higher values of soil available K2O was observed in melia (573 kg ha-1) at 0-15cm depth over all other plantations. In all the tree-based land use systems, soil macro nutrients (OC, N, P2O5 and K2O) decreased from surface soil (0 - 15 cm) to subsurface soil layers (15 - 30 cm, 30 - 45 cm). Significant and positive interaction was observed between the land use systems and soil depth. Significantly higher values of organic carbon fractions (CVL - 3.07 g kg-1, CL - 2.75 g kg-1, CLL - 3.10 g kg-1, CNL - 2.64 g kg-1 and total organic carbon - 11.56 g kg-1), microbial biomass carbon (231.43 mg kg-1) were recorded in tamarind block plantation and lower values of carbon fractions were recorded in simarouba block plantation (CVL-3.07 g kg-1, CL-1.65 g kg-1, CLL- 1.91 g kg-1, CNL 1.93 g kg-1) and teak block plantation (CVL-2.82 g kg-1, CL-1.80 g kg-1, CLL- 2.24 g kg-1, CNL 1.70 g kg-1 and total organic carbon -8.56 g kg-1). Soil organic carbon was significantly and positively correlated with all available nutrients (0.63*) and total organic carbon (0.986**).