Carbon Pools and Nutrient Dynamics under Eucalyptus-based Agroforestry System in Semi-arid Region of North-west India

Abstract

Agroforestry systems play diverse ecosystem services. Soil properties are substantially altered in both surface and sub-surface layers by agroforestry systems. Information on the effect of agroforestry, land uses and seasonal soil samplings on soil properties and organic C dynamics is very limited. The present study investigates short-term (6-year-old) changes in eucalyptus (Eucalyptus tereticornis) based agroforestry and monocropped (2-years) sugarcane-sugarcane (Saccharum officinarum) system for soil physicochemical properties in the semi-arid region of north-west India. For this purpose, replicated soil samples with 15 cm interval up to 105 cm soil depth were collected before the onset of the monsoon in March 2013 and at the end of the rainy season (September 2013) for analyzing different soil properties. Microbial biomass C (MBC), Walkley and Black C (WBC), total organic C (TOC), macro and micronutrients concentrations decreased with soil depth. Averaged across depth, soil under eucalyptus had 17 and 77 per cent higher values of available N and P; 100 per cent higher DTPA extractable Zn and Cu; and 38 per cent greater Mn than monocropped sugarcane. Furthermore, eucalyptus based agroforestry system contained 22 and 13 per cent greater TOC stock; and 15 and 23 per cent greater MBC concentration in soils sampled in March and September 2013, respectively compared with monocropped sugarcane in averaged across depth of 105 cm soil layer. Despite surface soils in eucalyptus showed greater values of WBC in the month of September compared with March 2013, it was nearly similar for monocropped sugarcane system in both samplings.