Chapter 22 - Soil health status in coffee-based agroforestry systems in Western Ghats of Karnataka, India

Abstract

Comparative soil health status in landscape elements such as natural forests (NFs), sacred groves (SGs), and coffee plantations (CFPs) was undertaken in Central Western Ghats of Kodagu district, Karnataka, Southern India. Three bioclimatic zones: evergreen, transition, and dry deciduous forest belts were categorized according to rainfall and temperature. In each bioclimatic zone, three landscape elements were selected for the study. The amount of carbon stored per hectare was obtained considering soil depth (cm) and the percentage of soil organic carbon (SOC). In the selected sites, stratified random sampling was done for collection of soil samples of depths of 0–30 and 30–60 cm using soil sampling equipment. At each site and for each depth, total of three samples were randomly selected from different landscape elements and one composite sample was made. Soil organic content was done by volumetric titration method of Walkley and Black. In bioclimatic zone-1, SOC ranged from 64.14 to 19.89 Mg ha−1 across different landscape elements. At 0–0.30 m depth, SGs recorded the highest SOC (33.48 Mg ha−1). The content of SOC was highest in CFPs (64.14 Mg ha−1) and SGs (34.7 Mg ha−1). At 0–0.30 m depth, NFs of bioclimatic zone-2 had the highest SOC (39.36 Mg ha−1). At 0.30–0.60 m depth, CFPs were found to have more SOC (44.10 Mg ha−1) followed by NFs (40.50 Mg ha−1). In bioclimatic zone-3 the SOC content ranged from 16.38 Mg ha−1 to 65.94 Mg ha−1. At 0.03 m depth, CFPs recorded the highest SOC (25.74 Mg ha−1). Higher quantum of CO2e pools was recorded in SGs (122.53 Mg ha−1) followed by NFs (110.12 Mg ha−1) at 0.00–0.30 m soil depth in bioclimatic zone-1. At 0.30–0.60 m soil depth, CFPs noticed maximum quantum of CO2e pool (234.75 Mg ha−1). In bioclimatic zone-2, NFs had higher quantum of CO2e pools (144.05 Mg ha−1) followed by SGs (115.01 Mg ha−1) at 0.00–0.30 m soil depth. At 0.30–0.60 m soil depth the NFs recorded highest CO2e pools (527.25 Mg ha−1) followed by CFPs (161.40 Mg ha−1). In BCZ-3, at 0.00–0.30 m soil depth, CFPs recorded the highest quantum of CO2e pools (94.20 Mg ha−1) followed by SGs (65.77 Mg ha−1). At 0.30–0.60 m soil depth the NFs had the highest quantum of CO2e pools (241.34 Mg ha−1) followed by scared groves (181.93 Mg ha−1).