Assessing soil organic carbon in agroforestry systems in different altitudes of Tehri District, Uttarakhand, India

Abstract

An agroforestry system that combines trees and shrubs with crops, increases organic carbon accumulation in soil by providing continuous supply of organic matter over time. Soil organic carbon is a key component of terrestrial ecosystem that helps in enhanced sequestration of atmospheric CO2 in the soil. This study was carried out during the year 2017 in Tehri Garhwal of Uttarakhand. Three agroforestry systems selected were Agrihorticulture (AH), Agrisilviculture (AS) and Agrihortisilviculture (AHS) in three altitude viz., Lower altitude (286-1200 m), Middle altitude (1200-2000 m), and Upper altitude (2000-2800 m). Ten sample plots (100m2) were randomly laid out in each agroforestry system on each altitude of each block. Soil organic carbon was determined using the Walkley and Black method. Soil physico-chemical properties revealed that maximum bulk density (1.38 g cm-3) was recorded in the agrisilviculture system and minimum in agrihorticulture system (1.29 g cm-3). Maximum soil organic carbon (2.74%) was found in the agrihorticulture system and minimum in agrisilviculture system (2.48%). The soil organic carbon percent also increased significantly with the ascending altitudes. It was concluded that upper altitude (2000-2800m) and agrihorticulture system had accumulated greater soil organic carbon pool and suggested that, if need be, conversion of agriculture field should be into agrihorticulture system in Northwestern Himalayas for better soil carbon sequestration.