Land use practices in the Central Himalayan region affect soil enzyme activities and their relationship with carbon pools

Abstract

Activities of soil enzymes dehydrogenase, acid phosphatase, alkaline phosphatase, and arylsulfatase were evaluated under the different land use and cropping systems in the Almora region of Central Himalaya, India. The dehydrogenase activity recorded the highest value in undisturbed forest (4.68 μg TPF g-1 h-1) and lowest in barren land (0.74 μg TPF g-1 h-1). The acid phosphatase activities varied between different systems; being lowest in barren land followed by fodder, soybean-wheat, organic system, and the highest in undisturbed forest soil. The average alkaline phosphatase activity ranged from 13.3 μg PNP g-1 h-1 in barren land to 139.9 μg PNP g-1 h-1 in undisturbed forest. The average arylsulfatase activity ranged from 7.30 μg PNP g-1 h-1 in barren land to 184.9 μg PNP g-1 h-1 in undisturbed forest. Most of the enzyme activities showed higher values in summer and at 0-5 cm depth. Significant positive correlations were obtained between enzyme activities and various carbon fractions such as microbial biomass C, particulate organic C and labile C, of which labile carbon was found to be the most strongly associated fraction with the enzyme activities. Our study thus revealed that the cultivation of Himalayan soils has significantly reduced the enzyme activities and that needs adequate attention for long-term sustainable use of soil resources in the region. © 2013 Copyright Taylor and Francis Group, LLC.