Long-Term Impact of Forest-Based Land Uses on Soil Quality Indicators in Himalayan Region

Abstract

The objective of this study was to assess the long-term cumulative effects of forest land use on soil properties under four forests, Chir pine (Pinus roxburghii), Deodar (Cedrus deodara), Oak (Quercus leucotrichophora) and mixed (Chir Pine\u2009+\u2009Deodar) forest. Tree litter samples were drawn from each of forest by forming a 1\xa0m\u2009×\u20091\xa0m quadrant. Litter sampling was done at three months interval in a year. Tree biomass estimation was done by laying 10\xa0m\u2009×\u200910\xa0m quadrant for each forest site, and DBH (Diameter at Breast Height) of all trees within quadrate was recorded. Soil sample was randomly collected at soil depth of 0–15 (surface layer) and 15–30\xa0cm (sub-surface layer) in triplicate in each forest for two successive years. The sampling and analysis of soil and plant was done during 2016–2017 and 2017–2018. Biomass production varied from 28.01 to 156.64\xa0Mg\xa0ha−1. Total carbon (soil\u2009+\u2009biomass) in mixed forest was highest (89.9\xa0Mg\xa0ha−1) and the least in deodar (39.21\xa0Mg\xa0ha−1). Soil under Oak plantation contributed more carbon (64.5%) to the total carbon (C). Soil organic carbon (SOC) in surface soil was higher in oak (29.73\xa0g\xa0kg−1) followed by deodar, pine and the least (9.9\xa0g\xa0kg−1) in mixed forest. Highest BD was observed in surface soils of mixed forest (1.52\xa0Mg\xa0m−3), and it was lowest in surface (1.11\xa0Mg\xa0m−3) as well as in sub-surface (1.13\xa0Mg\xa0m−3) soils of oak forests.\xa0Total porosity in surface layer was maximum (53.17%) in Oak forests and minimum (39.39%) in mixed forests. Soil bulk density, particle density and aggregate bulk density followed order mixed\u2009>\u2009chir pine\u2009>\u2009deodar\u2009>\u2009oak. Pearson correlation analysis revealed significant negative relationship between SOC and bulk density. Thus, keeping in view ecological benefits of forests, assessment of parameters like biomass, SOC and other soil physical parameters like particle density, bulk density, total porosity, maximum water holding capacity, mean weight diameter and field capacity will help in designing strategies for long-term sustainable management of forest ecosystems.