Effects of tree fostering on soil health and microbial biomass under different land use systems in the Central Himalayas

This study evaluated the impact of predominant land uses on the physico-chemical and biological properties of soils along an altitudinal gradient in Indian Central Himalaya to enhance the scientific knowledge and identify suitable land use pattern. Soil samples were collected from six predominant agricultural land uses including (a) open cropland, (b) cropland with multiple tree species (C + mT), (c) cropland with single tree species, (d) crop near rhizosphere of trees, (e) home gardens (HGs), and (f) agriculturally discarded land (ADL). The physico-chemical properties showed the significant differences with land use systems and altitude. Soil texture varied from sandy loam to clayey loam with altitude. The minimum bulk density and higher porosity were recorded for the HG system whereas water holding capacity, moisture, pH, C, oil carbon stock, N, soil nitrogen stock, and P in the C + mT system. Soil microbial biomass carbon (16-397 mu g g(-1)) and soil microbial biomass nitrogen (28-68 mu g g(-1)) were significantly higher in C + mT and lowest under open cropland. The highest microbial biomass was recorded in the lower altitudinal region of Tarai, and the lowest was recorded in the higher altitudinal region. Across the seasons, soil microbial biomass was maximum during the rainy season and minimum during the winter season. Interestingly, ADL also showed significant contribution in soil microbial biomass carbon and soil microbial biomass nitrogen and could be used for crop production in the future. This study concludes that good soil health, higher amount of microbial biomass, and better soil qualities occurred in tree planted soils than in open crop lands, mainly attributed to the greater availability of organic matter, litter diversity, and fine roots.