Profile distribution of phyto-available nutrients as influenced by land use systems of dominant soil orders in north-west India

Changes in land use practices affect the distribution of nutrients in soil and their availability to plants, thus necessitating for sound understanding of their status in the soil profile and causes of variability. The primary challenges faced in this study were addressing the considerable variation in soil nutrients caused by different land uses and soil orders while also distinguishing the specific impacts of these factors from other influencing environmental and management conditions. Therefore, this study aims to investigate the nutrient dynamics in soil profiles of forest and agriculture/horticulture land use systems across four prominent soil orders i.e. Inceptisols, Entisols, Aridisols and Alfisols, existing in north-west India. Soil samples were collected from five depths (0-20, 20-40, 40-60, 60-80 and 80-100 cm) of each land use system prevailing under soil orders. Results revealed that among various soil orders, overall pH, EC and SOC ranged from 7.60 to 9.04, 0.05-0.96 dS m-1 and 0.15-0.79 %, respectively. The DTPA extractable Zn varied from 0.26-1.56, 0.19-2.42, 0.16- 1.27 and 0.18-1.04 mg kg-1; Fe from 4.90-14.94, 1.94-11.84, 0.73-3.40 and 2.94-12.56 mg kg-1; Mn from 2.79-8.50, 2.58-10.27 1.80-7.54 and 2.44-7.98 mg kg-1 and Cu from 0.58-1.63, 0.42-1.21, 0.18-0.35 and 0.33-2.01 mg kg-1 in Inceptisols, Entisols, Aridisols and Alfisols, respectively. Micronutrient concentration generally exhibited a decreasing trend with increasing soil depth. Under both land use systems, organic carbon showed a significant positive correlation with DTPA extractable micronutrients. The findings underscore the importance of understanding nutrient dynamics to soil profile characteristics and land use systems. This study offer a foundation for developing precise soil management strategies aimed at enhancing sustainable farming and preserving soil quality.