Land-use pattern influenced quality and climate-resilience of soil in the Brahmaputra valley at Himalayan foothill in India

The land-use pattern has considerable impact on the organic carbon pool in soil and carbon management index (CMI) in tea and rice was estimated at 82.09 and 38.70, respectively. The lability indices (LI) of tea and rice fields were 0.983 ± 0.114 and 0.675 ± 0.095, respectively, while LI of forest soil was 1.178 ± 0.183. This suggested that tea cultivation was able to periodically incorporate organic matter in soil, which enabled to maintain stable as well as labile organic carbon pool of soil. The carbon degradation potential (CDP) of rice cultivation (0.765) was much higher than tea plantation (0.440). The carbon deterioration potential (CDP) of rice paddy soils was estimated at 0.765 and such high CDP value was attributed to 498.50 kg ha ^-1 yr ^-1 organic C loss for rice fields of this region. These data indicated that immediate adaptation of suitable soil management strategies is required for sustaining and then restoring soil quality of rice fields in this region. The Brahmaputra valley in Northeast India belongs to the sub-tropical humid climatic condition with mean annual rainfall 2500 mm. Northeast India has a high forest cover and it accounts for about 21% of the total forest area in spite of covering only 8% of the nation’s land area. It was estimated that the region suffered a loss of more than 3000 sq. km forest area between year 2013 and 2023. Along with rapid urbanization, shifting cultivation (Jhum cultivation) or conventional cultivation of rice and large-scale plantations of tea and rubber are major factors of deforestation in this region. In this study, soil samples were collected from Nameri National Park near Tezpur, Assam, India and surrounding commercial tea gardens and rice fields for evaluating effect of changed land-use on soil quality and sustainability. It was observed that total organic carbon content of forest soil was significantly (P < 0.05) higher than that of both tea-growing soil and rice paddy soil. All the fractions of organic carbon in soil were subsequently decreased due to utilization of deforested land for tea plantation and rice cultivation.