Land use patterns influenced the quality and climate resilience of soil in the Brahmaputra Valley at the Himalayan foothill in India
摘要
The Brahmaputra Valley in Northeast India belongs to the sub-tropical humid climatic condition with mean annual rainfall of 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 forest area is shrinking due to expansion of rice cultivation and tea and rubber plantation 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 the effect of changed land use on soil quality and sustainability. The land-use pattern has a considerable impact on the organic carbon pool in soil, and the 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. The carbon degradation potential (CDP) of rice cultivation (0.765) was much higher than tea plantations (0.440). The carbon deterioration potential (CDP) of rice paddy soils was estimated at 0.765, and such a high CDP value was attributed to 650 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 the soil quality of rice fields in this region.