Litter decomposition and nutrient release pattern in two nitrogen fixing shrubs (Flemingia macrophylla and Tephrosia candida) growing in SALT farm in Lunglei district of Mizoram


We studied litter decomposition and nutrient release patterns in different components of two nitrogen (N) fixing shrub species, (Flemingia macrophylla and Tephrosia candida) planted on sloping agriculture land technology (SALT) farm in 2002 and 2010. The two sites were 10 yrs old and 2 yrs old farms at the beginning of this study, i.e. July 2012. Sites were within the same permanent agriculture farm having similar climatic conditions. We collected different litter components (leaves green and senesced, wood and roots fine and coarse) of two species having different ages. Known amount (7 g) of all litter components were enclosed in nylon net mesh bags and placed in their respective habitats for decomposition and these samples were retrieved periodically to assess the rate of change of mass and nutrient. Our results suggest that the mean relative decomposition rates of different litter were maximum in the rainy season and minimum in the summer season for both sites and species. Among the litter components, fine roots (<2 mm) of both species showed higher rates of organic matter decomposition and rates of nutrient release to the soil. The rate of release of organic matter and nutrient was slightly greater in F. macrophylla than the T. candida. Annually, these species added significant amount of organic matter and nutrients to the soil that supported considerably higher production compared to shifting cultivation sites on sustained basis.

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