Influence of zeolite on heavy metal immobilization in municipal solid waste compost contaminated soil

The application of Municipal solid waste as compost (MSWC) in agricultural fields has become one of the most common practices. Besides its benefits, it poses some harmful effects on soil, as it increases the heavy metal content in MSWC of the soil. It is necessary to find a way to reduce the bioavailability of heavy metals in MSWC  before its application into the soil. This study aimed at exploring the efficiency of zeolite as an immobilizer to dwindle heavy metal bioavailability. An incubation experiment was conducted wherein the soil samples were artificially spiked with different rates of MSWC (0, 5, and 10 t ha-1). The zeolite was added to the spiked soil at 5 different levels, namely 0, 5, 10, 15, and 20 %, and their effect on bioavailable heavy metal status was observed during different incubation intervals (0, 15. 30, 60, 90, and 120 days). Results unveiled that applying 10% zeolite significantly (P<0.05) reduced the bioavailability of lead (Pb) and nickel (Ni)  to Below the detectable limit (Bdl) in all soil samples. Furthermore, the organic carbon status of soil was also enriched by MSWC and 10% zeolite application. The soil pH slightly increased (7.39) with applying 10% zeolite resulting in the immobilization of heavy metals. Hence, 10% zeolite application was one of the most effective immobilizers in eliminating the bioavailability of heavy metals. Therefore, it can be concluded that mixing zeolite with MSWC before applying it to crop fields can reduce the heavy metal overload in soil. Hence, this study highlights the potential of zeolite as an effective choice in dwindling the soil's bioavailability of heavy metal content

Estimation of soil carbon pools under major cropping systems of Mayiladuthurai district of Cauvery Delta Zone, Tamil Nadu, India

Soil organic carbon (SOC) is a potential indicator of soil quality and ecosystem sustainability. The present study aimed to evaluate SOC pools under major cropping systems of Mayiladuthurai district of Tamil Nadu. The composite samples were collected from two depths (0-15 and 15-30 cm) by stratified random sampling and were analysed for pH, EC (Electrical conductivity), C fractions, inorganic carbon and permanganate oxidisable carbon by standard procedures. The SOC content under different land use was in the order of Forestry > Rice – pulses > Rice – cotton > Sugarcane > Uncultivated. The mean SOC content of the study area was 12.58 Mg ha-1, where the majority of the area falls under low to medium rating of SOC. Hence, cultivation practices should incorporate activities that increase SOC to maintain soil quality. SOC was positively correlated with fractions of carbon – CVL (r = 0.37**), CL (r = 0.65**) and CLL (r = 0.58**), indicating changes in land use would affect the carbon dynamics of the ecosystem. The root biomass, aeration status, microbial activity, nutrient reserves and inherent soil characteristics influenced SOC to decrease with depth. The PCA analysis revealed that the variation in carbon dynamics of the study area was influenced by SOC, CLC, CLL and non-labile carbon due to differences in land management practices. Therefore, such soil management practices will be a powerful tool to sequester carbon, which supplements climate change mitigation

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Not AvailableIndia launched National Agroforestry Policy on 10th February, 2014 which has the potential to substantially reduce poverty in rural India and revive wood based industry, besides integrating food production with environmental services. The policy is not only crucial to India’s ambitious goal of achieving 33 per cent forest and tree cover but also to mitigate GHG emissions from agriculture sector. Dynamic CO2FIXv3.1 model has been used to estimate the carbon sequestration potential (CSP) of existing agroforestry systems (AFS) for simulation period of 30 years in twenty six districts from ten selected states of India. The observed number of trees on farmers’ field in these districts varied from 1.81 to 204 per hectare with an average value of 19.44 trees per hectare. The biomass in the tree component varied from 0.58 to 48.50 Mg DM ha-1, whereas, the total biomass (tree and crop) ranged from 4.96 to 58.96 Mg DM ha-1. The soil organic carbon ranged from 4.28 to 24.13 Mg C ha-1. The average estimated carbon sequestration potential of the AFS, representing varying edaphoclimatic conditions, on farmers field at country level was 0.21 Mg C ha-1yr-1. At national level, existing AFS are estimated to mitigate 109.34 million tons CO2 annually, which may offsets one-third (33 %) of the total GHG emissions from agriculture sector.Not Availabl