Effective Utilization of Gypsum-Enriched Water Hyacinth (Pontederia crassipes Mart.) Chunks as Green Manure for Groundnut Fields

Water hyacinth (Pontederia crassipes Mart. 1843) is an invasive weed species that poses a significant threat to aquatic ecosystems due to eutrophication caused by natural or anthropogenic effects. The cost of controlling these plants is high. Despite this challenge, water hyacinth offers beneficial and economic advantages, making it a valuable resource for recovery. Due to its invasive nature, water hyacinth causes ecological, social, and economic problems in tropical and subtropical areas. It can be controlled by lowering water levels (drawdown) to “strand” and desiccate the plants on exposed shorelines; however, the time required to dry large mats of the plant can be extended. Additionally, drawdowns and droughts trigger seed germination, rapidly re-establishing water hyacinth when water levels rise. Countries like India, China, Japan, and Vietnam have addressed the problem by utilizing the beneficial aspects of water hyacinth, thus avoiding the high costs of controlling it. This paper discusses one of the beneficial uses of water hyacinth: its application as green manure enriched with gypsum for groundnut fields (Alfisols) in tropical regions. Being an organic source, water hyacinth builds up soil organic matter and enriches the soil’s physical, chemical, and biological properties. This approach demonstrates a significant increase in the agronomic growth parameters of groundnut plants.