ABSTRACT

Cadmium (Cd) contamination in agricultural soil is a global issue of concern because of its potential transfer to the human body through food chain interactions. Phosphate fertilizers used in the agricultural soils contain a high concentration of Cd. Composts are good sources of phosphorus, thus mixing of compost with phosphate fertilizer could reduce the total phosphate fertilizer use and subsequent Cd enrichment in agricultural soils. However, the optimum mixing ratio of compost and phosphate fertilizer is of paramount importance to obtain the desired outcome. In this study, experimental pot trials were performed to assess plant growth and Cd accumulation in two leafy vegetables, red amaranth (Amaranthus cruentus) and water spinach (Ipomoea aquatica), grown in Cd-contaminated loamy sandy soil under varying rates of compost and phosphate fertilizer application, either alone or in mixture. The study revealed that application of compost in combination with phosphate fertilizer is more effective from both environmental and economic perspectives rather than the application of compost alone, wherein 10 t/ha compost in combination with 40 kg/ha phosphate fertilizer was found as the best treatment for reducing Cd phytoaccumulation in both vegetable species and increasing the plant growth. Moreover, this optimum mixing ratio of compost and phosphate fertilizer showed positive impacts on soil pH and EC. The results also observed that phytoaccumulation of Cd decreases with decreasing the rate of phosphate fertilizer application, either alone or in mixture. Moreover, further study is necessary to determine the impact of combined treatments on microorganisms influencing Cd dynamics in soils.

摘要

农业土壤中的镉 (Cd) 污染是一个全球关注的问题，因为它可能通过食物链相互作用转移到人体。农业土壤中使用的磷肥含有高浓度的 Cd。堆肥是磷的良好来源，因此将堆肥与磷肥混合可以减少磷肥的总用量和随后农业土壤中镉的富集。然而，堆肥和磷肥的最佳混合比例对于获得预期结果至关重要。在这项研究中，进行了盆栽试验，以评估两种叶菜类，红苋菜 ( Amaranthus cruentus ) 和菠菜 ( Ipomoea Aquatica ) 的植物生长和 Cd 积累。)，在不同比例的堆肥和磷肥施用下，单独或混合施用，生长在受镉污染的壤质沙质土壤中。研究表明，从环境和经济角度来看，堆肥与磷肥结合施用比单独施用堆肥更有效，其中发现 10 t/ha 堆肥结合 40 kg/ha 磷肥是最佳处理用于减少两种蔬菜中镉的植物积累并促进植物生长。此外，这种堆肥和磷肥的最佳混合比例对土壤 pH 值和 EC 有积极影响。结果还观察到，Cd 的植物积累量随着磷肥施用率的降低而减少，无论是单独施用还是混合施用。而且，