Remediating Severely Salt-Affected Soil with Vermicompost and Organic Amendments for Cultivating Salt-Tolerant Crops as a Functional Food Source

Abstract

Salt-affected soils are a prevalent issue globally, resulting in a severe degradation of soil sustainability and plant productivity, reducing the area of agricultural land, and affecting food security. Therefore, eco-solutions and remediation approaches are needed. The needed remediation for salt-affected soil can be addressed via engineering, physical, chemical, or biological techniques. Salt-tolerant crops are normally used for the remediation of slight and moderate saline soil conditions. However, no crops, including salt-tolerant crops, can be cultivated in areas with extreme salinity levels (ECe 8–16 dS/m). Therefore, the aim of this study was to investigate the effect of vermicompost and organic amendment on the cultivation of salt-tolerant crops (Sesbania rostrata) in severely salt-affected soil under field conditions in order to improve saline soil and crop productivity. The design of the experiment followed a randomized complete block design (RCBD) with three treatments and four replications: T1, severely salt-affected soil (control); T2, severely salt-affected soil + vermicompost at a ratio of 25:75; T3, severely salt-affected soil + vermicompost + rice husk biochar + coconut coir at a ratio of 25:25:25:25. The results found that using vermicompost and organic amendment improved the soil quality, increased the soil fertility (organic matter and plant nutrients N, P, and K), and reduced the soil salinity. Sesbania rostrate could not grow in severely salt-affected soil (T1) alone, but could grow in the treatments with vermicompost and organic amendments (T2 and T3). The percentage of Sesbania survival per plot was also high in the treatments with vermicompost and organic amendments (T2 and T3). The highest growth rate, flower production, biomass, and root morphology of Sesbania rostrata were found in T3, with severely salt-affected soil + vermicompost + rice husk biochar + coconut coir at a ratio of 25:25:25:25 with a statistically significant difference (p < 0.05). Moreover, the Sesbania flowers treated with vermicompost and organic amendments have a higher nutritional value due to their minerals and vitamins than Sesbania flowers grown without using vermicompost and organic amendments. This study’s findings suggest that incorporating vermicompost and organic amendments is a feasible and economical method for enhancing the quality of salt-affected soils in a sustainable manner. The results of this study demonstrate that utilizing vermicompost and organic amendments is a sustainable and economical strategy for enhancing the quality of salt-affected soils and improving yields in severely salt-affected areas, thereby increasing crop production and the nutritional value of the plants as well as helping to increase farmers’ income.