Recycling Selected Wetlands’ Sediments for a Vegetable Crop Cultivation in Terrestrial Ecosystem of a Humid Region

Abstract

This study aimed to evaluate the selected wetlands' sediments regarding physicochemical attributes including heavy metals (HMs), and their potentiality to be used in crop cultivation with or without mixing with different generic farmers' field soils in the upland. Forty geo-referenced sediment samples were collected from each study site (n=3), and mixed to get three separate composite samples for mineral nutrients, HMs analyses and experimentation. Two pot experiments were conducted following Completely Randomized Design (CRD) with three replicates using farmers’ field soils (FFS) Gleysols and Cambisols to grow amaranth. The treatments were: T0: FFS; T1: FFS + wetland sediment of hilly area I (1:1); T2: FFS + wetland sediment of hilly area II (1:1); T3: FFS + wetland sediment of a floodplain area (1:1); T4: wetland sediment of hilly area I; T5: wetland sediment of hilly area II; T6: wetland sediment of a floodplain area. Regarding nutrient elements, exchangeable K, extractable P, Ca, and Zn were observed higher in wetland sediment of hilly area II except organic carbon (OC). Only Cd, Pb, and Ni were individually found higher than the maximum permissible addition for all wetland sediments, but all HMs collectively posed no “ecological risk”. The highest values of the plant growth index of amaranth were  observed for T5 treatment. Moreover, the highest total fresh and dry biomasses were found in T5 treatment. The highest nutrient uptake was observed in T5 treatment for the most of nutrients. Studied wetlands’ soil materials, OC, and nutrients could be used to benefit upland crop cultivation.