Abstract
The availability of water resources of marginal quality such as drainage water or high-salt containing groundwater is turning into an important issue in Tunisia and other countries with scarce water resources. A pot experiment was carried out to evaluate plant production, nutrient content and heavy metal bioaccumulation in agricultural soils amended with MSW compost and irrigated with salty water, by using two different soil textures (clay and sandy). Salt water supply decreased plant dry yield in both soils. Salt stress had significantly reduction in plant biomass in sandy soil compared to those in clay soil (biomass of dry weight is significantly higher in clay soil than those in sandy soil in presence of salt: percentage of growth compared to control was 55% for clay soil and 45% for sandy soil). The application of Municipal Solid Wastes (MSW) Compost increased significantly alfalfa productivity in both soils (Dry weight is significantly higher in presence of compost: 140% for clay soil and 125% for sandy soil). In non-amended soil, the growth was reduced significantly by salt stress (50% in clay soil, 26% in sandy compared to the soils without salty water application). Plants irrigated with salty water accumulated much more sodium on sandy soil (1.74 mmol g(-1)) than on clay one (0.87 mmol g(-1) DW). Compost did not reduce sodium accumulation in aerial parts on sandy soil, whereas it slightly reduced it in those grown on clay soil. Zinc (Zn), Copper (Cu), Lead (Pb) and Cadmium (Cd) concentrations showed the same trend for both soil types. They increased statistically significant by salinity to 124-189%, the highest rise was found in Cu concentration on clay soil. The order of metal uptake was: Zn > Cu > Pb > Cd. A higher significant shoot accumulation of heavy metals (up to 305% of the control) was noticed in the presence of compost with no difference between salt-treated and non-treated. MSW compost amendment caused an increase of the studied heavy metals in alfalfa shoots grown that was higher on sandy soils than clay soils. Heavy metals in plants remained lower than phytotoxic level and these level of accumulation did not restrain the enhancement of alfalfa yield. MSW compost at 40 t ha(-1) was convinent to do not attend phytotoxic level. These results suggest that MSW compost compensates, at least partially, the negative effect of salinity on plant growth and nutrient uptake and that it is important to know soil texture to apply compost to remediate salty degraded soils. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.