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The food security in today's world is endangered by several threats, including accelerated increases in the world's population, depletion of the Earth's resources, exaggerated environmental pollution, and foreseen climatic changes. As a strategy to diminish these threats, the wise disposal of the huge amounts of sewage sludge (SS) to agricultural soils as a bio‐fertilizer represents a worthy practice for recirculating valuable nutrients to food chains via crop plants. The current study was designed to scientifically test the feasibility of SS application to agricultural soils without causing environmental or health threats. Different SS amendment doses of 0, 10, 20, 30, 40, and 50 g/kg were supplied for soil‐grown barley (Hordeum vulgare L.) plants. Our results show that all of the SS amendment doses improved the postharvest soil properties and enhanced barley growth, with the best results obtained at the 40 g/kg dose. At this amendment dose, the organic matter (OM) content increased to 6.7% compared with 1.4% in control soil. Analysis of the postharvest soils showed that the concentrations of the investigated heavy metals (HMs) (Co, Cu, Mo, Ni, Zn, Cd, Cr, and Pb) were within the allowable limits for agricultural soils at all of the SS amendment doses, except for Co. All of the SS amendment rates enhanced barley growth and yield parameters, including shoot and root lengths and dry weights, spike weight and number of spikes per plant. Up to the 40 g/kg amendment dose, the concentrations of the investigated HMs in the harvested plant tissues were within safe limits, with most of the absorbed HMs persisting in roots. Taking these results together, the current study suggests that controlled application of SS to agricultural soils represents an eco‐friendly SS disposal procedure, which can recycle macro‐ and micronutrients to food chains and hence provide a promising approach for sustainable food security. [ABSTRACT FROM AUTHOR]

A greenhouse experiment was performed to assess the soil heavy metal pools, growth, yield, and heavy metal uptake of wheat plants (Triticum aestivum L.) that are grown at different rates in soils supplemented with sewage sludge (SS). The experimental design was completely randomized, with six replicates per treatment. The application of SS significantly increased the soil organic matter content. Generally, most growth parameters, as well as the biomass of treated wheat, were significantly increased with the amendment of SS, up to the addition rate of 40 g kg−1. The content of all heavy metals (except Cr in grains and Pb in spikes) significantly increased in different tissues of treated wheat with the increasing rate of SS application. However, all heavy metal concentrations (except for Al, Cr, Fe, and Mn in the roots) were normal and did not overcome the phytotoxic levels. The wheat was recognized by a bioaccumulation factor < 1.0 for most of the heavy metals. The translocation factor for all of the heavy metals was < 1.0. Therefore, the SS utilized in the present study could be used as a valuable organic fertilizer in wheat cultivation areas in Saudi Arabia and could also act as an eco-friendly method for the recycling of SS. [ABSTRACT FROM AUTHOR]

The application of sewage sludge (SS) in agriculture is an alternative disposal method for wastewater recycling and soil fertilization. This study evaluated heavy metal bioaccumulation, growth, and yield of Pisum sativum (pea) grown in agricultural soil amended with SS at rates of 0, 10, 20, 30, and 40 g/kg. The results show that root, shoot, pod length, biomass, and number of leaves and pods increased with SS amendments of 10 and 20 g/kg, while rates declined at 30 and 40 g/kg. SS had greater salinity and organic content than the soil. Heavy metals in the postharvest soil samples increased for all SS application rates except Fe and Mo. The significant increase in Cd content started at the lowest amendment rate 10 g/kg; for Co, Mn, and Pb, the significant increase was detected at the highest amendment rate (40 g/kg). Generally, all heavy metals increased significantly in portions of P. sativum except Cd in the shoot. At an amendment rate of 10 g/kg, Co in the shoot and root, Cr in the fruit, Cu in the root, Fe in the fruit, Mn in the shoot and fruit, Mo in the fruit, Pb in the shoot, and Zn in the fruit were elevated significantly. In contrast, the concentrations of Cd in the fruit, Cr in the root, Cu in the shoot, Fe in the shoot and root, Ni in the fruit and root, Pb in the fruit and root, and Zn in the root significantly increased only at the highest rate of 40 g/kg. The highest regression R2 was 0.927 for Mn in pods and the lowest was 0.154 for Cd in shoots. Bioaccumulation and translocation factors were > 1 for Mo and the bioaccumulation of Pb was >1. SS could be used for pea fertilization but only at rates below 20 g/kg to avoid environmental and health hazards. [ABSTRACT FROM AUTHOR]