Availability of Trace Elements in Soil with Simulated Cadmium, Lead and Zinc Pollution

The research was based on a pot experiment in which the impact of increasing Cd, Zn and Pb doses on the content of available trace elements in soil was compared. Seven series of trials were designed: 1 (Cd), 2 (Pb), 3 (Zn), 4 (Cd + Pb), 5 (Cd + Zn), 6 (Pb + Zn), 7 (Cd + Pb + Zn). Aside from the control one (without the metals), three increasing levels of contamination were considered within each series. Mobile forms of trace elements (Cd, Pb, Zn, Fe, Mn, Cu, Ni, Co, and Cr) in soil were determined, in addition to which selected physicochemical soil properties—reaction (pH), salinity (EC), hydrolytic acidity (HAC), total exchange bases (TEB)—were identified while cation exchange capacity (CEC), base saturation (BS) and availability factor (AF) were calculated. The application of Cd and Pb to soil resulted in an increase in the share of potentially available forms of these metals in their total content. The availability factor (AF) in the pots polluted with these metals was higher than in the control, in the range 17.5–20.0% for Cd, and 62.8–71.5% for Pb. In turn, the share of Zn mobile forms was comparable in most experimental objects, oscillating around 30%. Moreover, addition to soil of Cd, Pb and Zn usually caused a significant decrease in the content of available forms of Fe, Mn and Cu, and resulted in significantly higher content of available forms of Cr in the soil.

Yield Enhancement and Better Micronutrients Uptake in Tomato Fruit through Potassium Humate Combined with Micronutrients Mixture

The deficiency of micronutrients and low organic matter (OM) status of soils are major hurdles in the optimum crop yield achievements. Humic substances can play an imperative role in the micronutrient bioavailability and improved crop yield by ameliorating the physicochemical soil properties. consumed as fresh food and in processed form. However, its susceptibility towards micronutrient deficiency causes a significant reduction in yield. That is why a current study was done to examine the influence of different potassium humate (KH) levels, i.e., 0, 5, 10, and 15 kg ha−1 with micronutrients mixture (MC), i.e., 0, 50 (Zn = 2.50, B = 0.75, Fe = 2.50 kg ha−1), 75 (Zn = 3.75, B = 1.125, Fe = 3.75 kg ha−1) and 100% (Zn = 5.0, B = 1.5, Fe = 5.0 kg ha−1) on the yield, biomass, harvesting index and uptake of the micronutrients in tomato. The results showed that increasing the level of K-humate significantly improved the yield (7.4 and 7.17%), total biomass (6.38 and 6.59%), and harvesting the index (0.46 and 0.76%) of tomato. It also enhanced Fe uptake but did not affect B and Zn concentrations in the tomato fruit at 100% MC + 15 kg ha−1 KH over control in the autumn and spring seasons. In conclusion, both levels of K-humate 10 and 15 kg ha−1 and MC 75 and 100% effectively enhance the yield, biomass, harvesting the index, and micronutrients (B, Zn, and Fe) uptake in tomatoes.

Quantitative characteristics, regeneration status, Physicochemical soil properties within and at different distance of abandoned skid trails in the Hyrcanian forests.

The authors have withdrawn this preprint due to author disagreement.