Journal of Soil and Plant Interactions

To investigate the effects of phosphorus (P) and pistachio waste (raw and dry) on growth and chemical composition of pistachio (Pistacia vera L. cv. Badami Zarand) seedlings, a factorial experiment in a completely randomized design with four replications was conducted. Treatments were three levels of P (0, 50 and 100 mg P/kg soil) and three levels of pistachio green hull (0, 3 and 6% w/w). The results showed that at the first level of P application, the 3% pistachio waste treatment increased root and shoot dry weight, number of leaves and leaf area of pistachio seedlings. While, application of 6% pistachio hull significantly decreased these parameters, as compared to the control. However, root and shoot nutrient concentrations including P, sodium, zinc, iron and copper at the first level of P were reduced by pistachio waste application. At the first level of pistachio waste, P application increased root and shoot dry weight, number of leaves and leaf area of pistachio seedlings. But, all nutrient concentrations of root and shoots, except P, were reduced by increasing P level. The best response of dry weight of roots and shoots, number of leaves and leaf area of pistachio seedlings was observed from application of 3% pistachio hulls and 50 mg P/kg of soil. In general, the results of this experiment indicated that application of 50 mg P/kg soil was more effective than 100 mg P/kg soil on growth and chemical composition of pistachio seedlings. Application of 3% pistachio green hull and 50 mg P/kg soil improved growth of pistachio seedlings.

Biochar reduces the bioavailability of a wide range of pollutants, especially heavy metals (HMs).To evaluate the effects of waste biochar of cutflower rose on growth characteristics and accumulation of lead (Pb) and cadmium (Cd) HMs of in lettuce, a factorial experiment, based on completely randomized design, with four replications was conducted. The amount of rose biochar at 3 levels (0, 5 and 10 g/kg), Cd at 3 levels (0, 10 and 20 mg/kg) and Pb at 3 levels (0, 300, 600 mg/kg) were tested. Results showed that the highest amount of leaf area, fresh and dry weight of shoots, and root volume were observed at 5 g/kg level of rose biochar. Increasing the rose-biochar level from 5 to 10 g/kg decreased all traits except height and diameter of shoots. Application of 600 mg/kg Pb decreased the number of leaves, fresh and dry weight of the shoots, fresh and dry weights of roots, and root length by 6.92, 13.38, 18.04, 22.44, 12.66 and 8.61%, respectively, compared to the control treatment. The highest amount of fresh and dry weight of shoots and root volume was observed in 5 g/kg rose biochar and 300 mg/kg Pb treatment, and the least amount of all of the abovementioned traits was observed at the highest levels of biochar and Pb. Increasing the level of biochar from zero to 5 and 10 g/kg and 20 mg/kg of Cd reduced the loss of root Cd by 92.9 and 24.17 percent, respectively. In fact, rose biochar (especially at 5 g/kg level) has improved the lettuce growth characteristics by reducing the bioavailability of Pb and Cd in the soil.