Effects of mulching with Solanum spp. straw on phosphorus, iron, and cadmium uptake by rice plants.

The cadmium (Cd) contaminated paddy soil has seriously affected the safe production of rice, and returning straw to fields changes the Cd accumulation in crops. To decrease the Cd accumulation in rice and clarify the relationships among phosphorus (P), iron, and Cd contents in rice, the effects of Solanum spp. (including non‐hyperaccumulators Solanum diphyllum and Solanum alatum, and Cd‐hyperaccumulators Solanum nigrum and Solanum photeinocarpum) straws on the P, iron, and Cd uptakes in rice in Cd‐contaminated soil were investigated. The application of four Solanum spp. straws increased the biomass of rice. Only the S. alatum straw increased the chlorophyll a, chlorophyll b, total chlorophyll, and carotenoid contents in rice. Regarding the P, iron, and Cd contents in rice, the four Solanum spp. straws either decreased the P content or had no significant effects, and tended to increase and decrease the iron and Cd contents, respectively. In addition, the Cd content was negatively correlated with the iron content and the soil available P concentration, and was positively correlated with the soil exchangeable Cd concentration. Therefore, Solanum spp. straws can decrease the Cd uptake and increase the iron uptake by rice. Furthermore, the Cd content in rice is related to the iron content in rice as well as the concentrations of soil available P and soil exchangeable Cd. [ABSTRACT FROM AUTHOR]