Three Different Fertilizers Enhance Spinach Growth and Reduce Spinach Cd Concentration in Cd Contaminated Alkaline Soil

Abstract

In order to investigate the impact of peach branch derived fertilizer (PB), cow manure derived fertilizer (CM) and silicon liquid fertilizer (Si) on the growth and Cd uptake of the Spinacia oleracea L. in the Cd contaminated soil, a pot experiment was conducted. The fertilizers were applied with low (L), medium (M) or high (H) levels, leading to nine treatments and a control group (CK). As a result, compared to CK, PB increased shoot dry mass by 15 to 46% and reduced shoot Cd by 19 to 56%; CM increased shoot dry mass by 6.1 to 162% and reduced shoot Cd by 38 to 55%; Si showed no effect on plant biomass but significantly reduced the root Cd bioconcentration factor. The CMM and CMH significantly reduced soil-available Cd by 6.5 and 7.5%, respectively, compared to CK. The CM enhanced the plant biomass dilution of Cd and decreased soil-available Cd, but led to higher total shoot Cd accumulation. PB led to simultaneous decline of the shoot Cd and total shoot Cd accumulation, indicating a stronger plant Cd “rejection” effect, independent from biomass accumulation. Si reduced plant root Cd with the sacrifice of biomass accumulation.