Assessing changes in Cd phytoavailability to tomato in amended calcareous soils

Area of Science:

• Environmental Science
• Agronomy
• Soil Science

Background:

• Cadmium (Cd) contamination in agricultural soils poses risks to food safety and human health.
• Understanding Cd phytoavailability and plant uptake is crucial for managing contaminated sites.
• Tomato (Solanum lycopersicum) is a widely consumed crop susceptible to heavy metal accumulation.

Purpose of the Study:

• To evaluate the effect of sewage sludge and mineral fertilizer amendments on Cd phytoavailability in a tomato cultivar.
• To assess the time-dependent accumulation and distribution of Cd in different tomato plant parts.
• To investigate the influence of varying Cd levels on plant uptake under different soil amendment conditions.

Main Methods:

• A plot study was conducted on a Calcidic Haploxeroll soil in Southeastern Spain.
• Soil amendments included sewage sludge (A) and mineral fertilizer (B), with an unamended control (C).
• Controlled CdCl2 additions (0, 3, 30, 100 mg kg(-1)) were applied, and DTPA/ammonium acetate extractable Cd was analyzed. Plant Cd accumulation was tracked over time in stems, leaves, and fruits.

Main Results:

• Both sewage sludge and mineral fertilizer amendments significantly altered Cd phytoavailability to tomato plants.
• A notable increase in plant Cd concentration was observed after the initial cropping period.
• Differential accumulation and distribution of Cd were detected across tomato plant organs (stems, leaves, fruits).

Conclusions:

• Soil amendments influence Cd phytoavailability and subsequent uptake by tomato plants.
• Cd accumulation in edible parts of tomatoes is a concern, necessitating careful management of contaminated soils.
• Further research is needed to optimize amendment strategies for minimizing Cd transfer into the food chain.