Cadmium Uptake by Lettuce in Fields Treated with Cadmium‐Spiked Phosphorus Fertilizers

Abstract

The rate of cadmium (Cd) uptake by lettuce (Lactuca savita var. longifolia) over an entire growing season was investigated in a field treated with phosphorus (P) fertilizers spiked to different Cd levels. Romaine lettuce was planted following the standard cultivation practices. Over the growing period, soil and plant samples were taken to determine the total soil Cd content, Cd concentration of 1:0.5 (soil‐to‐water) extracts, and Cd content of plant tissue. Results indicated that lettuce can accumulate as much as 20 mg Cd per kilogram dry biomass without adverse effects on growth. The Cd content in the plant tissues decreased exponentially with time, indicating a dilution factor existing along with the plant growth. The plant uptake rate on a per‐unit‐area basis increased over time and can be simulated by a sigmoid pattern model. The plant uptake coefficient (α, L solution kg biomass⁻¹ day⁻¹) decreased as the Cd treatment level increased.

Keywords:

• Model
• P fertilizer
• plant uptake
• trace element