MITIGATION OF CADMIUM ACCUMULATION IN COCOA BEANS USING ARBUSCULAR MYCORRHIZAL FUNGI, BIOCHAR AND Callisia repens

Abstract

Cocoa beans serve as a vital raw material for chocolate production. However, the presence of cadmium (Cd) contamination poses a significant threat to cocoa crops and the chocolate industry due to its adverse effects on human health and cocoa quality. To reduce Cd concentration in cocoa beans, three mitigation strategies were evaluated: application of arbuscular mycorrhizal fungi (AMF), Callisia repens alone, the combined application of AMF and C. repens, and biochar at 1% and 2% w/w as an organic alternative. An untreated control was included for comparison. The field experiment was conducted in a mature cacao plantation (genotype CCN51) using a randomized complete block design with three replications in Huánuco, where the soil presents high total Cd levels (0.78 mg.kg^-1). Six months after experiment establishment, AMF and C. repens applied individually reduced Cd concentration in cocoa beans by 40.43% and 30.85% respectively, compared with the control. Total soil Cd remained unchanged across treatments; however, Cd availability decreases with the application of AMF, C. repens, their combination, and 2% biochar. These findings highlight the high potential of AMF and C. repens to reduce Cd availability in soil and consequently limit its accumulation in cocoa beans; however, Cd concentrations still exceed European Union limits. The short-term results of these findings highlight the need for further evaluation over multiple harvest cycles to confirm the effectiveness and stability of these mitigation strategies.