Effect of growing season, Trichoderma and clinoptilolite applications on potentially toxic elements (PTEs) uptake by Cucumis melo L.

Abstract Aim: The extent at which different agricultural strategies may affect the uptake of potentially toxic elements (PTEs) by cropped plants is not completely understood at a field scale. This study dealt with the effect of seasonality, Trichoderma inoculation alone or combined to different applications of commercial grade clinoptilolite (i.e., foliar action, fertigation, and pellet) on the PTEs content of early- and late-ripening cultivars Cucumis Melo L. Methods: Two similar field experiments were performed in spring and summer. For each cultivar/treatment combination, the input of PTEs (namely, Cr, Cu, and Pb) to the soil-crop system through irrigation water, fertilizers, pesticides, and treatment products (i.e., Trichoderma and clinoptilolite products), as well as the PTE content of melon stem, leaves and fruit, were assessed through Inductively Coupled Plasma - Optic Emission Spectrometry. Results: Neither Trichoderma alone nor associated with clinoptilolite had visible effect on PTEs uptake by plants, while early season cultivation was strongly associated with lower uptake of Cu and Pb. The high correlation of Cu and Pb content with Ca content in stem and leaves, used as a proxy for different transpiration rates under different growing seasons, indicated a possible uptake of these metals through Ca-nonselective cation channels as a drought stress defence. Lower Cu and Pb concentration were found in early-ripening melon fruit cultivated in spring. Conclusions: To the scope of Cu and Pb risk management, in case of significant contamination in Mediterranean calcareous soils, the use of early-ripening Cucumis melo L. cultivars in place of late-ripening ones is suggested.