Chabazite and seaweed extract effects on lettuce water relations and growth

Biostimulants and soil amendments play essential roles in sustainable agriculture. This research aims to highlight the potential benefit deriving from the use of a seaweed extract biostimulant (Ascophyllum nodosum-based biostimulant, Acadian) combined with chabazite as amendment in the sustainable management of lettuce. In particular, the effects of chabazite and seaweed extract on the lettuce water relations and growth were studied under controlled conditions. The lettuce plants were cultivated in pots filled with a sandy-loam soil mixed with chabazite, a commercial zeolite, and seaweed extract, applied to the soil by irrigation water at a concentration of 0.08 % (w/v) in two applications, to create four experimental treatments: (1) soil with 2 % chabazite; (2) soil with seaweed extract (Acadian); (3) soil with both 2 % chabazite and seaweed extract (chabazite + Acadian), and (4) soil as a control. The chabazite treatment was characterized by measuring soil water retention curves (SWRCs). Soil moisture, gas exchange parameters, leaf water potential, and growth parameters were measured. Both seaweed extract and chabazite improved photosynthesis and leaf water use efficiency. A positive effect on plant growth of lettuce plants by measuring the higher fresh weight and leaf area in the chabazite + Acadian treatment was recorded. Results carried out on lettuce plant growth suggest the possibility to obtain benefits deriving from the combined application of chabazite and seaweed extract biostimulant. The latter helps to mitigate the negative impact of chabazite in the water uptake by improving the physiological responses of lettuce plants. However, chabazite supports water retention, which could collectively enhance crop resilience and gas exchange efficiency.