Phytotoxicity assessment of sodium for lettuce grown in NEREA®-based hydroponics

(Photo courtesy of Niagara College Canada)
Determine if sodium levels in NEREA® may lead to toxicities within lettuce grown in hydroponic growing system

Conduct growth trial of lettuce crops with NEREA® in a hydroponic system and measure sodium content in both leaves and nutrient solution

NEREA®, being higher in sodium compared to a standard hydroponic fertilizer produced lettuce overall higher in sodium, although these plants showed no visible negative effects and were more advanced in size, leaf count and roof mass

International Zeolite (IZ) is an international marketer and supplier of natural zeolite and zeolite-infused products. IZ has acquired permission to test a zeolite-based substrate, called NEREA®, developed at the University of Havana, with the goal of assessing potential market adoption by and corresponding benefit to the greenhouse sector of agriculture in Canada and the US. The NEREA® technology is based on charging zeolite with plant-available nutrients.

A trial was carried out to evaluate the sodium content and solubility of NEREA®, and eventual uptake by the plant, when used as a media substitute for lettuce grown in a greenhouse using a hydroponic Nutrient Film Technique (NFT) system.

In the previous trial, the NEREA® product demonstrated potential for use as a hydroponic medium to grow leafy greens. From that trial, it was noted that potential toxic levels of sodium may be present in the NEREA® product, and thus may lead to toxicities within produce grown in NEREA®.

As a follow-up trial, Niagara College’s (NC) Horticultural & Environmental Science Innovation Centre (HESIC) ran parallel crops of lettuce that were grown in a hydroponic Nutrient Film Technique (NFT) system in NEREA® and standard Oasis® rockwool at the NC greenhouse located in Niagara-on-the-Lake, Ontario, with the goal being to determine sodium concentration in both hydroponic solutions and the edible portion of lettuce.

The results of this study showed that NEREA®, both in raw form and the leachate from NEREA®, is higher in sodium content compared to the amount measured in a standard hydroponic fertilizer recipe.

Sodium uptake into the leaves of lettuce was higher in those grown in NEREA® than in the standard Oasis® rockwool.

While the sodium level within the nutrient solution and within the leaves at harvest were considered higher than recommended, there were no visual negative effects of this excess.

In fact, overall, the lettuce grown in NEREA® was more advanced in size, leaf count, and root mass than the lettuce grown in Oasis®.

International Zeolite Corp. and Niagara College’s Horticultural & Environmental Sciences Innovation Centre (HESIC) have an ongoing agreement in place that provides priority and support for research projects in relationship to IZ’s proprietary NEREA® technology, which will be carried out by HESIC.

This project is funded by the Government of Canada through the Federal Economic Development Agency for Southern Ontario

Visit Niagara College’s Horticultural & Environmental Sciences Innovation Centre page to learn more about its resources and capabilities.