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22 August 2022
Sustainable micronutrients for organic farming produced from recycled alkaline batteries

AS scientists look to find alternatives to current nutrient sources, technology is constantly evolving and enabling new innovations in the fertiliser industry. 

The latest example is from a Finnish company called Tracegrow, which manufactures micronutrient fertilisers from recycled alkaline batteries, and claims trials show that potato crops have been amongst those to benefit.

Billions of the batteries are produced globally each year and have been traditionally treated as hazardous waste, resulting in a harmful outcome for the environment, but the company claims they are now taking on a beneficial, rather than harmful role.

The proprietary process enables Tracegrow to separate zinc and manganese from recycled alkaline batteries and process them into organic circular economy fertilisers ZM-Grow and ZMC-Grow.  Tracegrow has paid special attention to minimisation of emissions and waste.

A company spokesman stated: "In general, some may think that fertilisers are made with the environment and nature in mind, but how many of them have truly stopped to think about the true origin of fertilisers? What about the emissions and waste from production, their recycling and usage minimisation?"

Zn and Mn application has previously been shown to increase all plant characteristics relating to yield and quality of potato crops - tuber yield per plant, dry matter percentage, specific weight, protein and starch contents of the tuber.

The Tracegrow product has been tested in 12 countries with good yield increase results, and received "very positive" feedback from growers, the company states, with trials being made both by independent research institutes and individual growers.

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Potato, wheat, barley, grass, corn, citrus, avocado, cotton and tomato crops were used in the trials earlier over the past couple of years. Results showed very good absorption, often giving better results compared to competing products.

NIAB trialled the variety Marfona, seeing a yield increase of 3,23 t/ha (6,6 %) and 2153% return on investment (ROI) according to the company's results. A research facility field test was carried out for 21 m2 plots, four replicates, 200 l/ha water. Treatment was shown to increase tuber size.

PETLA (The Potato Research Institute of Finland) carried out a field test for 25 m2 plots, with four replicates, with the Posmo variety. First spraying with fungicides at stem elongation, second spraying one of them two weeks later, with a water 200 l/ha mix. It saw a yield increase of 1,3 t/ha (3,1%) and a return on investment (ROI) of 346%, the company claims.

"In all the tests ZM-Grow™ gave the best results compared to areas that were untreated or treated with a competing fertiliser. ZM-Grow™ raised both the crop yield (kg/ha) and plant micronutrient contents (mg/kg of dry matter) the most. ROI values were calculated with prices were valid during experiments," the company spokesman said.

The products are applied by mixing with water and spraying onto the plant’s leaves. This way the micronutrients are absorbed directly into the plant. Foliar application is an efficient way of correcting micronutrient deficiencies in plants. In addition, they can also be applied with NPK-fertilisers through the soil. The most effective method of increasing micronutrient content is by application through combined foliar and soil fertilisation. 

ZM-Grow™ is a foliar fertiliser containing zinc, manganese and sulphur extracted from recycled alkaline batteries. It is 100% sulphate-based and has been approved for organic farming. It is recommended as a foliar fertiliser, seed dressing or coating for granular fertilisers.

Photo: John Cameron

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