Best natural pesticide? Beer and manure mix is perfect recipe for keeping farms chemical and bug-free!

BASQUE COUNTRY, Spain — Over the years, many chemical pesticides for crops and agriculture have been banned due to their harmful effects on both human health and the environment. Now, a new study reveals the answer to a more natural solution may be sitting in your local brewery. Researchers believe they can create a much safer pesticide alternative by mixing a beer by-product with manure.

Study authors, based out of the Neiker Basque Institute for Agricultural Research and Development in Spain, set out to find a way to simultaneously cut back on agricultural waste while also reducing the use of harmful chemicals. That line of thinking led them to the idea of using beer production by-products and farming by-products as a possible avenue of disinfesting soils, preserving healthy soil microorganisms, and increasing crop yields.

So which beer ingredients may help farmers?

More specifically, the team looked to two distinct agricultural by-products: rapeseed cake and beer bagasse (spent beer grains). Researchers tested those two by-products, in combination with fresh cow manure, as organic biodisinfestation treatments.

“Rapeseed cake and beer bagasse are two potential organic treatments which have shown really positive results in previous studies,” says lead study author Maite Gandariasbeitia in a media release. “Their high nitrogen content promotes the activity of beneficial microorganisms in the soil, which helps to break down organic matter like manure and kill off nematodes and other parasites which damage crops.”

Nematodes are particularly detrimental and destructive to crop yields, researchers explain.

“Root-knot nematodes are a type of common soil parasite which penetrate a plant’s root tissue to lay their eggs and this activity causes galls, or knot-like swellings, to form on the root,” Gandariasbeitia notes. “This damage negatively impacts root development and means the crop can’t take up nutrients efficiently, slowing plant growth and ultimately, leading to reduced yields for farmers.”

When researchers incorporated beer bagasse and rapeseed cake into some soil along with fresh cow manure a significant reduction in galling on plant roots was seen after just one treatment.

Do natural pesticides lead to more crops?

After one year, plots given this unique blend also showed 15 percent higher crop yields than control plots. Additionally, experimental plots showed boosted populations of beneficial microorganisms in the soils, signified by a significantly higher soil respiration rate.

“There are still many questions to answer so that we can gain a better understanding of what happens in the soil during and after these biodisinfestation treatments,” Gandariasbeitia concludes. “This can help us to really elucidate what characteristics we should be looking for in other potential organic treatments to be effective in tackling soil parasite populations.”

The study appears in the journal Frontiers in Sustainable Food Systems.