Of the hundred-million-plus tons of fertilizer sprayed onto farm fields each year, much of it eventually ends up polluting the air or flowing into water, where it can cause toxic algae blooms like the green slime seen in Florida. One startup is helping farmers begin to replace standard chemical fertilizers with microbes that help them grow without the bad side effect of pollution. The first product, designers for corn farmers, is a microbe-filled liquid that can be added to fields using standard equipment when a farmer plants seeds. Like chemical fertilizers, this allows the plants to access nitrogen they need to grow. Right now, the first product supplies 25 pounds of nitrogen per acre–for corn farmers, that’s only about 20% of the total nitrogen needed, so farmers use it in combination with chemical fertilizer. But given the huge volumes of fertilizer that are used, that reduction has an impact. Pivot Bio estimates that if the product was used on 35% of corn fields, it would cut nearly 20,000 metric tons of nitric oxide emissions, or the equivalent of taking 1.5 million cars off the road.