As the cellulosic industry gets closer to bringing cellulosic ethanol to market, there have been some concerns regarding how biomass harvesting will affect soil health and yields. These very issues were discussed by Dr. Stuart Birrell a professor at Iowa State University, whom with his team, have been studying soil sustainability as it relates to biomass harvesting.
His latest research has been in partnership with POET’s Biomass division, who is now in the midst of the largest biomass harvesting of light corn stover and corn cobs in the world. Birrell notes that to determine how much biomass a farmer can remove from his field without having adverse effects, it is important to the farmer to understand the health of his soil.
Birrell said during Project Liberty’s BIomass Harvest Kickoff, that there is a lot of variability in fields. In some fields, a farmer won’t be able to remove much, if any biomass whereas in other fields, he may remove more. On average, POET is asking for 1 ton from each field, which averages out to around 20-25 percent of the total biomass. However this could change in the future as bushels per acre increases. In fact, seed companies are predicting that within the next 15 years, corn harvests will double and this feat will be achieved without putting any additional land into production.
Birrell also noted that biomass harvesting may encourage some farmers to move to no-till techniques, which help reduce the amount of carbon released from the soil.
So ultimately, how will a farmer know how much biomass he can remove from his field? With some new technology that Birrell’s team is working on – variable rate removal machines. As a farmer is harvesting his biomass, the machine will automatically adjust how much biomass is removed based on certain soil health characteristics. This will ensure that soil health is not jeopardize by removing too much biomass.