Waseca, Minn.-Studies by the Agriculture Utilization Research Institute (AURI) could result in a new source of phosphorus, potassium, and micronutrients for crop fertilizer from the ash of biomass. According to AURI, the effectiveness of ash left after burning crop residues for energy will be evaluated as corn fertilizer on test plots at the University of Minnesota’s Southern Research and Outreach Center here. “Many ag-processing facilities generate ash, which is often spread on cropland. But every kind of ash is a little bit different,” reported UM Soil Scientist Jeff Vetsch, who will lead the research trials. The ash from burning turkey litter to generate electricity is being marketed in a limited area in Minnesota by Cargill, but so far there’s little experimental evidence demonstrating how field crops respond to biomass ash, Vetsch reported. “That’s why we are doing these trials. We want to see how available the nutrients are compared to conventional fertilizers. We expect to show growers that ash waste is a valuable source of fertilizer, and that there are no negative effects on crop production.” In general, he noted, agricultural ash contains about 200 to 300 pounds of phosphorus and potassium per ton, plus important micronutrients such as sulfur and zinc, but very little nitrogen. Vetsch added that ash’s high pH may provide a small liming effect as well.
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