Increasing Soybean Meal Protein Level Reduces GHG Emissions and Improves Farm and Food Sector Sustainability Metrics

Abstract

Soybean [Glycine max (L.) Merr.] is the most important legume crop in the United States, being rich in essential amino acids, essential fatty acids, and oil. However, soybean protein content has been declining for decades, and a comprehensive ecosystem-based approach to address that decline does not exist. Furthermore, feed production comprises about 90 percent of greenhouse gas emissions from pig and poultry production, so improving soybean meal protein has significant farm revenue and emissions implications. Our goal was to develop a system model that characterizes and quantifies the link between improved soybean protein, improved corn demand, and reduced emissions. Our research objectives were to (i) quantify and predict the feed value of improving soybean protein, and volume required, (ii) quantify the effect of improved soybean meal protein on increasing feed corn demand, and (iii) quantify the impact of increased soybean meal protein on emissions of swine and poultry operations. Our results show that when soybean meal protein increases from 44 percent to 50 percent, corn demand increases up to 13.8 percent, lifecycle emissions decrease by up to 4.6 percent in pig diets and decrease by up to 4.5 percent in poultry diets; while improving implied soybean value by enough to offset the volume lost by improving protein. Our findings also indicate that as soybean protein content declined, crop farmers have lost billions of dollars in corn and soybean revenue since about 2000 to synthetic amino acids and corn distillers-dried grain with solubles (DDGS), and GHG emissions in feed has been gradually increasing. These findings are significant to AOCS membership because they illustrate how GHG emissions can be reduced by improved soybean protein, thereby delivering on farmer goals of increasing feed value, and supporting food company goals of improving environmental sustainability.