Impact of Small Grains on Water Quality - Literature Review

Nutrient loading from agricultural sources is one of the greatest barriers to water quality in the Upper Midwest. The potential for integration of small grains—cereal crops including barley, oats, rye, and wheat—into existing dominant corn and soy rotations may provide an opportunity to reduce nutrients leaving fields. Despite the acknowledgement of diversification and extension of cropping systems (including with small grains) as a conservation practice, the ability for these crops to manage nutrients is not well understood, specifically when planted as a cash crop rather than a cover crop. Nutrient reductions from agricultural land as a whole would contribute significantly to nutrient reduction goals throughout the region, thus supporting beneficial and designated uses of water bodies including the Great Lakes. Lowering nutrient and sediment loading will lead to greater water clarity, improve oxygen levels, and reduce toxicity related to algal blooms. 

Research supports the addition of small grains to rotations to promote organic matter, increase microbial biomass, and enhance water and nutrient retention, all resulting in improved soil health. Increased diversity in above- and below-ground biomass supports soil life, leading to improved soil structure, reduced soil erosion, improved water infiltration, and bolstered system resilience. Other documented small grains benefits include reductions in pesticide and synthetic fertilizer use by smothering weeds, breaking pest/disease cycles, and opening windows to plant nitrogen-fixing legumes and spread manure.

This review of literature seeks to better understand the nutrient reduction qualities and potential of small grain crops in the Upper Midwest.