Contour prairie strips affect adjacent soil but have only slight effects on crops

Prairie strips, or plantings of diverse perennial vegetation integrated into cropland, can have disproportionate ecological benefits compared to the amount of land they occupy. These benefits include improved water quality, reduced soil loss, reduced nutrient loss, and increased abundance and diversity of wildlife. However, the impacts of prairie strips on the adjacent cropland soil and crop health are unknown. We assessed the effect of long-term prairie strips on plant-available nutrients in adjacent soils (from 0.1 to 9 m distance from prairie strips), gravimetric soil moisture, soybean (Glycine max (L.) Merr.) and maize (Zea mays L.) leaf greenness (via soil plant analysis development or SPAD), and yield. Our results show strong effects of prairie strips on plant-available nutrients and early crop health in adjacent soils but little effect on soybean and maize grain yields. The prairie strip effects were strongly determined by crop (maize vs. soybean) but also likely climate. Prairie strips reduced soil moisture by 6% in adjacent cropland soils (<1 m) during a wet year, decreased salt-extractable nitrate by 23%, and increased Mehlich-III phosphorus and potassium by 63% and 24%, respectively, upslope compared to downslope from the prairie strip. Prairie strips had a marginal benefit to soybean SPAD but decreased maize SPAD by 7% within 1 m of the prairie strip. While prairie strips can significantly affect soils under adjacent cropland, they have little effect on crop yield.