Soil Heating and Drying Among Reduced Tillage Practices in Frigid Corn-Soybean Fields.

The long winters in the frigid Upper Great Plains region of the United States result in short growing seasons for corn-soybean systems. Historically, producers implement aggressive tillage practices to warm the soil in the spring months. However, many producers show a growing interest in reduced tillage practices to build soil health. Our objectives were to measure the effects of soil heating and drying in the planting and early growing seasons under vertical till (VT), strip till with shanks (ST-S), strip till with coulters (ST-C), and chisel plow (CP) and to measure crop yields respectively. Tillage plots (12 x 550m per plot) were installed at three producer farms in North Dakota and Minnesota using randomized complete block designs with three replicates at each farm. Soils textures among the farms ranged from sandy loams to silty clays. Soil temperature (T) and volumetric water contents (θ), soil thermal properties, soil penetration resistance, plant residue cover, plant populations, and crop yields were evaluated in 2015 and 2016. Soil T and θ was measured near the soil surface using handheld sensors and at 5, 10, 25, and 40 cm depths with near-continuously deployed sensors and data loggers.