Data from: Depth Matters: Soil pH and Dilution Effects in the Northern Great Plains

Near-surface soil acidification is becoming prevalent in dryland cropping systems throughout the northern Great Plains. To ensure management recommendations are optimized for crop production, soil sampling guidelines are needed that account for depth stratification of soil pH in surface horizons. Soil pH data from two long-term dryland cropping system experiments were evaluated to document outcomes from three depth increments: 0-7.6 cm, 0-15.2 cm, and 0-30.5 cm. The experiments were established in 1984 and 1993 on the Area IV Soil Conservation Districts Cooperative Research Farm near Mandan, North Dakota USA. Soil cores were collected from the surface 30.5-cm depth near the middle of each experimental plot using a hydraulic probe. Collected soil cores were carefully split into 0-7.6, 7.6-15.2, and 15.2-30.5-cm increments and composited by depth. Samples were dried, mechanically ground, and analyzed within 6 wk of collection. Soil pH was measured in a 1:1 soil/water mixture (by mass) with an ion-selective glass electrode. From the sampled depths, weighted averages were used to calculate soil pH at 0-15.2 and 0-30.5 cm. Data may be used to better understand depth effects on soil pH under dryland cropping systems within a semiarid continental climate. Applicable USDA soil types include Temvik, Wilton, Grassna, Linton, Mandan, and Williams.