Boron on upland positions was lowest from the Missouri Couteau west, with highest levels in the Red River Valley and the Souris Lake Plain. Boron levels were lowest west of the Missouri Coteau. In depressional positions, boron was highest in the east and northeast and lowest west of the Missouri Coteau. It is important to note that although soil levels appear low in boron, critical levels for boron application in North Dakota have not been established. The line between not enough and too much boron is very fine.
Toxicity is a hazard of boron application when adequate amounts are present for plant uptake.
Figure 10 . Boron levels, ppm, upland positions. Boron levels, ppm, sloping positions. Boron levels, ppm, depressional positions. Organic matter and soil texture will eventually be determined on these samples to further define probable areas of copper response on these landscape positions.