North Dakota State University

Research Interests:

I was hired in June, 1993 as Extension Soil Specialist in spite of my background in precision agriculture, corn and soybean production and tile drainage. Now, most of my presentations and research activities are in these areas. My previous Illinois research indicated that it took about 1 soil sample per acre in a grid pattern to depict the soil nutrient (P, K, soil pH) patterns in a field. My work in North Dakota resulted in the same conclusion. A 2 ½ acre grid in the ‘I’ states is only ‘successful’ because the values are mostly in the ‘high’ range, and although variability is present at a smaller spatial scale, the recommendation for P, K is the same; soil pH being the exception. However, into the second year of North Dakota sampling research it became clear that residual nitrate levels form patterns (zones) that are stable from year to year, related to topography. A number of zone delineation tools were researched across Montana, North Dakota and western Minnesota under a mutual USDA grant and we found that these zone delineation tools, including soil EC sensor, aerial photography, satellite imagery, multi-year yield maps, and particularly topography, were useful in forming relevant zones across the region. Today, zone sampling is the most-utilized method of sampling for site-specific nutrient management. The method is preferred over any grid sampling for residual nitrate, but also for all other soil nutrients, except where large buildup quantities of nutrients have previously been applied or large manure applications have been made to a field. After this work, it was also clear that the soil nutrient recommendations for North Dakota were inadequate to relate to the new sampling science. Therefore, from 2005 through the present, significant energy and funds were expended to modernize spring wheat/durum wheat, corn and sunflower recommendations. As part of these studies, active-optical sensors were also used to relate readings with yield prediction. Corn algorithms for use with active-optical sensors to direct side-dress N application for corn have now been published, with investigations on-going for sunflower, wheat and sugar beet. For more detailed information, see my published works under Extension publications and Scientific publications.