After reading recent questions from readers of Strip-Till Strategies about soil-sampling procedures and nitrogen credits — as well as nitrogen rates in strip-tilled corn following soybeans — Orthman Mfg. Co. lead agronomist Mike Petersen offered some recommendations.
After a crop of soybean,s there are 25 to 40 pounds of organic nitrogen in the upper 12 inches of the soil, says Petersen, who served as a soil scientist with the USDA’s NRCS for more than 30 years. That amount of nitrogen offsets the amount of total inorganic nitrogen that needs to be applied, he says.
Petersen recommends that strip-tillers pull soil samples parallel to the previous year’s rows. Move left or right every year to take soil samples in the zone where the crop will be planted, he says. This gives strip-tillers a good picture of where nutrients are located in the soil in relation to the root zone.
This method of sampling requires that strip-tillers take soil samples annually, Petersen says.
“Annual soil sampling provides growers an up-to-date picture for every crop and makes incremental adjustments to the nutrition picture,” he says. “With fertilizer prices remaining high, annual strip-till zone sampling is a wise step in better fertilizer management.”
Send your recommendations about soil sampling techniques and fertilizer rates, along with any other strip-till questions, and we’ll share those in future issues of Strip-Till Strategies. E-mail them to me at firstname.lastname@example.org or call me at 503-507-4423.