Deep Banding–One Year Later
Deep placement of potassium and phosphorus fertilizer is a practice that PFI members have researched for several years. ISU soil scientist Antonio Mallarino has also been working on the topic (see The Practical Farmer, Fall, 1997), and reports that, for producers using no-till and ridge-tillage, deep placement of potassium fertilizer sometimes gives a yield response even beyond that of the same fertilizer surface-applied. In 1997, two cooperators followed up on deep banding research that they carried out in 1996.
In 1996, both Jeff and Gayle Olson (Mt. Pleasant) and Paul and Karen Mugge (Sutherland) saw significant corn yield increases from fertilizer that was deep banded, compared to no fertilizer at all. Both used a combination of 18-46-0 and 0-0-60, so these were not single-nutrient trials. However, they applied enough total nitrogen that the crop should not have been affected by the N in the deep band. Their question in 1997 was whether the benefit would last another year. As Table 1 shows, neither Paul Mugge’s soybeans nor Jeff Olson’s corn showed a residual fertilizer effect in 1997.