A 3-year study says that strip-till with deep banding of phosphate and potash increased soybean yields 10% vs. no-till and broadcasting fertilizer and 7% more than no-till with deep banding of fertilizer.
The 3-year research study was done by University of Illinois scientists Bhupinder S. Farmaha, Fabián G. Fernández and Emerson D. Nafziger, all faculty at the University of Illinois' Department of Crop Sciences.
The researchers also reported that strip-till can offer improved seedbed conditions and deep banding of fertilizer vs. no-till.
The researchers decided to quantify the effect of rate and placement of phosphate and potash in strip-till and no-till on soybean seed yield. They conducted their research near Urbana, Ill., on Flanagan silt-loam and silty-clay-loam soils with soybeans planted following corn.
In the main research plot, they studied tillage and fertilizer placement with strip-till and deep band (STDB); no-till and broadcasting fertilizer (NTBC); no-till and deep banding (NTDB); and deep band placement 6 inches beneath the planted row.
In the sub plot, researchers analyzed phosphate fertilizer rates (0, 10.7, 21.4 and 32.1 pounds of phosphate an acre per year) and potassium fertilizer rates (0, 37.5, 75 and 150 pounds of potash acre per year). Soil, water and trifoliate phosphorus and potassium yield were measured.
The research found that yield, number of pods per plant, trifoliate phosphorus concentration and accumulation increased with phosphorus fertilization uniformly across tillage and fertilizer placement.
The scientists say this indicates that fertilization can't be reduced with deep-band applications relative to broadcast applications without a yield reduction. But they reported that deep banding increased subsurface soil-test levels.
Potassium fertilization decreased yield in both no-till systems, but not in the strip-till/deep-band system. While phosphate and potash placement produced no differences, improved soybean yield and nutrient accumulation resulted from a tillage effect with strip-till/deep-band relative to the no-till systems.