02/28/06 Sugarbeets and phosphorus

Sugarbeets are unique, says University of Idaho's Bryan Hopkins, because they send down a dominate tap root without lateral branching until about the third month of growth. Because it is drawing nutrients from the subsoil Hopkins says the root system doesn't help the sugarbeet plant absorb what little phosphorus there is. HOPKINS "The bottom line is that we found we didn't get much of a response when we broadcast the nutrients or when we placed the fertilizer band shallowly but if we put the fertilizer band directly below the seed about six inches deep we were routinely getting a two to three ton increase in yield without a drop in sugar percentage. We think that the roots are more active down at six inches than they would be closer to the surface and that the beet plant is getting more of that phosphorus for a longer period of time." There is the cost of the fertilizer and some extra fuel expense to pull an injection shank through the field while marking the rows. But there's also a cost just to broadcast the fertilizer and Hopkins' four year study in eastern Idaho and the Magic Valley shows benefits from deep injection prior to or at sugarbeet planting. Voice of Idaho Agriculture Bill Scott