06/01/06 Nitrogen testing for potato fields

Bryan Hopkins has some interesting results from tests he did in Idaho potato fields. With support from Valley Wide Co-op and the Idaho Potato Commission Hopkins used aerial images as a guide to set up management zones for productivity. HOPKINS "In the good soil areas we were putting on substantially more nitrogen than we would normally do and we were getting real nice yield increases in those areas and then in the poor soils we're backing the nitrogen off. In some cases increase yields there too but usually we just had better tuber quality." The University of Idaho potato specialist says a blanket approach to nitrogen application might not work in all fields especially where there is a rolling terrain or soil erosion. Hopkins' variable rate nitrogen tests were conducted in grower's fields, on a large scale with consistent results. HOPKINS "We're looking at about a 200 dollar per acre increase in gross crop value and the cost of the technology is only right around 15 or 20 dollars." Bottom line, says Hopkins, growers need to add nitrogen where yield is highest and back off on the low yield areas. Hopkins feels it's important that growers take the time to manage each zone based on its condition and soil tests. Voice of Idaho Agriculture Bill Scott