AN ECONOMIC-ANALYSIS OF REDUCING NITROGEN ON EARLY HARVEST SUGAR-BEETS

Both sugarbeet (Beta vulgaris L.) producers and sugar processors have interests in lengthening the harvest and processing season by harvesting a certain percentage of sugarbeet acreage earlier in the year. As a general practice, many growers have not adjusted their rates of N on acres intended for earlier harvest. Previous research has shown benefits of increased production from reducing the rate of N on acreage planned for earlier harvest. However, similar benefits of increased profitability were not considered. This study was designed to examine the economic benefit of reducing N on acreage intended for earlier harvest. A response function was estimated from three years (1988-1990) of field trials at the University of Wyoming Powell Research and Extension Center to relate net return from sugarbeets to (i) the amount of N/acre (0-300 lb) and (ii) selected date of harvest (from 10 September-24 October). For each of the 45 harvest dates (10 September-24 October), the optimal (highest profit) rate of N was identified. A fourth year of field data (1991) was then used to test the predictive performance of the estimated function. As opposed to simply applying N at a constant rate of 200 lb/acre (with no regard to time of intended harvest), reducing the rate of N by 12 to 14 lb/acre for each week of earlier harvest increased net return in the early (September) harvest season. Specifically, the increase in net return (from lower rates of N) ranged from $5/acre for sugarbeets harvested in late September (24-30 September), to $14/acre for sugarbeets harvested in early September (10-16 September).