Measuring the Nutrient Accumulation Rates of High-Yielding Potatoes and Sugar Beets

One important aspect of 4R Nutrient Stewardship is applying fertilizer at the right time. This study with the University of Idaho was designed to measure the accumulation of nutrients in the tops and roots of sugarbeets during the growing season. Samples of leaves and roots were taken every 16 days between June and the October harvest. Harvested plants were partitioned, weighed, and their chemical composition analyzed to determine seasonal nutrient accumulation patterns. Data were fit to accumulation curves using the clamped cubic spline interpolant program.

Total beet root yield was 42 t/ha. Total seasonal N accumulation was 270 kg/ha, with 50% found in the plant top. Total seasonal P accumulation was 69 kg P/ha with 20% of the P in the tops. Total seasonal K was unexpectedly high at 530 kg K/ha, with 52% in the tops. The total seasonal accumulation was also measured for the other essential nutrients, but not reported here. In addition to the total accumulation, the pattern of uptake during the growing season was measured and will be used to refine the timing of fertilizer application to match peak demand periods.