Nitrogen and Phosphorous Fertilizer Timing, Source, and Placement in Sugarbeet

Abstract

Core Ideas Evaluated 4R strategies of fertilizer N source, placement, timing in sugarbeet. No benefit of N with P fertilizer in 5‐ by 5‐cm band based on root and sucrose yield. No need to modify fertilizer N and P based on anticipated sugarbeet harvest date. Late harvest may mitigate N losses due to lower soil mineral N at late than early. An industry‐led renaissance of nutrient management is occurring in North America to apply the correct rate, source, placement, and timing. Crop consultants have recently recommended including fertilizer N in a 5‐ by 5‐cm band during sugarbeet (Beta vulgaris L.) planting, but this practice has not been rigorously evaluated regarding its influence on N dynamics and/or yield. In 2013 to 2015 at two fields in southwestern Ontario, an experiment evaluated the impact of fertilizer application on sugarbeet (Beta vulgaris L.) productivity at two harvest timings (mid‐September vs. late October–early November). Treatments were a negative control: no fertilizer (N0P0), positive controls: pre‐plant broadcast incorporated N (NpreP0) and in‐season, injected N (NseasonP0) and six fertilizer application method and timing combinations, all at an equal N application rate (112 kg N ha−1) to determine the need to include both N and P applied in a 5‐ by 5‐cm band (N5x5P5x5). The lack of treatment × harvest date interaction on all parameters suggested no need to adjust fertilizer based on harvest date. Average root yield in N5x5P5x5 treatment was 82 Mg ha−1, which was 15 to 20 Mg ha−1 greater than N0P0 but not different than other treatments. Sucrose yield and soil mineral nitrogen (SMN) did not differ among the fertilized treatments. From an agronomic and environment perspective, there was little evidence to suggest the need to band fertilizer N with the seed.