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Sugarbeet productivity as influenced by fertilizer band depth and nitrogen rate in strip tillage

Stevens, W.B., Evans, R.G., Jabro, J.D., Iversen, W.M.
Journal of sugar beet research. 2011 v.48 no.3-4 pp. 137
Beta vulgaris, aboveground biomass, band placement, climate, crop yield, fertilizer rates, monoammonium phosphate, nitrogen, nitrogen content, phosphorus fertilizers, risk, roots, sandy soils, seedling emergence, seedlings, seeds, spring, strip tillage, sucrose, sugar beet, urea, urea fertilizers, Montana
Most modern strip tillage (ST) implements are capable of banding fertilizer below the seed. For sugarbeet (Beta vulgaris L.), placement either too close or too far away from the seed may be detrimental. A field study was conducted at Sidney, MT to determine (1) the optimum depth of the fertilizer band for fall ST and (2) if the optimum band depth is affected by N application rate. Strip tillage was performed in the fall using a shank-type implement. Nitrogen and P were banded below the seed row at depths of 2.5, 7.5, or 12.5 cm from the soil surface. Nitrogen was applied as dry urea at 78, 146, or 212 kg N ha-1 and P as monoammonium phosphate at 24.4 kg P ha-1. Interactions between band depth and N rate were not significant. Fertilizer band depth affected plant population in one of two years resulting in reductions of 7 to 13% when fertilizer was 2.5 or 7.5 cm deep compared to the 12.5-cm band depth. Nitrogen content of above-ground biomass (AGBM-N) was greatest with the 7.5-cm depth. Plant population was somewhat lower when N was applied at 212 kg N ha-1 resulting in a harvest population that was 7% less than when N was applied at 78 or 146 kg ha-1. Fertilizer band depth did not affect root sucrose content, root yield or recoverable sucrose yield. It was concluded that fertilizer band placement between 7.5 and 12.5 cm deep (5 to 10 cm below the seed) resulted in the best combination of N uptake and seedling emergence. Caution is warranted when banding N shallower than 12.5 cm and/or at rates greater than 145 kg N ha-1 where conditions maximize the risk of seedling injury (e.g., dry climate, sandy textured soil, spring ST).