Seed Placement Relative to Fertilizer Band Position in Conventional and Strip Till Sugar Beet.

Strip tillage (ST) equipment typically bands fertilizer below the seed; however, for sugar beet (Beta vulgaris L.) placement either too close or too far away from the seed may be detrimental. Two field experiments were conducted to determine (1) the optimum depth of the fertilizer band for fall ST at difference fertilizer N application rates, and (2) the effect of lateral seed placement relative to the fertilizer band on plant growth and harvest yield. Strip tillage was performed in the fall using a shank-type implement that tills 30-cm wide strips spaced 60 cm apart in small grain residue. In Experiment1, N and P fertilizers were banded below the seed at depths of 2.5, 7.5, or 12.5 cm from the soil surface and urea N was applied at 78, 146, or 212 kg N ha^-1. In Experiment 2, seed was planted directly above the fertilizer band (0 cm) or at lateral offsets of 7.5, 15.0 or 22.5 cm. Plant population tended to be lowest when fertilizer was placed at 2.5 cm. In 2008 plant population was 7 to 13% less when placed at 2.5 or 7.5 cm compared to the 12.5-cm depth. Nitrogen content of above-ground biomass (AGBM) was greatest with the 7.5-cm depth. Plant population was consistently 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. Optimum band depth did not depend on N application rate. Early season plant dry weight and N uptake was greatest when seed was planted directly above the fertilizer band and decreased as the lateral offset increased. Sugar beet yield was unaffected by seeding offset except at the 22.5 cm offset where sugar yield was between 10 and 15% less than all other offset distances. It was concluded that (1) 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, and that (2) the lateral offset between plant row and fertilizer band should be no more than 7.5 cm for optimum early plant growth and harvest yield.