Hill Shape Influences on Potato Yield, Quality, and Nitrogen Use Efficiency

As hill shape significantly influences water infiltration into potato hills, modification of hill shape may be an opportunity for improving fertilizer nitrogen use efficiency on sandy soils. The interactive effect of different hill shapes and rate of nitrogen (N) fertilizer application on N use efficiency was assessed in a 3-year potato (Solanum tuberosum L. cv, Russet Burbank) field experiment on Plainfield loamy sand soil at Hancock, Wisconsin, USA. A split-plot design was used with hill shape (shaped-plateau, pointed, or standard) as the main plots and in-season N rates (0, 135, 202, 269 kg N ha(-1)) as the split plots with four replications in randomized complete blocks. In 1 of 3 years, potato yield and quality were increased and less N was needed to optimize yield and quality where the hills were shaped. In the other 2 years, the more blocky hills (shaped-plateau and standard) showed consistent tendencies (p = 0.02 to 0.19) toward better crop performance; however, time of hill formation was influencing these results with root pruning likely the influencing factor. Results of this study show more blocky hills with only one hilling operation at emergence can significantly improve potato yield and quality and N use efficiency on these sandy soils.