Nitrogen Requirements for Potatoes Grown in a Bed-Planting Configuration

Start Date: 2018
Principal Investigator: Carl Rosen
Organization: University of Minnesota, Department of Soil, Water, and Climate
Status: Complete

summary

Planting potatoes in a bed configuration, with several rows planted between each pair of furrows, may be expected to confer advantages over the conventional hilled-row configuration. In particular, the more uniform spacing of the bed configuration may allow the crop to more efficiently intercept sunlight, nutrients, and water, which may result in improved yields and reduced nutrient losses. Our research on this approach to date indicates that the bed configuration may be superior to the hilled-row configuration for whole seed tuber production, but perhaps not for processing tuber production. To determine whether these findings are robust, we planted Russet Burbank potatoes in two configurations (bed and hilled-row) at two densities (13,000 and 34,000 seeds·ac-1), applying N at three rates (150, 200, and 250 lbs·ac-1 N). The study had a split-plot randomized complete block design with four replicates, whole plots defined by planting configuration, and subplots defined by planting density and N rate. We analyzed the effects of these treatments on tuber yield, grade, size, and quality. Potatoes grown in the bed configuration produced somewhat more undersized tubers (suitable as whole seed) and fewer marketable tubers, with less marketable yield in tubers over six ounces, than those grown in the hilled-row configuration. Planting density had a stronger effect, with potatoes planted at high density producing substantially more undersized tubers, fewer marketable tubers for processing, and less of their marketable yield in tubers over six or ten ounces than potatoes planted at low density. N rate had little effect on tuber yield, but potatoes grown at the lowest N rate (150 lbs·ac-1 N) had less of their yield in tubers over six ounces than those receiving N at higher rates. Both tuber specific gravity and tuber dry matter content were higher in the bed configuration than the hilled row configuration, higher at high density than low density, and lower in the lowest-N treatments than in treatments receiving higher rates of N. However, the results for tuber dry matter are difficult to interpret due to a significant effect of the interaction among planting configuration, density, and N rate. Petiole NO3 –N concentrations were higher in hilled-row plots than bed plots, were higher at low density than high density, and increased with the application rate of N. Soil water NO3 –N concentrations were higher in low-density subplots than high-density subplots. Vine and tuber N concentrations, as well as vine and total (vine plus tuber) N uptake, were lower in subplots receiving 150 lbs·ac-1 N than in those receiving the two higher rates. Vine N concentration and vine, tuber, and total N uptake were higher in hilled-row plots than bed plots. End-of-season soil NO3 —N concentration was not related to treatment. Based on results over two years, planting at high density in a bed configuration is superior to planting at low density or in a hilled-row configuration for whole seed tuber production. Conversely, the hilled-row configuration at low density is superior for processing-tuber production. A benefit of bed planting for lower soil water nitrate concentrations below the root zone was found in 2018, but not in 2019. Overall, bed configuration did not confer the benefits in terms of N uptake, yield, and tuber size for processing potatoes or reduced nitrate leaching originally hoped for.

Objectives

Determine whether the bed-planning configuration increased N uptake and tuber yield and decreased N requirements and N losses to leaching relative to the conventional hilled-row configuration, and whether these benefits were more pronounced at the higher density.

Key Findings