Yield and Quality Responses of Ivory Russet and Russet Burbank Potatoes to P Rate, Banded P Application, Soil Fumigation, and Mycorrhizal Inoculation in High-P Soils

Summary

The reason why potatoes sometimes respond to P fertilizer in high P testing soils continues to be puzzling. However, based on this research, it is unlikely due to lack of mycorrhizal associations. Ivory Russet was more responsive to P the first year of the study than Russet Burbank, but both varieties responded to P fertilizer the second and third years. Phosphorus response was observed under both fumigated and nonfumigated conditions but there seemed to be a greater response to P when fumigation was used. Banding was effective in two of the three years and may reduce the need for higher P application rates. While potatoes can respond to P fertilizer in high P testing soils, yield increases may not be sufficient to offset the cost of P fertilizer when fertilizer prices are high, especially if soilborne diseases are prevalent. Further research is needed to determine if new potato varieties can be developed that can more efficiently take up and utilize P at lower soil test P levels.