Improving Phosphorus Management on Irrigated Potato
Assessed the effect of phosphorus management on potato yield and quality under Manitoba’s irrigated production systems.
IPNI-2003-CAN-MB19
13 May 2003
Justification
- Manitoba’s processing potato industry has undergone rapid expansion in recent years, contributing to significant increases in potato production in this province. In Manitoba in 2001-02, an estimated 12.8 million cwt of processing potatoes valued at $97.3 million were marketed. As of 2001, potatoes were being produced on an estimated 78,500 acres. Within the near future, Manitoba’s potato acreage is expected to exceed 100,000 acres as production grows to meet the demand of new and existing processing facilities.
Limited research has been conducted to assess the effect of phosphorus management on potato yield and quality under Manitoba’s irrigated production systems. Tomasiewicz (1994) found no effect on potato yield or quality when P fertilizer was applied to a soil that would typically receive a P recommendation. Results of petiole testing indicated that petiole P concentration responded consistently to P fertilizer treatment, but that critical nutrient concentrations developed for other areas may not be directly applicable for Manitoba conditions. However, this study was conducted only at one site for one year. In studies conducted from 1991 through 1994, Geisel (1995) found that P fertilization increased tuber yield at 2 of 5 sites. Both responsive sites contained less than 40 lb extractable P/acre, and achieved optimum yields with the addition of 35 to 50 lbs P2O5/acre. Geisel (1995) also concluded from this study that petiole P concentration did not correlate well with fertilizer P rate or yield and, as a result, questioned the value of petiole testing for P.
Currently, much of the information available to producers is based on research conducted outside of Manitoba that may not be directly applicable under local soil and environmental conditions. A better understanding of phosphorus requirements for potato may assist in the development of phosphorus management practices that optimize potato yield and quality, and thereby enhance returns for producers.