Improving Phosphorus Management on Irrigated Potato

Assessed the effect of phosphorus management on potato yield and quality under Manitoba’s irrigated production systems.


16 Feb 2006

2005 Annual Interpretive Summary

Improving Phosphorus Management on Irrigated Potato, 2005

Rapid expansion of the processing potato industry in Manitoba has generated a need for information regarding fertilizer management strategies for irrigated potato. The third year of a 3-year study was conducted in 2005 to determine the impact of phosphorus (P) fertilizer rate on potato tuber yield and quality, and the effectiveness of petiole P concentration in assessing P status of potato (cv. Russet Burbank).

A field experiment was conducted at one location near Carberry in 2005 to assess the effect of four P rates (0, 30, 60, 90 lb P2O5/A as broadcast/incorporated monoammonium phosphate) on tuber yield and quality, petiole P status, and post-harvest soil P status. The experimental site selected had a spring soil test P level of 15 parts per million (ppm) Olsen P which would have resulted in a recommendation for P fertilizer. In 2005, total tuber yield was considerably higher than in previous years of the study, averaging 463 cwt/A. Preliminary analysis indicated that increasing P fertilizer rate resulted in a linear increase both in total tuber yield and in the yield of tubers greater than 12 oz. While the yield of small and maingrade tubers was not affected by fertilizer treatments, bonus tuber yield increased linearly with increasing P fertilizer rate. Phosphorus fertilizer application appeared to have little effect on quality parameters including specific gravity, fry color, sugar ends, and yield losses due to hollow heart and brown center. MB-19F