Improving Phosphorus Management on Irrigated Potato

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


01 Feb 2005

2004 Annual Interpretive Summary

Improving Phosphorus Management in Irrigated Potato Production Systems, 2004

Rapid expansion of the processing potato industry in Manitoba has generated a need for information regarding fertilizer management strategies for irrigated potato. The second year of a 3-year study was conducted in 2004 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 2004 to assess the effect of four P rates (0, 30, 60, and 90 lb P2O5/A as broadcast/incorporated monoammonium phosphate) on tuber yield and quality, petiole P status, and post-harvest soil P status. Spring soil test P levels at the experimental site ranged from 20 to 29 lb NaHCO3-extractable P/A across replicates, and would have resulted in a recommendation for P fertilizer. Preliminary analysis indicated that P fertilizer rate did not have a statistically significant effect on total tuber yield, which averaged 306 cwt/A, or on tuber size distribution. Phosphorus fertilizer rate had no effect on main grade or bonus tuber yield, but did affect marketable yield. Contrast analysis revealed a significantly (p=0.005) lower marketable yield with the application of 30 lb P2O5/A compared to other treatments. However, the reason for this effect is unclear. Studies continue in 2005. MB-19F