Phosphorus and Compost on Potatoes
Compare compost with mineral P fertilizer as a means of supplying P to potato.
IPNI-2001-CAN-AB21
10 Apr 2001
Justification
- The potato industry in southern Alberta has expanded from about 22,000 acres in 1997 to about 43,000 acres anticipated in 2001. This has occurred because of construction of two potato processing plants; Lamb Weston and McCains. Further expansion of the industry is anticipated.
Labs and agronomists in Alberta are uncertain as to what phosphorus recommendations should be used for potatoes. The farmers are usually applying from 120 to 140 lbs/A P2O5, regardless of what the soil test results are. Petiole testing for phosphorus has been commonly used only in the past three years. Standards for what are adequate levels of phosphorus in petioles are not adequately defined for Southern Alberta. At Brooks from 1996 to 1999, as part of our project for potatoes, we measured soil and tissue phosphorus on potatoes. Tissue phosphorus frequently was adequate, according to USA standards, in early July but became deficient later in the season. In some cases we applied strips of higher rates of phosphorus but got no response in yield of tubers.