Iowa does not grow enough potatoes to supply its own needs. The average yield is about 100 bushels per acre. Because of high summer temperatures and uneven distribution of rainfall during the growing season, the climate is not ideal for the production of potatoes. However, yields in farm and home gardens could easily be doubled by following the practices outlined here. Several large commercial growers in Iowa average 400 to 500 bushels per acre of marketable potatoes each year.
An ideal potato soil should be high in fertility, friable, deep, high in organic matter, and should have an acid to slightly acid reaction. Soil type definitely influences the shape of the tuber. Light, well-aerated soils produce better shaped tubers than heavy soils. Sandy soils are excellent for early potatoes, but in dry seasons the crop may suffer from lack of moisture. Heavy clays fail to produce tubers of good quality or shape. Sandy loams and medium loams are the most satisfactory upland soils. Much of the commercial acreage in Iowa is on peat and muck. They are excellent potato soils when they have adequate drainage. Because of their high percentage of organic matter and lower temperature, they yield more heavily than mineral or upland soils, when properly managed.
Haber, E. S.
"Potato growing in Iowa,"
Bulletin P: Vol. 4
, Article 1.
Available at: http://lib.dr.iastate.edu/bulletinp/vol4/iss104/1