LESSONS FOR AMERICAN POTATO GROWERS. 5 



as to other reasons. We have, in fact, better soils than Europe in 

 almost unlimited area, including types especially adapted for pota- 

 toes, and we actually produce, in a few sections where potato growing 

 is made a specialty, as large crops as the Germans. 



CLIMATE. 



It must be recognized that northern Europe, with its cool and 

 equable summer, has a climate better adapted to the potato than any 

 except possibly the most northern part of the United States. The 

 average mean temperature for July in Posen, in north Germany, is 

 64° F. Practically all of our potato districts, with the exception of 

 Aroostook County, Me., lie south of the isotherm of 65° F., and the 

 average summer heat in most of our potato States is not far from 10° 

 higher than in Germany. Most of our varieties of potatoes are unable 

 to withstand high temperatures and in the southern two-thirds of our 

 country are subject to tip -burn, sun scald, and other troubles, which 

 result in abnormal maturity. Farther south, as is well known, only 

 early spring or fall crops can be grown. Much of the area of the 

 United States is not in the potato belt. 



On the other hand, the rainfall of Germany is often less than is 

 needed for maximum production, and if we had a heat-resistant potato 

 our more liberal precipitation would give us a decided advantage. 

 The average annual rainfall in Posen is less than 19 inches, of which 

 nearly 13 inches fall in the growing season, from April to October, 

 inclusive. Northern Maine has, however, 20 inches during the same 

 summer period, western New York about 24 inches, and Michigan 

 20 'inches. In the irrigated districts of the Western States the pota- 

 toes receive perhaps even more water than they require. The cool 

 nights of these regions and their midday heat subject the potatoes 

 to temperature changes greater than are found in Germany. 



COMPETITION WITH MAIZE AND PETROLEUM. 



There is a fundamental economic condition in the United States 

 that will always influence the extension of potato culture. The hot 

 summers which are so injurious to the potato plant are ideal for the 

 development of Indian corn, so that in the corn belt there can be no 

 profit in growing potatoes in excess of those needed locally for table 

 use. Corn can be produced more economically, is better for stock 

 feeding, and is a cheaper source of starch, glucose, and alcohol. The 

 scarcity and high cost of farm labor in the United States are other 

 economic factors that influence the result. Farther north, however, 

 and in the elevated districts of the West where corn can not so well be 

 grown, the potato has a larger place. 



