Climate, Soils and Rotation 99 



tilizers is steadily increasing, being very hea\y in the 

 East from Maine to Xew York. Spraying with bordeaux 

 mixture for the late blight and rot is prevalent in the East. 

 Digging comes so near to freezing weather that the grain 

 crops grown in rotation with potatoes are those sown in 

 spring. Oats are used mostly with spring wheat in the 

 Red River section. Oats and peas and barley are grown 

 to less extent. 



(3) An intermediate belt between these two from 

 Nebraska to New Jersey and Long Island. Potatoes 

 from this belt come on city markets in summer and early 

 fall, part being stored for winter shipment. Summer heat 

 is not so dangerous as in the South, but there is usually 

 an effort to avoid its effects to some degree either by 

 planting early enough to get the crop nearly mature 

 before midsummer or else late enough to have much of 

 the gro\rth come in the cool fall months. The effect of 

 summer heat on seed vitality is often severe, but a large 

 share of the seed is grown locally. The use of imported 

 seed from the North is increasing, particularly in the 

 regions of more intensive culture, such as Long Island. 

 Winter wheat and rye often follow the potato in rotation 

 in this belt. 



(4) The irrigated sections of the West, destined to 

 great extension m the future. The problems of the 

 potato-grower in other sections are here largely replaced 

 by those peculiar to the growth of the crop under irriga- 

 tion. New systems of culture have been worked out to 

 meet the new conditions. Control of moisture has en- 

 abled some of the heaviest yields ever grown in the 

 United States. Owing to the natural high fertility of 

 arid soils, fertilizers are unknown. Nitrogen and organic 

 matter are secured bv rotation with alfalfa. 



