Climate, Soib and Rotation 109 



the potato. In the northeastern states the most common 

 rotation is one of a tilled crop like potatoes or corn the 

 first year, a small grain crop usually oats or wheat the 

 second year, in which grass seeds are sown. In regions 

 of the most intensive culture, this hay crop is cut only 

 one year and in that case it is clover. In others the mix- 

 ture is clover and timothy with occasionally redtop, which 

 is cut several years. Further South, where grasses do 

 not grow well, it is necessary to use annual hay crops like 

 crimson clover or cowpeas. In the North grass seeds 

 are seldom sown alone. The practice of summer tillage 

 before sowing alfalfa has been found so valuable that it is 

 coming into use for the sowing of the grasses as well, 

 particularly on weedy soils, or on those on which it is 

 difficult to get seeds sown with grain to catch. 



The relative profit to be expected from the growth of 

 potatoes, grain and hay determines the number of years 

 which each wdll use in a given rotation for any locality. 

 In New England hay and potatoes are both relati^'ely 

 more valuable than grain, and each may occupy the soil 

 for two years out of a five-year rotation. In New York 

 and Pennsylvania the hay may be cut for several years. 

 Going South, hay is grown less and less until in the truck- 

 ing section potatoes are rotated mainly W' ith other truck 

 crops as spinach and cabbage. In the middle West the 

 higher cost of transportation of potatoes and hay com- 

 pared with grain causes the latter to be grown several 

 years in a rotation, as is often the case in the Red River 

 section. 



Hai/ plants 



Alfalfa is the best crop to rotate with potatoes where 

 it can be grown with profit, as in the Rocky ^Mountain 



