THIUSE YEAR ROTATION. 171 



having two sections grass, hay or pasture, and the 

 third section grain, seeding with the regular mixture 

 mentioned in the four years' rotation. 



The section that has been in grass for two years 

 is plowed in August and thoroughly harrowed and 

 cultivated alternately until October; then ribbed 

 and sown with grain the following spring, and again 

 seeded. 



With this system soil fertility can be maintained 

 without applying manure. 



In any rotation land should not remain in grass 

 longer than two years, on account of wire worms 

 and other insects multiplying and so injuring the 

 following crops. 



Land intended for pasture only should be reno- 

 vated every few years by plowing in August, and in 

 order to destroy the wire worms which are almost 

 certain to be in the soil. 



Harrow and cultivate alternately and continu- 

 ously until the winter, say November. The object 

 is, first to rot the sod, and second, to rid the ground of 

 wire worms by disturbing them late in the fall or 

 beginning of winter, so that they may be frozen and 

 destroyed. Seed again in the spring with the 

 pasture mixture of clover and grass seed mentioned 

 on page 168, seeding with any kind of spring grain 

 (barley preferred) sown according to prexnous 

 directions. 



