16 THE HANDBOOK FOR PRACTICAL FARMERS 



around the roots so that they may renew their growth. Rollers 

 usually are made in two or more sections for convenience in 

 turning, and have a basket or some other arrangement for load- 

 ing in order to increase the weight. As a pulverizer the solid 

 roller is inefficient. Its weight is distributed over too much 

 surface and it is likely to press the clods into the soft soil rather 

 than to crush them. 



Another type of roller is the subsurface packer, wiiich comes 

 near to being an ordinary clod-crusher. Its surface is broken 



f"-^*^- 







■^■^Mr' 



«s?'*' i-^-^/^^^/^^^fc^i**;^ ''-^'Mirs-^ 





Fig. 8. — This cormjrated roller is an effective pulverizer and at the same 

 makes a compact seedbed. — Bij permission of DnnJiain Co., Bcrea, Ohio. 



time 



so that it cuts into the soil and exerts pressure to considerable 

 depth. It is especiall}^ useful in the spring of the year and in 

 arid regions, in pressing the furrow slice into close contact with 

 the subsoil and at the same time leaving a loose la^^er of soil on 

 the surface as a mulch to save water. ^ 



Farm manures and commercial fertilizers. — To the practical 

 farmer there is no question of greater importance than that of 

 soil fertility. Good farm management consists in producing 

 profitable crops and at the same time maintaining or even 

 increasing the productive capacity of the soil. Many farmers 



