HANDLING THE SOIL 43 



and sometimes is made by bolting narrow planks on iron 

 wheels. Another kind of roller, called a clod-crusher, is made 

 entirely of cast-iron wheels. The roller is always a heavy tool 

 and crushes the clods and at the same time packs the land. 

 After the land is rolled it should be harrowed with a spike- 

 harrow to loosen the surface and tear the crushed clods apart. 



Frequently the land is too loose for the crop that is to be 

 planted. The roller can then be used to pack the land. At 

 other times the soil is quite dry when the seed is planted. 

 Rolling will pack the soil about the seed so that the moisture 

 will come in contact with it and help the germination. By 

 packing the soil the capillary rise of moisture is increased and 

 water is brought from below to the surface. Thus rolling in 

 a dry time tends to make the soil wetter near the surface, but 

 it should not be left smooth very long. It should be harrowed 

 as soon as the planted seed has germinated to prevent the 

 evaporation from the surface. 



Disking. — We have just said that a disk harrow is a good 

 tool to cut up the clods and to loosen a packed surface. Some- 

 times in the spring before the farmer can get all of his corn- 

 stubble ground plowed, the surface has become quite hard 

 and dry. When this is plowed with the ordinary plow the 

 clods turned over will be big and it will take a good deal 

 of work to make them fine. Even after a good deal of har- 

 rowing and rolling there will still be clods in the under part 

 of the furrow-slice. These clods will interfere with the up- 

 ward movement of moisture and will also keep the roots of 

 plants from getting their food. The clods being hard the 

 roots will not penetrate them freely, so the food that is in 

 such clods cannot be easily obtained. It is a good prac- 

 tice for the farmer to disk his corn-stubble ground before hq 



