44 AGRICULTURE FOR COMMON SCHOOLS 



plows it. Disking will keep the hard crust from forming and 

 will also save the moisture by keeping it from evaporating. 

 Land treated in this way will plow more easily and there v/ill 

 not be so many hard clods turned over. The work of prepar- 

 ing the plowed ground for seed will be less, for there are fewer 

 clods and the furrow-slice will pulverize better in turning over. 



If the field to be plowed was in clover last year so that 

 there is a good deal of stubble left on the ground, it is a good 

 plan to disk it before plowing. Besides preventing a crust, the 

 disking will mix the stubble more or less with the soil. This 

 is desirable because the stubble will rot more quickly, and 

 because if the stubble were not mixed with the soil but simply 

 turned under, it would tend to check the upward movement 

 of capillary moisture and so hinder the growth of the plant's 

 roots, especially if the weather is dry. For the same reason 

 disking is good for land covered with manure. It is also good 

 for sod land before plowing, but the cutting action of the disk 

 is not so great on sod as on stubble. 



Cultivation. — By cultivation we mean the stirring of the 

 soil after the crop has been planted. Usually it is not done 

 until the plants have come up and can be easily seen. Corn 

 and potatoes are the main farm crops cultivated. Cultivation 

 has two main objects. One is to kill weeds and the other is 

 to save moisture. Usually it is not the purpose of cultivation 

 to loosen the soil, although this is sometimes necessary after 

 a packing rain. The plowing of the ground, if it was well 

 done, did that. We need to kill the weeds because they use 

 water and plant food and also choke out the young plants 

 that we want to grow. It takes just as much food and water 

 to grow a rag-weed as it does a corn plant of the same size. 

 We need to save moisture, for during the summer we have 



