CULTIVATED CROPS 



7§ 



is a dry, hot day the leaves will soon begin to curl up on 

 the plant thus injured, showing that a portion of its water 

 supply has been cut off. 



It is necessary, however, to cultivate to kill weeds, to 

 let air into the soil and to form a surface mulch to save 

 moisture; and many times it is necessary to cultivate deep 

 enough to injure corn roots in order to accomphsh these 

 various things; but the aim should always be to cultivate 

 no deeper than necessary. If deep cultivation is to be 

 practiced at all it should be done while the com is smaU, as 

 it is injured less at this time. 



Cultivator. — The kind of cultivator used has much to 

 do with the depth of cultivation. If a cultivator with two 



large shovels on a side 

 is used, it must be run 

 deeper to cover all the 

 space between the rows, 

 than one which has 

 three, four or five shov- 

 els on a side. The small 

 shovels and more of 

 them do finer, shallow- 

 er work than the large 

 shovels; but where corn 

 has been neglected until 

 the weeds are large, the 

 larger shovels are bet- 

 ter, because they do not 

 clog up so easily and 

 because they plow out 

 the weeds instead of 

 cultivating them. 



Surface Cultivators. 

 —At present many far- 

 mers are using what are 

 called surface cultiva- 

 tors. In place of ehov- 

 els there are two or more knives or blades that run 

 an inch or so below the surface of the ground, separating 

 the surface soil from the soil below and cutting off inet 



Figure 31-- 



-The root system of corn, 

 sas Bulletin No. 147 



Kan- 



