76 FIELD CROP PRODUCTION 



the earth mulch and kill the weeds that are just starting. 

 The weeder or harrow should be run over the field fre- 

 quently until the plants are seven or eight inches high. 

 These implements should not be used early in the morning 

 or on cloudy days, since at this time the plant cells are 

 filled with water and the plants are easily broken off. 

 After the corn is too big to cultivate with the weeder, 

 the mulch should be maintained by a cultivator equipped 

 with small shovels, which should be run about 2 inches deep. 

 Shallow cultivation will conserve the moisture and kill 

 the small weeds quite as well as deep cultivation. How- 

 ever, if large annual weeds are started, it may be necessary 

 to run the shovel somewhat deeper in order to uproot 

 them. Deep cultivation cuts off many of the corn roots 

 and turns up a lot of moist soil which will dry out by ex- 

 posure to the wind, thus causing a greater amount of 

 moisture to be lost than by shallow cultivation. After 

 the corn is too large for the cultivator, and the roots have 

 grown in the upper soil, the mulch can be maintained by 

 dragging a mower wheel or a plank drag between the 

 rows. This will not only keep the dust mulch and kill 

 the weeds, but will also provide a good seed bed for the 

 seeding of catch-crops in the corn, or for the seeding of 

 wheat later in the season. The frequency of cultivation 

 will depend largely on the nature of the soil, the number of 

 weeds present, and the amount of rainfall. In a very dry 

 season it will be profitable to continue the cultivation until 

 late in the summer, while in seasons of plentiful rainfall, 

 such cultivation may not be necessary. 



HAHVESTING AND STORING 



62. Harvesting. — The method of harvesting depends 

 largely upon the use that is to be made of the crop. If 



