182 CORN 



Depth of Cultivation. Corn should be cultivated, not plowed. The 

 depth of cultivating corn depends first upon the size of the corn. Corn 

 which is being cultivated for the first time has not long since begun 

 feeding on the soil. When germinating and pushing to the surface, 

 the sprout drew the nourishment from the endosperm of the kerne). 

 Therefore, the roots have not spread very far horizontally or ver- 

 tically. At this time the rows should be cultivated deeply and closely 

 because it can be done without injuring the roots. There is no ques- 

 tion but that a few may be disturbed and even cut off, but as the 

 plant is young and the ground is moist, growth is not seriously 

 checked. Deep cultivation should not be practiced after the first time 

 over. 



If the cultivator is kept from the hill and set to throw dirt to 

 cover the weeds, rather than to uproot them, there is left in the row 

 a compact ridge which is unfit for the corn roots to penetrate. Fur- 

 thermore, the ridge is so high that by the time of the second cultivat- 

 ing, the weeds then growing cannot be properly covered. When a 

 cultivator shovel passes close to a hill of corn, the loosened soil be- 

 comes warmer because of the admitting of the air. Early in the spring, 

 the roots of corn wait especially for the soil to rise in temperature 

 before pushing out. This loosened soil, if it dries out, will te^d also 

 to direct root growth downward, because of more moisture at lower 

 depths. This is particularly valuable, because a shallow rooted corn 

 plant cannot so well withstand the drying winds and lowering water 

 level of July and August. 



Deep cultivation cannot be done at any other time than the first 

 time over. According to investigations in North Dakota, the roots 

 of rows of corn three feet apart were interlaced at the end of 30 days 

 after planting. The bulk of the roots were within the first eight 

 inches of soil. Six inches from the hill the main roots were within 

 2J/2 to three inches of the surface. 



The depth of cultivation depends also upon the texture and forma- 

 tion of the soil. Some types of soil contain a large amount of humus 

 and are of a loose structure. These may be cutivated the first time with 

 a surface cultivator. The corn soils of central Iowa and central Illi- 

 nois require but one deep loosening, and produce the highest yields 

 when tilled thereafter with surface tools. There are, however, soils 

 of a compact, less friable nature ; for example, the loess soils of soutn- 

 ern Iowa and Illinois, which require deeper cultivation. If a beatmg 

 rain follows the first cultivation, this soil will become so compact that 

 the ordinary surface cultivator simply scrapes the ground, leaving 



