DEPTH OF PLANTING 



163 



shallow. Kernels covered more than two inches in such a soil will, 

 if the surface receives a beating rain, remain dormant a long time 

 because of lack of oxygen. The plant food is not in available form 

 except near the surface. A loose, sandy soil requires deeper planting 

 because of a lower water level. Although the moisture level of sod 

 land is usually very low, as a rule it is difficult to plant corn very deep 

 in such soil. 



Second. The position of the water level. Farmers of north cen- 

 tral Iowa cannot plant deeply because the water level is near the sur- 

 face. This excess of moisture removes two essentials for germination 

 — warmth and oxygen. The western edge of the corn belt is lacking 

 in moisture, consequently the planter must be set more deeply. It 

 is seldom advisable to plant deeper than 2 1-2 inches. It will be re- 

 membered that the young plant depends entirely upon being nourished 

 from the endosperm of the seed, or the food supply within the kernel, 

 until such time as it is able to draw its food directly from the 

 soil. Should this kernel of corn be placed four or five inches beneath 

 the surface of the ground, it is often found that while the seed will 

 germinate, there is not enough plant food to maintain the growth of 

 the sprout until it can reach the surface. Naturally, in this case the 

 plant dies, while if it had been planted shallow, so that the young 

 plant could have come to the surface before the plant food in the 

 kernel had been exhausted, it would have grown to maturity. 



Third. The time of planting. In the spring the atmosphere warms 

 early and by penetrating the seed bed gradually raises its tempera- 

 ture. Therefore, in early planting, only the surface soil is warm 

 enough to germinate the kernels. The sub-surface strata is cold and 

 wet. Later when the surface soil has become warmer, the seed may 

 be covered to greater depth. 



TABLE NO. 33 



YIELD OF CORN FROM PLANTINGS OF DIFFERENT DEPTHS 



(Average for three years) 



Depth 



Bushels per acre 



Average 



The above figures taken from Bulletin No. 13 of Illinois, show 

 from an average of three years, with corn planted at different depths, 



