190 SOILS AND PLANT LIFE 



In any given case, the number that should be planted in 

 each hill ordinarily depends upon several factors. These 

 are as follows : 



(1) Quality of the Seed. — If the percentage of germin- 

 able kernels is known to be low, the number planted in 

 each hill is usually increased. 



(2) Fertility of the Soil. — If plant food is abundant 

 in the soil, a greater number of kernels may be planted in 

 each hill, since a greater number of plants can be supported. 



(3) Average Rainfall. — In regions where the rainfall 

 is scant, fewer kernels are planted in each hill than in 

 humid sections. 



(4) Insects. — If the soil is infested by destructive 

 insects, it is deemed prudent to increase the number of 

 kernels in each hill. 



(5) Use to be made of the Crop. — If the crop is to be 

 used for fodder or silage, the number of kernels in each 

 hill may be increased. 



128. The Replanting of the Missing Hills. — If for 



any reason the stand proves to be poor, the question of 

 replanting arises. This is not at all the simple matter that 

 it appears to be. It is easy enough, of course, to replant 

 the occasional missing hills. The difficulty, however, 

 arises in the fact that the plants in these hills, being younger 

 than those about them, will not put forth flowers until the 

 remainder of the field has passed the flowering stage. 

 Most of the pollen from the older plants will have been 

 shed before the silks of the younger plants are ready to 

 receive it, the usual result being that the pistillate flowers 

 of the latter are but poorly fertihzed and small ears, or 

 none at all, are formed. This may be avoided in a meas- 

 ure by replanting with seed of some earUer variety, but 

 the result in this case is a mixture of varieties. For these 



