184 Irrigation and Drainage 



yield or inferior quality results. The taller the plants 

 which are brought together, the farther apart as a 

 rule must they be placed, in order that sufficient sun- 

 light for the best results can be had. The flint varie- 

 ties of maize are readily grown closer together than the 

 smaller of the dent varieties, and these, in their turn, 

 may stand closer on the ground than the large southern 

 varieties. 



Neither the starches nor the cellulose out of which 

 plant tissues are built can be properly organized and 

 laid down in too feeble a light, for its actinic power is 

 demanded to accomplish this work, just as it is in pho- 

 tography. When it is remembered that an instanta- 

 neous exposure of a plate in the bright sunshine may 

 accomplish more chemical change in the negative than 

 can be done in two minutes in the diffused light of a 

 well-lighted room, it can be readily understood that the 

 work of assimilation in the lower leaves in close plant- 

 ing must be greatly enfeebled. 



It is for this reason, apparently, that ears will not 

 form on stalks of maize planted too closely, and that 

 they form more abundantly in closer planting on the 

 small, low varieties than on those which are taller. 



It is for the same reason, too, that too closely 

 planted crops of almost any kind have weak stems and 

 are unable to stand up well, often lodging ; neither the 

 starches for the kernels, in the former case, nor the 

 cellulose in the latter for the building of the frame- 

 work, are able to form rapidly, and abnormal growth 

 is the result. Whoever has entered and emerged from 

 a tunnel has been surprised at the short distance from 



