520 IOWA DEPARTMENT OF AGRICULTURE. 



justment of these cases can be more effectually applied by the commissioners 

 of assessment and by the board of supervisors who have familiarized them- 

 selves with these matters than they can by any outside court. Every land- 

 owner affected by drainage work, as well as officials in charge of its admin- 

 istration, should look at these questions on all sides before deciding whether 

 or not an equitable assessment has been made. 



THE RELATION OF THE SOIL TO UNDERDAINAGE, 



Address of Prof. W. H . Stevenson , Secretary of the State Drainage Asso- 

 ciation, Before the lozvx State Drainage Convention, Ames, Iowa, Janu- 

 ary 13 and 14, 1905 . 



A year ago an effort was made to prove that there were many thousand 

 acres in Iowa which were not wholly productive because of a lack of 

 adequate drainage. Investigations made at that time showed that there 

 ware nearly five million acres of such land in the State. During the past 

 few months a number of factors have induced many landowners to become 

 thoroughly interested in the problem of land drainage. Not a few of this 

 number have drained extensive areas; others arc diligently seeking 

 for information which will enable them to proceed with their drainage 

 work intelligently and with the assurance that the methods of construction 

 adopted are correct. 



At the present time there was a goodly number of drainage engineers who 

 are well qualified by training and experience to handle the majority of the 

 engineering problems which they encounter in field work. Much valuable 

 data has been secured regarding the location of drains, the fall or gradient, 

 the size of tile and the construction of outlets. But there is one fundamental 

 problem which is little understood, which is ever troublesome and which 

 gives rise to a great many important questions on the part of engineers and 

 landowners. 



The problem is this: "What is the relation of underdrainage to the 

 soil? " There are at least two phases of the question which merit our atten- 

 tion: "How is the soil benefited by underdrainage? " "To what extent 

 doss the character of the soil determine the depth to which drains should 

 be laid and the distance between drains? " 



A fund of qiite defiaite information in now available regarding the first 

 of these questions and therefore we do not propose to enter into a detailed 

 dis3U5sioa of the benefits to the soil from drainage. However, numerous 

 inqiiries have baen received during the past few months for data along this 

 line, and we take this opportunity to emphasize the fact that the soil is 

 greatly benefited by underdrainage, as is definitely proven by the following 

 facts: 



Tae soil which the farmsr plows and cultivates is not a solid mass of 

 material. It is mide up of an almost iafiiite number of fine particles of 



