Department of Soil and Agricultur,\l Chemistry. 525 



with tillage and harvesting operations, and because of their smaller annual 

 cost for repairs as well as the more free use of the land they are in the 

 end the least expensive form of drainage. 



Tile drains should be adapted to the soil. On clay land the average 

 depth should be about two feet, on sandy land two and a half to three 

 feet is the best depth for laterals. They need not be placed at regular 

 intervals through the field. They should first be installed in the low 

 places, and extended as their benefits become apparent. The greater 

 part of the land drained has been greatly improved by the use of only 

 10 to 20 rods of tile per acre. On some land more thorough drainage is 

 highly profitable. 



Tile smaller than' 2]/! inches in diameter should not be used as they 

 are too easily clogged. Water enters the tile through the joints and not 

 to any appreciable extent through the walls of the tile. Hence there 

 should be no hesitation to use the hard tile, which are most durable. 



Tile drains cost 60 cents to $1.25 per rod, according to the size, 

 character of the soil and the cost of labor. Ditching plows and machines 

 are now available, which do good work and are economical. 



Land drained at a cost of $10 to $25 per acre has its value increased 

 from 50 per cent, to more than 200 per cent. The wet lands which are 

 most thoroughly drained are among the most productive and profitable 

 to be found anywhere. Wet land when drained is the most productive 

 part of the farm. 



C. Liming 



The tendency of soils to become sour is indicated by the increasing 

 difficulty in securing a stand of clover. Clover and alfalfa are particu- 

 larly sensitive to this soil condition, although other crops are also 

 affected. 



This sour condition of soils results from two continuous processes: 



( i) The absorption by crops and the removal from the soil of those 

 plant food elements which hold acidity in check, leaving behind those 

 which make the soil sour. 



(2) The more rapid leaching from the soil of those same substances 

 which prevent acidity. 



Marl and ground limestone are the easiest to spread. As both of 

 these are likely to vary greatly in the quantity of lime they contain, the 

 per cent, of lime should be guaranteed. The only way to know how 

 much to use is to try the effect of different treatments on separate strips 

 of land. From 500 to 2000 pounds per acre should be tried on these 

 strips. The most common forms of lime and their equivalent composi- 

 tion are as follows: 



Lump lime 5^ 



Hydrated lime, water slaked 74 



Ground limestone, Marl 100 



D. Tillage 



The reasons why more thorough tillage is now necessary are: 



( t) The changes which soil has undergone during many years of 

 cultivation has increased its tendency to compact, and this must be over- 

 come b^- more careful working. 



