LAND DRAINAGE 35 



As a consequence of all tliese changes (4) the soil actually car- 

 ries more water available to crops and drouth periods are l3etter 

 withstood than on poorly drained land, especially intermittently 

 wet ujoland. One wa}^ to locate wet land is to observe the wet 

 spots where the leaves of crops are curled in dry weather. 

 (5) They are less subject to the damaging effect of freezing and 

 thawing, especially on winter croj)S. (6) All the myriads of 

 beneficial bacteria in the soil and necessary to its fertility are 

 favored by good drainage and the conditions incident to it. This 

 includes the organisms that bring about the formation of humus 

 and the fixation of nitrogen and its changes into available forms. 

 (7) Drained soil Avarms earlier in the sjoring and maintains a 

 higher average temperature than wet soil. (8) Less time is lost 

 after a rain and in getting crops jilanted in the spring. The 

 farm equipment and labor may be more efficiently managed. 

 (9) All the various materials in the soil used by the plant as 

 food are rendered more available by the conditions that have 

 been enmnerated. The need for fertilizers may be reduced and 

 the efficiency of that applied will be increased. 



AVet land is usually the potentially best land on the farm and 

 it usiially responds with big crops Avhen this condition is 

 corrected. 



Open drains. — Very little need be said to the average farmer 

 concerning open drains. The smaller sizes suitable for the small 

 farm are simple trenches with such slope to the wall as to pre- 

 vent serious covering of the banks. Usually they may be fairly 

 steep. For large channels a one-half slope is common. This is 

 a slope formed by a one-foot vertical rise for a foot of horizontal 

 distance on the bank. For smaller channels a steeper slope, 

 namely, one foot vertical to one-half foot horizontal, or even less, 

 is used. Bends should begin and end gradually like the curve in 

 a railroad. Right-angle turns should be avoided. Keep the 

 channel clean and in good form. 



lender the best conditions, open ditches are veiy objection- 

 able. (1) They obstruct and waste the land surface. (2) They 

 are very likely to be filled up with weeds and sediment. 

 (3) They harbor weeds. (4) Most serious of all, the smaller 

 ditches, especially those so frequently made Avith a shovel or 

 turning plow and which are only six to ten inches deep, scarcely 

 remove surface Avater and do not accomplish the purposes of 

 real internal soil drainage. At the best, this type of open ditch 

 is very inefficient. On the other hand, due to the need for tem- 

 porary results, or on very Ioav, flat land, or Avhere a very large 



