16 



Campbell's 1902 Soil Culture Manual. 



contain the major part of the feeding roots is that of increasing the water 

 holding capacity of the soil. The more completely we can separate one 

 particle from another, reducing the soil to the greatest fineness, then 

 thoroughly firming it, the greater is its water holding capacity. Water is 

 not held in tbe soil in cavities or spaces, but is held in the form of films or 

 coverings around each diminutive soil particle, consequently the greater 

 number of small particles of soil we have the greater the amount of water 

 held. We can illustrate by a cube one inch square; this contains six square 

 inches of surface. Cut this cube into eight squares one-half inch square 

 and we have twelve square inches of surface. Now, cutting each half- 

 inch cube into eight one-fourth inch squares we have twenty-iour square 

 inches of surface, thereby increasing the water holding capacity three 

 hundred per cent. The tendency of all soil that is left for one or more 

 years without being plowed or pulverized, is to form into larger soil grains. 

 By the little particles adhering to each other, cemented or attach* d by 

 the salts, magnesias and alkalies that are dissolved by the water as it per- 

 colates down and then moves upward, holding these properties in solution, 

 and as the moisture passes off by evaporation, these salts and alkalies fill 

 the little spaces, and the smaller particles form larger soil grains and thus 

 decrease the water holding capacity. 



There is still another important point, and that is the thorough cir- 

 culation of air in the soil. Air, like water, is an important element in the 

 soil, and, like water, it must be finely and evenly distributed. 



In further discussing the question of what is the proper physical 

 condition of the soil when plowing is done, we would call your attention to 

 the furrow as it is turned over by the plow when the soil is simply moist — 

 not very wet nor very dry. How nicely each little particle of soil seems to 

 separate, one from the other, when, if too dry, a cloddy condition is ob- 

 served; and the same is true when the soil is too wet. We should try to 

 secure the most uniform, fine condition of our soil for the threefold pur- 

 pose that it may contain more water, that moisture may move more rap- 

 idly through it, and that there may be a more prolific growth of roots. 

 By close observation and careful attention to these important points we 

 may secure a crop result fully one hundred per cent, greater than we could 

 obtain if these items were disregarded. 



The proper depth of plowing must be governed very largely by 

 the kind of tools you have for after-fitting and care and attention 

 which you give the work. In some localities the sub-surface packer is 

 quite commonly used. If you have one of these tools it is advisable to plow 

 at least six or seven inches deep, following the plow closely with the sub- 

 surface packer; provided, however, the ground has been previously disced so 

 as to retain the moisture, when you will be able to completely obliterate 

 all the cavities, leaving the under portion of the furrow slice thoroughly 

 fine and firm as shown in cut No. 2. If you have no sub-surface packer I 



