28 



Campbell's 1902 Soil Culture Manual. 



Under the heading of Evaporation, we have given the results of some 

 experiments by Prof. King of the Wisconsin Agricultural College, showing 

 the rapidity with which moisture will rise through the soil by what is 

 known as capillary attraction, reach the surface and pass off in vapor into 

 the atmosphere in a single day. Not until the farmer begins to grasp the 

 vital importance of keeping even a little additional water in his soil can he 

 be expected to use all due diligence in preventing this evaporation. The 

 observation of the farmers throughout the semi-arid west, during the 

 growing season of 1901, especially Kansas and Nebraska, ought to be amply 

 convincing with reference to the value of stored water in the soil. There 

 were frequent remarks during its prolonged and severe drought of the mid- 

 summer with reference to how the corn continued day after day and week 

 after week contending against this extreme heat without rain, without 

 showing any apparent effect of drought; but this was simply the direct 

 result of the unusual heavy rains in early spring that percolated down into 

 the soil, in many instances 18 inches to 2 feet deeper than usual, and there 

 acting as a reserve, continued to return by capillary attraction and feed 

 the corn plants and other grain until it was exhausted. In this same 

 chapter on Evaporation we make mention of several instances where the 

 early discing of the ground resulted in retaining a suflQcient amoant of 

 additional water to carry a crop of corn through, increasing its yield in 

 some instances as high as twenty bushels, which was not secured in adjoin- 

 ing fields, not disced, simply because the moisture was allowed to evaporate 

 by leaving the surface hard and compact, as is always the condition after 

 a heavy rain or snow. 



To the average farmer who has been accustomed to doing his work 

 in the cultivation and plowing of his fields at times when most convenient, 

 it seems rather difficult to grasp the full importance of doing all his work 

 just at a time when the condition of the soil is best adapted. To grasp 

 the idea that by plowing to-day we may get ten bushels of wheat to the 

 acre, when if we plowed the ground four days later we would get fifteen 

 bushels or vice versa seems rather ridiculous. While this statement and 

 the figures used, may in most cases be a little strong, yet it is a fact that 

 the average yield of a field is frequently increased or decreased quite a per 

 cent, by a few days variation in the time the work is done. This is espec- 

 ially true with reference to cultivation. I have in mind a case near Fair- 

 mont, Neb., where the phenominal difference of fifteen to eighteen bushels 

 per acre was made by cultivating a part of the field before a heavy rain of 

 nearly five inches and the balance of it after this rain. The reason of this 

 remarkable difference was simply what we have been dwelling upon, the 

 result of retaining a large per cent, of moisture by the soil mulch produced 

 by the cultivation after the rain, that was lost from the balance of the 

 field by rapid evaporation. This occurred in July, and was the last culti- 

 vation preparatory to what is called laying the corn by. The rain was a 



