138 DRY-FARMING 



farmer does not want his soils to be unnecessarly 

 moist. The dry-farmer can reduce the per cent of 

 water in the soil without diminishing the total amount 

 of water by so treating the soil that the water will 

 distribute itself to considerable depths. This brings 

 into prominence again the practices of fall plowing, 

 deep plowing, subsoiling, and the choice of deep soils 

 for dry-farming. 



Very much for the same reasons, evaporation goes 

 on more slowly from water in which salt or other 

 substances have been dissolved. The attraction 

 between the water and the dissolved salt seems to 

 be strong enough to resist partially the force causing 

 evaporation. Soil-water always contains some of 

 the soil ingredients in solut on, and consecjuently 

 under the given conditions evaporation occurs more 

 slowly from soil-water than from pure water. Now, 

 the more fertile a soil is, that is, the more soluble 

 plant-food it contains, the more material will be 

 dissolved in the soil-water, and as a result the more 

 sl(jwly will evaporati(jn take place. Fallowing, 

 cultivation, thorough plowing and manuring, which 

 increase the store of soluljle plant-food, all tend to 

 diminish evaporation. Wliile these conditions may 

 have little value in the eyes of the armer who is 

 under an abundant rainfall, they are of great impor- 

 tance to the dry-farmer. It is only by utilizing every 

 possibility of conserving water and fertility that dry- 

 farming may be made a perfectly safe practice. 



