Dec. 1909.] POTASH IN CLAY LOAM SOILS. 53 



connection the freezing and thawing processes which take place 

 during the winter play a very important role. There is no evi- 

 dence that these processes increase in any way the solubility of 

 the plant food. On the other hand the soils are usually more 

 porous in the spring after the frost is gone. During the freez- 

 ing and thawing, ice is formed, melted, and reformed between 

 the soil particles. This pushes the particles farther and farther 

 apart and permits of both better drainage and aeration. On this 

 account the effect of freezing and thawing is much the same as 

 the effect of lime and other chemicals. 



WHAT BECOMES OF THE POTASH ADDED IN THE 



FERTILIZERS? 



What interests us in a practical way is the natural disposition 

 of fertilizer after it is applied to the soil. Do the rains wash 

 it into the brooks and away, does it leach deep into the soil and 

 change into a different and insoluble condition, or do the plant 

 roots gather it up to use for food? 



We know with certainty that the rains, except in special cases, 

 carry very small amounts of fertilizer into the brooks. Very 

 little waste comes about in that direction. In some localities, 

 the heavy rains carry away the entire top portions of the soil 

 and, of course, such losses are great, but not at all common. 

 Excepting in sandy soils, the fertilizer does not readily leach 

 downward to any great extent. In most crops the root system 

 is very extensive and the entire few surface inches of the soil 

 are filled with a mass and network of roots. These may take up 

 large quantities of the added fertilizer and remove it in this 

 way. 



In this connection a very important process is going on con- 

 tinuously in the soil. The soluble matter is changed into an 

 insoluble condition. More dissolves and is again made insoluble. 

 This changing from a soluble to an insoluble form is known as 

 absorption. 



The absorption of the soil is shown in a large and practical 

 way by an examination of the brook and spring waters. Often 

 less than one part in 5,000 parts of these waters is mineral mat- 

 ter, or stated otherwise, the brook and spring waters carry less 



