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Being ready to plant our crop, let us turn for a moment to soils in 

 general and corn soils in particular. Soil is not just dirt. It is a wonder- 

 fully interesting, wonderfully diversified, wonderfully vital thing. And let 

 me tell you right now, it takes just as much brains to handle a soil properly 

 as it does to handle an office full of men. 



[Displaying a home-made outfit consisting of three lamp chimneys, 

 filled with sand, silt and clay, and their ends immersed in a pan of water. 

 It can be seen that the water has climbed highest in the clay, and lowest 

 in the sand.] 



This shows the absorbent capacity of different soils. Water is the 

 main factor in the environmental success or failure of a crop of corn. 

 You can see that a sandy soil is liable to prove deficient in this necessity. 

 Generally speaking, therefore, a clay loam is best for corn. The reason 

 the water has climbed higher in the clay than in the sand is because of 

 the smaller pore space. Here [displaying a set-up apparatus consisting 

 simply of two plates of window-glass touching at one end and divided by 

 a broom straw at the other] is a simple affair which shows the thing at 

 a glance. Here where the glasses practically touch, the water has crept up 

 all the way to the top. Here where they are divided about a thirty- 

 second of an inch by this broom straw you will see scarcely any rise. 

 The tapering line as the space increases indicates that the capillary capac- 

 ity of a soil is directly proportional to its pore space. 



That experiment is to show how different soils take up water. Here 

 is another to show how they retain it. [Displaying home-made rack hold- 

 ing four lamp chimneys containing sand, sand and manure, clay, clay and 

 manure. Under the bottom of the suspended chimneys are glasses. Water 

 is poured in at the top and allowed to seep through and gather in the 

 glasses.] 



You will notice that the most leachy soil is the sand. Next comes 

 the sand and manure, third the clay and manure, and lastly, the clay. 

 This illustrates well the curious fact that manure applied to a sandy soil 

 makes it more porous and to a clay soil, less porous. In this capacity of 

 regulating the water supply of soils of different texture, manure finds a 

 function almost as important as its fertilizing power. 



These next two experiments serve to show how the corn plant draws 

 in its nourishment through the roots. All that is taken in must be in 

 solution. When two liquids are separated by a membrane, the less dense 

 will pass more rapidly through the membrane. Minute membranes are 

 at the point of every root and the soil water is drawn through them by 

 force of the stronger sap solution within the plant. The technical name 

 for this process is "osmosis." You will notice that here [indicating in- 

 verted tube partially filled with red liquid and separated from white solu- 

 tion by parchment] the salt solutions within the thistle tube has drawn the 

 thinner liquid through the membrane and raised its level. Again, see how 

 flabby is this piece of potato and how crisp this one is. One was immersed 

 in salt solution thicker than its own sap; the other in pure water. 



