VERTICAL FARMING 



27 



The other great amendment is lime, the chief use of which 

 has been described in the correction of sour or acid soils. 



Use What You Already Have. From the foregoing we see 

 that there are supplies of practically aft the plant foods in 

 normal soils, and that additions of fertilizing materials, while 

 absolutely essential in some cases, are expensive. Some of the 

 foods already in the soil are not in the form needed by the plant, 

 but can be changed into usable forms by properly controlled 

 natural agencies. The agencies needed for these changes are 

 always at their best under certain soil conditions. For the 

 different changes the conditions are identical a moist but 

 well drained soil, an abundant supply of air in the soil, the pres- 

 ence of more or less humus, and a suitable temperature. To 

 obtain most of these is easy, when we consider only the soil, as 

 it can be done with a plow, but the surface is not half of the 

 farm we want to use several feet of depth 

 for a good reservoir for moisture, a factory 

 to rework and prepare the foods, and a good 

 home for the roots. This naturally de- 

 mands that the clay or hardpan be broken 

 up. The plow cannot get down to the 

 trouble and there is but one other agent that 

 can do the work a reliable low-freezing 

 explosive. 



Making Fertilizers More Effective. 

 Heavy applications of fertilizers to force 

 bumper crops are attended with certain 

 dangers. If everything goes along all right, 

 and there is always plenty of moisture to 

 dissolve the fertilizers and prevent the 

 soil solution from becoming too rich, the desired results will in 

 all probability follow. In most regions where such fertilization 

 is practised, such constant supplies of soil moisture are not 

 always to be relied upon. The result is that when the young 

 plants get vigorously started on their nourishing ration and 

 then meet a season of drouth they are " scorched " or " burned " 



SECTION BREATH- 

 PORE OF A 



(GREATLY ENLARGED) 



SURFACE VIEW 

 SAME 



