SOIL FERTILITY 



clay will dry, cake, and crack open when the sur- 

 face moisture is sunned out. 



It is known that plants take from 50 to 90 per 

 cent of their food, of which three-fourths is carbon, 

 from the air. This carbon is derived from the car- 

 bonic acid gas, which is at least 30 per cent greater 

 in the ground air than in the air we breathe. Where 

 there is sufficient moisture in the ground to allow 

 a free circulation, there is sure to be both a con- 

 stant supply of air, of available plant food in the 

 soil, and also a sufficiently deep passage of sun- 

 light to keep plants healthy. Accordingly, if the 

 garden site has too much clay and is soggy, it 

 may be treated with quicklime to sweeten it* and 

 break it up into finer particles, or with coarse 

 manures and turned-in cover crops. Both will 

 furnish readily available plant food and help to 

 lighten the soil. Sand and even coal ashes, in 

 reasonable quantities, leaves, and any organic 

 matter, if decaying rapidly enough to quickly 

 disintegrate, may also be used. Furthermore, 

 paths can be laid to act as surface drains. f 



If one has to deal with a too sandy soil, the 

 need is for an admixture of clay and humus, which 

 will act, as will also manure, to help conserve soil 



♦ Five to ten barrels per acre. The sourness of soil can be detected 

 by its turning blue litmus paper red. 



t Land where the water stands in pools upon the surface must be 

 drained by trenching or the equivalent as above; where water is held 

 too freely the soil must be tiled. Occasionally, a small and perhaps 

 temporary ditch will carry off the excess of water due to spring rains. 



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