FliRTILlTY AND FERTIUZER HINTS 



Occurrence of Mineral Elements in Plants. — According to 

 P'orbes ;^ Mineral substances of foodstuffs are present in four 

 mechanical conditions: i. In solution in the plant juices; 2. as 

 crystals in the tissues; 3. as incrustations in cells and 4. in 

 chemical combination with the living substance. 



The mineral content of any species of plant varies consider- 

 ably as affected (i) by the composition of the soil and the soil 

 water, (2) by the various factors controlling transpiration of 

 water by the plant and (3) by the loss of mineral substance 

 either through shedding of parts or through the leaching effect 

 of dews and rains. 



Distribution of Ash in Plants. — Roots and seeds generally con- 

 tain much less ash than leaves because the mineral elements are 

 carried to the leaves for the elaboration (manufacturing) of 

 food and then the water evaporates and the ash remains. The 

 ash present in roots and seeds is usually needed for supporting 

 germination and early growth of the plant, while some of that 

 in the leaves is in excess of what is really needed. 



Phosphorus and potassium are present in the largest amounts 

 in seeds, followed by magnesia. Silicon and potassium pre- 

 dominate in cereal grasses and straws, and the per cent, of cal- 

 cium is usually larger than phosphorus or magnesium. The 

 leguminous crops (alfalfa, clovers, cowpeas, soy beans, etc.) con- 

 tain more calcium than phosphorus or potassium. Roots and 

 legumes contain much less silicon than straws. 



Ash of Young and Mature Plants. — According to Wolfif the per 

 cent, of ash of the dry matter of wheat, oats, rye, and clover 

 decreases with the growth of the plant. The ash of healthful 

 plants is generally higher in calcium than in sickly plants. The 

 per cent, of calcium and potassium in the ash of grass plants 

 decreases in the growing of the plant and the silicon increases. 

 In the ash of the dry matter of clover, the magnesium and cal- 

 cium increase while the potassium decreases. 



1 Bui. 201. Ohio Experiment Station. 



