ASH IN PLANTS 17 



is usually larger than phosphorus or magnesium. The legumin- 

 ous crops (alfalfa, clovers, cowpeas, soy beans, etc.) contain 

 more calcium than phosphorus or potassium. Roots and legumes 

 contain much less silicon than straws. 



Ash of Young and Mature Plants. According to Wolff 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 calcium 

 increase while the potassium decreases. 



Suggestion: Take a small quantity of hay and have the 

 pupils approximate the weight of it. Burn this hay in a dish 

 and show the students the remaining portion or ash. Ask them 

 the loss in weight. Let them rub the ash between their fingers. 



