OUTLINE OF COURSE IN PLANT CULTURE. 
237 
(a) Capillary attraction. 
( b ) Percolation of water. 
(c) Specific gravity. 
5. Classification; light, warm, sandy, heavy, cold 
clay, loamy, humus. 
b. Chemically considered. 
1. Chemical composition. 
2. Chemical elements necessary for plant growth: 
Oxygen, Hydrogen, Nitrogen, Carbon, Sul¬ 
phur, Phosphorus, Potassium, Magnesium, 
Iron, Calcium and Chlorine. 
3. Subsidiary substances: Sodium, Silicon. 
4. Admixtures, Zinc, Copper, Nickel, Aluminum, 
Cobalt, Manganese, Lithium, Strontium, 
Barium, etc. 
5. Use of the different elements in the growth of 
plants. 
6. Water and Quartz sand cultures. 
7. Absorption of free Nitrogen by Leguminosae. 
8. Chemical substances that it is necessary to supply 
to the soil: Potash, Nitrogen, Phosphorus. 
9. Sources of supply. 
Potash 
Commercial 
fertilizers 
Nitrate of Soda 
Nitrogen - Sulphate of 
Ammonia 
Phosphorus 
South Carolina Rock 
Thomas Slag 
Bone Meal 
Bone Black 
^ , Green Manuring 
Organic 1 
' Stable Manures 
Organic j 
Supplied by rain. 
10. Pot culture (liquid manuring). 
11. Humus. 
12. Mycorrhiza (trees). 
