100 TRANSACTIONS OF THE ILLINOIS 



matter is the wood, roots, leaves, and twigs from forest, grass, straw, 

 or some green crop ploAved into the soil, or compost of barn manure. 

 The clay and lime are the product of the gradual crumbling and 

 decomposition of the rocky crust of the earth. We must learn what 

 mineral substances plants take from the soil b}^ an analysis of their 

 ashes. The bases are found to be potassia, lime, and magnesia, and 

 the oxides of manganese and iron. These are combined in the 

 ashes with silicic, sulphuric, and phosphoric acid, along with a small 

 portion of common salt. The phosphates predominate in grains; 

 lime exists in large proportions in grapes; potash in edible roots, and 

 silica is found in straw. The clay of soil is necessary to retain the 

 ammonia, however supplied, and store it up for the future use of the 

 plants. It serves also to retain moisture in the soil, and gives a 

 tenacity that enables the roots to secure a firm hold in the ground. 

 Sand should also exist, or should be supplied in due proportions, in 

 order to give the proper degree of porosity to the soil, and thus 

 insure the entrance of the air and fertilizing liquids, and the drain- 

 ing away of all excess of water. Lime is directly the building 

 material for all forms of vegetation, and unlocks other treasures in 

 the soil, which then becomes ready food for plants. Chalk, marl, or 

 limestone have the desirable effect of sweetening peaty and marshy 

 soils, which soils are rendered sour by having too large a proportion 

 of vegetable matter. This sweetening process has the effect of ren- 

 dering such soils highly productive. Different portions of the 

 earth's surface are adapted to the production of different vegetable 

 products on account of natural differences of soil. Hence the great 

 variety in forest growth, almost endless variety of grasses, shrubs, 

 and weeds distributed over the earth. When these conditions of 

 soil are radically changed the natural products are correspondingly 

 changed. It has been observed that when a forest growth of hard 

 wood has been removed, a growth of soft wood takes its place, and 

 vice versa. In nature we find many soils so very rich in plant fer- 

 tilizers that they are adapted to a wide range of different plant 

 products, while others are so poor as to produce nothing superior to 

 the detested sand-burr. , 



FERTILIZERS. 



Soils can be changed, inodified and improved by fertilizers. 

 Hence the necessity of the producer's knowing just what fertilizers 

 to use in order to produce the largest and best yield of the product. 

 In supplying fertilizers to the soil for the food of plants the nature 

 and habit of the plant must be carefully studied. Some plants are 

 gross feeders, as the currant, and will thrive on almost any coarse 

 litter at hand, while the finer fruits require highly pulverized and 

 well rotted fertilizers; and the delicate flowers require a fine compost 

 adapted to their wants. It is true that 2)lants take a large portion of 



