AGRICULTURAL SOIL. 11 



use this food, and live upon it, develop into healthful 

 flowers, fruit, and yield crops for the benefit and 

 sustenance of man and animal life generally. 



The Process of Soil Formation. The changes, the 

 growth, the evolution in soil, from the first breaking down 

 of rocks, upon the dust of which woody lichens may grow, 

 until it becomes rich enough to produce the heaviest 

 vegetation, say 100 bushels of maize, or 60 tons of sugar 

 cane per acre, offer a wonderful lesson the forethought 

 and industry of the great Creator a lesson, valuable, 

 curious, and interesting. The process is visible all through 

 the stages of development in our new country. The rocks, 

 broken down, as we see, by the agency of the weather 

 " weathering down " is a very suitable term applied to the 

 process and the fine dust thus produced is the first stage of 

 soil formation. Coarse, woody plants manage to live upon 

 it. They decay, helped by bacterial action, and go to the 

 formation of richer soil, upon which richer plants live. 

 Then animal life comes in, living upon the vegetation, 

 and decaying in due course, help to make still richer soil ; 

 and so the process goes on until the land is rich enough to 

 support the wants of man and the more exacting require- 

 ments of woman, upon whom man himself is dependent ! 



The combined contents of various rocks give us the 

 minerals lime, magnesia, potash, soda, sulphur, iron, silica. 

 From air and water come nitrogen, oxygen, carbon, and 

 hydrogen. All of these must be in agricultural soil and 

 the air around it. They all enter into plant life and 

 animal life; and the work of the agriculturist is to use, 

 maintain, and increase this plant food, and by supplying 

 what becomes necessary, and by the admission of air and 

 rain into the soil by "cultivation," in short secure the 

 conditions necessary for making crops. 



Sources of Soil. The rocks are the sources of all soils, 

 but, as explained in the chapter on soil selecting, where 

 analyses are given representing several of the leading 

 formations of New South Wales, they differ very much 

 in the proportions of material they hold for the use of 

 plants. In Australia the disintegration, or breaking up of 

 the rocks, is going on very rapidly, the agents being rain 



