10 AUSTRALIAN AGRICULTURE. %, 



" Selecting and Classifying Land," Chapter II. But, as an 

 introduction to the nature and qualities of soils, it may be 

 desirable to make before proceeding to soil selection a 

 commencement here. The time is not so far past, and 

 there may be the idea still, that soil is just a mass of dead, 

 inert, mineral matter, in which, by some means or other, 

 plants grow somehow, and when they are good enough, 

 animals can live by eating the plants, and crops can be got 

 from such soil by merely turning it over. As an advance in 

 knowledge concerning the real practical nature of soils, we 

 may see that decayed and dead vegetation, insects, and 

 animals, with the mineral matter, all go to aid the formation 

 of rich soils. The vegetable contents make up the loamy or 

 humus matter of the agriculturist, the organic matter of 

 scientific agriculture. We may next, and in perfect safety, 

 go another step forward, and treat soil as a mass of 

 living material, having more or less life and richness in 

 proportion to its contents of mineral substances and 

 healthy humus, or vegetable, or organic matter. 



It is at this stage that first acquaintance may be made 

 with the wonders and the extreme usefulness of that 

 microscopic life which connects the dead past with the 

 living present. The purpose of those minute organisms 

 so small that myriads of them in a body would scarcely be 

 visible to the human eye is to break down what has been 

 in growth both vegetable and animal into the elements, 

 the plant food, which we use again for building up flowers, 

 fruit, vegetables, grains, grasses, for nourishing*animal life ! 

 This is one of the visible purposes of the micro-organisms, 

 the microbes, the bacterial life upon which the very 

 existence of all other progressive life is dependent. 



Next we may find that these minute things have 

 another purpose ; that they are the means by which that 

 most valuable aid to agriculture, nitrogen, which we may- 

 know more intimately as ammonia, is absorbed from the air, 

 becomes part of the soil, an essential part of the nourishing 

 food of both plants and animals. Such, in brief, is an 

 outline of the process by which soils have been formed ; 

 their richness being dependent upon the proportions of 

 mineral and orgcinic matter in such state that plants can 



