SELECTING AND CLASSIFYING LAND. 21 



tion of lime, in some of its many forms, in sufficient 

 quantity for grass and crops, is one of the least costly of 

 soil improvements, and one of the most effective. Lime is 

 abundant in Australia. 



Magnesia is an alkaline earth in much the same sense 

 as lime. It is not a scarce ingredient in New South Wales 

 soils. 



Phosphorus as Phosphates, in combination with other 

 substances, is fairly plentiful in our soils, but, as a rule, 

 additions of this mineral are desirable in the form of bone 

 material. In conjunction with lime, &c., the phosphates form 

 bone, and not a few of the defects in grazing and dairying 

 countiy can be traced to scarcity of these materials. Wheat 

 is very heavy on phosphates, an ordinary crop of 30 bushels 

 absorbing some 251b., a demand which but few soils in a 

 state of nature can supply for many successive crops. But, 

 like lime, the phosphates can be easily made good by 

 manuring. 



Sulphur, or Sulphuric Acid, is an essential to plant 

 life. It is fairly plentiful, though additions are advan- 

 tageous for some crops, such as peas, onions, &c. 



Carbon, as carbonic acid, is gathered by plants from 

 the air. 



Potash is not plentiful in our soils. It is a most essen- 

 tial part of plant life. Where it is scarce the indigenous 

 vegetation, both grass and timber, is poor and coarse. 

 Fruit trees, as a rule, search greedily after potash ; the 

 success of potato crops, tobacco, and grape vines is depen- 

 dent upon it. Wool also absorbs much potash, and a 

 deficiency in sheep feed is quickly seen in less and less 

 yolk in the wool. Potash, as a mineral, may be present in 

 the subsoil more plentifully than in the surface soil. 



Soda has, to some extent, the same characteristics as 

 potash in plant life ; but, unlike potash, soda is not 

 uniformly present in the ash of healthy crops. Potash also 

 acts as a substitute for soda in manurial operations, but 

 soda is not found to act for potash in ordinary crops. 



Chloride of Sodium (common salt) is abundant in our 

 soils as a rule, and supplies the soda that is necessary. 



