Distribution of Wheat, Sheep, and Cattle in Australia. 119 



will vary widely in fertility, but it is safe to say that, within the 

 regions to be indicated as suitable, and not yet used for wheat 

 production, though there are areas of low soil fertility, there are 

 many thousands of acres of which the soil is eminently suited to 

 the growth of wheat. As regards the other two factors, rainfall 

 and temperature, the rainfall both in its total amount and 

 incidence in respect to the growing period of wheat, is far the 

 more important. Temperature, in fact, can be almost disregarded 

 as a limiting factor ; there is no extensive area of cultivable land 

 in Australia which is actually too cold for the growth of wheat, 

 though in our colder districts other conditions combine to make it 

 less profitable to grow wheat than other crops. Similarly, though 

 wheat is not grown north of the 70 deg. isotherm, there is a 

 considerable area north of this line climatically similar to the 

 wheat-growing areas of India. ^ Here, again, it is the question 

 of the degree of profitableness as compared with other agricul- 

 tural and pastoral pursuits under our present conditions of 

 development, rather than temperature, which limits the exten- 

 sion of the wheat area in a northerly direction. At the same time 

 there is evidently an optium condition of temperature for wheat 

 in Australia, for practically the whole of the area sown to wheat 

 is situated between the 60 and 65 deg. F. isotherms, there being 

 a marked coincidence between the 60 deg. isotherm and the 

 southern limit of the wheat belt. 



Considering the distribution of acreage in relation to the 

 more important factor of rainfall , the rain of importance to 

 wheat is that falling during the growing period of the crop, i.e., 

 April-October, inclusive, the rain falling during the summer 

 being largely lost by evaporation, and also sometimes tending 

 to reduce the wheat yield by causing lodging of the crop and the 

 spread of rust. Therefore the lines of rainfall shown are those 

 for this period. It is seen that practically all our wheat is now 

 grown between the lines of 7.5 and 15 inches of winter rainfall. 

 In Western Australia there is certainly a considerable area 

 between the 15 and 20 inch lines, but here settlement is so sparse 

 that more intensive agriculture has not yet pushed the wheat 

 belt back into its true sphere in the dry farming regions. In 

 South Australia, Victoria and New South Wales, the 15-inch line 

 corresponds very closely with the southern boundary of the 

 wheat belt, this line approximately separating the dry farming 



iVide Griffith Taylor, "The Australian Environment. 



