AGRICULTURAL MACHINERY 153 



indirectly assisting the progress of animal industries, it appears 

 doubtful whether machinery (except as described above) will be 

 of much further direct service in these industries. Indeed, the 

 process of intensification upon which an increased future pro- 

 duction largely depends, involves greater human care in the handling 

 of the more highly specialised animals. 



Closely connected with the question of the utilisation of 

 machinery in the service of animal industries, is that of the density 

 of agricultural population which determines largely whether the 

 extensive or the intensive system is followed. Obviously in those 

 regions where the agricultural population is sparse and labour is 

 scarce, only those types of food production can be followed that 

 utilise machinery on a large scale, such as cereal cropping, or that 

 make little demands upon labour in any form, such as large-scale 

 cattle-ranching on natural pastures. Mixed farming and all forms 

 of animal industries, except the purely pastoral, make considerable 

 demands for labour and require a certain minimum density of 

 population in consequence ; but clearly also, the more machinery 

 c an be used in mixed fanning and ordinary animal industries, the 

 j ower may be the density of agricultural population for the effective 

 production of foodstuffs. 



Owing to the increased demand throughout the world for cereals 

 and other products, there is a tendency for animal industries to 

 leave the open prairie or steppe, which, as above explained, is in 

 some ways better suited to grain crops, 1 and to remain or to return 

 only to such an extent as the preservation of soil fertility demands. 2 

 A survey of the world's producing areas shows that most of the 

 large pasture regions in the temperate zones are already occupied, 

 and animal industries are therefore thrown back on one of two ways 

 of increasing their output, both of which involve a considerable 

 amount of human labour. The first of these is by the application 

 of more intensive methods on land already in use, and the second 

 is by clearing forest lands for pastures, a process which is still in 

 progress in a number of the newer countries. This process, how- 

 ever, is limited by the necessity of preserving timber supplies and 

 by the comparative low productivity of much of the land remaining 

 to be cleared. 3 The labour involved in clearing is often great, and 

 a long time must often elapse before production becomes effective. 



Owing to the labour question, the lands now being taken up, 

 and likely to be taken up in the near future in the temperate 

 regions, are often more favourable initially to cereal cultivation 



1 See Chap, iv., above, p 87. 



2 The rising price of land has in some cases in the prairie lands of North 

 America made it necessary to substitute mixed farming with dairying and pig- 

 rearing, for the one-crop system, in order to secure an adequate return. 



3 In spite of the large areas still under forest in the temperate regions, it 

 is doubtful whether any large effective additions will in future be made from 

 them to pastoral or agricultural lands (see Chap, xi., below). In any case 

 forests often cover mountainous, swampy and unduly cold areas that arc 

 of little agricultural value. 



