194 THE ROTHAMSTED EXPERIMENTS. 



the population of the United States in the past, the Central, 

 Northern, and Western States, from which we now derive 

 such large supplies of grain, will, before many years have 

 passed, be as densely populated as the Eastern States are 

 now ; and that then the export of grain will be rapidly 

 diminished. In this calculation, however, the essential dif- 

 ference in the character of the land in the Eastern States, 

 and in the prairie districts of the Central, Northern, and 

 Western States, is not taken into account. It is true that both 

 western meat and western wheat are materially reducing the 

 production of them in the Eastern States ; so that the popula- 

 tion of the east as well as of the west will consume more and 

 more of the western produce, leaving of course the less for 

 export. And if, in addition to this, it be true, as alleged, 

 that the western lands themselves are losing their fertility, 

 there would indeed seem that there is some likelihood of 

 material reduction in exports before very long. 



Certain it is, however, that large areas of formerly prairie 

 land, which provide so much of the exports, were originally 

 as rich as ploughed-up old grass-land in our own country, 

 and sometimes so to a considerable depth. Hitherto the 

 land has, as a rule, only been skimmed, practically no 

 labour bestowed on cleaning, and compared with the pro- 

 duce which such lands should yield if properly cultivated, 

 very small crops of grain have been obtained. But the large 

 crops occasionally yielded under favourable conditions are 

 evidence of the inherent fertility, and of the possible pro- 

 ductiveness, of the soil. Further, from what has been said, 

 it is almost impossible to believe that such soils can have 

 become seriously exhausted within comparatively so few 

 years, at any rate so far as available nitrogen is concerned. 

 Indeed, if there be palpable exhaustion at all, it would seem 

 more likely that it is of some mineral constituents — potash, 

 lime, or phosphoric acid, for example. However this may 

 be, so long as wheat is grown under the conditions frequent, 

 and indeed almost inevitable, in the case of new settlement, 

 with sparse population — that is, growing it for several years 

 in succession, with deficient cultivation, luxuriance of weeds, 

 the burning of the straw, and generally the wasting of the 

 manure of the working stock — only low yields can be ex- 

 pected. The practice naturally results from the fact that, 

 under such conditions, fertility is cheap and labour dear. 

 As population becomes more dense, however, local markets 

 will arise for rotation products, more stock will be kept, the 

 straw and the manure will be utilised, cultivation will be 

 improved, and weeds will lose their ascendency. Nor can 

 there be much doubt that under such conditions it will be 



