CH. Vl] TOOLS, TILLAGE, MANURING, CROPPING, ETC. 29 



and thus to exhaust it at a far slower rate than would one 

 single crop, which would use up some single constituent of the 

 soil at a rapid rate. In fact, the group of plants growing on 

 the soil forms a "plant society" like the natural plant societies 

 that grow on any piece of soil left to nature. On a heath in 

 Scotland, for instance, there may be a very large amount of 

 heather, a small amount of bell-heather, and smaller amounts 

 of rockrose and many other plants, and on any two similar 

 pieces of ground the same plants will always be found in about 

 the same proportions. Now rough observation shows that 

 something not unlike this is the case in these mixed gardens of 

 the villagers, they nearly always containing the same plants, 

 and in not dissimilar amounts. It must not for a moment be 

 supposed, however, that the villager has adopted this method of 

 "cultivation" with any advantages of this kind in view, but 

 rather it is that by using this method, the troublesome labour 

 of cultivation is practically entirely done away with, for he 

 never tills the soil among his mixed crops. Though his return 

 is very small from this method of cultivation, it is probable, 

 therefore, that he gets one of the two great advantages of 

 rotation, though of course he loses the other, of the proper 

 tillage of the ground for which opportunity is given by the 

 change of crop, for example from wheat to roots. 



Not only is there this mixture of perennial crops, but 

 mixture of annuals is very common in the East : pulses are 

 sown among the grain, different kinds of grain with one another, 

 and so on. Here again the gain is somewhat like that obtained 

 with rotation, or the season may suit one and not the other, so 

 that there is not a total failure. 



