152 STATES OF THE RIVER PLATE. 



lucerne (alfalfa), which is mown for ' soiling ' or hay- 

 year after year until it is worn out. During all this 

 time it is but rarely that there is any restoration to the 

 soil of the fertilising matter abstracted from it in the 

 crops. The extent to which the land is impoverished by 

 this course in a few years, say the duration of the alfalfa, 

 is very great, this being a plant which exhausts the soil 

 probably to a degree unequalled by any other. Alfalfa 

 hay taking more or less 12 per cent, of its weight of the 

 mineral food of plants from the soil, the result is, that on 

 the majority of lands on whicli this plant has been grown, 

 it will not again thrive, and there is no other crop grown 

 here that wUl as profitably replace it. These lands are, 

 therefore, thrown out of cultivation, and fresh land must 

 be had recourse to, or the farmer has to content himself 

 with less remunerative crops. 



When cereals alone have been grown, the usual tillage 

 for which is shallow, a new surface can be provided by a 

 deeper tillage, and a renewal of fertility is brought about 

 for a time. On the other hand, alfalfa is an exceedingly 

 deep-rooting plant, and impoverishes the soil to a cor- 

 responding depth. It has been explained that the means 

 of maintaining the fertility of a soil consist of the re- 

 storation to it of the matters abstracted from it in the 

 crops, in the form of manure. Now this is next to an 

 impossibility on the majority of farms (chacras) as at 

 present managed. 



On very few chacras are there any more animals kept 

 than suffice to do the work of tillage, so that almost the 

 whole of the crops are removed from the land, and the 

 elements of reproduction with them ; and there is no 

 means of obtaining manure except at a cost in labour 

 and carriage out of all proportion to the value of the 

 crops themselves. 



