SOIC EXHAUSTION AND ROTATION OF CROPS.. OQf 



cannot grow rye without interruption, and anybody can find cases 

 in which none of our crops will succeed, for several years in suc- 

 ion, or even succeed at all. These differences depend chiefly 

 up >'.i the soil, not upon the plant, and it is dangerous to make any 

 sweeping or absolute general statement where so variable a thing 

 as the soil is concerned. 



Clover is a plant which has often given farmers a great deal of 

 trouble to grow year after year, or to cultivate in quick succes- 

 sion. It is generally admitted as a rule of practice that there is, 

 ordinarily, no profit in attempting to grow wheat two years, or, at 

 the furthest, three years in succession on the same soil. It is 

 admitted to be a good plan generally not to grow any crop more 

 than two or three years in succession. Even our natural grasses 

 areincluded'in this rule, although in some particular localities they 

 do well indefinitely. We have indeed natural meadows and pastures 

 which are as old as the memory of man, and just as good now, 

 for aught that can be seen, as they ever were. But even in the 

 case of natural pastures we know that "circumstances alter 

 cases." Each farm, perhaps, may have some low-lying piece of 

 moist land occasionally flooded by a river, where grass can be cut 

 year after year, year after year. Then we have uplands which 

 must be broken up once in a while; they get "hide-bound," and 

 the grass runs out. These facts are familiar to you all, and illus- 

 trate the broad statement that there are some soils where the 

 same crops can be cultivated for a succession of years and other 

 soils on which rotation is quite indispensable. There are soils 

 where clover has been grown once in three years for a very long 

 period. I have in mind a valley in the Austrian Tyrol — the valley 

 of Saint Martin — where this has been done. No one living can 

 remember the time when this practice was not followed on certain 

 parts of that valley. They have a marl which is regularly put 

 upon the land, and by its use the clover crop continues undi- 

 minished from generation to generation. Its growth there is also 

 very luxuriant, the ordinary clover stems being five or six feet in 

 height. This is a very remarkable case of ground, naturally 

 adapted to clover, kept in continued productiveness by the use of 

 a native fertilizer. But the land of Mr. Lawes, adjoining the 

 fields where he raised wheat without interruption for twenty- seven 

 years, would not carry clover except at quite long intervals Mr. 

 Lawes made a series of experiments on this land, beginning in 

 1848 and going on until 1860, in which he applied stable dung, 



