250 



TALKS ON MANURES. 



uble ammonia-salts or nitrate of socla, a considerable amount of 

 the nitrogen is left in the soil an.lyet this nitrogen is of compara- 

 tively jittla benefit to the succeeding crops of wheat or barley, 

 while a fresh dressing of ammonia-salts or nitrate of soda is of 

 great benefit to the crop. 



In other words, when wheat is sown after wheat, or barley 

 after bar! ay, we do not get half the benefit from the manure which 

 it is theoretically capable of producing. 



Now, the question is, whether by a judicious rotation of crops, 

 we can avoid this great loss of manure ? 



There was a time when it was thought that the growth of tur- 

 nips enriched the soil. I have heard it said, again and again, that 

 the reason English farmers grow larger crops of wheat and bailey 

 than we do, is because they grow so many acres of turnips. 



" So I have often heard," said the Deacon, "and I supposed the 

 broad turnip leaves absorbed nitrogen from the atmosphere." 



There is no evidence that leaves have any such power ; while 

 there are many facts which point in an opposite direction. The 

 following experiments of Lawes and Gilbert seem to show that the 

 mere growth of turnips does not enrich land for grain crops. 



Turnips were grown on the same land, year after year, for ten 

 years. Ths land was then plowed and sown to barley for three 

 years. The following table gives the results : 



THREE YEARS OF BARLEY- AFTER TEN TEARS OF TURNIPS. 



Produce of Barley per Acre. 



The yield of barley after turnips is less than it is after grain 

 crops, and it is evident that this is due to a lack of available nitro- 



