AN AGRICULTURAL POINT OF VIEW 



265 



different varieties, is equivalent to the application of 35 to 

 43 tons of farmyard manure to the hectare. 



At the same time we see the rate at which decomposition 

 takes place. 



Organic matter per hectare. 



Decomposition 



of the leaves and stems 



left on the fields 



The following tables show the different proportions of 

 lime, magnesia, potash, and phosphoric acid contained in 

 the ash, dry matter, green matter, and the amount of these 

 elements abstracted per hectare : — 



In 100 PARTS OF PURE ASH 



