MANURING OF PLOTS 



71 



no potash or alkali salts ; (3) potash, magnesia, and soda, no 

 phosphoric acid ; and (4) complete mineral manure, supplying 

 both phosphoric acid and the alkaline salts. Each of these is 

 combined with the four different cross-dressings of nitrogenous 

 manures Series O no nitrogen, Series A ammonium-salts, 

 Series A A nitrate of soda, and Series C rape cake. There 

 are other plots, one of which has received farmyard manure 

 each year, and a second which received farmyard manure for 

 the first twenty years but has since been unmanured. 



Table XXVIII. shows the nature and quantity of the 



TABLE XXVIII. Experiments on Barley, ffoos Field. Manuring of 

 the Plots per acre per annum, 1852 and since. 



manures applied each year to the plots. Table XXIX. shows 

 the average production of grain and straw for the whole 

 period, for the last ten years, and for the single year 1911. 

 Table XXX. shows the average production during each fo the 

 successive ten-year periods from 1852. 



