BARLEY 



33 



Table XVI. — Experiments on Barley ^ Hoos Field. Produce oj Grain and Straw 

 per acre. Averages over 51 years (1852-1902), ami over 10 (1893-1902). Also 

 Produce in 1905. 



Average 31 years (1872-1902). 



Effect of Nitrogenous Manures 



The effect of nitrogenous manures upon the barley crop is best seen by 

 comparing the yields of the various Plots 4, all of which receive the same 

 mineral manures ; the diagram, Fig. 11, shows this comparison in a graphic 

 form. 



Effect of Mineral Manures 



The diagram, Fig 12, shows in a graphic form the effects of the various 

 mineral manures, the nitrogen supply being the same in all cases. 



The great importance of phosphoric acid to the barley crop is seen on 

 comparing Plots 3 and 4, which only differ from one another in the 

 omission of phosphoric acid on Plot 3. In the field the most striking 

 effect is seen in the hastened maturity brought about by the phosphoric 

 acid. By comparing Plot 2 with Plot 4 we can see the effect of omitting 

 potash from the manure. Where nitrate of soda is used as the source of 

 nitrogen the soda liberates sufficient potash from the soil to supply the 

 needs of the crop, but with ammonium-salts the omission of potash has 

 latterly begun to tell upon the yield, though it did not do so in the earlier 

 years of the experiment. 



C 



