KXI'KIM.MKXTAL RTATK »X^^ — IIKPOKT FOR 1879. 



287 



fouiLli {•oluiiui, iuilicutiiiL;- the total wuii^lit of j^raiu per acre 

 proclucLHl on each plot. 



Total Weiuht ok 1!uain tku Acrk. 



We thus sec that l>y simply dissolving the iJiosphates of the 

 manure the average yield of grain jtcr acre has been increased 

 about 14 per cent. 



The weight of straw has also been increased in nearly a 

 correspondino- ratio. 



A very noteworthy point l)rought out by these figures is the 

 great regularity of the results obtained on the dissolved phos- 

 phate plots, compared with the irregularity in the amounts of 

 crop produced with undissolved phosphates. This gives support 

 to the view that phosphates from whatever source are alike in 

 their effects as manures, so soon as they have been dissolved. 

 In their undissolved state their etticacy is influenced by various 

 circumstances, such as the fineness of their state of division, 

 their hartlness and resistance to chemical action, oi- the presence 

 of fatty matter, which protects the phosphates from the action of 

 water, and so tends to retard their decomposition in the soil. Jt 

 is no doubt partly due to this last characteristic that bone dust un- 

 dissolved forms so inactive a manure. 



The want of phosphates, as seen by plot 11, has been followed 

 by a diminution in grain, and especially in the quality of the 

 grain, but it has had comparatively little influence on the pro- 

 duce of straw. The sole application of phosphates has failed to 

 produce a good crop of straw, and this is no doubt due to the 

 absence of nitrogen, as seen from the yield of straw in plot 17 

 from which nitrogen was withheld. The want of potash has 

 probably nothing to do with it, for we find on plot 22 that where 

 potash alone was applied the crop was a signal failure. 



Of the two most common forms of nitrogenous manure, nitrate 

 of soda and sulphate of ammonia, the latter has a slight ad\antage. 



