210 



MniniriiKj Jar Hmj 



Influence upon Chemical Composilion of Soil. 



Analyses were also made in I'JII of the soils of the different plots 

 and it is of interest to compare the results obtained with the soils 

 with those given above for the crops. The essential data are sum- 

 marised in Table VIII^. 



Taule V'lll. " A):ailablc" I'lanl Food in Soils. 



It will be found on comparison that there is a fair degree of correlation 

 between Tables YIl and VllI, as, for e.xample, in the accunmlation 

 of potash on the dunged plots and its scarcity on Plots 1 and 9-13. 

 It is further of interest to note the dej)letii)n of the supplies of available 

 potash on Plots 9 and II which receive nitrate of soda as compared 

 with the corresponding ammonia plots (10, 12). 



There is little sign of correlation with regard to phosphoric acid. 

 The lowest proportion is recorded on Plot 12 (ammonium salts alone), 

 a fact which is in accord with the known power of ammonium salts 

 of facilitating the taking up of phosphates by plants. 



The general lowness of the supplies of calcium carboiuite has been 

 referred to already. It will be observed how the use of sulphate of 

 anmionia on Plots 8, 10 and 12 has accentuated this poverty. 



The indications of soil analysis with regard to the calcium carbonate 

 were borne out by the results of determinations of the "lime-fixing" 

 powers of the soils of the plots, made by shaking up separate equal 



' The chemical composition of the soils was more exhaustively studinl but it is not 

 proposed to deal with the results here. 



