348 SOILS: PROPERTIES AND MANAGEMENT 



Complete analyses of the soil from the several plats were 

 also made : — 



Yields of Crops, and Composition of Soil and Water 

 Extract of Soil, on Rothamsted Experiment Station 

 Farm 



Unmanured . . . 

 N + P 2 6 . . • 

 N + K 2 . . . 

 Complete fertilizer 

 Farm manure . . 



Yield 



to THE 



Acre 



(Pounds) 



1,276 

 3,972 



2,985 

 5,087 

 6,184 



Complete Analysis 



PjOs 

 (percentage) 



0.099 

 0.173 

 0.102 

 0.182 

 0.176 



K 2 



(percentage) 



0.183 

 0.248 

 0.257 

 0.326 

 0.167 



Water Extract 



PjOs 

 (p. p. m.) 



0.525 

 3.900 

 0.808 

 4.025 

 4.463 



KjO 

 (p. p. m.) 



3.40 



3.88 



30.33 



24.03 



26.45 



A similarly treated set of plats, which had been planted 

 to another crop and analyzed as were these, gave similar 

 results. It is a very striking example of the effect of 

 long-continued treatment of the soil with a certain fertilizer 

 on the composition of the water extract. The subject, 

 however, must be investigated further, as it is of funda- 

 mental importance to a knowledge of the properties of 

 soils. 



