MANURED YJKLD AND SOLUBLE SALTS IN SOILS. 



dency to an increase in yield from the sub-plots to which noth- 

 ing was added to the ones receiving 15 tons of stable manure. 

 In the case of the Hagerstown Loam, it was found, when the 

 field came to be studied in detail, that there were great physi- 

 cal as well as chemical differences in the area chosen on this 

 type, rendering it unsuited to a comparative study of this kind. 

 There were also shown to be considerable irregularities in the 

 soil conditions of the Sassafras Sandy Loam and in the two 

 Goldsboro types, which could not be entirely eliminated by the 

 repetition adopted of sub-plots, in alternate series. 



If these yields are expressed: percentagely on the yields of 

 the 15-ton fertilization as a base, taking those as 100, the re- 

 sults stand as indicated below. 



Percentage, relation* of yield under different fertilizations. 



It will be seen that in the case of the poorer soils there is a 

 percentage difference of 46 between the yields from the 15-ton 

 sub-plots and those to which nothing was added; but a differ- 

 ence of only 18 on the stronger soils. 



The 5-ton suVplots have made a relatively greater gain than 

 have the sub-plots to which the 300-lbs. of guano w r ere added. 



If the differences in yield are expressed in pounds per acre, 

 using the mean yields on the untreated soils as a basis, the re- 

 sults will stand as next given. 



