192 



ANNUAL REPORT OF THE 



Off. Doc. 



ities OYor the world has shown that it is often valuably suggestive, 

 but that there are soils for which its results are not indicative of 

 the true state of fertility. Thus the red volcanic soils of Hawaii, 

 exceedingly rich in iron, give to the citric acid solution more pros- 

 phoric acid than sugar can remove, and for these soils, aspartic 

 acid has been found the preferable solvent. The Dyer method has 

 been employed in the examination of a number of Pennsylvania soils. 

 We will very briefly consider the results obtained. 



ANALYSIS BY DILUTE CITRIC ACID. 



o 

 Si . 



LIMESTONE SOILS. 

 Hag-erstown Loam, Donegal, Lancaster co. : 



Surface, 



Sub-soil 



Conestoga Loam, Rocky Spring-, Lancaster co. : 



Surface, 



Sub-soil 



Morrison's Cove, Bedford co., Pa 



Nittany Valley, Silt Loam, State College, Pa., 



OTHER SOILS. 



Iron Bearing Clay, Edgely, Pa., 



Cecil Clay, Adams co 



Micaceous Clay, Haverford 



Hagerstown Sliale Loam, Blanchard, Center co. 

 Mauch Chunk Red Shale, Gratz, Dauphin co.. 



Black Slate, Cumberland co 



Norfolk Silt Loam, Blanchard, Pa 



Venango Glacial Loam, 



.053 

 .064 



.037 

 .010 

 .0136 

 .0190 



.016 

 .0133 



.1041 

 .0150 

 .0107 

 .0220 

 .0150 

 .0117 



.044 

 .042 



.123 

 .055 

 .0082 

 .0139 



.015 



.0057 



.0571 



.0306 



.0088 



.0111 



.0146 



.0130 



Not one of the soils examined appears deficient in potash, accord- 

 ing to Dyer's standard. It must be recalled that this standard is 

 based chiefly upon results obtained \\ith barlev and grasses, and is 

 not sti'ictly a|)plicablc !(• ctopB of ditlerejit feeding habit. Although 

 the available potash shown by the citric acid method in the lime- 

 stone soils of Lancaster county is far more abundant than the min- 

 imum standard, tobacco required for its best development liberal 

 potash dressings on both the Hagerstown and the Conestoga loams. 

 But for staple crops, with the possible exception of potatoes and 

 other root crops, the much smaller percentage found in the Nittany 

 Valley limestone loam is sufficient. 



As to phosphoric acid, the results show the Morrison's Cove lime- 

 stone, the Edgely and Cecil clays, the Dauphin red shale, Cumber- 

 land black slate and Venango glacial drift soils, seriously near or 

 even below the danger point. The Nittany Valley silt loam, though 

 it holds more than Dyer's minimum, .01 per cent., of citric soluble 

 phosphoric acid, requires that element for the best development of 

 all staple crops, including even such vigorous feeders as oats and 

 rye. Tobacco shows for phosphoric acid the same low feeding power 

 that it exhibits for potash, and five years' experiment at Donegal 

 showed a marked return from phosphoric fertilization, while the 

 Conestoga loam, with three times the citric soluble phosphoric acid 



