Oct. 14, 1918 Fertilizer Potash Residues in Hagerstown Silty Loam 75 



belonging to Tiers in and IV, of the same General Fertilizer Experiments. 

 The former of these sets of analyses was made by Pingree (8), using 

 the oat crop harvested in 1 904 from Tier IV. The second set is composed 

 of unpublished analyses made by senior students of the Department of 

 Agricultural Chemistry of The Permsylvania State College under the 

 direction of Dr. C. W. Stoddart, who has kindly permitted the use of 

 the results obtained. This second set of analyses represents the crops 

 of a complete rotation, 1910-1913, from plots i, 14, 26, and 36 (untreated) 

 collectively, and from plot 4, dressed with potash, all of Tier III. 



The following is a condensed summary of these crop analyses, with 

 respect to the potash found : 



In every one of these crops the percentage of potash was very markedly 

 greater in that grown upon the plot dressed with potash, than in the 

 corresponding crop grown upon the untreated plot i , or upon its similars 

 in treatment, plots 14, 26, and 34. The excesses on plot 4 for each unit 

 weight of crop harvested varied from 15.7 to 75.6 per cent, and averaged 

 43.7 per cent for the five crops analyzed; 41.9 per cerut for the four crops 

 of 1910-1913, representing one complete rotation. 



Since the potash fertilizer was applied just before the planting of the 

 corn and wheat crops, it is perhaps not unexpected that these crops as 

 harvested contain more potash than crops from lands receiving no ferti- 

 lizer dressing. It is strikingly clear, however, that the larger excesses 

 appear in the oats and hay crops, harvested 14 and 21 months, respec- 

 tively, after the potash dressing had been applied. Furthermore, the 

 excesses of potash in the plot 4 crops are possibly the more indicative 

 of the ready availability of the potash in the soil of that plot from the 

 fact that the crop yields were not increased by the potash fertilization. 



The evidence from plant composition confirms, therefore, the indi- 

 cations obtained by the action of weak solvents upon the soil to the 

 effect that of the potash in plot 4 much more exists in a state of avail- 

 ability to plants than of the potash in plot i despite the greater absolute 

 quantity of the element present in the latter plot. 

 78774°— 18^— 2 



