1190 EARLE V. HARDENBURG 



which indicates 'that probably potash ' is not a limiting factor in the soil 

 at the Florida station. 



Under the recent war conditions, growers in the Eastern States were 

 forced to do without potash or to use less. Woods (1918), at the Maine 

 station, has attempted to determine the possibility of obtaining satis- 

 factory yields without this element. His average results for the three 

 years 1915, 1916, and 1917 show that, whereas fairly good yields have 

 been obtained with no potash, the yield has been increased 26 bushels 

 an acre by the addition of 3 per cent of potash. The additions of 5 and 8 

 per cent of potash have given practically no increase above that from 3 

 per cent. The high percentage of potash previously used in Maine was 

 evidently not needed, or else the soil had become temporarily stocked 

 with a surplus. Chemical analyses have shown that the sandier soils 

 of the coastal plain are more deficient in potash than the heavier soils 

 farther inland. This fact and the more intensive cultivation of potatoes 

 probably account for the larger amounts of potash previously used in 

 these regions. It might be supposed, therefore, that yields of potatoes 

 cannot long be maintained without this constituent. The recent studies 

 of Dr. Oswald Schreiner, of the United States Department of Agriculture, 

 on potash hunger in the Aroostook potato region in Maine and in the 

 Norfolk potato truck areas, bear out this conclusion. The writer has 

 recently observed marked examples of potash hunger in the potato fields 

 of Long Island. Evidently the shortage of potash is beginning to be felt. 



Of the two principal forms of potash muriate, or the chloride form, 

 and sulfate the muriate has always been the more commonly used on 

 this crop. The reasons for this are the greater cost and the lesser supply 

 of the sulfate form. It is occasionally stated, tho the point does not 

 seem to be borne out by much experimental evidence, that the chlorine 

 in muriate of potash is detrimental to quality in the potato. There has 

 generally been little difference between the two forms as to the yield 

 resulting. Rane and Hunt (1897), in a one-year test, used 87 varieties 

 of potatoes and obtained a very slight advantage in favor of muriate of 

 potash. Many years later, Brooks (1914) obtained an increase in yield of 

 11 bushels per acre in favor of the sulfate form, with an additional improve- 

 ment in quality. 



The experiments of Conner (1906) show results from the use of various 

 amounts of ammonia and of phosphoric acid in complete fertilizer, which 

 not only are inconsistent but also show average yields not essentially 

 different from those from the check plots. T. C. Johnson (1916), com- 

 paring the results from 2, 4, and 8 per cent, respectively, of phosphoric 

 acid in complete fertilizer, found the best results from the 8-per-cent 

 analysis. His results with varying amounts of nitrogen were incon- 

 clusive. Woods (1918), in a test to compare nitrogenous fertilizers in 

 combinations of nitrate of soda, ammonium sulfate, and organic forms, 



