232 EXPERIMENT STATION RECORD. 



With basic slag the reversion was rapid, over 50 per cent of the acid being in an 

 insoluble form within 3 hours. Only about 7 per cent of the phosphoric acid was 

 revetted in 18 days in the kainit mixture. In the slaked lime mixture 94 per centof 

 the soluble phosphoric acid was reverted within 3 hours and the whole amount pres- 

 ent within 24 hours. Reversion was not so rapid with calcium carbonate as with 

 slaked lime, but 80 per cent of the water-soluble phosphoric acid was converted into 

 citrate-soluble acid in 24 hours. 



Plant peculiarities as shown by the influence of sodium salts, H. J. Wheeler 

 ( Rhode Island Sta. Bui. 104, j>j>- 49-92, pis. 8, dgms. 12).— This is a report on a con- 

 tinuation of observations and experiments, previous accounts of which with a partial 

 resume of literature are given in earlier reports of the station (E. S. R., 11, p. 915). 



The experiments have been conducted since 1894 on 48 sixtieth-acre plats, one 

 series of which was fertilized with various combinations of sodium chlorid and muriate 

 of potash, another with sodium carbonate and potassium carbonate. One subseries 

 with each of these fertilizer combinations was limed in 1894 at the rate of 2 tons of 

 slaked lime per acre. The experiments reported in this bulletin were made in 1899 

 with certain plants which it was thought might perhaps be helped by soda and with 

 others which seemed doubtful. 



" The w r ork of the first 5 years demonstrated conclusively that soda could not per- 

 form all of the functions possibly attributable to potash, for where soda was substi- 

 tuted entirely for potash the crops became poorer from year to year. During the 

 earlier years also few reliable indications were afforded that sodium salts were of 

 benefit so long as a full ration of potassium salts was used. One of the chief objects 

 attained in the first 5 years was the exhaustion to a striking degree of the assimilable 

 potash, thus preparing the soil for use in making more satisfactory trials of sodium 

 salts than were possible before." 



In 1899 each plat was manured as follows: Dried blood 1,020, dissolved boneblack 

 600, floats ( finely pulverized phosphate rock) 480, and magnesium sulphate 420 lbs. 

 per acre. Sodium and potassium salts were each substituted for the other upon some 

 one or more of the 48 plats in "quarter," "half," "three-quarter," and "full" 

 rations. The full rations of the sodium and potassium salts used were as follows: 

 Sodium chlorid (common salt) 231.6, sodium carbonate (soda ash) 202.2, muriate of 

 potash (80 to 85 per cent potassium chlorid) 331.8, and potassium carbonate (pearl 

 ash) 300 lbs. per acre. Spring rye, golden millet, chicory, Bloomsdale spinach, 

 white Strasburg radish, flat turnip, Manshury barley, Norbiton Giant beet, Danvers 

 carrot, Iceberg lettuce, white pea-bean, and Budlong turnip (ruta-baga) were used in 

 the experiment. 



The results without exception indicate that soda is not as efficient as potash as a 

 plant nutrient. "It can not be disputed, however, that soda is of some use in some 

 manner with many varieties of plants, when the supply of potash is quite limited, 

 and also with at least a few varieties of plants even in the presence of a fairly abun- 

 dant supply of potash. Whether sodium salts would be rendered useless with all 

 varieties of plants if the supply of potassium salts were greatly increased is a point 

 which is not as yet fully proved, nor is it fully clear as yet in just what manner the 

 sodium salt has been helpful in this particular experiment. This is a question 

 which will be considered later in connection with the chemical analyses of the crops. 



"It may, however, be stated here that sodium salts seem to liberate at least phos- 

 phoric acid and potash, so that under certain circumstances they may act as indirect 

 manures. They also appear under certain conditions to prevent plants from assimi- 

 lating large amounts of potash in excess of their needs, thereby conserving the 

 potash supply within the soil. It does not appear unlikely, when the supply of 

 potash is limited, that sodium salts may aid in some degree in performing some 

 function of potassium." 



