286 EXPERIMENT STATION RECORD. 



The action of nitrates on the assimilability of potash in poor 

 sandy soils, P. Piohard {Compt. Rend., 11'.) {1S9-I), Ko. 10, pp. 471-473). 

 Three series of experiments ou White Burley tobacco grown on fine, 

 white, siliceous sand are reported. In these nitrogen was furnished in 

 the fonn of nitrate of soda, nitrate of lime, nitrate of magnesia, and 

 l)eanut cake; phosphoric acid in the form of superphosphate, phosphate 

 of soda, phosphate of potash, phosphate of lime, and phosphate of 

 magnesia; and potash in the form of nitrate, sulphate, and phospliate. 



Of the 5.0 gm. of insoluble potash which the soil contained the tobacco 

 which received the nitrate of lime, nitrate of soda, and nitrate of mag- 

 nesia assimilated, respectively, O.OG, 3.21, and 0.48 gm. Practically the 

 same results were obtained where peanut cake was applied, especially 

 when nitrification was promoted by applications of i)liosphate or car- 

 bonate of lime. The amounts of insoluble potash assimilated by the 

 ])hints varied from 1.02 to 3.04 gm., the highest amount being assimi- 

 lated where carbonate of lime was applied. 



This beneficial action of nitrates in increasing the assimilability of 

 potash is undoubtedly not peculiar to tobacco, but would be manifested 

 in case of other i)lants, especially the potato, which belongs to the same 

 family and has similar fertilizer requirements. 



It has been observed that on the siliceous soils of Brittany, which 

 are poor in assimilable i)otash and lime and rich in organic nitrogen, the 

 application of lime or carbonate of lime increased the yield of fodder 

 beets fourfold to sixfold. Land plaster, in addition to the lime or car- 

 bonate of lime, still further increased the yield. 



Viticnlturists find the continued use of plaster in soils rich in organic 

 nitrogen profitable on account of its action in promoting nitrification 

 and the consequent assimilation of potash, for it is. probable that the 

 beneficial effect resulting from the use of various calcareous manures 

 is due not only to the nitrates formed but to their indirect action in 

 promoting the assimilability of potash. 



In view of these facts the amount of potash in a soil soluble in aqua 

 regia can no longer be considered as the extreme limit of assimilability 

 of this element, but it becomes necessary to determine the total com- 

 bined i)otash. 



Fertilizers, how to make and how to use them, A. A. Persoxs {Florida Sta. 

 Bid. 22, 2)}). .^7).— The principles underlj'ing the use of fertilizers, the nature of the 

 various fertilizing materials in common nse, and the fertilizer reqnireraents of difter- 

 ent crops are discnssed, and formulas for compounding fertilizers for diflerent crops 

 as calciilated l)y Sempers ' are given. 



The use of mixed fertilizers , .J. B. Lav^es {Rural Xew Yorker, 1894, Sept. S, p. 

 565). — Popular article. 



Progress in the domain of fertilizing, with special reference to liming, O. 

 ScniLLENBEiiGEK {Fiihlhif/'s Landic. Ztg., 43 {1S94), No. 17, pp. 533-545; No. IS, pp. 

 557-565). 



' Manures: How to Make and How to Use Them. 



