518 EXPERIMENT STATION RECORD. 



military purposes and malviiig IIh-iu valualjlo only as fertilizers. Upon the 

 receipt of the report of the commission the potash syndicate will confer with 

 the 'Government relative to moderating the embargo on potash. . . . 



"The United States imported during the fiscal year ended June 30, 1914. 

 German potash salts for fertilizers aggregating 1,0GG,929 tons gross, equivalent 

 of 250,979 tons of potash (K^O). Importations for the six months July 1 to 

 December 31, 1914, totaled only 184,192 tons, against 507,595 tons during the 

 similar i^eriod of 1913, thus leaviug a shortage on January 1, 1915, of 383,403 

 tons." 



Vegetation experiments, J. G. Lipman et al. {New Jersey Stas. Bui. 269 

 {1914), pp. 12-18, pi. 1; Rpt. 1913, pp. 4^8-484, pi. l).—Fot experiments, making 

 comparative tests of a so-called rock potash fertilizer with other fertilizing 

 materials and of basic slag with other phosphates are reporte4. 



In the first case the rock potash fertilizer appears to have had a depressing 

 effect upon the yield of dry matter. It is suggested that in view of the fact 

 that this product is a low-grade material and must be used in comparatively 

 large amounts it is possible that other soluble compounds are introduced in 

 sufiicient amounts to prove toxic. 



In the comparison of phosphatic fertilizers the greatest increase resulted 

 from the use of one of the basic slags, the lowest from rock phosphate. The 

 test included comparisons of four different samples of the slag with acid 

 phosphate, double superphosphate, sodium phosphate, and blue rock phosi^hate. 



Comparison of magnesian and nonmagnesian limestone in rotation experi- 

 ments, J. G. Lipman et al. (New Jersey Stas. Bui. 267 (1914), PP- 0-4O, fi'J- 1,' 

 Rpt. 1913, pp. 42I-457, fig- !)• — This is an account of a continuation of experi- 

 ments begun in 1908, in which " four five-year rotations were carried out on 

 28 one-twentieth acre plats, so arranged that for each rotation there was a 

 check plat and three plats which received nonmagnesian limestone at the 

 rate of l, 1, and 2 tons per acre, and three plats which received like amounts 

 of magnesian limestone. At the close of the rotation, samples of soil were 

 collected from the various i3lats and the lime requirement for each determined. 



" The results show that nearly all the plats were acid at that time. With 

 but few exceptions, however, the acidity decreased as the amount of applied 

 lime increased. The check plats showed the highest lime requirement. 



"A comparison of the amount of nitrogen present in the surface G§ in. at 

 the close of the rotation, with the amount present soon after the experiment 

 was started, indicates a gradual loss of nitrogen. That is, with an annual 

 application of nitrogenous fertilizers and with the use of two or more 

 leguminous crops in the rotation, the nitrogen supply was not maintained. 



" With comparatively few exceptions, both forms of lime resulted in an 

 increased crop yield over the check plats, the most notable exceptions being 

 the potatoes which were grown in two of the rotations. 



" The yields were usually somewhat higher with the magnesian than with the 

 nonmagnesian limestone. 



" One ton of nonmagnesian limestone gave about the same increase as one- 

 half ton, but two tons gave a decidedly greater increase than one ton. 



" One ton of magnesian limestone gave, in most cases, higher yields than a 

 half ton, but two tons did not materially increase the yield over one ton. 



" In the majority of cases, the dry matter of the crops from the limed plata 

 showed a higher percentage of nitrogen than that from the uulimed plats. This 

 is important in the case of feeding materials and human foods, inasmuch as it 

 means a higher protein content. 



"The value of the total increased yield on the limed plats, as compared with 

 the yield on the check plats, varies from a few dollars to $50 or $60 i^er acre 



