1906.] LIMING SOILS AND PLANTS. 79 



Here are seen two lots of corn at the left which were grown 

 at Hope Valley, Rhode Island, by the use of a " full ration " of 

 nitrate of soda. The lot at the extreme left grew upon the 

 limed section of the plat and the one at its right grew^ upon 

 the unhmed section. Little difference in the tw^o is noticeable. 

 Nitrate of soda is, therefore, an immediately efficient nitro- 

 srenous manure for soils that lack carbonate of lime and bv its 

 continued use the conditions often improve rather than grow 

 worse. In this respect it differs wholly from sulphate of am- 

 monia. The two lots of corn shown at the right, were grown 

 where a " full ration '' of sulphate of ammonia had been ap- 

 plied. The large lot at the left was from the limed area of the 

 plat and the small one at the right was from the section where 

 no lime had been used. 



At the same time that these and other ex-periments were in 

 progress in Rhode Island, Wagner and Dorsch in Germany ex- 

 perimented with summer rape grown upon a muck soil by the 

 use of sulphate of ammonia. It was found that when used 

 without carbonate of lime its effect was equal to 28 per cent, of 

 the effect of the same amount of nitrogen in nitrate of soda 

 but that after liming it rose to 90 per cent. 



In connection with the publication of this experimental 

 work in Rhode Island, attention was called to the falling off in 

 yields with the ammonium salts as compared with the results 

 with nitrate of soda, at both Rothemstead and Woburn, Eng- 

 land. In fact it was shown at the Rhode Island Station in 

 1893 that the cereals were affected in a very unlike degree by 

 the conditions vrhich cause the ill effect of the sulphate of am- 

 monia. For example, Indian corn and rye withstood the con- 

 ditions best, then oats, w-heat, and finally barley. In this con- 

 nection it is of interest to note that in 1897 J. A. \'oelcker, 

 chemist to the Royal Agricultural Society of England, called 

 attention to the greater falling off of barley than of wheat in 

 experiments with a mixture of ammonium sulphate and am- 

 monium chloride at Woburn. He attributed it at that time to 

 ability on the part of wheat to send its roots deeper and to ap- 

 propriate lime which the barley roots could not reach. Not 

 until 1 901 did Voelcker test his soil with blue litmus paper, 

 when it was found to give an acid reaction. In 1902 he 

 reached the conclusion that the dift'erences in barley and wheat, 

 which were observed earlier, were reallv attributable to a differ- 



