June i6, 1919 Sulphates Affecting Plant Growth and Composition 



97 



The rape plant did not show this general response to sulphur treatment 

 like the other plants, for in several instances the growth is greater in those 

 pots receiving no sulphur. However, if a comparison is made between 

 the soil and sand pots receiving sodium nitrate and those receiving sodium 

 nitrate plus sodium sulphate, it is observed from the data in Table VIII 

 that increased growth has resulted from the addition of sodium sulphate 

 on both the sand and the soil. The growths of rape on the soils and 

 their extracts parallel each other very well. The rape grew very poorly 

 on the extract from soil C, so no data are given. Where a comparison 

 is made on the growths of the crops on the different soils they do not 

 follow the same order, and the sulphur and nitrogen content do not 

 show the same change from the different fertilizer treatments; but the 

 rape grown in pots receiving sulphur, sodium nitrate, and calcium carbo- 

 nate has a higher percentage of sulphur than that grown in the other 

 pots, yet the total sulphur removed is not much larger. The plants 

 grown on the sand have higher percentages of nitrogen and sulphur 

 but the total sulphur and nitrogen removed is no greater than for' those 

 plants grown in the soil. 



The total sulphur present in plants is far greater where sulphur ferti- 

 lizer was used. On account of the small amount of material, the sul- 

 phate sulphur was not determined so that it is not possible to tell whether 

 the organic sulphur was increased. Analysis, in this laboratory, for 

 organic sulphur and sulphate sulphur in alfalfa hay grown on soils receiv- 

 ing 300 pounds of sulphur per acre and on the same soils receiving no 

 sulphur fertilizer as given in Table IX shows that the organic sulphur was 

 increased by the application of sulphur. Shedd (24) found an increase in 

 organic sulphur in soybeans from the use of ammonium sulphate fertilizer. 



Table VIII.- 



-Weight of rape and its percentage of sulphur and nitrogen on the different 

 soils and sand cultures 



a A=beaverdanisoiland sand; B = Medford loam; C=antelope-clay-adobe. 



