EXPEPvIMEXTS OX THE CULTURE OF TUPtNlPS. 



!47 



tlie form of sulphate of ammonia, analysing 25*12 per cent, of 

 ammonia. Both these salts were carefully pulverized before 

 beinoj mixed for sowino-. 



I had several reasons for selecting these sources of the various 

 manures. My reason for choosing the curacoa was its high 

 percentage of phosphates, it being thus less likely to contain 

 impurities than a lower class phosphate, besides being capable 

 of being ground into an exceedingly fine powder. 



In a trial of ground versus soluble phosphate, fineness of 

 division is of primary importance, as it constitutes the main 

 value of the phosphate, in regard to its immediate availability 

 as plant-food. The superphosphate, from the same source, was 

 used for fair comparison, both ground and soluble being almost 

 the highest possible of their respective classes. Sulphate of 

 potash was chosen because it suited best for mixing, besides hav- 

 ing given me the best results in previous years. Sulphate of 

 ammonia was used as a quick-acting source of nitrogen, and not 

 so readily washed away in the drains as nitrate of soda ; at the 

 same time beino; better suited for mixinf^ with the other imiire- 

 dients, without causing any chemical change. 



The weight and value per acre of the manures used are as 

 undernoted : — 



The Xo. IV. ph)ts, of both tlie sohible and insohible sec- 

 tions, were suggested to me by Mr Jamieson of Aberdeen, too 

 late for being tried at the Sandy ford station,, but were tried at 

 the other three stations. 



As soon as the soil was prepared for sowing at eacli oLthe 

 stations, I went ])ersonally and a])plied the manures, and imme- 

 diately afti-rwards they were covered up jind the turnip seed 

 sown. Aberdeen yellows were the variety sown at all the 

 stations, unless tlie l\o. 1. station at Sandvford, which was 

 sown with swedes. 



