AND NlTllOGEN ON THE GROWTH OF TURNIPS. 99 



The dissolved bones is tlie most disap])(>intin^' plot of all, jriving 

 till", worst returns for tlie lari-est expenditure, and eontainiiiL;-, as 

 they do, equal proportions of sohd)le and insoluble ])liospliates, 

 and also a fair quantity of nitrogen, in proof of which the plants 

 came away quickly at first, and became unhealtliy only at an 

 advanced stage of their growth. The dissolved ]»hospliate in 

 plot 4 exhibited tlie same unhealthy state amongst tlie turnip 

 plants. I can see no reason for it, unless there miglit liave been 

 ail excess of sulphuric acid or some deleterious substance in the 

 niainire. As the no-manure plot alongside was quite healthy, 

 the cause, therefore, could not be in tlie natural condition of tlie 

 soil. In Section II., the addition of sulphate of potash to gnniml 

 mineral phosphates, produces fully three times the excess oi 

 weight of the coprolite alone, and, in the case of potash and 

 su])erphosphate, as compared with the solubh; phosphates alone, 

 also shows three times the excess weight of ro(jts, both sliowing 

 a corresponding increase of shaws in comparison to the roots. 

 The soluble pliosphate here again takes a slight lead, but barel}^ 

 suHicient to cover tlie extra cost of the manure. Nitrogen added 

 to coprolites clearly shows a large increase of crop, both roots 

 and shaws, but certainly an excess of the latter as compared with 

 the potash plots, more especially the sulpliate of ammonia and 

 nitrate of soda plots. The fish guano plot looked very well all 

 along, and rooted earlier than the sulpliate and nitrate plots. 

 The azote guano plot came away at first the worst of all four, 

 Ijut made up its lee-way rapidly at the end. The extra wet season 

 may account for the more soluble salts of sulpliate of ammonia 

 and nitrate of soda being beaten in results by their less soluble 

 neighbours, fish and azote guanos. As they would be more 

 readily washed away into the drains in such a porous soil, a 

 drawback to which the guanos were not very much exposed, the 

 nitrogen in them beinu; in comliination with animal matter instead 

 of in a solulile salt. Judging from the results of these experi- 

 ments, it is quite clear that in such a season, and on the kind of 

 soil to which I have already referred, the most economical manure 

 for the growth of a bulky crop of turnips, would be ground phos- 

 phates, with the addition of the sulphate of potash and a little 

 nitrogen in a convenient form to stimulate the plant during its 

 early stages. I am ver}' sorry I did not try that mixture, but 

 the results of the potash plots were such as to astonish me. Had 

 I been aware of the value of that salt as a fertilizer, I would 

 certainly have tried it along with nitrogen and phosphates. I 

 have used that mixture above farmyard manure, to which I shall 

 have occasion to refer presently. 



I shall now show in tabulated form the extra weight of turnips 

 grown by addition of various compounds of phosphates and 

 nitrogen to farmyard manure, in each case deducting the weight 



