Ammonia-salts versus Nitrate of Soda. 169 



of soda, an increase in each of the three items over the later 

 period. 



In considering these results, special reference should be 

 made to the droughty season of 1870, in which the fact that 

 the nitrogen of nitrate of soda distributes much more rapidly 

 through the soil than does that of ammonia- salts was in a 

 marked degree illustrated. 



As compared with plot 9, the nitrate plot (14) produces 

 more Alopecurus, very much more Bromus inollis and Poa 

 trivialis, and more Lolium perenne ; but, on the other hand, 

 very much less Poa pratensis and Festuca ovina, much less 

 Agrostis, and, upon the whole, less Holcus, with, in all, more 

 total G-raminese. The nitrate plot is the richer in leguminous 

 herbage, but this on both plots falls below 1 per cent. Of 

 miscellaneous herbage, the ammonia-salts have generally 

 yielded more than the nitrate, but latterly not so much. 

 Eumex Acetosa is most prominent under the influence of the 

 ammonia-salts, Conopodium denudatum and Achillea Mille- 

 folium coming next in order, and others occurring in quite 

 immaterial amounts. On the nitrate plot also Eumex Acetosa 

 comes to the front, but Anthriscus sylvestris (beaked parsley, 

 an umbellifer) is about equally developed, and is increasing ; 

 Achillea Millefolium and Conopodium denudatum follow 

 next ; whilst Taraxacum officinale (dandelion) is more plenti- 

 ful than on plot 9. 



The striking differences in the amount of produce, in the 

 amount of total mineral matter taken up, in the botanical 

 composition of the herbage, in the character and distribution 

 of the roots, and in the influence of the vegetation and the 

 manures on the mechanical condition and on the chemical 

 composition of the subsoil, according as the nitrogen is 

 applied as ammonia-salts or as nitrate of soda, are associated 

 with important differences in the chemical composition of the 

 produce. As shown in Table XL., there was, with much 

 more vegetable matter produced, even less nitrogen taken up 

 and retained in the produce grown by the nitrate than in that 



