NITRATE OF SODA T. AM MOM T M SA l.TS h;:; 



the great excess of iiitrogm applied to tliis jtli.t any >iilistaiR'«' 

 like soda, which supplements and economises the potash avail 

 able, will be of service to the plant. 



Turning now to Plot 14, which receives the same manure 

 as Plot 9, ])ut with its nitrogen in the form of nitrate (tf soda, 

 we notice first that the nitrate of soda has been the more 

 effective soiu'ce of nitrogen, giving an average crop of .")!> cwt. 

 against 54 cwt. with ammonium-salts. The superiority tA' iUv. 

 nitrate of soda has been most pronounced in dry seasons, 

 owing to the generally deeper-rooted habit of the grasses found 

 on this plot. 



Daring the great drought of 1870, holes were dug for the 

 examination of the subsoil on this plot and on Plot 0. On the 

 latter, where ammonium-salts formed the source of nitrogen, 

 very few roots could be distinguished below 36 inches, and the 

 ijubsoil below 27 inches seemed to have been but little changed 

 by the development of roots and their decay. On Plot 14. 

 Avith the nitrate of soda, wiry roots extended nearly to 4 feet, 

 and the subsoil down to 4 feet 6 inches had suffered a marked 

 change. 



The vegetation on plots grown with nitrate of soda is more 

 varied, nor are the leguminous plants so completely .suppresse<l 

 by the large amount of nitrogen. This j^lot, for I'xampU'. 

 showed in 1903 more than 8 per cent, of ]\read"\v ^'('t(•llli^g 

 and a trace of White Clover. The aspect of the nitrate and 

 ammonia plots is strikingly different, as may be seen by com- 

 paring the tAvo photographs taken in 1903, Figs. 26 and 24. 

 With the nitrate of soda a great part of the herbage, 23 \)vv 

 cent., is composed of Soft Brome, a grass hardly to be found 

 on any of the other plots. Again, Beaked I'arsh'v is very 

 prominent, though it is hardly to l^e found on any of the otlicr 

 plots; it constituted 10 per cent, of the herbage in 19(13. so 

 that just ])efore hay time the whole plot .shows white with its 

 flowers. In addition to the Soft Brome, the gra.sses whu-li 

 predominate are Meadow F'oxtail, l^ilsc Oat. and Smooth- 

 .stalked Meadow^ Grass. 



