115 BOARD OF AGRICULTURE. 



VI— APPENDIX. ExGLisn Expep.iments. 



As an appendix to the foregoing, I re-publish from the same 

 source. as the above, a letter from J. B. Lawes, the veteran experi- 

 rnentor of Rothamstead, Herts, England, which from the source of 

 high authority from which it comes, entitles it to great weight 

 and careful study : 



The field upon which the sugar beet has been growTi has been 

 under experiment for thirty-three years, and during the whole of 

 this period, except for two or three years, root crops have been 

 grown, and the produce carried away from the laud. Also with 

 very few and trifling exceptions the same manures have been applied 

 to the same spaces of land. Without attempting to give a com- 

 plete explanation of the figures, one or two points of interest 

 may be alluded to. 



The plot manured with mineral manures alone gives the lowest 

 produce in the series — five tons, sixteen cwt. of roots. It also 

 gives the highest amount of dry matter, the highest per cent, of 

 sugar, the lowest per cent, of nitrogen and ash of the series. The 

 addition of nitrate of soda to these minerals increases the produce 

 from five tons sixteen cwt. to fifteen tons. The percentage of 

 dry matter and sugar is lower, and the nitrogen and ash is higher 

 than in the last plot. Sulphate of ammonia containing the same 

 amount of nitrogen as the nitrate of soda, gives a less gross pro- 

 duce, higher per cent, of dry matter and sugar, lower per cent, of 

 nitrogen and ash than the nitrate. The 2,000 lbs. of rape cake which 

 also contains the same amount of nitrogen as the nitrate and salts of 

 ammonia, gives a produce resembling more closely that of the salts 

 of ammonia than of the nitrate. The dung, which supplied more 

 than twice the quantity of nitrogen supplied by the nitrate, gives 

 very little more gross produce. In the dung and rape cake large 

 quantities of organic matter is supplied, with the nitrate and salts 

 of ammonia none; nor has any organic matter been applied to the 

 land during the whole experimental period. We may therefore 

 assume that sugar is a product obtained by the plant from the 

 atmosphere, by the decomposition of carbonic acid. 



A similar law appears to be followed by the cereal crops in the 

 production of starch. No more carbon has been given bj' wheat 

 manured with fourteen tons of farm-yard dung per acre for thirty- 

 three consecutive years, than there was on another plot manured 

 during the same period by minerals and nitrogen. 



