ACTION OF SOOT UPON WHEAT AND OATS. 439 



that of rye-grass. Will any of you, by experiment, ascertain if such 

 be really the case with the soot of your own neighborhood? 



b. The presence of ammonia in soot causes it, when laid in heaps, 

 to destroy all the plants upon the spot ; and Dr. Anderson adds the in- 

 teresting observation, " that the first plant which appears after^vards 

 is constantly the common couch-grass (triticum repens). (Dr. Ander- 

 son's Essays, edit. 1800, ii., p. 305.) 



c. This ammonia also causes soot to injure and diminish the crop in 

 very dry seasons. Thus the produce of a crop of beans, after oats, in 

 1842, upon an 



Unmanured part of the field was 29| bushels. 



Dressed with 4 bushels of soot 28 bushels.* 



It also diminished, in a small degree, the potatoe crop in the same 

 vear in the experiments of Lord Blantyre, atErskine (Appendix, No. 



ix.)- 



With manure alone, the produce was 11 tons 17 cwt. 



With 30 bushels of soot sprinkled over the dung. 11 tons 4 cwt. 



Like rape-dust (p. 434) and saline substances, therefore, soot seems 

 to require moist weather, or a naturally moist soil, to bring out all its 

 virtues. 



d. Yet even in the dry season of 1842, its effect upon wheat and oats 

 in the same locahty (Erskine) was very beneficial. Thus the com- 

 parative produce of these crops, when undressed and when top-dress- 

 ed with 10 bushels of soot per acre, was as follows : — 



Unmanured Wheat 44 Oats 49. 



Top-dressed with soot Wheat 54 Oats 55. 



But the dressed wheat was inferior in quality to the undressed — the 

 former weighing only 58, the latter 62 lbs. a bushel. In the oats there 

 was no difference. Are we to infer from these results that, even in 

 dry seasons, soot may be safely applied to crops of corn, while to pulse 

 and roots it is sure to do no good ? Further precise observations, no 

 doubt, are still necessary — and the more especially as the experiments 

 upon oats and wheat, made in the still drier locality of Lennox Love 

 (Appendix, No, VIII.). gave a decrease in the produce of grain — while 

 in Mr. Fleming's experiments upon turnips (Appendix, No. VIII.), 50 

 bushels of soot, applied alone, gave an increase of 4 tons in the crop. 



e. An experiment of Lord Blantyre's (Appendix, No. IX.), enables 

 us to judge of the efficacy of soot in a dry season, compared with that 

 of nitrate of soda and of guano upon the produce of hay. Thus the 

 crop of hay, per imperial acre, from the 



Cost, 

 tons. cwts. £ s. d. 



Undressed portion, weighed 1 8 • 



Dressed with 40 bushels of soot 1 15 11 8 



160 lbs. nitrate of soda 1 19 1 15 9 



160 lbs. guano 2 2 1 15 9 



In this experiment the soot proved a more profitable application than 

 either of the other manures. 

 /. In regard to this substance, I shall only advert to one other obser- 



• See >..5pendix, No. VIII. 



