On the Growth of Barley by different Manures, Sfc. 485 



yield of 1543 lbs. of gross dry substance in the increase of pro- 

 duce, by the use of about 7840 lbs. of gross dry substance in 

 manure. It is clear, therefore, that the great bulk of the solid 

 matter of the dung, which consists mainly of highly carbonaceous 

 organic substance, had little to do with the increase in the pro- 

 duce of ihe barley. 



A study of the effects of the other individual manures, which 

 replace one or more, as the case may be, of the constituents of 

 the dung, should enable us to judge to which constituent, or 

 constituents, of the latter, its effects on the barley-crop are 

 mainly due. 



By the annual use of " mixed alkalies " — sulphates of potash, 

 soda, and magnesia — in amounts containing much more of the 

 respective bases than the total annual produce, we obtain an ave- 

 rage annual increase of only 42 lljs. of corn and 36 lbs. of straw, 

 = 78 lbs. total increase. 



The annual application of the superphosphate of lime alone gave 

 a yearly increase of 163 lbs. of corn, and 86 lbs. of straw, = 

 249 lbs. of total increase ; or 171 lbs. more than the " mixed 

 alhaliesr 



The combination of both the " mixed alkalies " and the svper- 

 phosphate of lime gave an annual increase of 329 lbs. of corn and 

 252 lbs. oi' straw, = 581 lbs. of total increase; that is 503 lbs. 

 more total increase than the " mixed alkalies " alone ; 332 lbs. more 

 than the superphosphate of lime alone ; and 254 lbs. more than 

 the sum of the increase by the two manures when each was used 

 separately. 



We shall refer more specially to the beneficial action of direct 

 mineral manures on the barley crop further on ; but that we may- 

 do so with advantage, it will be convenient first to consider the 

 results of Series 3 and 4, in which they were employed, not 

 alone as in the cases just considered, but in conjunction with 

 nitrogenous manures. 



Instead of 3345 lbs. of total produce, the average annual amount 

 without manure, we have by the use of nitrate of soda alone 

 (containing nitrogen equal to about 50 lbs. of ammonia), 5226 lbs., 

 and by salts of ammonia alone (supplying about the same acreage 

 amount of nitrogen) we have an average annual total produce of 

 4729 lbs. The average annual increase by nitrate of soda was 

 rather more than 14 bushels of dressed corn (779 lbs. total corn), 

 and 1102 lbs. of straw ; and that by the ammoniacal salts was about 

 lOf bushels of dressed corn ( = 606 lbs. total corn), and 778 lbs. of 

 straw. There was, indeed, by nitrate of soda alone, only 43 lbs. 

 less corn, and even more straw and total gross produce, than by 

 the 14 tons of farmyard-manure. The salts of ammonia alone, which 



VOL. xviir. 2 K 



