On the Growth of Barley hy different Manures^ &,'c. 503 



The turnips of each course, of Rotation No. 2, were to be 

 manured with superphosphate of lime alone. 



The turnips of Rotation No. 3 were, each time they came 

 round, to be manured with superphosphate of lime, the sulphates 

 of potash, soda, and magnesia, 2000 lbs. rape-cake, and 100 lbs. 

 each sulphate and muriate of ammonia, per acre. 



We have here, therefore, three parallel rotations with the same 

 crops — the one with no manure whatever, course after course ; 

 a second with superphosphate of lime alone once in four years ; 

 and a third with, after the same interval, a mixed manure, sup- 

 plying liberally to the soil phosphates and other mineral consti- 

 tuents, and both nitrogen and carbonaceous organic substance. 



As each of these three foui-course rotation experiments has 

 been in progress since 1848, they have each afforded us three 

 barley crops, after turnips respectively so variously manured ; 

 namely, in 1849, in 1853, and 1857. And, as from half of each 

 turnip plot, the entire produce, leaf and bulb, was carted off, and 

 on the other half the roots were eaten by sheep, and the leaves 

 distributed over the land, we have the produce of the barley on 

 each turnip plot subdivided, so as to show the comparative effects 

 on each, of the drawing off and folding. 



Without going into any lengthened detail regarding any other 

 crops of these rotations than the barley, it may be stated generally, 

 that the turnips grown by the full mixed manure, averaged over 

 20 tons each course, of entire produce, leaf and bulb together ; the 

 crop of the last course was, however, rather the smallest of Jthe 

 three. The superphosphated turnips gave an average per course 

 of 13 to 14 tons leaf and bulb, the first crop being some tons 

 above, and the last some below that amount. The unmanured 

 turnips again, gave an average of 4 to 4^ tons per course, leaf and 

 bulb. But whilst the first unmanured crop amounted to from 

 9 to 10 tons, the second and third did not reach 2 tons each of 

 total produce. It need only be further remarked, that as there 

 was a much greater falling off in each succeeding turnip crop 

 where it was unmanured, or received only superphosphate of 

 lime, than where there was a full manuring each course, it may 

 be judged that the soil contained a larger unexhausted residue of 

 available constituents from previous cropping, &c., at the com- 

 mencement of the first course, than at that of the others. 



Table XIV., which follows, gives the produce of barley, in each 

 of the three courses, of each of these three differently-manured 

 rotations. It is also in each case given separately for the portions 

 where the turnips were respectively carted off, or eaten on the 

 land. 



2 L 2 



