36 report — 1859. 



time it appeared to me desirable to ascertain the effects of alkalies on turnips, 

 and ammonia, potash, and soda applied in the shape of sulphates. We have 

 thus in these experiments sulphuric acid in all the different states of com- 

 bination in which it is likely to occur in arable land. 



Two plots, it will be noticed, were left unmanured. This should always be 

 done in field experiments ; for otherwise it is impossible to ascertain whether 

 or not an experimental field is uniform, and what are the unavoidable varia- 

 tions in the produce of two plots of the same field. 



It will be noticed that in nearly all plots nothing but simple salts were used, 

 in order not to complicate the interpretation of the results. It is useful, how- 

 ever, to ascertain how far the natural produce may be increased by a com- 

 pound and approved fertilizer, such as farmyard manure, and in such an ex- 

 periment ordinary manure should be as liberally supplied as in Plot 1. 



The Swedes were taken up in the last week of November, topped and tailed, 

 and the whole produce of each plot weighed. 



Table, showing the produce of trimmed Swedes of Experimental Plots, 

 calculated per acre, and increase over the unmanured part of field. 



tons cwt. lbs. tons cwt. lbs. 



Plot 1(15 tons of farmyard manure) yielded 7 16 38 5 75 



Decrease* 



Plot 2 (6 cwt. of gypsum) yielded 2 1 45 1 1 30 



Plot 3 (6 cwt. of dissolved bone-ash) yielded 8 3 38 5 7 40 



Decrease. 



Plot 4 (6 cwt. of sulphate of ammonia) yielded . . 2 12 51 3 24 

 Plot 5 (6 cwt. of sulphate of ammonia, and 6 cwt. 



of dissolved bone-ash) yielded 8 6 41 5 10 78 



Plot 6 (12 cwt. of dissolved bone-ash) yielded .. 8 12 90 5 17 15 



Decrease. 



Plot 7 (6 cwt. of sulphate of potash) yielded 2 10 5 75 



Plot 8 (unmanured) yielded 3 019 



Plot 9 (12 cwt. of crystallized sulphate of soda) 



yielded 3 6 9 10 46 



Plot 10 (6 cwt. of dissolved bone-ash, 6 cwt. of sul- 

 phate of ammonia, 6 cwt. of sulphate of 



potash) yielded 6 17 6 4 2 43 



Plot 11 (3 cwt. of dissolved bone-ash) yielded .. 7 19 51 5 4 88 



Plot 12 (unmanured) yielded ". 2 1119 



The natural produce of the experimental field was taken at 2 tons 15 cwt. 

 75 lbs., being the average of the two unmanured plots No. 8 and 12. 

 These results suggest the following remarks: — 



1. The natural produce of this field was very small, as it scarcely 

 amounted to 3 tons per acre ; special fertilizing ingredients, such as phos- 

 phoric acid, ammonia, &c, therefore may be expected to have full play in a 

 soil like the one of the experimental field. 



2. Only those plots yielded an increase which contained phosphates ; the 

 other manuring constituents had no effect upon the turnip crop in these ex- 

 periments. 



3. Gypsum cannot replace phosphate of lime in manuring matters. In 

 these experiments it had no effect whatever, which need not surprise if it be 

 remembered that the soil contained naturally \ of a per cent, of sulphate of 

 lime. 



4. None of the other sulphates produced any effect upon the crop. Sul- 

 phates, especially sulphate of lime, are much more abundant in nature than 

 phosphates, There are few soils which do not contain abundance of sulphate 



