162 REPORT— 1861. 



tons. cwt. qra, lbs. 



Produce 17 6 3 4. 



Increase 2 12 2 



In comparing the weight of roots from these two plots, it would appear 

 that the additional quantity of supersulphate has had rather an injurious than a 

 beneficial eifect. We must, however, not entertain such a view, although 

 the experiments before us appear to favour it ; for the common experience 

 of farmers is, that even well-manured land yields a better crop of swedes when 

 the seed is drilled in with 2 or 3 cwt. of superphosphate of lime. I have 

 reason for believing that on plot No. 1 more roots were grown than on 

 plot No. 2 ; for I find the land on one side of the experimental plots yielded 



17 tons 6 cwt. 1 qr. 20 lbs. per acre, and on the other side it gave 17 tons 



18 cwt. 24? lbs. per acre. This land was manured with about 15 tons of 

 farmyard manure and 3 cwt. of superphosphate per acre. This produce 

 agrees well with the weight of the roots on the second plot, manured with 

 dung and superphosphate. Still we have a difference of nearly 12 cwt. of 

 roots in the two plots adjoining the experimental lots ; and ought, therefore, 

 to remember that the natural variations of the land, and other purely acci- 

 dental circumstances, may readily give a difference in the produce of differ- 

 ent portions of land which have been treated in every respect alike. Indeed, 

 if the difference in the produce does not amount to more than 1 ton or even 

 I5 ton, I fear we cannot do much with the results. It certainly would be 

 rash to lay stress on such differences, and to use them as arguments in proving 

 or denying the efficacy of certain manuring matters. 



Plots 3, 4, and 5. Manured with superphosphate of lime. 



The superphosphate used in these experiments had the following composi- 

 tions : — 



Manure 10-80 



Organic matter* 4'21 



Biphosphate of lime 20*28 



Equal to bone-earth (rendered soluble) (31"63) 



Insoluble phosphates 4*11 



Hy drated sulphate of lime 46'63 



Alkaline salts (common salt chiefly) 10*78 



Sand 3-19 



100-00 



This superphosphate was chiefly made from bone-ash, and contained but 

 very little nitrogen. We have thus here another proof that a good crop of 

 roots can be obtained on clay land with superphosphate alone, containing but 

 little nitrogenized or other organic matters. 



Plot 7. Manured with Peruvian guano and superphosphate. 



Plot 8. Manured with Peruvian guano. 



The difference in the yield of these two plots is not more than 6 cwt., which 

 is too insignificant to decide the question whether in the case before us 

 Peruvian guano alone had a better effect upon the crop than the mixture of 

 superphosphate and guano. In former years, however, I have found that 

 Peruvian guano produced not nearly so great an increase as superphosphate 

 alone, or a mixture of superphospjiate and guano. There are, no doubt, 

 soils for which guano is the mqst- profitable manure, even for root-crops; 

 but this is rather the exception, and not the rule. 



On the soil of the experimental field, nitrogenized matters a[)pear to have 



* Containing nitrogen ...» -34 



Equal to ammonia -41 



