12 PLANT PRODUCTS 



at prices varying from about £9 to £20 per ton at British 

 ports. Roughly speaking £14 per ton is considered a general 

 average of English prices. 



The demand for sulphate of ammonia for agricultural pur- 

 poses is almost certain to increase, as the need for it is better 

 recognized. That the value of, say, -£1^ per ton is, from the 

 user's point of view, not an unreasonable one, may be judged 

 from Table 2, which is based on recent field experiments and 

 shows the average increase in the various crops with the value 

 of such increase that may be expected from the use of i cwt. 

 of sulphate of ammonia per acre, costing about seventeen 

 shillings. The crops have been valued at low prices. 



Table 2. 



Wheat 



Wlieat Straw. 

 Barley 



Barley Straw. 

 Oats . . 

 Oat Straw 



Increase due to i cwt. sulphate of ammonia costing 17s. 



i s. d. i s. d. 



4 bush, at 555. per qr. 504 lbs. i T ^ \ 1 n €> 



5 cwt. at 40S. per ton . . o 10 o ^ ' 



6 bush, at 50s. per qr. 448 lbs. iiyd) 66 



6 cwt. at 30s. per ton . . o 9 o > 



7 bush, at 30S. per qr. 336 lbs. i 63 

 7 cwts. at 40S. per ton . . o 14 o 



Meadow Hay. 



Mangolds 



Potatoes 



\ 



Rye Grass Hay 10 cwts. at loos. per ton . . 2 10 o 



8 cwts. at 90s. per ton . . i 16 o 



32 cwts. at I2S. 6d. per ton . . 100 



20 cwts. at Cos. per ton . . 300 



Consideration of the foregoing figures shows that there 

 is ample justification for the liberal use of reliable manures. 



For practical purposes sulphate of ammonia may either 

 be applied by itself or in mixtures. Probably most of the 

 sulphate of ammonia actually used is applied in mixtures, 

 either made by the farmer himself or purchased ready made 

 from the manufacturer. 



Certain of these mixtures are very practicable and useful, 

 others are not desirable, and others must be avoided at all 

 costs. 



One of the commonest and most useful mixtures is com- 

 pounded from sulphate of ammonia and super-phosphate. 

 This mixture has the following special advantages : — both 

 manures are moderately quick in action ; neither are 

 mstantly available for plant life. 



