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Notes on Manures. 



[Oct., 



than about any other single subject. It is evident from their 

 inquiries and from our own observation in the country that 

 Hming is still one of the farmers' big problems. It is very 

 desirable that new sources of supply should be opened out and 

 that old limestone or chalk quarries and limekilns should be 

 examined with a view to restarting. There is often a fear that 

 the local limestone is not good agricultural lime. It may not 

 be the best obtainable, but it may be the cheapest because of the 

 saving in transport charges. County authorities, Farm Institutes 

 and Farmers' Clubs who are desirous of making some useful 

 field trials could very well explore the local supplies of limestone 

 and lay out the following test : — 



Plot 1. — 2 tons per acre locarl limestone. 

 ,, 2. — 2 tons per acre ground limestone of recognised good quality. 

 ,, 3. — 10 to 15 cwt. per acre local burnt lime. 



The information would be valuable, enabling a farmer to decide 

 whether he can use local lime or limestone, or whether it will 

 be more profitable to him to go further afield and purchase a 

 recognised good quality limestone at a higher price. 



Neutral Sulphate of Ammonia and Acid Sulphate of 

 Ammonia. — A correspondent inquires what is the difference 

 between these two fertilisers and whether one has any advantage 

 over the other. The ordinary pre-war and wartime sulphate of 

 ammonia was always slightly acid, but in recent years a modifica- 

 tion in the method of manufacture has been introduced which 

 gives a product having an acidity which is so slight as to be 

 negligible; it is always less than 0.02 per cent, and sometimes 

 only about 0.01 per cent. This is called " neutral " sulphate 

 'of ammonia, and it has several advantages over the ordinary 

 " acid " product because: — 



a. It is often in smaller crystals and can therefore be more evenly 



distributed by the machine. 

 h. It does not cake and therefore does not require to be broken up before 



use. 



c. Tt is not wet. 



These advantages would ensure that a farmer would always- 

 take the "neutral " product if he could obtain it. The process, 

 however, is not yet widely adopted by gas works and other 

 makers, and until it becomes more general many farmers must 

 perforce use the old " acid " material. 



Composition of Purchased Manures. — A correspondent asks 

 for the composition of the ordinary purchased manures. The 

 information is given in the table below: — 



