40 



quoted to show that the best way to apply ammonia salts 

 is to put on a small part of the dressing in the autumn, 

 and the rest about three-quarters in spring. Another 

 question arises as to whether the spring dressing should 

 be put on at one time or in several applications. It is 

 generally known that nitrate of soda gives a better return 

 when applied in two or three dressings. Should sulphate 

 of ammonia be used in the same way ? An early experi- 

 ment at Rothamsted answers this question as far as heavy 

 land is concerned. In the wheat experiments of 1845, 

 two plots were manured with ammonia salts one re- 

 ceiving all the manure at one time in the early spring, the 

 other in four different dressings. The results were as 

 follows : 



TABLE XVIII. 



Corn. Straw. 



Busb. Pks. Lbs. Per 100 of Corn. 



Ammonia salts in one dressing . . 33 1 . . 4058 190 



in four dressings. .31 3 . . 4266 215 



There was evidently an advantage in applying the whole 

 of the manure at once. The lower yield of grain, the in- 

 crease in straw, and the large increase in the amount of 

 straw per 100 of grain, all showed that with four dressings 

 part of the manure had been applied too late in the growth 

 of the crop. As already mentioned, very light soils form a 

 possible exception to the rule of applying all the sulphate 

 at once. 



Practically a dressing of about i cwt. of sulphate, of 

 ammonia per acre will generally be found enough for 

 wheat grown in rotation. If the crop be very weak and 

 thin after the winter, a rather heavier dressing up to 

 2 cwt. as a maximum may be given; while on the other 

 hand, if the land be in high condition, f cwt. or even ^ cwt. 

 will be better. 



BARLEY. 



EFFECT OF SULPHATE ON YIELD. 



For this crop, we find that nitrogenous manures are even 

 more effective than for wheat. Otherwise the differences 

 between the two crops are not very important. We will 

 first consider the use of sulphate of ammonia with reference 

 to the yield only. At Rothamsted, Sir John Lawes and 

 Sir Henry Gilbert obtained the following results per acre 

 per annum on the average of forty years' experiments in 

 continuous barley growing: 



