ii88 



Notes on Manures. 



[mar.. 



At one time 15 successive crops were raised on the Barnfield 

 at Rothamsted, and so long as manure was applied the crops 

 did well. 



Effect of Ammonia on Wireworms. — Certain observations at the 

 Rothamsted Experimental Station have shown that ammonia 

 (not sulphate of ammonia, but the base itself) is distinctly 

 harmful to wireworms. This substance is produced in soils 

 where liquid manure is applied and where sheep are folded on 

 the land. A correspondent sends us a letter from a manure 

 merchant quoting these facts, and stating that his organic 

 manure is also a cure for wireworms, presumably through the 

 liberation of ammonia. It should be pointed out that there 

 is no evidence that ammonia is liberated from organic manures 

 in sufficient quantity at any one time to injure wireworms, 

 and in no case is the material as unstable as urea, which is 

 present in the excretions of sheep and in liquid manure. 



Use of Basic Slag on Crass Land.— The attention of farmers in 

 the eastern counties is directed to the interesting results obtained 

 by Mr. G. Scott Robertson in Essex from the use of basic slag 

 on grass land. As is well known there are several grades of 

 slag, and Mr. Robertson's object was to find out what difference 

 existed between one and another. Broadly speaking, it appears 

 that the high-grade slag is on the whole the best material to 

 use, but it is approached very closely by the lower-grade slags, 

 especially when these are used at a rate to ensure the applica- 

 tion of sufficient phosphoric acid per acre. It would be un- 

 reasonable, for example, to expect 5 cwt. of a 20 per cent, slag 

 to be as effective as 5 cwt. of a 40 per cent, slag, and yet this is 

 sometimes expected. The proper method is to allow for the 

 percentage of phosphate in the slag in deciding what dressing 

 to give, regarding 10 cwt. of the 20 per cent, slag as the true 

 equivalent of 5 cwt. of the 40 per cent. slag. 



Perhaps the most striking feature of the results is the fact 

 that the slag has acted well on the Essex grass land in spite of 

 the prevailing dryness. The rainfall is low, the soils are not 

 wet, and yet the slag has proved effective. This is shown not 

 only by the yields, but to a remarkable extent by the botanical 

 analysis of the herbage. On the unmanured grass land only 

 about one-third of the soil is covered with grass and clover ; 

 of the remainder nearly half the surface of the soil is bare, and 

 about a quarter is covered with weeds. On the slagged land, 

 however, practically the whole surface is covered — ^half of it 

 with clover, the remainder mainly with grass and with only a 

 small proportion of weeds. 



