25 



USE OF SULPHATE ON DIFFERENT SOILS. 



The time and manner of application which enables sul- 

 phate of ammonia to give its best results will, however, 

 depend a good deal on the soil treated. On light sandy soils, 

 which have little power of holding manure of any kind, and 

 in which nitrification takes place rapidly, sulphate should 

 be applied just when the plant needs the nitrogen that is, 

 when growth is just beginning. Two, or even three, small 

 dressings will also give better results than the same quantity 

 of the manure put on at one time. By carrying out these 

 principles, the crop will have the opportunity of using a 

 larger proportion of the nitrogen, and less will be washed 

 away. 



On heavy land, the exact reverse is the case ; for such 

 soil has great power of holding ammonia, is not well adapted 

 for nitrification, and is so impervious to water that nitrates, 

 even when formed, are washed away comparatively slowly. 

 There is, therefore, less risk of loss, and the sulphate of 

 ammonia may be applied rather before the crop needs it, 

 and all at one time. 



Soils containing a large proportion of lime are in their 

 texture and physical properties generally similar to light 

 sandy land. There is, however, the difference already men- 

 tioned that there is more risk of loss of nitrogen to the air 

 in the form of carbonate of ammonia from calcareous soils 

 than from others. It has been shown that this loss, in the 

 case of most soils, is extremely small, and, it may be added, 

 even from calcareous soils need generally be considered only 

 when the usual plan of top-dressing is adopted. Less loss 

 will generally occur when the sulphate of ammonia is 

 ploughed or harrowed in at least if care be taken to apply 

 it a short time only before the seed is sown. Altogether, 

 these exceptionally calcareous soils are not so well adapted 

 for the use of quick-acting ammoniacal manures as either 

 light or heavy land. 



On the other hand, soils deficient in lime, whether they 

 are of vegetable or mineral origin, are also unsuibed for the 

 use of sulphate of ammonia. This will be understood from 

 what has been said as to the important part lime plays with 

 regard to the absorptive power of soils and the process of 

 nitrification, and need not be gone into more fully. It may 

 be added, however, that soils which are poor in lime often 

 contain large quantities of nitrogen in an organic form. 

 When this is the case, there is obviously greater economy 

 in bringing this nitrogen into action by liming, &c., than in 

 applying nitrogenous manures. 



What has been said with regard to the action of sulphate 

 of ammonia on different soils, must be taken as applying 

 directly to soils of extreme composition exceptionally 

 sandy, 'clayey, or calcareous. All the soils between these 



