500 Agricultural Gazette of y.S.W. {July 2, 1920. 



though not highly so, on account of the present high cost of potash fertilisers. 

 There has been an average increase, liowever, of about 3-| tons per acre from 

 the addition of 56 lb. sulphate of ammonia to superphosphate, giving a 

 net profit of 41s. per acre for this fertiliser. Similar results could no doul^t 

 be obtained from nitrate of soda in addition to the superphosphate. 



The following figures show the net profit from an application of 2 cwt. 

 superphosphate per acre : — 



No fertiliser. ^ cwt. Superphcspliate 



Average of six tests... 



Thus an average increase of 4 tons G cwt. of green fodder per acre has 

 been obtained, giving a profit of over 50s. per acre. From these figures it 

 is recommended that a mixture consisting of 2 cwt. superphosphate and 

 56 lb. sulphate of ammonia or niti^ate of soda be used for maize or other 

 summer fodder on the North Coast, except where a leguminous crop like cow 

 peas or field peas have been ploughed in for green manure, in which case the 

 superphosphate can be used alone. 



South Coast. 



On the South Coast 1 cwt. of superphosphate has given approximately the 

 same average increase of green fodder per acre as 2 cwt., so that the smaller 

 amount may be recommended as the most profitable here. P7 mixture has 

 given about the same profit per acre as 1 cwt. of superphosphate, but the 

 number of tests made are not yet sufficient to give definite conclusions. 



The addition of either sulphate of potash or sulphate of ammonia to the 

 superphosphate has in an average of thirteen tests not increased the yield of 

 fodder at all, so that neither of these fertilisers can be recommended. 

 The results obtained from 1 cwt. superphosphate per acre are as follows : — 



No fertiliser. ^ '''''^- Superphosphate 



per acre. 



tons cwt. tons cwt. 



Average of thirteen tests ... 8 3 . 10 11 



These figures show a profit of about 30s. per acre for 1 cwt. superphos- 

 phate, and this fertiliser may therefore be confidently recommended for 

 maize or other summer fodders on South Coast soils. 



Southern Tableland. 

 On the Southern Tableland superphosphate again stands out as the most 

 profitable fertiliser from the trials made to date. An average incr. asc of 

 12 cwt. green fodder per acre has been obtained from the ai^plication ©f 

 2 cwt. superphosphate per acre over that of 1 cwt. per acre, thus making 

 the larger quantity slightly more profitable here. P7 mixture lias given 

 encouraging results from two trials, but it is f(;lt that these are not yet 

 sufl&cient to recommend it. Although the resj^ective additions of sulphate 

 oi potash and sulphate of ammonia to superphosphate have given sliglit 

 increases in the yield of green fodder, the applications have not been 



