17 



Examined in detail the results appear to fall into two groups. 

 In both years the larger number of the values fall between 90 and 

 100, but a second group of values falls distinctly above 100. The 

 indications are that ammonium chloride would generally be about 

 5 to 10% less effective than ammonium sulphate containing the 

 same amount of nitrogen, but in some circumstances, which we 

 cannot yet define, it may be somewhat more effective. 



THE NKW BASIC SLAGS AND MINERAL PHOSPHATES. 



The object of these experiments is to compare the respective 

 fertiliser values of the old Bessemer slags, the more modern open- 

 hearth slags, some of which are of high and some of low solubility 

 in the official citric acid solution, and the mineral phosphates. 



The general result up to the present is that the high soluble 

 slags are quicker in action and more effective than those of low 

 solubility, but the low soluble slags are more effective than their 

 solubility indicates. These effects are seen in their simplest form 

 in pot experiments where all conditions of growth are carefully 

 controlled. In the field, however, the effects may be masked by 

 various factors, such as water supply, temperature, etc. 



A comparison made in 1922 gave the following results : — 



The turnip results in the field fall into line with those of the 

 pot experiments, although the differences are probably within the 

 experimental error, but the barley results fall out altogether. 

 Inspection of the growing crops, however, showed that up to the 

 end of June the appearance of the barley plants accorded with the 

 pot experiments, but all this was lost before harvest. 

 In the grass experiments two distinct cases arise : — 



1. If the herbage is poor, and the growth poor, the slags 

 may increase the yield of hay ; 

 If the grass is better and gives larger crops of hay, the 

 slags may not increase the yield, though they may in- 

 crease the amount of clover and thus improve the 

 quality, 

 is seen on inspection or on botanical analysis, or, better 

 still, by a grazing test. The following results were obtained in 

 the last two seasons : — 



2. 



This 



