504 AgricultiiraL Journal of Victoria. 



the South. Do tho couchisions to l)e drawn from the general average 

 ^pply to the fiekls of each group ■' An examination of the following 

 tables will afford an answer to this question : — 



An examination of the figares shows that in the group of fields of 

 •each district, the yields produced bj the condiination of phosphoric 

 acid and niti-ogen are considerably larger than those secured from 

 phosphoric acid only. There is distinct evidence throughout of the 

 necessity of nitrogenous manuring for hay crops at least. The 

 question of ])otash requirements will find elucidation in the following 

 figures : — 



In three oidy out of the five groups of fields do the j'ields of the 

 ])hosphoric acid and potash ]>lots exceed those of the plots with 

 phosj)honc acid oidy, and in one of these, the Geelong group, the 

 excess is so small that the yields may be considered practically 

 identical. In the two remaining groups, the yields with potash 

 are even lower than in the plots where it has been omitted. In 

 the Allansford district the effect of potash manuring is sufficiently 

 marked to merit consideration in the system of mannring 

 adopted for the soils of this group. In the Longwarry group 

 the opera,tive effect of potash was most pronounced, more so 

 even than that of nitrogen. It is worthy of note that the two 

 group^s of soils on which potash has shown a decidedly marked 

 effect, are for the most part of a light sandy nature, and it i-i 

 most probable that the effective action of |)otash will be limited to 

 this class of soils, and that, generally speaking, it will be phosphoric 

 acid and nitrogen only which will demand our princi})al attention in 

 the fertilization of southern soils. 



Before we leave the figares of this experiment, there are still one 

 ■or two minor points which claim consideration. There are, as you 

 know, different forms in which we can give the same manurial 

 ingredient. To take one instance, we can give pho.sphoric acid in 

 the three forms (besides others), of superphosphate, Thomas phos- 

 phate and bonednst. AV'e have done so in these experiments. It 

 will be of interest to ctjmpare the returns in each case. The figures 

 of the general average would appear to indicate that in the point of 



