Two Years' Work in the Chemical Branch. 177 



TWO YEARS' FIELD WORK OF THE CHEMICAL 



BRANCH. 



By F. J. Howell, Ph. D. 



(A Paper read before the Shepparton Conference, July, 1902.) . 

 Continued from page 14. 



PART 2— THE CENTRAL, SOUTHERN AND 

 WESTERN DISTRICTS 



We cau pass now to the soil requirements of the Central, Southern, 

 and Western districts, and shall find problems in each case of far 

 greater complexity. The one crop, or one class of crop of the North 

 gives place to variety — an unbroken succession of the same crop is 

 replaced by systems of rotation, and soil uniformities are lost in soil 

 diversities. Climatic conditious also reveal differences equally as 

 marked. All these differences have their influence on the matter of 

 manuring. A heavier rainfall admits of much heavier crops, and as the 

 greater the crop the greater the quantity of plant food removed from, 

 the soil, soil exhaustion becomes more rapid and more pronounced. 

 The system of farming also adopted on the various holdings will each 

 show its effect. Carefully thought out rotations might even, in certain 

 respects, add to the fertility of the soil. We know how the inclusion 

 of a pea, bean, or clover crop might add to the nitrogen in the soil ; 

 or how the repeated remt)val of root crops might exhaust it of its 

 available potash. In older settled districts then, with a rainfall 

 admitting of heavy crops, with various systems of farming and soils 

 showing large natural variations it will be difficult or impossible to 

 prescribe a system of manuring that might apply to every farm and 

 every crop, as it practically does to the Northern area, but, even 

 admitting this, there might be a feature common even to the soils of 

 all these farms, and our experiments, few as they are, allow us, with a 

 certain measure of certainty, to say what this is. The only. soil 

 deficiency requiring consideration in a system of manuring in the 

 North was found to be phosphoric acid. The soil deficiency requiring 

 the most, though not the only, consideration in our Central, Southern, 

 and Western districts, is, if our experiments are sufficiently numerous to 

 allow us to generalise, also one of phosphoric acid. There may be 

 soils where this is not so, but these may, I think, be regarded as 

 exceptions. An examination of the tables will show the dominant 

 influence of jihosphoric acid in the manures used even on the soils of 

 these areas. It will be seen from the tables of the Central district 

 that I have given the results of seven tests. The first three plots 

 have been treated with a complete manure, that is a manure contain- 

 ing the three ingredients, nitrogen, phosphoric acid and potash. The 

 No. 1 is a light dressing; No. 2, twice the quantity; No. o, three 

 times the quantity. On No. 4 plot, nitrogen has been left out of the 

 complete manure ; on No. 5 plot, phosphoric acid ; and on No. 6 plot, 

 ])otash. That is on plots 4, 5 and 6, manures containing only two 

 ingredients each have been given. Turning to the results of the 

 complete manures of plots 1, 2, and o, it will be found that the 



