LVI. CHEMICAL NATURE OF THE SOILS OF N.S W. 
Humus.—In the first place is to be remarked the deficient 
amount of humus matter. The absence of moisture is also 
equally noticeable, but although the comparative figures 
given probably represent very nearly the proportionate 
amounts as compared with other soils, the individual figures 
are not altogether trustworthy, since the amount found in 
the soil on arrival in the laboratory is by no means always 
an indication of its condition in situ. The soils were, how- 
ever, invariably dry, and the average probably very nearly 
represents the average contents of the soils if determined 
on the spot. The humus deficiency is, however, a definite 
one, and has to be seriously taken into account in any 
scheme for the improvement of these soils. It is due, of 
course, to the absence of moisture and the burning action 
of the sun. Moisture is necessary for the decay of vege- 
table matter. This defect will be remedied by irrigation ; 
firstly, by deposition of the silt which is carried in suspen- 
sion by even the clearest river water, and which contains 
a certain amount of organic matter; and, secondly, by 
supplying the necessary moisture to enable the decay of 
vegetable matter to proceed. 
Capacity for Water.—The next point of importance is 
the capacity of these soils for water, that is to say, their 
water-retaining power. These figures represent the per- 
centage amount of water which the soil is capable of holding. 
This property depends partly upon the amount of humus 
present, which has a very high capacity for holding water, 
and partly. upon the mechanical condition of the soil, the 
relative proportions of coarse and fine sand and clay. Itis 
noticeable that the light sandy loams, those soils in which 
the amount of clay does not exceed 12 or 15 per cent., have 
a very low retentive power for water. The average of 
these soils is, however, about the same as it is for similar 
light sandy loams in other parts of the State. This is true, 
also, of the soils in which the clay content is higher, in the 
