646 TRANSACTIONS OF SECTION M. 
the whole of Australia ‘dry farming’ does not begin until the 15-inch line of 
rainfall is passed, because the winter and the total rainfalls are nearly identical. 
The experience of the last fifteen years has shown :— 
(1) That with the assistance of small amounts of soluble phosphates profitable 
crops may be grown on less than 10 inches of winter rainfall. ; 
(2) Provided the land is fairly fertile rapid growth takes place in July and 
August, so that a considerable margin is available in autumn for early and late 
planting. 
: (3) The dry weather towards harvest-time materially reduces the risk from 
all fungus diseases in cereals. . 
(4) Wherever wheat can be grown peas may also be grown if necessary as 
an alternate crop. 
(5) Evaporation in winter is comparatively small, and consequently by fallow- 
ing and other modern methods a payable crop is obtained on a lower rainfall 
than is the case in any other part of the world. 
(6) The slight ground-frosts which often occur in the winter nights appear to 
stimulate the growth of the cereals when followed by ten hours of bright sun- 
shine. 
(7) The chief problem which has now to be solved is to devise methods by 
which large numbers of sheep and cattle can be profitably kept on the wheat 
farms in the 10-inch rainfall regions. 
(8) Lands originally covered with scrub and producing very little grass have 
been proved to be very suitable for wheat. With the gradual advances in the 
numbers of stock kept on these farms permanent agricultural settlement ‘is 
likely to extend well beyond the 10-inch line of rainfall. 
(u.) The Soil-Moisture Problem in Western Australia. 
By Professor Joun W. Paterson, B.Sc., Ph.D. 
The author said that a sufficient supply of soil-moisture was, practically 
speaking, the paramount factor in crop-production. This was true in the rela- 
tively moist climate of Great Britain; the fact was illustrated in an extreme 
degree in Australian agriculture. Seasonal variations were less marked in 
Western Australia than in the Eastern States, and a graph was exhibited show- 
ing the variations in wheat yields per acre of the various States since 1901. 
The effects of drought were not simply connected with the annual rainfall of 
a locality. This was a popular fallacy; but when a crop suffered from drought 
the result was contributed to by quite a number of factors. Among those he 
would mention—(1) the total annual rainfall, (2) its monthly distribution, 
(3) the rate of evaporation as from a free surface of water, (4) the effect of 
climate upon the transpiration ratio of the crop, (5) the amount of soluble salts 
in the soil, (6) the physical character of the soil, (7) the skill in cultivation 
of the farmer, (8) the selection of drought-resistant species and varieties of 
crop-plant. In regard to annual rainfall, the South-Western corner of the 
State averaged well over 30 inches, but on the Eastern fringe of the wheat- 
belt wheat could be successfully grown with a 10-inch rainfall, but the greater 
part of the wheat area had an average of 14 to 20 inches. To visitors these 
amounts would seem low. The monthly distribution, however, was highly 
advantageous, as from 70 to 80 per cent. fell between an autumn seed-time 
and harvest. The third factor, viz., rate of evaporation, tended, however, 
against success, and data were quoted from the Commonwealth Weather Bureau 
showing that the annual loss by evaporation in the wheat-belt ranges from 60 to 80 
inches of water, as against about 20 inches in the South of England. In England 
therefore the annual evaporation. would amount to about two-thirds of the 
annual rainfall, while in the chief farming districts of Western Australia it 
was from four to six times greater than the rainfall. Closely connected with 
this in some, but not all, of its contributing causes was the lower efficiency 
of water to the growing crop, as indicated by the amount required to produce 
a given weight of dry plant substance. The transpiration ratio was indeed 
less a function of the kind of crop (speaking of the common crops) than a 
function of the climate, and the author quoted from experiments he had carried 
