PRESIDENTS ADDRESS—SECTION G. 129 
stand conditions of drought. This phase of the utility of phos- 
phatic manures had puzzled me for many years. In my work 
I have had to advocate the extension of the use of phosphatic 
manures in South Australia for a number of years as the most 
profitable development of our farming possible for the time. 
Farmers from experience of the use of farmyard manure were 
sceptical in the extreme of its utility; the climate, they argued, 
forbids it; we have not rain enough they said. All the while 
I was conscious of the fact of experience that wheat treated 
with soluble phosphates gave a better account of itself in a 
drought than wheat which was sown on unmanured land, but 
otherwise under similar conditions. In 1897, for example—a 
year, I believe, of nearly record dryness, if not the very record 
minimum—I reaped 22 bushels of wheat on a block of land 
treated with 2 cwt. per acre of superphosphate after a rainfall 
of 12 in. for the year. There was no succumbing to the hot 
wind days of early summer, as would have been the case if 
fairly strong dressings of nitrogenous manures had been used, 
whether organic or mineral; the wheat stood up well, and filled 
well, and the grain was equal as a sample to that from un- 
manured land. It was difficult to explain from ordinary notions 
of the amounts of water transpired or evaporated from the leaves 
how the plant found moisture enough for the quantity of organic 
material to be elaborated. But the work of Lawes, at Rotham- 
sted, and of Marie Davy would have thrown light on the problem 
had one known of it. Lawes concluded from the researches 
at Rothamsted that the employment of mineral manures dimi- 
nished the transpiration of water required f r the elaboration of 
a unit of dry matter. Marie Davy, also carrying out investiga- 
tions on wheat, showed definitely enough that mineral manures 
enabled the plant to do with less water. In unmanured soil he 
found from exact measurement that an evaporation of 1324 
parts of water was required for the production of one part of 
grain, but that when he added to the soil for each 2 litres 
1 gramme of acid phosphate, of lime, saltpetre, common salt and 
gypsum, there was consumed only 887 parts of water for one 
pert of grain elaborated. This result, you will agree with me, 
is pregnant with importance in relation to wheat-growing in 
our climate. It is equivalent to s.ying that wheat dressed with 
mineral manures uses one-third less water for the elaboration 
of the same quantity of grain than it would require when grown 
on hungry or semi-exhausted land. It is a statement that must 
make any man engaged in active field work in this climate sit 
back and think. As Wendell Holmes would have said: “ It 
is one of those hot thoughts which now and again come crashing 
into the brain, and plough up the deep ruts that have been 
formed by the waggon trains of common ideas.” Our soils over 
extensive areas in Australia, I think I am justified in saying, 
I 
