50 
Continuous Corn Gr owing . 
that in respect of the essential constituents, phosphoric acid 
and potash, there has been no loss, but rather a gain, as the 
result of the continuous cultivation and cropping, aided by 
manuring. The soil is also practically as well supplied with 
nitrogen as it was twenty years ago, and there is an abundance 
of lime. The soil in its present condition, and taken by itself, 
would be considered as one well supplied with the essential 
ingredients of fertility, and it is clear that when considered 
in relation to its composition in 1877 there is no evidence 
of its having suffered any deterioration. The item of lime is 
sure to be a variable one ; for, owing to the uneven distribution 
of the chalk, one sample of soil will contain more chalk than 
another : indeed, this was observed when taking two samples 
from the same ground. Therefore, no great importance can be 
attached to this ; the main thing is to know that there is a 
sufficiency of lime present for the plant’s needs, and this is the 
case in all the samples taken in 1903. Included with the 
organic matter is “water of combination,” and this will vary 
to some extent according as there is more or less clay in a 
particular sample. Comparing the results of 1877 and 1903 
in the broad sense, it must be concluded that the soil of 
Broadfield is quite as well, or even better supplied now in 
elements of fertility than it was in 1877, and hence that it has 
not undergone deterioration. 
Practically the same result is brought out in the cases of 
Blackacre and White Moor. In Blackacre the lime is again 
variable, but there is the same increase in potash that was noted 
in Broadfield, while phosphoric acid remains to all intents the 
same, and nitrogen has increased in amount. In White Moor 
the variation in lime is in the opposite drection to that in 
Blackacre ; an increase is shown in potash and a slight gain 
in phosphoric acid, while the soil is also richer in nitrogen 
than it was. 
It is more than probable that the decided increase in 
potash shown in all three soils is the result of the continued 
thorough cultivation of the soil, aided by good drainage, the 
more dormant elements of the clay being gradually brought 
into action. Special manuring with potash salts is, therefore, 
not called for. It is noticeable, too, that both soda and 
magnesia have increased in amount. That there is no marked 
increase in phosphoric acid would seem to indicate the necessity 
for the continued use of phosphatic manures, though the 
present employment of mineral superphosphate (when, as here, 
there is sufficient lime in the soil) would appear to be quite 
justified. None of the soils is really rich in nitrogen, and 
the supply of this is a necessity in the case of corn crops. This 
was clearly demonstrated in 1905, when, on a small strip of 
