Experimental Crops at Rothamsted. 
113 
drainage of the pipes, on the other, what may be called the 
normal supply of water within the soil would, doubtless, at the 
commencement of active growth, be considerably less than that 
indicated by the percentages in the saturated soils. There is 
also good reason to suppose that, owing to the action of the 
manures, or their products of decomposition, within the soil and 
subsoil, the manured j)l()ts would retain more than the un- 
manured ; and further, that whilst the effects of the dung would 
be chiefly to increase the retention by the upper layers, those 
of the artificial manures would be more characteristically to 
increase the amount retained by the lower layers. 
This brings us to a comparison of the amount of water in 
each plot in the two conditions of unusual dryness and of satura- 
tion or abnormal wetness, as shown in the right-hand half of 
the Table V. 
Referring first to the unmanured soil, there is seen to be a 
difference of more than 17 per cent, of moisture between the wet 
and dry conditions of the staple, or uppermost 6 inches of soil. 
The difference then diminishes, more rapidly at first, until, in 
the lower layers, it ranges from under 8 to about 9 per cent. 
There is an average of about lOf per cent, more water in the wet 
than in the dry soil to the total depth examined. 
The difference between the saturated and the dry conditions 
of the various layers of the dunged soil is much more striking 
still : amounting to over 35 per cent, within the first 3 inches, 
to nearly 29 per cent, in the second 3 inches, to more than 
21 per cent, in the third 3 inches, and to nearly 16 per cent, within 
the next, or fourth, 3 inches. It then lessens considerably, again 
increases, and again diminishes to within the range of the drain- 
pipes. The result is that, within the uppermost 12 inches of 
soil, there is an increase of about 25 per cent, of moisture in the 
■wet as compared with the dry condition ; or, taking the total 
depth of 36 inches, there is an increase of over 15J per cent. 
The artificially manured soil also shows, almost throughout, 
greater difference in the amount of water retained in the two 
states than the unmanured, but less than the dunged soil. In 
the lower layers there are, as in the case of the dunged plot, 
some irregularities not satisfactorily explained. The final result, 
to the total depth of 36 inches, is an average of nearly 13 per 
cent, more water in the wet than in the dry condition. 
It will be useful to compare the actual amounts of water per 
acre, in the different soils to the total depths examined, which 
the percentage results represent. Reckoning, as before, the soil 
in the dry state to weigh, exclusive of stones, an average of 
1,000,000 lbs. per acre for each 3 inches of depth, we have 
12,000,000 lbs. for the weight of the dry soil to the depth of 
■ VOL. VII. — S S. I 
