There is no doubt but that the return of the plant food 
appropriated and deposited in the leaves and stems which 
fall upon the surface may be slower than it would be under 
humid atmospheric conditions’ still it goes forward some - 
what fastei under the influence of the shade and conserved 
moisture of a thick growth of alfalfa than it would other¬ 
wise do, and the surface soil must have a very considerable 
amount of. mineral ash constituents added to it in the 
course of six or more years. Some may be flooded off by 
irrigating, some may be blown away, and a large amount 
may be taken up in the production of subsequent alfalfa 
crops , still theie can scarcely fail to be a large residual 
amount of available plant food collected in the first few 
inches of the soil. I am satisfied that this factor in the 
improvement of the soil has not received the consideration 
it deserves. It is one of those factors, however, that is just 
as potent without as with recognition, for the leaves fall 
and can not be prevented. I have elsewhere, in speaking 
of the loss in hay making, stated that from fifteen to 
twenty per cent, is about the minimum, and taking it at 
twenty per cent., and this is scarcely too high, we 
have a top dressing of leaves weighing one ton for 
every five tons of hay taken off, and as^ this amount of 
hay may be cut from an acre in one season, though it is too 
[ihigh for the average, we may calculate the annual dressing 
of leaves, etc., at one ton per acre. The total ash in this 
is 269 pounds, taking the ash of the leaves at 13.45 per 
cent., which is the average of four determinations. The 
.269 pounds of ash contain 11.83 pounds of phosphoric acid 
and 49.22 pounds of potash, equal to 25.79 pounds bone 
phosphate and 77.73 pounds chemically pure muriate of 
potash, d o these are, of course, to be added the ash in¬ 
gredients, for instance, the lime equal to 76 pounds caustic 
ilime and upwards of 30 pounds sulphuric acid (S O3); also 
nitrogen, equal to 74 pounds. It would require 449 pounds 
□f soclic nitrate to furnish this amount of nitrogen. The 
yearly top dressing from this source alone is equal to 25.79 
bounds pure calcic phosphate (bone phosphate), 77.73 
bounds pure muriate of potash, and nitrogen equal to 449 
pounds pure sodic nitrate. We take into consideration the 
acts that the organic nitrogen is not worth as much as the 
nitric nitrogen ; that some of these constituents may be lost ; 
flso that much of it will be used by the growing plants, and 
’till, as Iihave before said, the residual manurial elements 
nust be large. 
I The value of the stubble and roots in the soil has been 
•hown to be about $35 per acre, for the nitrogen, p l es- 
