Suggested Changes of Fanning System. 235 



at once a manurial agent, and a maintainer of the physical condition 

 of the soil; but perhaps most valuable of all for its effect in 

 conserving that moisture -which is often of more importance to the 

 plant than the presence of any quantity of chemical manurial 

 constituents. It is, indeed, the very life and soul of the soil, and 

 that is why the farmer, the planter, or the gardener attaches so 

 much importance to farmyard manure, forest topsoil, turf, or any 

 substance which will supply this indispensable ingredient of fertile 

 soUs. These humus-supplying agents all have this immediate ad- 

 vantage — the fact that the results from them are certain, while the 

 results from all purchased manures are uncertain. For the latter 

 may be washed away, or enter into insoluble compounds in the soils, 

 and in the event of a drought the anticipated results might not be 

 gained. The experience in the United States seems to be that it 

 never can certainly be predicted whether profit or loss will result 

 from the purchase and the application of nitrogen, potash, or 

 phosphoric acid in any form. One thing is certain, says Roberts, 

 in his "TheFertility of theLand" (Macmillan & Co., price 5s.], and 

 that is that the application of farmyard manure, in almost any form, 

 will result in improved fertility and increased profits. But this 

 arises not from its, strictly speaking, chemical constituents, which 

 could, of course, be supplied by chemical mafiures, but from the 

 fertility which the decaying vegetable matter of the straw imparts 

 to the soil, the most important feature of which is probably owing 

 to the power of humus for conserving moisture, seeing that plants 

 more often fail from lack of moisture, at a critical period of their 

 growth, than from dearth of chemical constituents of plant food; 

 and it is of equal importance to note that as all the moisture in the 

 soil may be needed, and often is needed in the growing season, it is 

 most advisable to store, through humus, all that can be kept in the 

 land. In three years' experiments with farmyard manure (Roberts, 

 p. 148}, it was found that the first surface foot contained l8f tons more 

 water per acre than adjacent and similar but unmanured land, the 

 second 9*28 tons, and the third 6-38, or a total difference in the first 

 3 feet of soil of 34*41 tons per acre. If, then, the Bank field was 

 quite unaffected by last year's drought, it was mainly because the 

 land was well stored with ploughed-down turf, and was therefore 

 capable of retaining a full supply of moisture, though the land had 

 not been manured with farmyard manure for the last nineteen 

 years. But there was another important reason to which I would 

 desire to draw particular attention— the fact that the land was 

 thickly-shaded with plants, as it is from the want of this complete 

 shading that the land suffers su much more in a drought than it 

 need. For every vacant patch of soil is really a pump, as the 

 moisture, rising from below, is rapidly evaporated and carried away 

 by the wind, and water is also drawn into each patch by lateral 



