104 TILLAGE— MOVEMENTS OF SOIL WATER [chap. 



taken simultaneously from an adjacent piece of land 

 where the surface was kept smooth and firm. On the 

 cultivated land there was a daily loss equivalent to 

 14 \ tons of water per acre, which was increased on the 

 uncultivated land to 17-6 tons per acre; the difference 

 during the 49 days over which the trial was spread, 

 amounting to 1-7 inch of rain saved by the cultivation. 



The value of surface cultivation is well seen in other 

 trials of King's, where the water content down to a 

 depth of 4 feet was compared on two adjacent pieces of 

 land, one stirred to the depth of 3 and the other to 1 \ 

 inches only. The 3-inch soil mulch, taking the whole 

 season through, preserved more soil moisture than the 

 shallower cultivation, but by keeping the soil immedi- 

 ately below the mulch more moist and therefore with a 

 better developed water film, it also enabled this layer to 

 lift more moisture from the 3 or 4 foot depth into the 

 top or second foot, a position more available for the 

 crop. Thus the average of three determinations of 

 water content on 16th July gave the following results — 



On this occasion it is seen that the upper 2 feet of 

 soil are being kept moister by their greater power of 

 lifting water from the lower layers, which actually con- 

 tain more water under the ij-inch mulch than under 

 the 3-inch mulch. 



Although the gardener uses the hoe freely to estab- 

 lish soil mulches, he also employs dung, grass-clippings, 

 and even straw to the same end, anything to break the 



