EELATiONS OB* SOIL tO WATER 2? 



ceeds. It is the soil with coarsest particles and loosest 

 texture which dries quickest and to the greatest depth. ^ 

 Deep tillage must therefore be avoided in early summer, 

 if the land is intended to carry a crop. 



The greatest evaporation takes place from soil when 

 it grows a crop. The water in a barley soil, and in an 

 adjoining bare fallow, was determined at Kothamsted 

 at the end of June, daring the drought of 1870. It 

 was found that down to fifty-four inches below the 

 surface the barley soil contained nine inches less water 

 than the soil under bare fallow. The injurious effect 

 of weeds in summer-time is largely due to their robbing 

 the soil of water. 



Evaporation from the soil is diminished by protec- 

 tion from sun and wind. Stones lying on the surface 

 act favourably in this direction. A crop shading the 

 ground may keep the surface moist, while it is greatly 

 increasing the loss of water from the subsoil. Economy 

 of water is best effected by mulching with straw. 

 Keeping the surface stirred to the depth of an inch or 

 two, thus providing a mulching of loose, dry soil, is an 

 excellent plan, and forms a fundamental part of suc- 

 cessful cultivation in hot climates. 



A perfectly dry soil has the power of taking up a 

 small amount of water from moist air ; this power is 

 known as hygroscopicitij. It is possessed scarcely at 

 all by sand, to a greater extent by clay, especially 

 ferruginous clays, and in the largest degree by humus. 



• In a long drought a greater amount of water may finally be 

 evaporated from a consolidated soil of fine particles, owing to the 

 greater store of water present, and the movement of this toward the 

 surface; but for a long time such a soil will remain moister at the 

 surface than a soil of open texture. 



