344 ANNUAL JtEl'ORT OF THP] Off. Ddc. 



as the valves in our water lines become worn tbev will beein to 

 leak and if not properly packed the size of the leak will increase 

 until the waste will be as large as if no valve were there. So it is in 

 the soil. As the mnlcli has been formed by cultivation gradually 

 settles, capillarity will again be established and the loss will con- 

 iinue. Frequent cultivation is required to keep the connection at 

 the surface continually broken; to keep the valves at the surface 

 of the soil well packed. 



The plough, the harrow, the roller, the cultivator, all serve as 

 couservers of moisture. Tlie plough by breaking up the heavy soil, 

 making it loose, more pervious to water and by developing an open, 

 crumbly condition which checks the rise of capillary water. The 

 harrow and cultiA'ator by breaking the connections and forming the 

 mulch already noted. The relation of the roller to the moisture in 

 the soil is opposite to that of the cultivator. There are certain 

 classes of soils whose particles are not in close proximity to one 

 another, as gravelly soils, and capillary action can not take place 

 so readily. The effect of the roller is to compact these particles, 

 completing the connections between the reservoir and the surface. 

 When the roller is used it should be borne in mind that the soil is 

 then in the- best condition possible to part with its moisture, and if 

 the object sought is the fining of the soil and not the bringing of 

 water to the surface to assist in the germination of the seed, a mulch 

 should be placed a( the surface by following immediately with the 

 harroAV. In general, then, good drainage, humus and thorough cul- 

 tivation are the great factors Avhich materially inlluence the ability 

 of soils to retain moisture. 



In this connection, it is littiug (o refer to the belief entertained 

 in some quarters, that common salt and some fertilizers tend to 

 make soils more moist. This Ix'lief is not altogether Avithottt Avar- 

 rant. The rale ni which cajiillarity is able 1(i raise Avater in the 

 soil is influenced by substances dissoh'ed in llie soil water. The 

 presence of common salt or land })laster in the soil-Avater tends 1o 

 decrease the rate at which Avater Avill rise to the surface and hence 

 to decrease the amount of Avater eva])orating from the surface. 



Having referred briefly to a f(nv Avell known ])i'inciples relative to 

 the conservation of soil moisture, it uuiy be interesting and in- 

 structive to trace the relation existing betA\'een this question of 

 moisture and tliaf of soil temperature. There are limits beyond 

 which life cannot exist. In the case of our bodies, these limits 

 are quite narrow. A variation of a fcAv degrees means serious 

 consequences. Ninety-eight (98) degrees is the normal temperature 

 of the human body, and should this temperature rise 8 or ten degrees 

 it usually means death; or, on the other hand, the results would be 

 equally fatal should there be a di'0|» in lemperature. This ])rin- 



