114. 



as a resr-rvoir from which moisture is withdrawn by capiUar/ity, to off- 

 sot losses by evaporation. Water may be removed by capillarity from tfce 

 saturated zone to the point where the loss is trking nlace, and under 

 the so conditions the ground WRter--vrhen then becoir es capillary water-- 

 is directly beneficial, and the proc^r-..-: constitutes a form of natural 

 eub-irri :.;"' ti n . 



Hise of capillary water. 



In this connections look up the diagrams in Hilgard : Soils, on 



04 . 



,er rises fastest in sand, from 0.45 mm. to 15 M -l8". In salty 

 soils tlir; rise is rapid and to a grerat height, especially in the south- 

 western soils of lime and potash. In clay the rise of crater is slow but 

 it continues to a good height. 



Soil lji.se Time, 



.&&,$. &JuVl 4-&.04J& Ait^ ^2" 



ft&ac& to.oaj m). 120" 



Clay 60* in 250 days 



fine silt (0.016 rcm) 120" in 475 days 



silt (0.025 mm) 10!;'" in 300 d<*ys 



fin ,d (0.075 ram) 36" 144 days 



(0.3 Tom) 15" in 180 6 



r-holJin,: cnp city of Soil. 



.r-lioldir.,j o-.^aiity of soils Biiould vary v/ith the 

 of ;is. Pinir particles give a greater capacity. 



.Diain. in vol. 



n. cu.in. 



1 - 2 rmn. 3.; 



250 - 50C microns 4.6 



100 - 170 " 6.0 



10 - 70 " 35.0 



cl- y -eked 43.0 



clay tilled 32.0 



nee and movement of v; tcr in soil: 



ter in the soil is derived mainly from precipitation. The 

 entrance of this ws-.ter may be hindered by ground cover; it may be faci- 

 litated by coarse gr?es and a mellow stags (mulch helps in this), and 

 o prevents runoff. 



oveiuent is soil is fastest in coarse sand, and slo'v.'est in 

 y. It if- faster in the be^innifi^ and then gets slower; it is faster 

 in ivan:i th.i.n in cold weather. 



Liquid water ie not quite separate from capillary water. 

 ler levels are variable. 



vr/oor -tion frorr the soil may take pl?.cu: 



1) .From dirt 



2) Prom plants (transpiration) 



ion fro/r, dirt depends on: 



1) Temper-iture. 'I'v/ice as raucli water will evaporate at 65 F. 

 as at 50 ?. 



2} Relative humidity of air. 



