Prev | Current Page 131 | Next

Widtsoe, John Andreas, 1872-1952

"Dry-Farming : a System of Agriculture for Countries under a Low Rainfall"

84 8.83
2nd foot 20.06 8.87
3rd foot 19.62 11.03
4th foot 18.28 9.59
5th foot 18.70 11.27
6th foot 14.29 11.03
7th foot 14.48 8.95
8th foot 13.83 9.47
Avg 17.51 9.88

In this case water had undoubtedly passed by capillary movement from
the depth of eight feet to a point near the surface where direct
evaporation could occur. As explained in the last chapter, water
which is held as a film around the soil particles is called
capillary water; and it is in the capillary form that water may be
stored in dry-farm soils. Moreover, it is the capillary
soil-moisture alone which is of real value in crop production. This
capillary water tends to distribute itself uniformly throughout the
soil, in accordance with the prevailing conditions and forces. If no
water is removed from the soil, in course of time the distribution
of the soil-water will be such that the thickness of the film at any
point in the soil mass is a direct resultant of the various forces
acting at that particular point.


Pages:
119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143