CHAPTER XIII.. Water of Soils; the Regulation and Conservation of Soil,

WATER OF SOILS; THE REGULATION AND CONSERVATION OF SOIL, MOISTURE; IRRIGATION, 234.—Loosening of the Surface, 234.—Effects of Underdrains; Rain on Clay Soils, 235.—Winter Irrigation, 236.—Methods of Irrigation, 236.—Surface Sprinkling, 237.—Flooding, 237.—Check Flooding. Furrow Irrigation, 237, 238.—Figure Showing Penetration, 239.—Figure Showing Faulty Irrigation in Sandy Lands, 239.—Distance between Furrows and Ditches, 241.—Irrigation by Lateral Seepage, 242.—Basin Irrigation of Trees and Vines; Advantages and Objections, 243.—Irrigation from Underground Pipes, 245.—Quality of Irrigation Waters, 246.—Saline Waters; Figures of Effects on Orange Trees, 246.—Limits of Salinity, 246.—Mode of Using Saline Irrigation Waters; Apparent Paradox, 249.—Use of Drainage Waters for Irrigation, 250.—“Black Alkali” Waters, 250.—Variations in the Salinity of Deep and Shallow Wells, 250.—Muddy Waters, 251.—The Duty of Irrigation Waters, 251.—Causes of Losses, 252.—Loss by Percolation. Figure, 252.—Evaporation, 253.—Tables Showing same at California Stations, 255.—Evaporation in Different Climates; Table, 255.—Evaporation from Reservoirs and Ditches, 257.—Prevention of Evaporation; Protective Surface Layer, 257.—Illustrations of Effects of Tillage; Table, 258.—Evaporation through Roots and Leaves, 262.—Weeds waste Moisture, 264.—Distribution of Moisture in Soils as Affected by Vegetation, 264.—Forests and Steppes, 265.—Eucalyptus for Drying Wet Lands, 265.—Mulching; Effects on Temperature and Moisture, 266.