. Elementary lessons in the physics of agriculture . Fig. 36. Fig. 37. [Giant's Castle, near Camp Douglas, From a Photograph. After ChamberUu. Pillar Rock, Wis. From a Photograph. After Chamberlin. 149. Surface Soil.—Soils proper comprise the surface live to ten inches of fields and woodlands generally. Often- times the depth of the true soil may be less than five inches, and then again it may exceed a depth of ten inches by varying amounts. It is the portion which has been longest and niost com})letely exposed to the disintegrating and solvent action of rock-destroying agencies, and' as
. Elementary lessons in the physics of agriculture . Fig. 36. Fig. 37. [Giant's Castle, near Camp Douglas, From a Photograph. After ChamberUu. Pillar Rock, Wis. From a Photograph. After Chamberlin. 149. Surface Soil.—Soils proper comprise the surface live to ten inches of fields and woodlands generally. Often- times the depth of the true soil may be less than five inches, and then again it may exceed a depth of ten inches by varying amounts. It is the portion which has been longest and niost com})letely exposed to the disintegrating and solvent action of rock-destroying agencies, and' as a result of this fact it con- tains a smaller per cent, of the soluble minerals used by plants than the less altered subsoil below. Its chief ino'redients are: 1. Sand. 2. Clay. 3. Humus. Composing about 90 to 95',' of the dry weight; which arc commingled in varying proportions, giving rise to diiferent varieties according as one or another of tliese ingredi- ents predominates. The true soil, on account of its more complete aeration and its higher temperature, is tlie chief lab-
Size: 2651px × 1885px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, bookpublishermadis, bookyear1894
