. Farm development; an introductory book in agriculture, including a discussion of soils, selecting & planning farms, subduing the fields, drainage, irrigation, roads, fences, together with introductory chapters concerning farm business, and the relations of general science to agriculture . y. Gravita- ^^\^\J^\^^^;^^^^l tion. of course, aids the down-ed tirsoilTas b^e^sSeI n^e^ ward capillary movement, andhalf way clown through the mass. slightly retards its upward movement, as in the sponge. \Ahen filled, or saturated, toits full capacity with capillary water, the lOO pounds oforiginal dried,
. Farm development; an introductory book in agriculture, including a discussion of soils, selecting & planning farms, subduing the fields, drainage, irrigation, roads, fences, together with introductory chapters concerning farm business, and the relations of general science to agriculture . y. Gravita- ^^\^\J^\^^^;^^^^l tion. of course, aids the down-ed tirsoilTas b^e^sSeI n^e^ ward capillary movement, andhalf way clown through the mass. slightly retards its upward movement, as in the sponge. \Ahen filled, or saturated, toits full capacity with capillary water, the lOO pounds oforiginal dried, water-free soil, with its added water,weighs, perhaps. 145 pounds. In Figure 22 the soil isshown to have its capillarypowers saturated in the upperhalf. Crops could not thrive insoil as dry as that representedin Figure 20 or even that inFigure 21, with only hygro-scopic water present, but plantswhich thrive in our arable Figure 23- capniaiy poweis of the soil satisfied to the bottom of the lands have, through the cen- i^*- turies of their development, become accustomed tosoils with their capillary forces only partly with its capillary forces fully satisfied with 45pounds of water to the hundred pounds of soil, wouldbe so wet that corn, and most other crops, would not. 78 FARM DICVELOPMENT llinve SO well as if il contained only 20 to 35 poundsi>r water to the hundred pounds. If the rainfallcontinues until no more soil with unsatisfied capillarypower exists below, the excess of water percolates tothe bottom of the pot, obe^^ing the law of gravitation,and there fills the larger interstices,crowding- out the air. This water iscalled ground water. As the rain con-tinues until the ground water has filledall the openings in the soil, the sur-face of this ground water gradually rises Figure 24. Tot of .-^-lil , *= ., . , ° , / after rain has fallen on amOUg tllC SOll partlClCS Ul tllC bottOmIt nntil the capillary ^ ■ l,7%atisLi? ami^he ^^ ^hc pot, forclug the air
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
