Soils and fertilizers . chcauses the tile to crumble when buried in the soil. It is not necessary that tile shall be permeable to water,as it is through the openings between the ends of the tilethat water enters, and not through the pores. Vitrifiedtile may well be used, as they are less likely to be injuredby freezing than are porous tile, because expansion of ab-sorbed water on freezing causes the latter to disintegrate. Concrete tile are often used and these maj be made onthe farm, with forms constructed for the purpose. Silt and fine sand may enter the tiles through the open-ings between t
Soils and fertilizers . chcauses the tile to crumble when buried in the soil. It is not necessary that tile shall be permeable to water,as it is through the openings between the ends of the tilethat water enters, and not through the pores. Vitrifiedtile may well be used, as they are less likely to be injuredby freezing than are porous tile, because expansion of ab-sorbed water on freezing causes the latter to disintegrate. Concrete tile are often used and these maj be made onthe farm, with forms constructed for the purpose. Silt and fine sand may enter the tiles through the open-ings between them, and to guard against this collars aresometimes placed over the joints, but with proper gradesthis is not necessary. Sometimes tile are hexagonal on theoutside, for the purpose of preventing settling of the tilein places, with a consequent stoppage with silt. However,if the bottom of the ditch is carefully made, round tile arenot likely to deviate from alignment and they are more easilylaid. 82 SOILS AND FERTILIZERS. 103. Arrangement of drains. — In laying out a systemof drains certain rules must be regarded. A main drainusually follows a depression in the land, rising with the natural grade, orif that does notgive a sufficientrise, becomingshallower as itascends. Some-times this will besufficient to re-move the surpluswater, but moreoften lateraldrains will be nec-essary. These areof smaller tile andare usually paral-lel to each otherand from twentyto a hundred feetapart. This ar-rangement iscalled the herringbone system.(See Fig. 15.)There may also besubmains branch-ing off of the maindrain, and lateralsrunning into the submains. This is known as the gridironsystem. (See Fig. 15.) Sometimes the laterals are runacross the slope, but usually it is better to run them lateral should not enter a main drain at a right angle, I I
Size: 1809px × 1381px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauth, bookcentury1900, bookdecade1910, booksubjectfertilizers
