AGRICULTURE 



water in the soil. A coarse, sandy soil has little power to lift 

 water by capillarity, because its particles are so far apart. In a 

 clay soil, on the other hand, the particles are so close together 

 that they hinder capillary movement. Capillarity works best in 

 soils of medium texture. 



Soil Loss of Water. The soil loses water in three ways, 

 by per co la/tion, by trans pi ra/tion, and by e vap o ra/tion. 

 Percolation. By percolation water passes through the soil, 



and is carried by the force of 

 gravity out of reach of plant 

 roots. This loss is greatest in 

 coarse, loose soils. They need to 

 be kept compact to hold the wa- 

 ter near the surface. 



Evaporation. Evaporation is 

 the passing off of moisture into the 

 air as a vapor. If you spill water 

 on the floor, in a little while it dis- 

 appears. It evaporates. Much 

 of the moisture brought to the soil 

 surface by capillarity is removed by 

 evaporation. In hot, dry weather, 

 it removes water faster than capil- 



The moisture condensed on the glass l ar i t y can Supply it; that is why the 

 was transpired by the plant. I 



surface becomes dry and parched. 



Transpiration. Much of the water taken up by plants is 

 returned to the air by transpiration, or being given out through 

 the pores of their leaves. Transpiration is greatest in hot, dry, 

 windy weather. Plants differ greatly in the amount of water 

 which they transpire. Willows, poplars, and other wet-loving 

 trees are like great pumps, drawing water out of the soil and 



