EXERCISE 113 

 SOIL PARTICLES 



Materials. A sandy loam ; glass tube one-half inch in diameter 

 and about five feet long ; set of sieves. The sieves may be made by 

 tacking wire gauze of different degrees of fineness on small wooden 

 frames. 



Directions for work. 1. Soak a small amount of the soil in 

 water for several hours, making a thick mud. Stopper one end 

 of the long glass tube and pour in enough of the soil to fill the 

 tube about six inches. Add water until the tube is filled with 

 water to within an inch of the upper end. Stopper the upper 

 end of the tube and reverse it, thus bringing the tube to a 

 vertical position with the soil at the top. Stand the tube upright 

 and allow it to remain in that position until the following day. 

 As the soil falls through the water the particles will be assorted 

 in accordance with their size and weight. 



Describe the composition of the soil with relation to size of 

 particles. 



2. Place a good-sized sample of the soil in one of the soil pans 

 and heat over the flame until the organic material is well burned 

 out. Pass it through a series of sieves of increasing fineness, 

 thus separating it into fractions depending on size of particles. 

 The separate fractions of the sample may be weighed and the 

 size of particles estimated by the size of the mesh through 

 which they are able to pass. 



Tabulate the facts regarding the physical composition of the 

 soil, which you have secured by the aid of the sieves. 



References 



BERGEN and CALDWELL. Practical Botany, pp. 434, 435. 

 CALDWELL and EIKENBERRY. Elements of General Science, Rev. Ed., 

 chap, xxiii. 



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