CAPACITY OF SOILS TO HOLD MOISTURE 45 



ganic matter holds the soil particles apart, gives a greater 

 amount of pore space, and thus increases the total water- 

 absorbing power of the soil. Well-decayed organic matter 

 is spongy in nature. It has great ability to absorb and hold 

 water itself, just as a sponge holds water. Therefore, it greatly 

 increases the water-retaining power of the soil. 



Equipment. 1. Four soil tubes, the same as used in 

 Ex.8. 



2. A four-gallon crock. 



3. Balances weighing to half a gram. 



4. Cheesecloth. 



5. Pair of shears. 



6. Wash pan. 



7. Four pieces of glass three inches square. 



8. Well-decayed barnyard manure. 



9. Three soils: sand, loam, and clay. 



Directions. Cut disks of cheesecloth to cover the open- 

 ings in the bottom of the tubes. Place the cheesecloth 

 in position in the tubes. 



Number and weigh the four tubes; record weight in ac- 

 companying outline form. 



Fill the tubes to within one inch of the top with the fol- 

 lowing soils : 



No. 1. Sand No. 3. Clay 



No. 2. Loam No. 4. Sand and manure. 



Prepare the sand and manure for tube No. 4 by mixing 

 ten parts of sand with one part of manure. Proportions 

 determined by weight. Weigh and record weight of all 

 tubes filled with soil. 



Place the tubes hi the four-gallon crock provided for the 



