94 SOILS 



Pack each very tightly. Fill three quart jars with 

 water and pour water slowly from one of them into 

 the top of the chimney of humus; water the chim- 

 neys of sand and clay likewise from the other two 

 jars. Pour in only a very little water at a time so 

 as to allow it to settle slowly and wet all the soil 

 thoroughly. Stop pouring water when the soil is 

 wet to the bottom, and water begins to seep from 

 the bottom of the chimney. Note first, how 

 quickly water passes through sand and how little 

 water it holds it is leacny. Observe that the 

 humus also absorbs the water quite readily, but 

 holds much more of it. The clay takes up the 

 water very slowly but holds a large quantity of it. 

 The water left in each of the three jars shows the 

 relative water-holding capacity of the soils. 



The chimneys of soil represent actual conditions 

 in the field ; the water held by the soil in the chim- 

 neys is film or capillary water, while the water that 

 seeps out at the bottom of the chimney is free or 

 standing water. The same results may be secured 

 in another way by filling several flower pots 

 with different soils and drying them in an oven. 

 After weighing each pot of soil separately, add 

 water to it very slowly until it seeps out at the 

 bottom. Set the pots away to dram. When no 

 more water seeps out, weigh them again. The 

 difference in weight is the amount of film water 

 that the soil can nold. 



The several types of soil on the farm may now 

 be tested in the same way. Compare the water- 

 holding capacity of a sandy loam with a clay 

 loam. If you have a stiff clay soil, fill one chimney 

 with this, another with a sample of the same soil 

 which has had some humus mixed with it, and a 

 third chimney with another sample of the same 



