138 LESSONS IN AGRICULTURE 



Loam. Loam is a mixture of sand, clay and humus 

 in such proportions as to be easily tilled, and suitable 

 for most crops. Good soil must also have a constant 

 supply of moisture and air. Loam is neither too coarse 

 nor too fine to allow the best supply of air and moisture 

 in the soil. 



Practical Exercises 



(Use notebooks and record results and observations) 

 1. Comparison of Soils 



With samples of clay, sand, and humus loams, spread 

 on sheets of paper before each pupil, let the student fill 

 out the following table : 



The use of a hand lens will help in this study. 



2. Composition of Soil 



Carefully weigh a small handful of rich black soil. 

 Then dry it thoroughly, being careful not to burn it, 

 and weigh again. The difference is the weight of the 

 water content of the soil. What per cent of this soil 

 was water? Now place the dry soil in a dish or iron 

 pan and burn it. Cool, weigh again, and examine care- 

 fully. The loss is the weight of the humus or organic 

 matter. What per cent of this soil is organic mat- 

 ter? Do you believe that you could burn all of the 

 soil? The portion remaining is the mineral matter. 

 What per cent is mineral matter? We shall learn what 



