72 Gardening 



Things to Do and Observe 



1. To observe how soil is made. Search inroad cuts, along river 

 banks, and other places where rock is exposed. Note that in 

 some of these places the compact rocks are crumbling into the 

 small particles that make soil. 



2. To observe the formation of humus. Examine the surface 

 soil in a forest, or if this cannot be done, examine a compost heap. 

 Note that this soil contains parts of plants in various stages of 

 decay. Observe also its color and texture. What is the color of 

 soils that lack humus? 



3. To observe soil particles and granules. Crush and examine, 

 first with the eye and then with a hand lens, dry, finely pulverized 

 samples of various soils (clay, humus, sand, and loam). In 

 which are the particles or granules largest ? smallest ? Compare 

 as to uniformity in the size of the granules. 



4. To show the effect of working soils when they are too wet. 

 Secure some dry, finely powdered clay or soil in which clay pre- 

 dominates, and two large shallow dishes or pans. Place one 

 quart of the clay in the first dish, flood with water and stir, leaving 

 the clay in irregular, sticky masses. 



Place the same amount of clay soil in the second dish, add the 

 same amount of water as was added to the first dish, but do not 

 stir. 



Allow the soil in the two dishes to become quite dry. Note that 

 the soil that was stirred is in hard lumps which do not readily 

 break up into granules. Is the soil in the second dish more 

 easily cultivated? 



This experiment shows how particles of clay soil may become 

 grouped into large lumps if worked before the excess of water 

 has dried out. Why is a soil of coarse lumps unsuited for plant- 

 ing seeds and growing crops? What should the gardener do to 

 such a soil? 



Repeat the above experiment, using first sand and then loam. 

 Are these soils more easily cultivated when wet than is a clay soil ? 



5. To determine when a garden soil is dry enough for cultivation. 

 Fill a flat two-thirds full of clay soil, another with the same amount 

 of sand, and a third with loam. Flood each to the top of the flat 

 with water. Allow the excess of water to drain off through the 

 cracks in the bottom of the flat. Test each soil, as described 



