118 



SCHOOL AND HOME GAHDENING 



capillar}' contact of the particles and thus checks upward, 

 movement of moisture into the air. 



10. Dust Mulch on Sugar. — Tiy an experiment as illustrated 

 in figures liO and ()7. Tlie liquid may be water colored with ink. 

 Explain why the loaf sugar becomes wet so quickly and why the 

 powdered sugar is very slow in taking up the moisture. 



Figures 68 and 69 show soil packed with roller packer 

 *S~^"5W 7-'"^T^ which leaves a loose mulch 



on top. Moisture is thus 

 drawn up near the top, but 

 is not allowed to escape 

 into the air. ' 



II. Baking of Sand an.d 

 Clay. — Nearly fill two cans, 

 one with a light sandy soil or 

 pure sand, the other with 

 heavy clay soil. Have them 

 both as nearly the same in 

 moisture as possible. Place 

 them in a sunny window or 

 sheltered sunny spot out of 

 doors. After drying a few 

 days compare them as to 

 shrinkage from the sides of 



Fig. 65.— a footprint packs the soil but *''« <=^"S- '^<^^ either show 

 destroys the surface mulch. A rake will re- signs of crackinsf? The same 

 storethemulchagain. (Dunham Co., Berea.O.) . 



experiment may be tried by 



placing the two soils in cigar boxes. 



Heavy clay soils are much more apt to bake or become 

 crusty and then form cracks or fissures (Fig. 64). Younn- 

 people have noticed the large cracks found in hard roads 

 during the dry summer weather. Such fissures allow soil to 

 dry out more rapidly. 



Sandy soils seldom form fissures because the particles are 

 so loose they crumble and fall together. 



Tilling the soil soon enough after each heavy, beating rain 

 will prevent the formation of a crust and thus prevent crack- 



