EFFECTS OF CULTIVATION ON SOIL 301 



Method: Tie two thicknesses of cheesecloth over the bottoms of the 

 tubes. Fill the tubes respectively with coarse sand, fine sand, clay, 

 and loam. Support the tubes so that their lower ends are half an inch 

 above the bottom of the basin. Pour water in the basin to a depth 

 of one inch. 



Observation and Conclusion: Compare these soils in the rapidity with which 

 the water rises and the height which it finally reaches. Which soil 

 can take the water the greatest distance above the water table? 



Air in soil. This same loose, porous structure of the 

 soil allows a certain amount of air to remain in the spaces. 

 Plants breathe, and need the oxygen of the air just as 

 much as we do. And since the delicate roots of plants 

 absorb air as well as water, porosity of soil is very necessary 

 for the garden. 



Experiment. To show the effect of cultivation in preventing loss of soil 

 water. 



Materials: A box about 8 inches by 14 inches by 4 inches, filled with 

 garden soil. Two glass tumblers. 



Method: Let the box with soil stay out of doors until after a good rain, 

 then bring it into the house. The rain has made the soil compact. 

 After the surface appears dry 'rake the surface of one half of the box with 

 a fork to loosen the surface soil particles, making a loose, dry mulch. 

 Place one glass, mouth down, over the untouched surface, and the 

 other glass over the raked surface. Let the box stand in the sun for 

 an hour or so. Compare the amount of water that condenses on the 

 two glasses when they have cooled down a little. 



_ Conclusion: Does this experiment give you any evidence regarding the 

 method of conserving soil moisture? 



Effects of cultivation on soil. In order to keep the soil 

 broken up so that it may not become packed too firm 

 and hard, thus preventing water and air from passing 

 readily through it, we cultivate, or break up the top layer 

 of the soil either by hoeing, raking, harrowing, or by means 

 of a cultivator. Cultivation crumbles the soil, and allows 

 the plant roots to creep through it more easily. It breaks 



