A UNIT IN AGRICULTURE 41 



process that water containing plant food enters the fine root hairs of 

 plants. 



Ex. 22. Absorption of Moisture from Soil (continued). 



Material: thistle tube, piece of waste bladder, jar, water and 

 molasses. Partly fill the thistle tube with molasses. Tie the bladder 

 over the large end of the tube and insert into the jar of water. Put 

 the tube into the jar so that the molasses in the stem is just on the 

 level with the water in the jar. Fasten the tube in this position and 

 observe what happens. Explain. 



Ex. 23. Rise of Water in Plants. 



Fill a tumbler one-third full of luke warm water colored with a 

 few drops of red ink or some brilliant coloring matter. Place in the 

 colored water the freshjy cut stem of a white carnation, lily or almost 

 any soft green plant. Observe closely and explain what happens. 



Ex. 24. Rise of Water in Plants (continued). 



Pull up any good sized green plant, as, for instance, a bunch of 

 clover. Weigh it carefully and record the weight. Now dry the plant 

 thoroughly, being careful not to burn it, and weigh again. What are 

 the percentages of dry material and water as shown by the weights? 

 Estimate the number of pounds of water in one ton of freshly cut 

 clover hay. 



Note. It has been found that corn roots take up over 300 Ibs. 

 of water for each pound of dry matter produced. Oats and clover 

 take up 500 Ibs. What two important facts are shown by this experi- 

 ment? 



Ex. 25. Effects of Excluding Air from the Soil. 



Into a fruit jar or water-tight can containing a healthy growing 

 plant, pour water until the surface of the soil is covered to the depth 

 of one inch. Keep the soil covered with water, observe the plant 

 closely for several days and note results. Have you noticed the effects 

 of standing water on young corn ? If not, do so. Would you say the 

 plant lias been smothered or has it been drowned? Why? Can you 

 suggest a method of soil ventilation? 



