EXERCISE 114 

 EFFECT OF LACK OF DRAINAGE 



Materials. Prepare two or more waterproof plant pots by soak- 

 ing common pots in melted paraffin, or use empty fruit or vegetable 

 tins. Each of the pots should have a drainage hole in the bottom, 

 and coarse gravel or broken pieces of flowerpots should be placed 

 in the bottom before filling with soil. This will allow very effective 

 drainage. 



Directions for work. Plant wheat, oats, corn, or other grain 

 in both pots. When the seedlings are three or four inches tall, 

 plug the drainage opening in the bottom of one pot with a cork 

 stopper. See that the plug fits tightly. Water both of the pots 

 alike and supply sufficient water from time to time for several 

 days to keep the soil in the plugged pot continually saturated. 

 The excess water will be able to escape from the other pot. 



Compare the seedlings in the two pots from time to time for 

 several days, or until there is a very distinct difference between 

 them. What is the effect of lack of drainage ? When satisfied 

 on the point mentioned above remove the plug, thus allowing 

 the water to drain from the soil. What is the effect upon 

 the seedlings? Do they recover from the effects of lack of 

 drainage ? Do they become the equals of the seedlings which 

 have been grown all the time in properly drained soil ? 



If a larger number of pots are prepared and subjected to the 

 undrained conditions, it will be possible to unplug one on each 

 of several successive days and thus determine approximately 

 how long the seedlings may remain in saturated soil and yet 

 be able to recover when conditions are corrected. 



References 



BERGEN and CALDWELL. Practical Botany, pp. 437-441. 

 BERGEN and CALDWELL. Introduction to Botany, pp. 321-323. 

 WATERS. Essentials of Agriculture, pp. 122-126. Ginn and Company. 



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