Grade. 

 Date. . 



(46) EXERCISE 17 



Effect of Too Much Organic Matter on Rise of Water 

 The water used by plants is conveyed to them largely by means of the process 



called capillarity. 

 Purpose. — To show that certain farm practices may l)e harmful, cutting off 



the water supply to plant roots by a layer of organic matter. 



PLAN * 



1. Tie a cloth firmly over the ends of two large glass tubes 18 inches long. 



Fill to the height of one foot with fine soil, compacted by letting the tube 

 drop four times on a book for a distance of 6 inches for every G inches 

 of soil put in the tube. 



2. In one tube put about one inch of cut straw or sawdust; in the other about 



a half inch of well decayed fine manure. Finish filling the tubes with 

 soil. Place the ends of the tubes in a tray of water and note the rise of 

 water. 



3. In this exercise each student must make daily observations on the heights 



of the water in the tubes and note the effect of organic matter on the 

 rise of water. 



Results 



Height of wafer 

 Soil w ith fine manure 



Soil with cut straw 



QUESTIONS 



1. In which soil does the water rise the higher and why? 



2. What is the effect of plowing under poorly rotted manure, straw, or a 



heavy green crop in the spring? 



3. What damage to the ensuing crop might result if a heavy sod were plowed 



under late in the spring? 



4. Would there be any advantage in rolling the land directly after plowing? 



5. What advantage with relation to organic matter does fall plowing have? 



*Adapted from Mosier. 



