Grade. 

 Date. . 



EXERCISE 27 (71) 



Soil Ventilation 



Purpose. — To demonstrate the practical importance of soil ventilation and 

 drainage, and to call attention to the manner in which the soil ventilation 

 may be affected by the structure of the soil. 



PLAN* 



1. Secure four round pans about 8 inches deep. (Gallon cans will do.) 



2. Fill two of the pans to within one and one-half inches of the top with 



loose clay soil which has a good field condition of moisture. Then plant 

 twenty grains of com in each pan by laying the corn on the surface of 

 the soil and placing an inch of soil over the grains. 



3. Fill the third pan to the same height with the same kind of soil in a very 



compact condition. Plant twenty grains of corn in the same manner 

 as before, except compact the soil over the grains. Prepare soil for Nos. 

 1 and 3 together. 



4. Avoid puddling by giving plenty of time for diffusion of water. Great 



care is necessary to secure the right moisture conditions. 



5. Make a germinating pan of the fourth by filling it half full of sand. Place 



twenty grains of corn on the sand and cover with moist filter paper. 



6. Keep the pan moistened as showTi in table and cover with oilcloth or waxed 



paper until seedlings are well up. 



7. See that the different pans are kept under the proper moisture conditions. 



8. Observe the rate and percentage of germination each day in the shallow 



pan. 



9. At the end of ten days examine the pans closely and make the following 



observations. 



Ventilation and Germination 



♦Adapted from Department of Soil Technology, Cornell University. 



