Grade. 

 Date. 



(68) 



EXERCISE 26 



Color and Temperature 

 Purpose. — To determine the effect of color of soil on temperature. 

 The temperature of the soil influences indirectly the yield per acre. 



1. Secure four wooden boxes approximately 12 inches square by eight inches 



deep. Bore holes in the bottom for proper drainage. Fill with a uniform 

 lot of loam soil to within one-half inch of the top. 



2. Plant corn in one-half of one box at a uniform depth and a like numl^er 



of kernels in the other half. 



3. Cover the one-half of the soil with chalk dust or white sand and the other 



with lamp black or very dark humus soil. Be careful that the depth of 

 the seed is the same after these covers are put over the soil. 



4. In each of the other boxes plant equal numl^ers of wheat, beans and buck- 



wheat. Use the same light and dark covering as in (3). 



5. Moisten all the soil equally from time to time. 



6. Place the boxes where the sun will reach all the soil surfaces equally. 



7. Record in the table the number of plants up, in each half box twice a day. 



Number of Plants up Each Morning and Evening 



Select a clear day and make observations on the temperature of each half 

 of one box. Insert a thermometer one-half inch, and another four 

 inches deep, also place one two inches above the surface. Take readings 

 every two hours and record in the temperature table. 



Each student should make observations on all plots and keep results in 

 tabular form. 



* Adapted from M osier. 



