SOILS. 33 



others in wet soils. At the opening of the spring many 

 of the pegs which were driven in the wet soil will 

 be found partly raised out of the ground, and some 

 of them will be found lying upon the surface, as 



shown in Fig. 2. Those driven into well-drained soil 

 will be found to have been but slightly moved by the 

 frost. 



The heaving of the soil has much to do with the un- 

 settled condition of undrained dirt roads, for the reason 

 that the soil grains become completely disarranged and 

 thrown out of their natural position so that the com- 

 pactness of the load-bearing surface of the road is de- 

 stroyed. 



Conservatio7t of Soil Moisture, 



While the removal of surplus moisture from the soil 

 is of first importance, the retention of a proper quantity 

 is equally necessary. The object of underdrainage is 

 to secure and maintain a golden mean between a dry 

 and a wet soil. All observing and thorough cultivators 

 are particular during the growing season to give the 

 soil a thorough surface cultivation as soon after every 

 rain as practicable. This pulverization of the surface 

 — the finer the better — has been found to serve the pur- 

 pose of a mulch in dry weather, and to be conducive 

 to plant growth especially in underdrained soils. 



