THE USE OF MANURE 171 



2. By acting upon the soil, forming humates and 

 rendering the inert plant food of the soil more availa- 

 ble. 



3. By raising the temperature of the soil. 



4. By making the soil darker colored. 



5. By enabling soils to retain more water and to 

 give it up gradually to growing crops. 



6. By improving the physical condition of sandy 

 and clay soils. 



7. By preventing the denuding effects of heavy 

 wind storms. 



