HOW TO CARE FOR SOIL 333 



method is very simple. It can be done by keeping the 

 soil well supplied with humus and by keeping the surface 

 covered with vegetation, especially during the seasons 

 of the year when erosion goes on most rapidly. Large 

 quantities of humus or decaying material absorb much 

 water during showers and also keeps the soil loose so that 

 excess water will sink and be drained off as underground 



A CREEK BED 

 Filled with gravel and stone too heavy for the water to carry. 



water instead of on the surface. Vegetation holds the 

 water on the soil till it sinks in, and also prevents the 

 formation of small streams. Moreover, it keeps the soil 

 full of roots so that what little water runs off the surface 

 cannot carry much soil with it. Crops like corn which 

 need to be cultivated several times should not be grown 

 on the same land many times in succession because con- 

 tinuous cultivation causes the humus to decay rapidly and 

 these crops do not leave many roots in the ground to 

 prevent erosion; hence a cultivated crop should be fol- 

 lowed by a non-cultivated crop or several non-cultivated 



