46 



AGRICULTURE ON THE PACIFIC SLOPE 



How to prevent evaporation by mulching. To pre- 

 vent evaporation, all the farmer has to do is what most 



good farmers 

 in arid regions 

 do already in 

 their orchards. 

 When the rains 

 have stopped 

 and the time 

 has come to 

 "lay by" crops 

 for the summer, 

 the land is cul- 

 tivated and 

 harrowed fine 

 to a depth of 

 five to eight 

 inches, making 

 a loose layer 

 called the 

 summer mulch, 



through which 



moisture will 

 not rise to the surface any more. The effect of this 

 is shown in figure 22. 



In gardens we sometimes use straw, or other litter, 

 as mulch, especially to cover for a time seeds that would 

 otherwise be dried up by the hot sunshine. 



FIG. 21. Lamp chimneys filled with soil and placed 

 in water to see how fast it will be drawn up by 



