THE SOIL WATER 



93 



the plants. But the next rain could not get in ; and besides, 

 such a covering is not practical. A loose and pretty light 

 covering, like old manure, is very much better, and is often 

 put around plants. Straw is sometimes laid on the bare 

 ground of a potato patch, and makes a fine protection against 

 drying. But cheapest and simplest of all is simply to stir 

 the surface of the garden after a rain, to the depth of a 

 couple of inches. The 

 loose dirt speedily dries 

 out in the sun, and crum- 

 bles to dust. Of course we 

 have lost the moisture that 

 it contained ; but the dust 

 preserves the water that 

 remains below. 



This stirring of the sur- 

 face is called cultivation, 

 and the dust covering is 

 called a mulch. When we 

 spread manure or lawn clip- 

 pings around a plant, to 

 save the moisture, we are 

 mulching it. " Dry Farm- 

 ing," in our very dry re- 

 gions, depends on very deep cultivation, continued the year 

 round except during frost, to save the water. 



Take now our four pots of soil, which are shiny with the 

 moisture which they have taken up from the pan, and see 

 which of them will first allow the making of a mulch. Use 

 a table fork. The sandy soil will allow it almost at once, 

 and the sandier the better for this purpose. The clay soil 

 cannot be stirred sometimes for a day or more without run- 

 ning the danger of making lumps. These lumps, set in the 



FIG. 54. A clay soil left too long 

 after a rain. It has baked, and is drying 

 out through the cracks. 



