20 The Profitable Culture of Vegetables. 



ration wi/I take place, which will keep the surface cold and will 

 at the same time considerably diminish the storage of water in 

 the soil. To prevent this loss of water and to make a bed 

 suitable for the reception of seeds the surface soil should be 

 moved about as soon as it is dry enough to bear cultivation. 

 The stirring of the soil cuts off the capillary ducts and so 

 prevents evaporation, besides introducing air, drying the 

 surface, and making the soil warmer. This early aeration 

 and warming of the soil is a great help to the germination of 

 seed and promotes vigorous growth by encouraging the 

 nitrifying bacteria. 



Hoeing and Mulching. Having prepared a loose surface of 

 fine soil for a seed bed, it is often necessary after sowing, par- 

 ticularly on light land, to press the surface down again firmly 

 by rolling or treading or beating with the back of a spade. 

 This is done to establish a connection between the surface and 

 the capillary ducts below, so as to cause sufficient moisture to 

 rise again for the germination of the seed. As soon as the 

 rows of seedlings can be seen the surface soil should again be 

 stirred by hoeing, and this stirring of the surface soil should 

 be persisted in at frequent intervals during the summer. The 

 loose tilth which hoeing produces upon the surface practically 

 forms a mulch to the soil below, although the protecting 

 medium is soil itself. In fact, anything which breaks the con- 

 nection between the water-holding soil underneath and the 

 evaporating surface would serve the same purpose, some 

 things better, perhaps, than loose soil does, but the draw- 

 back to their employment is that they prevent the continual 

 stirring about of the surface. By this means aeration 

 of the soil and distribution of the nitrifying bacteria is 

 effected ; the surface layers of the soil become warm and 

 this makes nitrification active and so brings into a readily- 

 available condition the reserves of nitrogen in the humus. 

 Frequent hoeing preserves soil moisture, increases fertility, 

 encourages the growth of plants, and prevents weeds from 

 growing; therefore it increases the crop, saves manure, 

 keeps the ground clean, and makes the total work lighter 

 and easier. 



