104 



ELEMENTS OF AGRICULTURE 



vious stratum or layer. If the soil is bare and un- 

 covered to the sun and wind, the water from below 

 rises through the upper layer of soil and evaporates. 

 Cover the soil with either growing or dead plants to 

 protect its surface, and the evaporation is stopped, as 

 it is in the bucket. Anything used to cover the surface 

 of the soil to prevent evaporation, or washing, is called 

 a mulch, and the process is known as mulching. 



It is in the winter and early spring months that 

 most of the rains fall, and in protected soils the excess 

 of moisture is stored up for the use of plants during 

 the drier months of summer. If, however, the soil 

 be left bare, the winds and sunshine of spring evapo- 

 rate vast quantities, and when summer comes with its 

 hot, dry days the growing plants find but a poor supply 

 of water stored up for their use. 



102. Condition of Cultivated Fields. — Now, what is 

 the condition of many cultivated fields during the 

 season of heaviest rainfall? Take the tobacco lands, 

 for example; after a crop of tobacco is gathered the 

 soil is left almost perfectly bare. Tobacco is gathered 

 so late in the season that no weeds can grow, and the 

 only protection the soil has from the washing rains 

 of winter is the scattered stubble from the crop itself. 

 The cotton lands of the South fare but little better 

 than the tobacco lands ; their only protection being the 

 dry, dead stalks scattered over the fields. Often these 

 are collected and burned, leaving the soil with no pro- 

 tection for the winter. Wheat and oat lands fare much 

 better; for after these crops are cut heavy growths of 

 weeds spring up, and these, when plowed under, supply 



