122 SOILS 



to prevent the washing of clay soils is pointed out 

 in a following paragraph. 



Plowing to Drain the Soil. Plowing may also 

 be made the means of draining a soil. It is best 

 to have a soil of such texture that all water falling 

 on it will be absorbed or pass through it. But 

 this is rarely possible, particularly when the soil 

 is heavy. Such soils, especially if nearly level, 

 may often be plowed into "lands" to advantage. 

 The dead furrows may be in the same place for 

 several consecutive seasons, thus throwing the 

 soil into slightly elevated beds. Lands from 

 15 to 30 feet wide are often used, but lands 

 60 to 75 feet wide drain the soil more efficiently, 

 because not enough water may flow into narrow 

 dead-furrows to make sufficient current to carry 

 it off. Even when the field is fairly well drained, 

 naturally or artificially, it is best to leave dead fur- 

 rows from 30 to 50 feet apart, though not in the 

 same place for succeeding years. 



Plowing to Establish a Mulch. In addition to 

 its value for increasing the capacity of a soil to hold 

 water, plowing is one of the best means of prevent- 

 ing the evaporation of water already in the soil. 

 King, who has made many noteworthy experiments 

 on this subject, concludes "In the conservation of 

 soil moisture by tillage there is no way of develop- 

 ing a mulch more effective than that which is pro- 

 duced by a tool working in the manner of a plow, 

 to completely remove a layer of soil and lay it down 

 again, bottom side up, in a loose condition." 



HOW DEEP TO PLOW 



There is sometimes much discussion about how 

 deep the soil should be plowed. It is as impossible 



