THE PRINCIPLES OF INTERCULTURE 207 



Utah Station (Bul. 66) 



It has been shown by numerous experiments on bare 

 soils that a mulch of straw or of dry loose earth would 

 conserve considerable moisture. It has also been pointed 

 Out heretofore (page 87) that the need of water is the 

 most common limiting factor in corn production. Rea- 

 soning from this, it seems that interculture should play 

 an important part in conserving moisture and this increas- 

 ing yield, but practical experiments fail to show such 

 increases. 



WATER-LOSS FROM FALLOW SOIL 



142. For three months (April, May, and June) the 

 prospective cornfield is essentially a bare field, exposed to 

 wind and sunshine ; and it is to be expected that early 

 plowing and maintenance of a soil mulch will conserve 

 moisture during this period. 



At the Wisconsin station adjacent plots of land were 

 plowed in early spring seven days apart. During this 

 interval of seven days the unplowed plot lost 1.75 inch 

 of water, while the plowed plot had actually gained mois- 

 ture in the first 4 feet, probably due to capillary water 

 from below. 



