PREVENTION OF EROSION BY TERRACING. 



37 



keeps the point pressing slightly against the edge of the furrow and 

 prevents a tendency of the drag to jump out. 



Graded terraces commonly are built with a plow and drag scraper. 

 A strip is plowed, as heretofore described, and the loose earth on 

 the upper half of the strip is scraped up and deposited on the lower 

 half. By this method a channel is constructed for the jflow of the 

 water, and the earth used to build up the embankment. (See PL 

 VII, fig. 2.) 



MAINTENANCE AND CULTIVATION OF TERRACES. 



A newly built terrace is susceptible to failure until it becomes 

 thoroughly settled. For this reason it is not advisable to cultivate 

 the terrace the first year. It should be sown to some sort of cover 

 crop. Breaks in terraces in the first year tend to discourage a 

 novice in the use of terraces, but unless the embankment is built to 

 an abnormally large size breaks occur often in newly made terraces. 





^-^<^^,^<^' 



j>€ 







Fig. 18. — Method of laying out rows where distance between terraces varies (L, long 



rows; S, short rows). 



After the terrace has been established permanently, the soil should 

 be thrown toward the center at each plowing of the field, at least 

 once a year. This will increase the breadth and maintain the height 

 of the terrace and the field eventually will assume an appearance of 

 a succession of prominent waves, all of which may be cultivated 

 easily. (See fig. 2-D, E, and F.) 



In cultivating a terrace as much of the soil as possible should be 

 thrown toward its center. The best results are obtained where the 

 rows are run parallel with the terraces. At first, usually one row is 

 planted on the top (PL VIII, fig. 1), but as the terrace grows broader 

 several rows are planted as shown in Plate VIII, figure 2. These 

 rows invariably produce a greater yield than do those on the land 



