38 



CIRCULAR 863, U. S. DEPARTMENT OF AGRICULTURE 



Continuous measurements of rainfall, runoff and soil loss have 

 been ob earned at Watkmsville, Ga., 15 for several cropping methods 

 during the 10-year period, 1940-49. On steep, badly-eroded hill- 

 side class IV land of Cecil clay, with a 11 percent slope, a com- 

 parison of runoff on plots in continuous cotton, and on plots in 

 sericea lespedeza was made. 



During the first year, 1940, both the runoff and soil losses were 

 considerably higher from the sericea plot than from the cotton 

 plot, as shown in table 9. This is typical of first-year results 



Table 9. — A 10-year soil and water conservation comparison of 

 sericea lespedeza and cotton under depleted soil conditions on 

 a steep, badly eroded hillside 







Sericea 



Continuous cotton 



Year 



Rainfall 









Runoff 



Erosion 



Runoff 



Erosion 





Inches 



Percent 



Tons/acre 



Percent 



Tons/acre 



1940 



49.49 



26.7 



28.81 



15.6 



14.57 



1941__ 



40.06 



26.2 



3.49 



18.0 



19.67 



1942 



51.83 



14.5 



1.31 



19.5 



21.78 



1943 



53.31 



10.5 



1.27 



28.3 



33.30 



1944 



49.66 



11.0 



.08 



24.3 



26.61 



1945 



49.87 



6.4 



.40 



25.1 



32.81 



1946 



49.51 



6.4 



.08 



23.6 



22.82 



1947 



54.56 



1.6 



.09 



27.2 



13.31 



1948 



63.46 



2.9 



.00 



31.3 



27.84 



1949 



48.68 



1.0 .00 



23.1 



11.37 



with new plantings of sericea on very thin land, as the settled 

 clay subsoil became very hard and shed runoff readily, and the seri- 

 cea seedlings grew slowly, giving scant protection against erosion. 



In the second year, 1941, the runoff from sericea remained 

 relatively high, but the soil loss dropped to less than one-fifth 

 as much as was lost from cotton, as the sericea stand developed 

 its second year growth. 



In the early spring of the third year, a 2-ton per acre applica- 

 tion of grain straw mulch was spread on the sericea plot, causing 

 both runoff and erosion to be sharply reduced. 



During the next 7 years both soil and water losses dropped 

 progressively almost to the vanishing point. Seed were harvested 

 in 1941 and 1942; at least 2 hay cuttings were taken annually 

 during the following 7 years. 



Cotton, grown continuously during the entire 10-year period 

 on this class IV land, failed in each year to produce a single 

 paying crop. 



Such information leads to the conclusion that sericea is ex- 

 tremely useful in the control of erosion. During the growing 

 season the crop provides a canopy through which even the heaviest 



15 1948 Progress Report and Review of Results, 

 servation Exp. Sta., Watkinsville, Ga. 



Southern Piedmont Con- 



