18 



MISC. PUBLICATION 6 5 6, U. S. DEPT. OF AGRICULTURE 



30 40 50 60 70 80 90 100 



DAYS AFTER PLANTING 



SOIL CONSERVATION SERVICE, IASHINSTON, DC, 194 



Figtjee 11. — Rainfall distribution patterns during favorable and unfavorable 

 tobacco seasons, Beltsville, Md., 1940— 16 



tobacco production, occurring during the 7-year period, are shown in 

 figure 11. 



The tobacco crop values produced on 1-percent grade ridge rows and 

 on flat rows run with the slope are compared in relation to rainfall 

 distribution in table 5. These studies were conducted on Sunnyside fine 

 sandy loam soil with slopes ranging from 8 to 10 percent. 



The data in table 5 show that the 1-percent grade ridge rows pro- 

 duced better crop values under all rainfall conditions that occurred 

 during the experiment. The increase amounted to $32 per acre in the 

 years when crop production was reduced by excessive rainfall early 

 in the season, $97 per acre in the good crop years, and $71 per acre 

 in the year which was dry during the last part of the season. 



Direct comparisons of crop yields on ridge rows and flat rows on 

 the same row grade have not been made with tobacco, owing to limited 

 facilities for handling the crop. However, such comparisons were 

 made with corn at Beltsville in 1944, on a field of Sassafras fine sandy 

 loam with a slope of 6 percent. The fertilizer was mixed into the soil 

 with a light disking. The rows were laid out on a 1-percent grade and 

 three replications were used. In the ridged treatment corn was 

 planted on ridged rows and worked twice with a middlebuster, where- 

 as in the flat treatment the corn was planted flat and cultivated twice 

 with a 5-tooth cultivator which left the land flat. Comparative yields 

 are shown in table 6. 



Throughout the growing season the corn on the ridge rows showed 

 better growth than corn planted flat with the same 1-percent row 

 grade. The ridge rows increased the corn yield by 25 percent. Simi- 

 lar results have been obtained in other years with corn and lima beans. 



