BACKSLOPE 



\< 



DIKE 



ORIGINAL 

 S SLOPE 



tlzz L- - 



CUT 



5 



LEVEL BENCH WITHOUT CONTRIBUTING AREA 



.LEVEL 



BENCH 



DIKE 



FILL \LEVEL 



CONTRIBUTING AREA 



-CUT 



BENCH 



LEVEL BENCH WITH CONTRIBUTING AREA 



Figure 1.— Diagrammatic profile of level bench systems with and without 



contributing areas. 



of their profitability for the individual farmer, 

 compared with conventional farming methods 

 for land with similar soil and topography. Fac- 

 tors affecting the adoption of benches by 

 farmers were examined, and estimates were 

 developed of the potential land area on which 

 benches would be economically feasible and 

 otherwise desirable in a representative North 

 Dakota county. 



The study results represent only an ap- 

 proximation of the pertinent economic rela- 

 tionships. Most of the data used are based on 

 experimental trials or hypothetical situations, 

 because there are very few examples of the 

 practice having been adopted by farmers on 

 a field scale. The analysis can be refined as 

 more experimental data are collected and 

 more farmers adopt the practice. 



EXPERIMENTAL LOCATION AND DESCRIPTION 



Climate 



Water conservation in the Northern Great 

 Plains is always important — and sometimes 

 critical — in determining the level of crop 

 production. At Mandan, N. Dak., the long-term 

 average precipitation is almost 16 inches. 

 About 70 percent of the annual total occurs in 

 the 5 growing-season months, April through 

 August, and about 20 percent occurs as snow. 

 Winters are long and cold. Summers are short 

 and relatively cool, though periods of very high 

 temperature are not unusual; such periods are 

 often accompanied by very dry and windy con- 

 ditions. 



Following are precipitation data from 

 Mandan for 1962-68, with long-term averages 

 for comparison: 



Year 



April- August 



Annual 





Inches 



Inches 



1962 



12.34 



14.95 



1963 



15.51 



18.28 



1964 



12.10 



14.82 



1965 



19.12 



23.34 



1966 



12.10 



15.77 



1967 



6.79 



13.52 



1968 



14.15 



17.92 



Averages 







1962-68 



13.16 



16.94 



1915-68 



11.25 



15.88 



Description of Experiments 



A series of trials has been underway for 

 several years at the Northern Great Plains 

 Research Center at Mandan to test level bench 



