

**9P"lt*% 



w^yte%&& ■ 



^0^^S6; 





Figure 3. — Snowmelt water on a level bench. 



(table 1). Generally yields of grain corn have 

 not been increased by using level benches. In 

 both 1964 and 1965, for example, the non- 

 benched slopes produced more corn than the 

 benches, though the 4-year average yield was 

 about the same on the benches as on the slope. 6 

 For corn silage, the results were similar, with 

 an average yield of 8.02 tons per acre from 

 plots on the slope, 7.83 tons from the bench 

 without a contributing area, and 7.52 tons from 

 the bench with a contributing area. 



The pattern of yields from the plots seeded 

 to spring wheat were more nearly as expected. 

 The average yield from the untreated slope 

 was 29.0 bushels per acre, compared with 35.0 

 and 34.3 bushels, respectively, from benches 

 with and without contributing areas. This rep- 



In this section, the data on yield per acre for level 

 benches refer to the leveled portion only. In later sec- 

 tions, appropriate allowance is made for the fact that the 

 dike and backslope are not harvested and therefore do 

 not contribute directly to crop production. Tables are 

 grouped at the end of the report. 



6 An early frost reduced yields substantially in 1964, 

 and the damage was heavier on the benches and the con- 

 tributing areas than on the nonbenched slope. 



resents an increase in yield of 6.0 bushels for 

 the benches with a contributing area and 5.3 

 bushels without a contributing area. 



In the grassland study, yield comparisons 

 were made for both alfalfa and bromegrass. 

 The average yield of alfalfa from the benches 

 without a contributing area was about 1 ton 

 per acre higher than from the slope, though 

 there was little difference between the yields 

 from benches with and without contributing 

 areas. The bromegrass yield differential was 

 0.63 ton for benches without a contributing 

 area and 0.70 ton with a contributing area. 



In the contributing area study, data are 

 presented for 4 of the 5 years. 7 Water storage 

 and yield on benches with 3:1, 2:1, and 1:1 

 contributing area-to-bench ratios were not 

 related to ratio size, but appeared to be in- 

 fluenced more by favorable location for snow 

 collection. The data from these benches were 

 therefore averaged to give the figures shown 



7 The results for 1967 are omitted because runoff 

 from the large watershed was diverted to two of the 

 benches without contributing areas in that year. 



