28 MISCELLANEOUS PUBLICATION 952, U.S. DEPT. OF AGRICULTURE 



Table 19. — Rates, at several intervals, of water entry into a Chernozem soil 

 after 7 years of grasses and wheat, fallow, North Platte, Nebr., August 

 1954 * 





Rate of water entry, per hour, at end of — 



Species or rotation 



5 

 min. 



10 

 min. 



20 

 min. 



60 

 min. 



120 

 min. 



420 



min. 



Cool-season grasses: 



Agropyron smiihii (western wheat- 

 grass) 



Cm. 



7.4 

 6.8 



7. 1 



5. 

 4. 4 



Cm. 



6. 2 

 6. 1 



5. 9 



4. 1 

 3. 3 



Cm. 



5. 2 

 5. 5 



5. 2 



3.8 

 2. 8 



Cm. 



4. 8 

 5.0 



4. 6 



4.0 

 2. 8 



Cm. 



4. 9 



5. 1 



4. 7 



4. 4 

 3. 1 



Cm. 

 5. 4 



Elymus junceus (Russian wildrye) 



Agropyron intermedium (intermedi- 

 ate wheatgrass) 



5. 9 

 5 2 



Agropyron desertorum (desert wheat- 

 grass) 



5. 5 



Bromus inermis (smooth bromegrass) _ 



4. 1 



Mean 



6. 1 



5. 1 



4. 5 



4. 2 



4. 4 



5. 2 







Warm-season grasses: 



Andropogon gerardi (big bluestem)__ 



Bouteloua gracilis (blue grama) 



Buchloe dactyloides (buffalograss) 



Bouteloua curtipendula (side-oats 

 grama) 



7. 8 

 7.9 

 4. 6 



8.0 



6.9 

 6.9 

 3.3 



6.3 



6. 3 

 5. 7 

 2. 9 



5.3 



5. 7 

 4.7 

 2. 4 



4. 7 



5. 7 

 4.8 

 2. 2 



4.6 



5. 9 

 4. 9 

 2. 1 



4. 9 







Mean 



7. 1 



5.8 



5.0 



4. 4 



4.3 



4. 4 



Wheat, fallow 



9.4 



7.9 



6. 4 



4. 



3.2 



3. 1 



Least significant difference (5-per- 

 cent level) between means 



2.0 



1.6 



1. 6 



1.7 



1. 8 



2.0 



i Data from Mazurak and Conard (53). 



the highest rates of water entry 

 after 10 minutes for the plots 

 cropped to cool-season grasses were 

 the plots cropped to Agropyron 

 smithii, Elymus junceus, and A. in- 

 termedium. All plots cropped to 

 the warm-season grasses except that 

 to Buchloe dactyloides had high 

 rates of water entry at the end of 

 10 minutes. After 7 hours, all the 

 plots cropped to grasses except that 

 to B. dactyloides had higher rates of 

 water entry than the wheat, fallow 

 rotation plot. The plot cropped to 

 B. dactyloides had significantly lower 

 infiltration rates for the entire study 

 period than any of the other grass 

 plots. On the Chestnut soil, the 

 plot cropped to A. smithii had dis- 

 tinctly higher rates of water entry 



than the plots cropped to other 

 grasses or to grain at the end of 120 

 and 420 minutes. 



Nitrogen fertilizer did not signifi- 

 cantly alter the rates of water 

 entry into the two soils. 



McHenry and Newell (48) in- 

 vestigated the effects of perennial 

 grasses on total nitrogen, organic 

 matter, and soil structure. The 

 grasses were grown on Butler silty 

 clay loam (Planosol) at Lincoln, 

 from 1938 to 1945. Total nitrogen 

 and readily oxidizable organic-mat- 

 ter content of the soil increased 

 significantly under various grass 

 covers for the 0- to 6-inch depth. 

 The seasonal growth habits of the 

 various grasses showed no distinct 

 differences in total nitrogen and 



