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



indication that grass roots had 

 much effect on water intake. 



Duley and Russel (19) investi- 

 gated the use of sweetclover in 

 stubble-mulch farming. Along the 

 border of the Great Plains and the 

 Corn Belt, two objections to the use 

 of sweetclover as a soil-improve- 

 ment crop have been made by 

 farmers. First, it was considered a 

 moisture-depleting crop that af- 

 fected the growth of the following 

 crop, and secondly, it was believed 

 that sweetclover made the land 

 more erodible. The data (table 

 21) indicate that sub tilling the 

 sweetclover crop rather than plow- 

 ing for green manure was an ef- 

 fective way of handling the crop. 



The data illustrate the effective- 

 ness of surface sweetclover residue 

 in reducing runoff and erosion as 

 compared with the residue plowed 

 under. Crop yields after subtilling 

 and plowing the sweetclover were 

 essentially the same. 



McCalla and Russel (46) studied 

 production of soil nitrates as af- 



fected by sweetclover residues left 

 on the soil surface. Available ni- 

 trogen with first-year corn after 2 

 years of sweetclover was 10 percent 

 lower in sub tilled plots than in 

 plowed plots. The amount of 

 available nitrogen produced was 

 believed to be sufficient to produce 

 large yields of corn and other crops. 

 The authors suggested that lowered 

 nitrate production would reduce 

 overstimulation under limited mois- 

 ture conditions. No data were 

 presented to support this belief, 

 however. 



Duley and coworkers (20) re- 

 ported on soil conservation and 

 management on sandy farmland in 

 northeastern Nebraska. On the 

 sandy soils east of the Sand Hills 

 section, much of the land is culti- 

 vated. These soils are subject to 

 severe blowing and are relatively 

 low in productivity. Sloping land 

 soils are exposed to severe water 

 erosion. In 1950, the Research 

 Department of the U.S. Soil Con- 

 servation Service and the Agronomy 



Table 21. — Effects of subtilling and plowing sweetclover on runoff and 

 erosion, Lincoln, Nebr., 1942, 1946, 1947 1 



Date 



Crop and residue 



Runoff 



Erosion 





Subtilled 2 



Plowed 



Subtilled 2 



Plowed 



1942 



Second-year corn after 



1 year of sweetclover. 

 First-year corn after 



1 year of sweetclover. 

 Corn after 2 years of 



sweetclover. 

 Corn after 1 year of 



sweetclover. 

 Oats after 2 years of 



sweetclover. 



Inches 

 1.05 



.58 

 T 

 T 



.45 



Inches 

 1.93 



1.84 

 .36 

 .04 



1.76 



Tons per 

 oxre 

 3.64 



1.43 



T 



T 



.17 



Tons per 

 acre 

 7.36 



1942 



13.33 



1946 



1.49 



1946 



.03 



1947 



.21 







Totals _ _ _ 





2.08 

 1 



5.93 

 2.85 



5.24 



1 



22. 42 



Relative 





4.28 



amounts. 







i Data from Duley and Russel (W). 

 2 T, trace. 



