106 ROOT DEVELOPMENT IN THE GRASSLAND FORMATION. 



On a hillside in an adjoining field, the roots of rye were excavated. 

 The crop was planted during the first week in September in a field 

 where a similar crop had been grown the preceding year. The dark 

 eilty clay-loam gave way at a depth of about 0.8 foot to a tenacious 

 clayey subsoil underlaid at a depth of about 5 feet with sand and 

 giavel. Barnyard manure spread ovei the surface had induced a rank 

 growth. The rye was thick and about 4.5 feet tall. The roots reached a 

 working depth of about 4.7 feet, while the maximum penetration was 

 0.5 foot greater. 



The following example of root behavior is illustrative, although soil 

 conditions are hardly typical. Rye planted from the same lot of seed 

 and at the same time as the preceding field, but upon low-lying land 

 subject to overflow, was examined. The preceding crop was oats. 

 In both cases, as in all the soil described in the true-prairie region, 

 except where otherwise indicated, the land had been broken and culti- 

 vated for many years. The alluvial soil of mellow silt-loam extended 

 to a depth of 3 feet. This was underlaid with a thin sheet of sandy 

 loam which at 3.5 feet gave way to pure sand. The rye at the time 

 of harvest had reached an average height of 3.8 feet. The working 

 depth of the ioots was appioximately the same as the height, 3.9 feet; 

 none extended below the 4.2-foot level. They were veiy abundant to 

 3.0 feet, at which depth most of them ended rather abruptly in the sand. 



On a gently sloping hillside in an adjoining field, the roots of White 

 Kherson oats were examined. The crop, which had been harvested, 

 was 3 feet high and formed a thick stand on the rich black silt-loam 

 which extended to a depth of over 7 feet. The estimated yield was 50 

 bushels per acre. The preceding crop was corn. The ground had been 

 plowed and the oats sown early in March. Except for the surface 10 

 inches, which was quite dry, the soil was moist to the maximum depth 

 examined. The plants had well-developed root systems, with a work- 

 ing depth of 4.2 feet and a maximum root penetration of 5.3 feet. 



A final examination of the ioots of cereal crops in the true prairie 

 was made about 25 miles north of Lincoln and 4 miles south of Wahoo, 

 Nebraska. In the level upland area, where the trenches were dug, 

 the Marshall silt-loam was underlaid at a depth of about 2 feet with a 

 loess subsoil, although of a more compact type than that described 

 at Belmont (p. 105). A field of Yellow Kherson oats, which had been 

 preceded by corn and which was disked during the first week of April, 

 was examined. Although the stand was good and the plants of about 

 the normal height (3 feet), a hailstorm had consideiably reduced the 

 yield. The high fertility of the soil was indicated by the rank growth 

 of Andropogon scoparius, A. furcatus, Agropyrum glaucum, Amorpha 

 canescens, and other native prairie species along the roadway. The 

 roots reached a working depth of 4.1 feet, to which level they were 

 very abundant. A maximum depth of 5 to 5.3 feet was found for 



