THE ROOT SYSTEMS OF CEREALS. 105 



ance. It is quite impossible to show these finer roots and all of their 

 branches in the most carefully planned drawing. Below 4 feet the 

 roots were much less abundant. They were well-branched in the moist, 

 jointed soil, but often only in one plane, and clothed with root-hairs. 

 The last 6 inches of the deeper roots were poorly branched and the 

 laterals were only a few millimeters in length. 



A third examination of Turkey Red winter wheat was made about 

 2 miles north of Lincoln, on a high level tract adjoining the prairie area 

 where the base station was maintained (p. 28). The soil consisted of 

 dark-colored Marshall silt-loam, which had been broken only 4 years. 

 At a depth of about 1.5 feet it intergraded into a very deep, rather 

 mellow loess subsoil. Except for the first 0.5 foot, it was quite moi st to 

 a depth of many feet. The wheat, which had been drilled in the corn 

 on September 29, was about 3.5 feet high at the time of harvest, the 

 first week in July (plate 21, b). The stand was good and the yield 

 estimated at 40 bushels per acre. The root system was exceedingly 

 well developed. Many roots ran off obliquely, but usually for only 

 small distances, seldom extending more than 4 to 6 inches horizontally 

 from the base of the plant. While the main course of the bulk of the 

 roots was rather vertically downward, they often meandered from this 

 course, sometimes with rather sharp turns, and ran off obliquely or even 

 parallel with the soil surface for distances of 2 or 3 inches. Roots were 

 fairly abundant to a depth of 4.9 feet. Quite a few penetrated to 7 feet 

 and the maximum root-depth was 7.3 feet. The root branches were 

 short, mostly less than an inch in length, in the first 2 feet of soil. Many 

 of the roots were about 0.5 mm. in diameter. Near the ends they 

 frequently ran 2 to 5 inches without branching, but were densely 

 clothed with root-hairs. At the 13 stations where wheat roots were 

 examined, none reached depths greater than those here recorded. The 

 greater root extent in the mellow loess soil agrees entirely with the 

 greater root development of certain native grasses grown under 

 similar conditions. For example, Androvogon furcatus, ordinarily with 

 roots from 5 to 7 feet deep, reached a maximum depth of 9.3 feet in the 

 mellow loess soil at Peru, Nebraska (Weaver, 1919:15). 



Near Fairbury, Nebraska, about 50 miles southwest of Lincoln, but 

 still in the typical true-prairie region, further examinations of cereal- 

 crop roots were made. The natural plant cover, relatively large areas 

 of which still remain intact, indicates growth conditions like those at 

 the base station. Turkey Red wheat, sown about September 15, and 

 preceded by a similar crop, was examined 4 miles northwest of Fairbury 

 on a high, level area. The soil was a black, silty clay-loam, dry to a 

 depth of 0.7 foot, but otherwise moist and sticky. Below 3.5 feet it 

 became less clayey and lighter in color. In the spring the ground had 

 been exceedingly wet. At the time of harvest the wheat averaged 3 

 feet in height and the estimated yield was 15 bushels per acre. The 

 roots had a working depth of 3 feet and a maximum depth of 4.1 feet. 



