THE ROOT SYSTEMS OF CEREALS. 119 



strata of clay and sand were fairly moist and to the depth of the trench 

 (about 5 feet) easily formed a lump with slight pressure of the hand. 

 The oat roots had a working depth of only 2.7 feet, while the maximum 

 penetration was 3.2 feet. 



A field of rye was examined in the mixed prairie near the base station 

 at Colorado Springs. A description of the natural vegetation of this 

 area may be found on page 36. The hard loam had been broken for 

 only two seasons. The first crop was millet. The rye was sown about 

 the middle of November. As is often the case in dry-land cropping, 

 the stand was thin (plate 20, b). On June 23, when it was examined, 

 the crop averaged 3 feet in height and was past the blossoming stage. 

 Many of the abundant fibrous roots spread obliquely outward, so that at 

 5 to 10 inches horizontally from the base of the plant they were only 6 to 

 8 inches deep. Here most of them turned abruptly downward. In fact, 

 most of the roots took a more or less obliquely downward course, rela- 

 tively few descending vertically. The main roots were cordlike, quite 

 tough, and rather easily excavated. The branching was not so pro- 

 nounced as that described for rye growing in the sand at Central City 

 (p. 100) and Yuma (p. 116). The roots showed a marked tendency 

 (as is the case with so many native species) to follow the soil crevices 

 and branch in one plane only. Indeed, in such places of greater water- 

 content and better aeration, they showed their maximum development. 

 The working depth was determined at 3 feet, although the maximum 

 root penetration was about 4.7 feet. Below 4.3 feet roots were scarce. 



At Phillipsburg, Kansas, 90 miles east of Colby and well within the 

 mixed-prairie region (fig. 14), wheat and oat roots were again examined. 

 Both crops were growing on land that had been broken for 10 years. 

 The preceding crop was corn. The Turkey Red wheat had been 

 drilled in the corn on September 20 and the Texas Red oats about the 

 middle of March. On June 27, at the time of this investigation, both 

 crops were rapidly ripening and were harvested about a week later. 

 The stand was thick; the wheat averaged 3.8 feet in height and the oats 

 about the same. The soil is a dark-brown clay-loam to a depth of 1.7 

 feet, below which level it is somewhat sticky, although when wet it 

 maintains a dark-brown color, to a depth of 4.3 feet. At greater depths 

 it becomes lighter in color and more clayey in texture. It was thor- 

 oughly moist to a depth of at least 8 feet. The oat roots reached 

 a maximum depth of 4.8 feet and were fairly abundant at this 

 depth. The older roots on the first 2 feet of soil were usually tougher 

 and smaller in diameter than the remaining deeper portions. In the 

 deeper soils the roots may extend for several inches and give off scarcely 

 a single branch, while at other levels short laterals, 2 to 25 mm. in 

 lengtn, are quite abundant. These laterals are seldom rebranched. 

 The wheat roots were abundant to a depth of 4.8 feet, while a few ex- 



