Investigations at Peru, Nebraska. 



25 



a factor in causing the crop to mature somewhat prematurely and resulted in 

 a heavy reduction in yield. The plat averaged only 37 bushels per acre. 



Summarizing, the shallower part of the root system was extensive and 

 completed its development early, so far as lateral spread is concerned. 

 The group of roots which penetrated deeper developed later and continued 

 to increase in number and extent practically until the time of maturity. 

 The lateral spread on all sides of the plant was approximately 4 feet and the 

 maximum penetration was 8.2 feet. Thus, corn is furnished with a remark- 

 ably extensive and efficient root system. 



Earlier Investigations of Corn. 



With a few exceptions, most of the investigations of corn roots have been 

 carried on in connection with tillage experiments. Sturtevant (1882) 

 traced corn roots at the New York Agricultural Experiment Station to a 

 depth of 2.5 feet. He states that corn plants for that year produced 1,000 

 roots in the first 4 inches of soil to 1 root produced below that depth. Beck- 

 with (1885) working at the same station, found that the lateral roots reached 

 a distance of 3.7 feet on all sides of the plant, and that, while a few roots were 

 traced to a depth of 2.5 feet, the majority of them reached a depth not greater 

 than 1.4 feet. Goff (1887) covered the fertile soil in which corn was growing 

 with a 12-inch layer of infertile soil. The corn roots grew horizontally at 

 the upper surface of the fertile soil, but did not penetrate upward into the 

 layer of infertile soil. From this he decided that " abundant food and mois- 

 ture are more essential to the development of corn than a high soil tempera- 

 ture." Hickman (1887) stated that corn grown in a stiff clay loam in Penn- 

 sylvania "seemed to be a shallow rooted plant." He further observed that 

 "nodal roots, especially those later formed, branched out horizontally from the 

 stem for a considerable distance and then turned down quite rapidly." 

 Hays in 1888, working at St. Paul, Minnesota, got results which indicated 

 that corn roots, under his conditions, grow mainly near the surface if there 

 is a good supply of moisture in these layers, but in time of drought they tended 

 to grow deeper and extend shorter distances horizontally. The same investi- 

 gator (1889), by excavating the roots of corn planted several feet apart, 

 found that they at first grow horizontally because the surface soil is warm, 

 the upper soil is rich in plant food, and contains an abundance of moisture. 

 He further found, after about the fourth week, that both the primary roots 

 and those from the nodes as well take a downward course, the latter from 

 their very beginning. This investigation was carried on in a rather dry 

 season in "drift" soil only fairly retentive of moisture. 



King (1892) at Madison, Wisconsin, found that corn roots grow 4 feet 

 deep and in well-drained soil exceed this depth, and also stated that at tassel- 

 ing time "the roots have fully occupied the upper 3 feet of soil in the entire 

 field." Ten Eyck (1904), by washing out the roots of Kansas Sunflower 

 corn 60 days after planting, at Manhattan, Kansas, found the soil to be filled 

 with roots to a depth of 2.5 feet, while some reached a depth of over 3 feet. 

 He further observed that there were two classes of roots found, namely, 

 "those that curve out from the crown and strike more or less directly down- 

 ward into the soil" and "those that spread out from the root-stem in a hori- 

 zontal plane," then "curve more or less abruptly downward, often ending 



