104 ROOT DEVELOPMENT IN THE GRASSLAND FORMATION. 



This field was sown at the 

 rate of 60 pounds per acre early 

 in October and on land farmed 

 for many years. A crop of 

 wheat had been grown the pre- 

 ceding year. The moist, fertile 

 silt-loam was very similar to 

 that described for the low-lying 

 oat plats (p. 102). Spartina cy- 

 nosuroides, Andropogonfurcatus, 

 and Panicum virgatwn formed a 

 border about the field. At the 

 time of harvesting, about July 1, 

 the abundant crop had an aver- 

 age height of about 3.8 feet. 

 About a week later the roots 

 were examined. From the base 

 of the plant great numbers of 

 long fibrous roots originated. 

 Most of these penetrated rather 

 vertically downward, others ran 

 obliquely downward, but seldom 

 reached a greater horizontal 

 distance than 6 or 8 inches from 

 the base of the plant ; while still 

 others ran off somewhat parallel 

 with the soil surface for short 

 distances before turning down- 

 ward. The working depth was 

 found at approximately 4.4 feet, 

 while the maximum root depth 

 was 6.2 feet (fig. 33) . Beginning 

 just below the surface and 

 extending to a depth of 4 feet, 

 numerous laterals, several inches 

 in length, with countless smaller 

 ones, all profusely branched, ran 

 off in all directions and fairly 

 filled the soil . These light-color- 

 ed roots showed very plainly in 

 the black soil. They were cover- 

 ed with dense mats of root-hairs, 

 the rootlets intercrossing in the 

 jointed subsoil in such a manner 

 as to give a cobwebby appear- 



Fig. 33. — Root system of Triticum cestivum 

 grown in moist silt-loam soil. 



