116 ROOT DEVELOPMENT IN THE GRASSLAND FORMATION. 



ROOT DEVELOPMENT IN MIXED PRAIRIE. 



Mixed-prairie vegetation indicates growth conditions more favorable 

 than those in short-grass plains, but a water-content somewhat less 

 than that found in true-prairie areas. Frequently, because of edaphic 

 conditions, tongues of mixed prairie extend far into the short-grass- 

 plains association or occur as alternes in it. In general, the possibilities 

 of crop production on mixed prairie are much greater and a correspond- 

 ingly better root development may be anticipated. 



At Limon, Colorado, 1.5 miles distant from the fields already de- 

 scribed (p. 115), an examination of the roots of oats and winter wheat 

 was made on land formerly covered with and now adjacent to mixed 

 prairie. In both fields the soil consisted of about a foot of dark-colored 

 sandy loam, below which it became lighter in color. It was almost 

 identical with that described on page 74, where native plants were ex- 

 cavated. The oat land had been broken for 4 years, the wheat land 

 for about 8 years. The preceding crops were corn and pinto beans, 

 respectively. 



The White Kherson oats had been drilled late in April; on June 26 it 

 was well headed and had a good color, but the straw was only 1 .5 feet 

 high . The maximum root penetration was 4 feet and the average work- 

 ing depth 3.2 feet. Below 2 feet the soil was very moist to a depth of at 

 least 6 feet. This excess moisture was probably due to the blowing of 

 the snow from the field of wheat on a gentle west slope and its accumu- 

 lation in this field, lying on a slope somewhat north of east. 



The winter wheat was 1.8 feet high and in blossom. It had been 

 drilled about November 1, but did not come up well until spring. The 

 soil, which was of a somewhat sandier type than that in the oat field, 

 was dry throughout and the wheat was beginning to roll a little from 

 lack of moisture. The surface spread of laterals was from 0.4 to 0.8 

 foot on all sides of the plant, while the maximum depth of penetration 

 was 4 feet. However, the working depth was 3 feet, a foot greater than 

 in adjacent areas of short-grass land. 



About 12 miles southeast of Yuma, Colorado, rye roots were excavated 

 from the sandy soil which formerly was covered with mixed prairie. 

 The native vegetation in an adjoining area of this rather level tract, 

 where certain deep-rooted native plants were excavated, is described on 

 page 58. The rye land had been farmed for several years, the crop of 

 the preceding year also being rye. The seed was sowed late in Septem- 

 ber at the rate of 56 pounds per acre. It came up well in the fall, but 

 was of very thin stand and only 2.7 feet high at the time of harvest, 10 

 days before this investigation was made on July 19. The sandy soil, 

 which was rather uniform throughout, and quite dry to a depth of 2.5 

 or 3 feet, became gradually more moist and was wet at a depth of 5 

 feet. 



