Investigations at Phillipsburg, Kansas. 



57 



III INVESTIGATIONS AT PHILLIPSBURG, 

 KANSAS, IN 1920. 



A third station was maintained during 1920 at Phillipsburg, in north-central 

 Kansas. This station which is about midway between Lincoln, Nebraska, and 

 Burlington, Colorado, has an altitude of 1,935 feet and an annual precipita- 

 tion of 23 inches. The crop plats occupied an area, quite typical of the rolling 

 topography, on a hillside which sloped gently to the south and east. 



The fertile soil is a mellow dark-brown silt-loam of the Colby series. At 

 a depth of 1 to 1.2 feet it is slightly lighter in color and contains enough clay 

 to be quite sticky, although when wet it is dark in color to a depth of 2 feet. 

 Below this level it is light yellow, and shows throughout its loess origin. 

 The first 4 feet have a water-holding capacity of about 66 per cent. Excava- 

 tions for root examinations near this station on June 27, 1919, showed that the 

 soil was thoroughly moist to a depth of at least 8 feet and repeated excavations 

 in the plats during 1920 failed to reach the limit of water penetration. 



The crops grown here were from the same lot of seed as that used at 

 Lincoln and Burlington. Moreover, the methods and rate of seeding, etc., 

 were the same as those employed at the other stations. The field had been 

 broken for several years; the preceding crop was wheat. It was plowed to a 

 depth of about 5 inches, harrowed, and brought to good tilth before the crops 

 were hoed in on May 7. The late date of planting, unavoidable because of 

 weather conditions, should be noted, since it bears a close relation to the 

 later maturing of the crops and the injury done by a rust epidemic. 



Oats, Avena sativa. 



The first examination of root development was made on June 10. The crop 

 was in a thriving condition, and, although only 34 days old, had reached an 

 average height of 9 inches. The parent plants had 5 or 6 leaves each and had 

 tillered rather freely. Many had 2 or 3 tillers each. Some of the offshoots 

 were of equal or nearly equal height with the parent plants, while others were 

 only 1 or 2 inches high. The stand was quite uniform and the plants of 



even height. . 



The period as a whole had been one favorable to rapid growth, and, m tact, 

 the crop was as far developed as the oats at Lincoln at the age of 55 days 

 (i e on May 25). At the time of seeding 16 per cent available water was 

 present in the oat plats in the first 2 feet of soil and 11 or 12 per cent to a 

 depth of 4 feet. Frequent, well-distributed showers during the remainder 

 of May, totaling 3.4 inches, kept the soil in good condition. On June 2, 

 12 per cent available water was present to 4 feet depth, except that the surface 

 6 inches had only 10 per cent. Similar water-content conditions prevailed 

 until June 10 (table 13). 



The temperature of the soil from June 2 to 10 varied from 59 to 16 b. at 

 a depth of 6 inches, with an average daily temperature of 65° F. The air- 

 temperature during the same interval varied from 51° to 90° F. with a mean 

 of 69° F. The mean air-temperature for May was 60.6° F. The evaporating 

 power of the air (June 2-10) was only 11 c. c. daily. 



An examination of the roots showed that they had made a good growth and 

 were remarkably similar in development and distribution to those of the crops 



