Investigations at Peru, Nebraska. 



11 



oat is splendidly adapted not only for absorption in the surface soil, but also 

 at much deeper levels. This extensively developed root system undoubtedly 

 plays no small part in making this strain of Kherson oats one of those best 

 adapted to the semiarid condition of Nebraska. 



Growth conditions during June were very favorable. The mean day and 

 night temperatures were 74° and 64° F. respectively. The mean tempera- 

 ture of the first 3 feet of soil was 74.6° F. The rainfall was 4.3 inches, while 

 about 56 per cent of the days were cloudy. Hence the relative humidity was 

 rather high. The average daily evaporation for the month was 24 c. c. 

 Water-content determinations on June 23 and 28 showed a margin of about 

 6.5 per cent above the hygroscopic coefficient in the first 3 feet of soil. Except 

 for clear, dry weather during the last 10 days of this period, conditions were 

 such as to stimulate a very luxuriant vegetative growth. However, the 

 plants stood up well till the grain was ripe. The yield was at the rate of 

 62.5 bushels per acre. The yields of the small cereals were based upon the 

 yield by weight of a single square rod selected from a representative portion 

 of each plat. 



Swedish Select Oats, Avena sativa. 



The root system of the seedling stage of this plant was studied on April 19, 

 19 days after the seed had been planted. Each plant had a single leaf about 

 1.5 inches long, which had been above ground about 9 days. 3 or 4 roots 

 grew out from the hypocotyl. One of these, although not unlike the others 

 in general appearance, took a downward course similar to that of the tap-root, 

 reaching a depth of 10 inches. The other roots, which were 1 to 5 inches in 

 length, descended more obliquely. The roots were about 1.5 mm. in diam- 

 eter, entirely unbranched, but densely covered with root-hairs. They main- 

 tained such an intimate contact with the soil particles that no portion of 

 the excavated root was visible, except the very tips, upon which root-hairs 

 had not yet developed. Environmental conditions of the several intervals 

 of growth have already been given in the discussion of University No. 21 oats. 



The root system was again examined 60 days after planting. The crop 

 had reached a height of 10 to 12 inches, and the number of stalks, including 

 tillers, varied from 1 to 4 per plant. The roots originated both from the old 

 kernel and from a node just below the soil surface. Most of the roots either 

 pursued a course almost vertically downward or ran off obliquely to a dis- 

 tance of 6 to 10 inches and then turned downward with a long, graceful 

 curve (fig. 1b). A few were short and ran almost parallel with the soil 

 surface, where their ramifications terminated 6 to 10 inches from the base of 

 the plant. The deeper roots penetrated to depths of 3.2 to 3.5 feet, with a 

 maximum of 3.7 feet. The roots to within about 8 to 12 inches of the tip 

 were copiously branched. These branches varied in length from a few milli- 

 meters to 5 or 6 inches and the relative number of the longer branches was 

 unusually large. The laterals of the first order were in turn often branched 

 and rebranched. The deeply penetrating roots were usually from 4 to 6 

 in number, while shallower ones varied from 4 to 7, or even more. 



The last investigation of the underground parts of this plant was made 

 July 2. This was 93 days after the seed had been planted and when the crop 

 was beginning to ripen. Each plant had from 1 to 3 stalks, with an average 



