THE ROOT SYSTEMS OF CEREALS. 101 



stand was thick and the stalks 6 feet in height (plate 20, a). The soil 

 was plainly stratified. The surface 1.3 feet of nearly pure sand was 

 underlaid by 1.3 feet of dark-colored sandy loam. Below this, pure 

 sand occurred to the water-level at a depth of 7.5 feet. 



From the base of a single clump 15 to more than 40 roots originated 

 (plate 12, c). Most of the roots were 0.5 mm. or less in diameter, but 

 rather tough and easily excavated. While a few ran off obliquely, 

 most of them penetrated rather vertically downward, the soil being 

 filled with dense masses of roots to a depth of at least 3 feet. The 

 lateral spread, which was often more or less parallel with the soil 

 surface, did not exceed 1.2 feet; many of these shallower roots ran 

 obliquely so as to reach their greatest horizontal spread at a depth of 

 0.5 to 1 foot. Here they either ended or turned veitically downward. 

 The surface soil was especially well supplied with roots, many of which 

 ended at a depth of 0.4 to 1.2 feet. However, the roots were fairly 

 abundant to a depth of 6 feet, while not a few reached a maximum 

 depth of 7.7 feet. All of the roots were extremely well branched, but 

 the branches were mostly only 1 or 2 inches or less in length. They 

 were very fine, but well furnished with secondary laterals (cf. fig. 34). 

 In the deeper soil the loots were somewhat larger in diameter, and 

 while abundantly branched, the branches were coarser and not so well 

 furnished with minor branchlets. No differences were noted in the 

 root development in passing from one soil layer to another. The soil 

 was quite moist throughout, probably as a result of the recent heavy 

 rains. 



Other plants were examined in another portion of this area at about 

 the same level and only a few rods distant, but where the soil to a depth 

 of at least 7 feet was composed of pure sand. Here the rye was thin 

 and only 3.3 feet in average height. The maximum root depth was 

 4.6 feet. The general root habit was about the same as that described, 

 a cubic foot of soil containing approximately only half as many roots. 

 Roots were not at all abundant below 2.8 feet, but the soil was fairly 

 well occupied to this depth. Below 3.3 feet there were practically no 

 roots and only 2 or 3 were traced to the maximum depth indicated. 



The root system of rye was further examined at Lincoln, Nebraska. 

 Both the common rye and a variety known as "Rosen" rye, which 

 were growing in adjoining fields, were studied. They were growing on 

 a deep, black silt-loam underlaid with a somewhat clayey subsoil. 

 The land had been tilled for many years. The preceding crop was 

 spring wheat. The field had been plowed to a depth of 4 inches and the 

 rye sown late in September. Although the stand appeared poor in the 

 fall, yet at the time of harvest the yield was estimated at 40 bushels 

 per acre; the common rye reached an average height of 5.5 feet, 

 while the "Rosen'"' variety was about a foot taller. The crop had been 

 harvested at the time of these examinations. 



