. Development and activities of roots of crop plants; a study in crop ecology. Roots (Botany); Plant ecology; Crops and climate. Investigations at All Stations. 87 An exception to this occurred in the case of the number of heads of wheat at Burlington when compared with Phillipsburg, while the difference in this respect in the case of barley was small. However, a clear gradation in the reduction of total dry weight from east to west is apparent. Root extent, whether working depth or maximum penetration, is least at Burling- ton, intermediate at Lincoln, and greatest at Phillipsburg. As pointed


. Development and activities of roots of crop plants; a study in crop ecology. Roots (Botany); Plant ecology; Crops and climate. Investigations at All Stations. 87 An exception to this occurred in the case of the number of heads of wheat at Burlington when compared with Phillipsburg, while the difference in this respect in the case of barley was small. However, a clear gradation in the reduction of total dry weight from east to west is apparent. Root extent, whether working depth or maximum penetration, is least at Burling- ton, intermediate at Lincoln, and greatest at Phillipsburg. As pointed out elsewhere (p. 76), the very deep root penetration at Phillipsburg is thought to be due to an unusually high water-content of the mellow loess soil and especially the deeper subsoil. Summary of Environment and Crop Development. The season of 1921 was one of drought at the Peru station. A deficiency of rainfall, coupled with poor distribution, resulted in a much drier soil than in 1919, especially the deeper subsoil. The stands of oats, wheat, and barley were thin, the plants having tillered poorly, and the height-growth, which. Fig. 39—Mean precipitation in inches (black) and precipitation for 1921 at Lincoln (left), Phillipsburg, and Burlington. varied from 2 to feet, except in the case of barley, was 6 to 8 inches less than in 1919. The root systems, except in the case of oats, were somewhat less deeply seated than in 1919, reaching working depths of 4 feet and having a maximum depth of to feet. Oat roots were traced to depths of 8 feet. All of the smaller cereals showed a less marked development of the roots into a superficial and a deeply penetrating portion than in 1919. Potato roots, while very similar in distribution to those of 1919, showed a lesser tendency to turn downward at a later period in their development. This, like the lesser penetration of the roots of the cereals, may be due in part to the fact that the largest supply of available water occ


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Keywords: ., bookcentury1900, bookdecade1920, booksubjectcropsan, bookyear1922