Development and activities of roots of crop plants; a study in crop ecology,

Root Development of Wheat, Oats, and Barley Under Conditions of Soil Moisture Stress1

“…of the whole root system in treatment I in both barley and oats (Table XII). This supports the hypothesis that relatively dry conditions induce more branching as reported by Kmoch (37) and Weaver et al (86) who differentiated between the extent of root growth under dry conditions and that under heavy irrigation where more depth of penetration and a larger mass of roots were produced. The present experiment indicates that favorable moisture conditions induce root elongation through the moist layer, whereas dry conditions seem to cause more lateral spread and less penetration.…”

“…Weaver et al (86) reported that the roots of wheat at the seedling stage spread more widely than oats, and were lighter in color, tougher, and although abundantly supplied with root hairs they did not occur in such density as in oats.…”

Absorption of Nutrients from Subsoil in Relation to Crop Yield

“…in thickness. As shown in previous investigations, the seal has no effect upon root development (20). The nutrient salts used were chemically pure monocalcium phosphate and sodium nitrate.…”

“…WEAVER (20) has shown that the roots of barley when grown in a column of soil of adequate depth do not reach the lowest levels of their penetration to any considerable extent, and consequently do little absorbing there until the plants are nearing the blossoming stage. Root activities during the critical periods of blossoming and the filling of the grain have been shown to be exceedingly important.…”

The influence of zone-placed phosphorus fertilizer on yield, leaf composition, and nodulation of soybean varieties

“…Weaver (1922) stated that, "an exact knowledge of the root development of crop plants, of their position, extent and activity as absorbers of water and solutes at various stages of growth, is of paramount importance to a scientific understanding of plant production. A knowledge of root systems is again fundamental in the scientific application of fertilizer.…”