Root Growth of Cotton as Measured by P32 Uptake¹

Abstract

Development of the root system of cotton (Gossypium hirsutum L.) under irrigated conditions was measured by uptake of P32 variously placed throughout the soil in dissolvable gelatin capsules. Corrections were made for small differences in P32 availability within the soil profile as determined from a greenhouse study. The tap root grew at an average rate of 2.5 cm per day to a depth of 183 cm, the deepest placement. Lateral roots grew at one‐half this rate. The basic framework of the root system was established by the onset of flowering approximately 10 weeks after planting as evidenced by measurable activity at all placements, although twothirds of the total activity on this date was confined to the top 30 cm. Root activity at the lower depths intensified as the season progressed. This resulted in relatively uniform activity through the first 122 cm and significant activity down to 183 cm at the end of the 130 days

Root length densities of UK wheat and oilseed rape crops with implications for water capture and yield

“…Early and detailed work carried out by Weaver in the 1920s involved careful excavation of the soil around the roots and of drawing the root system (Weaver, 2006). Excavation techniques were adapted further by Schuurman and Goedewaagen (1964), Gooderham (1969), andBloomberg (1974), and various further in-field methods are available (Smit et al, 2000) including counting roots in soil pits (Hoad et al, 2004); using radioisotopes, in which a detectable isotope is placed at a particular soil depth and the plant shoots monitored for isotope uptake (Hall et al, 1953;Bassett et al, 1970;Ellis and Barnes, 1973); and mini-rhizotrons (Johnson et al, 2001;Metcalfe et al, 2007). However, with some mechanization (Wasson et al, 2012), soil coring coupled with root assessment after separation by washing is probably regarded as the most reliable measure of root systems in the field, even though this technique remains labour intensive.…”

Water relations of winter wheat: 1. Growth of the root system

“…Radioisotopic methods (Hall et al 1953;Bassett, Stockton & Dickens, 1970;Ellis & Barnes, 1973) are quick and generally less destructive but are restricted to studies in which either the depth of rooting or the relative distribution of roots or both is required.…”

Isotopic studies on the uptake of sulphur by pasture plants

“…Several complications could arise and some of these have been examined by several workers (e.g., Nye & Foster 1960;D'Aoust & Taylor 1965;Fried & Broeshart 1967;Newbold 1969;Bassett et al 1970). One of the major complications is the accurate placement of the isotope in the soil profile as its introduction may disturb the feeding activity of roots near the point of injection.…”