Fibrous root growth and water use of sugar beet

Abstract

SUMMARYDevelopment of the fibrous root system of sugar beet was studied by washing soil samples taken from field experiments through the growing season. At the beginning of June the root system was still poorly developed but during June there was rapid proliferation. In the top 70 cm there was only little further increase in root density after the end of June. Below 70 cm root density increased up to the end of August. Throughout the season fibrous root density decreased with depth. Despite the origin of the lateral roots from two grooves on the storage root, fibrous root distributions at each depth around individual plants were essentially uniform from mid-June onwards. In the absence of nitrogen fertilizer, fibrous root development exceeded that of a crop given fertilizer, particularly at depths greater than 50 cm early in the season. The maximum value of root density was 2·8 cm/cm3 soil recorded in the top 10 cm in mid-September. Compared with published data for other crops, the sugar-beet root system was sparser than that of winter wheat or maize but denser than that of a soya bean or cassava.Soil water content was measured with a neutron probe. Inflows to roots were calculated from soil water content changes in different soil layers. In the top 30 cm, inflows ranged up to 10·8 μl water/cm root.day and were up to five times higher than published inflows for winter wheat. At 30–100 cm sugar beet and winter wheat inflows were generally similar. The 0–30 and 30–120 cm layers contributed about 80 and 20% respectively of the total water use by sugar beet while no uptake was recorded below 110 cm. Previous studies have shown that sugar beet often takes up water from soil deeper than 110 cm, although it is not unknown for the depth of water removal to be restricted.

Epidemiology of beet necrotic yellow vein virus in sugar beet at different initial inoculum levels in the presence or absence of irrigation: Dynamics of inoculum

“…Growing a susceptible beet crop resulted in a remarkable increase in the inoculum levels after only one year. Even at the lowest initial inoculum levels plant roots encounter infective propagules, because during the season the root mass extends and root density increases, so that a large area will be explored by roots, to varying depths and resulting in various root densities (Brown and Biscoe, 1985). The total number of plants that became infected and the time of primary infection of plants differed for the different low inoculum levels of 1988, resulting in different amounts of infected root tissue.…”

Root systems and root:mass ratio-carbon allocation under current and projected atmospheric conditions in arable crops

“…Barraclough and Leigh, 1984 for wheat;Brown and Biscoe, 1985 for sugar beet; Vos and Groenwold, 1986 for potato). Studies of carbon flux to roots are comparatively recent and predominantly utilise young plants that have been pulselabelled with 14C (Meharg and Killham, 1990).…”

Measurement of root diameter in field-grown crops under a microscope without washing

“…The reported values of root traits varied greatly. For instance, the maximum root-length density (total root length per unit soil volume) of field-grown plants ranged from 9 (Morita et al 1988b) to 270 (Murakami and Yoneyama 1988) cm cm-3 in rice, from 8 (Gregory et al 1978) to 36 (Yamaguchi and Tanaka 1990b) cm cm-3 in wheat, and from 3 (Brown and Biscoe 1985) to 23 (Yamaguchi and Tanaka 1990b) cm cm-3 in sugar beet. Dittmer (1938) recorded much larger values including root hairs: i.e., 1,160 cm cm-3 in oats and 7,470 cm cm-3 in Kentucky bluegrass.…”