Root growth of a barley crop estimated by sampling with portable powered soil-coring equipment.
The shoots and roots of a barley crop were sampled periodically from 46 days after sowing up to the ripe stage (130 days after sowing). Root weights were estimated from soil core samples 60 cm deep. The roots had reached about 60%, but the shoots (+ ears) only about 20%, of their maximum dry weights by the first sampling. Root weights increased until 60 or 74 days after sowing and then declined, but the shoot weights increased more rapidly than root weights until 95 days after sowing; root: shoot ratio therefore declined with time. Most of the roots were in the top 15 cm of soil; about 12% of the root material recovered was between 15 and 30 cm deep, and about 10% between 30 and 60 cm deep. These fractions changed little during the sampling period. Applications of up to 100 kg N/ha increased the total weight of roots, most of the increase being in the top 15 cm of soil, but it increased the shoot weights much more, and so decreased the root: shoot ratio.-F.A.S.