The effect of soil compaction at various depths on root and shoot growth of oats.

Abstract

The effect of a loose topsoil of 23-63 cm depth overlying a dense subsoil of 35-75 cm depth on root and shoot development was compared with the effect of a homogeneous column of loose soil of 98 cm depth. Shoot weights and, to a large extent root weights, were similar during early growth, but, at later stages, they were higher in the heterogeneous soil columns. Throughout growth, root weights were greater in loose topsoil of the heterogeneous soil columns than in the corresponding layer of the homogeneous columns. Total root weights were higher in the homogeneous columns up to May 23rd, but, at later dates they were higher in the heterogeneous columns. Decreases in root weight at the boundary zone between the layers were mainly due to decreased root branching and, secondarily, to decreased root number. Rooting depth in the dense subsoil increased with increasing thickness of the topsoil, and probably with increasing depth of the water table. Shoot/root ratios at later growth stages were highest for the heterogeneous columns with thin top-soil layers, indicating the presence of favourable growing conditions despite restricted root development. This was confirmed by water consumption data. (Abstract retrieved from CAB Abstracts by CABI’s permission)