Typically in these soils, the sandy A horizon with <5% clay experiences severe water repellence at the soil surface, plus low fertility, and the clay-rich
subsoil experiences poor soil structure.
* Development and demonstration of practical methods that growers can use to identify, avoid, and manage hostile
subsoils;
Consequently, the characteristics of
subsoil could be different from those of the surface layer.
The Eden soil also has slightly lower clay content than the lower
subsoils of Switzerland or the fine-silty pedons.
Surface residue management by no-tillage practices was complicated by the general need to
subsoil for effective crop production (Campbell et al., 1974; Box and Langdale, 1984).
Geological Survey (USGS) in Denver, Colo., found that desert
subsoils in parts of the Southwest contain large reservoirs of nitrates that had been previously unrecognized in desert nitrogen budgets.
Similar to the observation that the trend in C stock in the topsoils was not observed in the
subsoils, Young et al.
Bakker AC, Emerson WW, Oades JM (1973) The comparative effects of exchangeable calcium, magnesium and sodium on some physical properties of red brown earths
subsoils. 1.
Subsoils at the Victorian sites were light to heavy clay and became more alkaline with depth, whereas the South Australian sites had clay loam
subsoils and neutral pH trends.
Experiments on texture-contrast soils have tested the addition of amendments to
subsoils to increase plant root penetration and extraction of stored water, thereby making crops less susceptible to the fluctuating moisture conditions in the surface horizons (Wang et al.
Accumulation or retention of sodium as an exchangeable cation has led to sodicity over large areas of the landscape and
subsoils are massive or are characterised by large prismatic and columnar structural units, offering only limited opportunities for root growth.
Crop yield on the sandy soils of the Western Australian wheatbelt is influenced strongly by the plant-available water (PAW) and strength of
subsoils. High soil strength may limit root growth and access to potentially available moisture.