Introduction
On weakly structured soils, low in organic matter, such as sands and silts, fine seed beds are at risk of capping and slumping, particularly after heavy rainfall or poorly delivered irrigation.  Capping and slumping can delay crop emergence and even reduce population density.  Capping reduces the ability of soils to absorb water leading to surface waterlogging, increasing the risk of runoff and erosion even on very gentle slopes.  By increasing soil organic matter at the surface soil permeability is improved and the risk of capping is reduced.

Slumping and capping as it applies to different sectors

Potatoes
Surface capping can delay crop emergence by 4-5 days and it has been suggested it can reduce population density too.  Slumping of soils can delay crop emergence and result in clods being lifted at harvest increasing risk of damage to the crop.  Following harvest, to minimise the risk of capping and runoff on sandy and silty soils, land should be rough ploughed to produce a cloddy coarse seed bed.

Horticulture
Adequate temperatures, combined with good moisture and oxygen availability, are required for satisfactory seed germination.  Capping and slumping delay seedling emergence and subsequent growth. Any soil impedance will damage fragile seedlings and reduce seedling emergence, thus leading to reduced plant populations. Allium seeds in particular are slow to germinate and emerge after sowing.  Capping restricts infiltration of water to around 1 mm per hour, so can lead to increased runoff and soil erosion.

Cereals and Oilseeds
A fine seedbed is unnecessary for cereals and oilseed estabishment as problems may arise from too many passes.  If too fine and low in soil organic matter surface capping can occur.  Soil capping reduces the ability of soils to absorb water falling on the surface leading to surface waterlogging and may also, in severe situations prevent the emergence of seedlings.  Increasing SOM at the surface improves penetrability, thereby reducing capping and the risk of run-off of sediment, nutrients and pesticides.

Sugar
To get rapid germination through good seed to soil contact, sugar beet requires a fine seedbed. On weakly structured soils such as silts, if heavy rain falls just after drilling the soil can slake and cap. If the soil remains moist this is not a problem but if it dries out, a hard cap can form which will restrict seedling emergence. This results in poorer light interception as the individual plants are late emerging and developing.

Pigs
The lighter soil types most commonly associated with outdoor pig keeping are prone to slumping and capping; cover reduces the risk of this.