Twyford

5,6 - Twyford

Soil Properties

Parent material	Water deposit (alluvium) from greywacke and/or sandstone
Characteristic site and soil features	Older levees more than 700 years old, beyond present river flood level. Deep, >100cm to Taupo pumice alluvium, with silt loams (5) on lower parts, and sandy loams over sands (6) on higher parts of levees
Associated soils not shown within map unit at map scale but separated out in more detailed maps. - Sample Location	13, 16, 14   F, G
Natural drainage and depth to gley and hence to water table after wet periods	Good 5, 6,  >90cm
Potential rooting depth, texture, and limiting layer	5,   >100cm deep >45cm silt loam on sand  5s,  30-45cm silt loam on sand  6,   >100cm deep >45cm sandy loam on sand   6s,  30-45cm sandy loam on sand
Available water capacity (AWC)	5,  100mm 5S,  50-75mm 6,  75mm 6s,  30-50mm
Infiltration rate	Moderate, but if compacted slow
Permeability rate	5, 6,  moderate 5s, 6s,  rapid
Susceptibility to pugging and compaction when wet	5,   high 5s,  moderate to high 6, 6s,  moderate
Susceptibility to wind erosion when dry	6s, high if sandy topsoil
Unfavourable soil characteristics	5,  silty soil difficult to manage if cultivated in  wet conditions 5s,  as above but <45cm to sand 6s,  susceptible to wind erosion if cultivation  removes topsoil exposing sand  <45cm to  sand    low AWC

 

Soil Management

Artificial drainage	5, 6,   none required
Cultivate when moist to avoid: compaction wind erosion	5, 5s 6s
Irrigation:- Recommended method Dripper spacing for continuous wetted strip Amount and frequency	6s - sprinklers to prevent water loss if 4 l/hr drippers used 6s -     30cm 6 -       40cm 5, 5s - 60cm: 6s -     little (15-25mm), often to prevent water loss

 
Twyford silt loam (5, 6) (photo J. Watt)