GP19

Site GP19 Landscape

Soil Profile Morphology:

Surface Soil

A1	0-20 cm	Greyish brown (10YR5/2); silty clay loam; weak blocky structure; firm consistence moist; pH 5.2; clear change to:	Site GP19 Profile
A2	20-35 cm	Pale brown (10YR6/3) with slight yellowish brown (10YR5/6) mottles; silty clay loam; weak blocky structure; firm consistence dry; contains a few (2-5%) ferromanganiferous nodules (and dark stains (8 mm size); pH 5.8; clear change to:
Subsoil
B21	35-90 cm	Pale brown (10YR6/3) with dark brown (7.5YR3/4) mottles; silty clay loam; weak blocky structure; very firm consistence dry; pH 5.9; clear change to:
B22	90+ cm	Pale brown (10YR6/3) with yellowish brown (10YR5/6) mottles; silty clay; pH 5.6.

• Lack of texture contrast between surface (A) horizons and weakly structured subsoil (B) horizons (i.e. Kandosolic).
• The soil profile is saturated for prolonged periods (i.e. several months) in most years (i.e. Hydrosol).

The surface horizon is strongly acid. The soil profile then becomes moderately acid throughout.	The salinity rating is very low throughout the profile.	The clay content remains uniform throughout most of the soil profile

Horizon	Horizon Depth (cm)	pH water	pH CaCl2	EC 1:5	Exchangeable Cations				Ex. Al mg/kg	Field Capacity pF 2.5	Wilting Point pF 4.2	Coarse Sand (0.2 -2.0 mm)	Fine Sand (0.02-0.2 mm)	Silt (0.002-0.02 mm)	Clay (<0.002 mm)
					Ca	Mg	K	Na
					meq/100g
A1	0-20	4.5	5.2	0.09	3	1.1	0.28	0.28	46	40.1	10.9	1	38	46	18
A2	20-35	4.7	5.8	<0.05	2.8	1.2	0.12	0.16		30.1	7	1	39	45	19
B21	35-90	4.9	5.9	<0.05	2.6	1.5	0.13	0.18		28.4	6.9	1	36	47	19
B22	90+	4.5	5.6	<0.05	2	1.5	0.13	0.27

• Plant available water capacity is considered to be low (estimated at 70 mm) for the top metre of the soil profile. This is based on available laboratory data.
  
  
• The soil profile is likely to be saturated for prolonged periods (i.e. several months) in most years.
  

• The surface soil has a low inherent nutrient status (based on the sum of the basic exchangeable cations).
  
  
• Aluminium toxicity can occur in strongly acid surface soils. The level of exchangeable aluminium measured in the laboratory (i.e. 46 ug/g) is, however, not high for this particular site. Manganese toxicity can also occur in strongly acid soils, particularly if waterlogging occurs. These measurements are best made using a bulked sample taken from across a paddock.
  
  
• Molybdenum deficiency can also occur in acid soils. Increasing pH by liming will increase molybdenum availability.
  
  
• Deterioration in surface soil structure is likely to occur (i.e. pugging, compaction) if overstocking takes place when the soil is wet.
  

• The subsoil has a low nutrient status (based on the sum of the basic exchangeable cations).