concretions. Intense, and occasionally prolonged, periods of
rain can occur in Northland at any time of the year and will
saturate the soil. Thus, all soils will benefit from artificial
drainage, particularly the Perch-gley Oxidic Soils.
Bypass flow occurs when drainage water, along with
nutrients and contaminants, escapes directly to the base of
the soil down pores and fissures. Bypass flow is a risk in
Oxidic Soils where there are slowly permeable horizons in
the lower subsoil, particularly in Perch-gley Oxidic Soils.
Although Oxidic Soils have favourable porosity and
structural qualities, sheet erosion is a risk where vegetation
cover is lacking and if the protective topsoil is removed and
less permeable subsoils are exposed then heavy rain will
rapidly run off causing rill and then gully erosion.
Soil water deficits occur in summer because of the warm
climate and high solar radiation (hence evapotranspiration is
high), so that the region is susceptible to drought when
rainfall is only a little less than usual. The soil water deficits
are exacerbated by low readily available water and limited
nutrient storage capacity, especially in the Nodular Oxidic
Soils where up to 50% of the soil volume may be ironstone
or gibbsitic gravels. Thus soils used for horticulture will
require irrigation in dry periods in most years.
Further Reading
Beinroth FH, Eswaran H, Uehara G et al (2012) Oxisols. In:
Huang PM, Li Y, Sumner ME, (eds) Handbook of soil sciences,
2nd edn. vol 1. Properties and Processes. CRC Press, Boca Raton,
FL, USA, pp 33.177–33.190
Blanchon DJ, de Lange PJ, Galloway DJ (2015) New records of
Ramalina (Ramalinaceae, Ascomycota) for mainland New Zealand.
NZ J Bot 53:192–201
Buol SW, Eswaran H (2000) Oxisols. Adv Agron 68:155–195
Cox JE, Bowen FE, Davidson JM (compilers) (1973) Guidebook for
excursion 4—Northland. IX INQUA Congress, Christchurch, New
Zealand, 142p
Cox JE, McLeod M, Griffiths E (1981) Soil survey and horticultural
potential of Kapiro Block, Kerikeri, Northland. Soil Bureau District
Office Report AK1. DSIR Soil Bureau, 11p
Fig. 9.7 The Te Waimate Mission House near Kerikeri marks the site of the first British-style farm in New Zealand, established on Oxidic Soils in
1830 Photo: David Lowe
142
9 Oxidic Soils
rain can occur in Northland at any time of the year and will
saturate the soil. Thus, all soils will benefit from artificial
drainage, particularly the Perch-gley Oxidic Soils.
Bypass flow occurs when drainage water, along with
nutrients and contaminants, escapes directly to the base of
the soil down pores and fissures. Bypass flow is a risk in
Oxidic Soils where there are slowly permeable horizons in
the lower subsoil, particularly in Perch-gley Oxidic Soils.
Although Oxidic Soils have favourable porosity and
structural qualities, sheet erosion is a risk where vegetation
cover is lacking and if the protective topsoil is removed and
less permeable subsoils are exposed then heavy rain will
rapidly run off causing rill and then gully erosion.
Soil water deficits occur in summer because of the warm
climate and high solar radiation (hence evapotranspiration is
high), so that the region is susceptible to drought when
rainfall is only a little less than usual. The soil water deficits
are exacerbated by low readily available water and limited
nutrient storage capacity, especially in the Nodular Oxidic
Soils where up to 50% of the soil volume may be ironstone
or gibbsitic gravels. Thus soils used for horticulture will
require irrigation in dry periods in most years.
Further Reading
Beinroth FH, Eswaran H, Uehara G et al (2012) Oxisols. In:
Huang PM, Li Y, Sumner ME, (eds) Handbook of soil sciences,
2nd edn. vol 1. Properties and Processes. CRC Press, Boca Raton,
FL, USA, pp 33.177–33.190
Blanchon DJ, de Lange PJ, Galloway DJ (2015) New records of
Ramalina (Ramalinaceae, Ascomycota) for mainland New Zealand.
NZ J Bot 53:192–201
Buol SW, Eswaran H (2000) Oxisols. Adv Agron 68:155–195
Cox JE, Bowen FE, Davidson JM (compilers) (1973) Guidebook for
excursion 4—Northland. IX INQUA Congress, Christchurch, New
Zealand, 142p
Cox JE, McLeod M, Griffiths E (1981) Soil survey and horticultural
potential of Kapiro Block, Kerikeri, Northland. Soil Bureau District
Office Report AK1. DSIR Soil Bureau, 11p
Fig. 9.7 The Te Waimate Mission House near Kerikeri marks the site of the first British-style farm in New Zealand, established on Oxidic Soils in
1830 Photo: David Lowe
142
9 Oxidic Soils