Meanwhile, Australian researchers, Eric Underwood and
John Filmer, were working on the equivalent problem to
bush sickness (known as ‘enzootic marasmus’) in Western
Australia. The breakthrough came in June 1935 when from
systematic trials, involving different groups of elements,
Underwood and Filmer concluded that ‘enzootic marasmus
is due to a deficiency of cobalt in the food’, and that ‘cobalt
must be regarded as an essential element in animal nutrition’.
In South Australia, Ted Lines reported almost simultaneously (in May, 1935) that tiny quantities of cobalt had
successfully treated the disease in sheep.
The South Australian success was reported in the journal
Nature on 28 September 1935. It was picked up by Hugh
Ramage in the UK, who had developed a new method for
measuring trace elements including cobalt. In New Zealand,
D.F.S. (Sandys) Wunsch (also known as Wunsh), who
managed a dairy factory at Edendale in Southland, and local
farmers, had begun trying to find a cure for Morton Mains
disease. They used ‘Whangarei’ limonite (unsuccessfully)
along with soils from Nelson and Bluff (successfully). In
1935, they obtained analyses from Ramage who found that
the Nelson and Bluff soils both contained nickel and cobalt,
but their local Southland soil did not. Wunsch and the
farmers, armed with the South Australian findings and
Ramage’s analyses, set about testing cobalt’s efficacy in
1935–36. Wunsch reported that ‘the results obtained have
been so spectacular that almost magical properties have been
ascribed to it [cobalt]’ and that it was ‘difficult to believe…
that traces of cobalt so minute’ were so effective.
In 1948, vitamin B 12 (cobalamin) was discovered and the
crucial role of cobalt in its formation was identified in 1950.
Vitamin B 12 is essential in ruminants (and humans) for
various functions including red blood cell production, the
development and functioning of brain and nerve cells, and
DNA synthesis. Thus cobalt deficiency may be more accurately described as a vitamin B 12 deficiency.
Soil surveyors related the tephra layers to cobalt levels
and so soil maps could be used to help identify areas of
cobalt deficiency, providing confidence in farm development
in the central North Island. On the pumice deposits (and
similar high-silica materials), cobalt was evidently an inherited deficiency. The amount of cobalt in Pumice Soils is
around 1 to 5 ppm, whereas similarly young soils on basaltic
tephras (Rangitoto Tephra and Tarawera Scoria) have about
100 ppm. In other (non-pumice-mantled) areas that had
displayed the symptoms of bush sickness, strong leaching
had removed most cobalt that had been present, and thus the
soils developed an acquired deficiency of cobalt. For
example, an Allophanic Soil at Waihi (with annual rainfall
*2000 mm yr
−1 ) contained only about 3 ppm of cobalt.
Ken McNaught developed a new method in 1938 for
assessing the cobalt content of pasture and found that
herbage on Pumice Soils contained on average <0.04 ppm,
whereas that from healthy areas averaged about 0.11 ppm.
Besides cobalt, the Pumice Soils are generally also deficient in boron, copper, molybdenum, iodine, and selenium.
There are low reserves of nutrient elements, with sulphur,
potassium, nitrogen, phosphorus, and magnesium usually
required for agricultural or horticulture crops. Reserve
potassium is low and exchangeable magnesium is very low,
particularly in subsoils.
12.7.3 Establishment of Plantation Forestry
Including Pinus radiata
Prior to the cause of bush sickness being established, with
livestock farming unsuccessful, exotic plantation trees such
as larch, Douglas fir, and eucalypts were planted to supplement the native-tree based forestry industry. Pinus radiata, the Monterey pine from California, was observed to
grow well. Initial plantings were made from 1898 at
Whakarewarewa (3250 ha, 17 million trees) and then near
Waiotapu from 1901 (3000 ha). A Royal Commission on
Forestry was established in 1913, and a proposal to plant
trees on the Kaingaroa Plains was developed in 1915. World
War I prevented any planting until 1923 when an extensive
planting campaign of P. radiata (‘radiata pine’) on the
Pumice Soils of the tussock-dominated Kaingaroa Plains
began, with 42 500 ha planted by the late 1920s.
Government-funded planting continued into the depression years from 1928 to 1933, partly to create work for
people desperate for employment. Smaller scale, but nevertheless extensive, pine forests were planted in the Tokoroa
plateau area from 1923 by private companies, and by 1930
included 47 700 ha of P. radiata (11.8 million trees) and
230 660 ha of P. ponderosa.
The radiata-dominated pine forestry became a success
story on the Pumice Soils with radiata able to be harvested at
about 25 years old and so many areas are now into fourth
and fifth rotations (crops) of trees. Pinus radiata is largely
tolerant of low fertility soils (boron deficiency aside) and it
has a long growing season. The low bulk densities of the
pumice deposits permit tree roots to penetrate deeply (up to
3–6 m) into buried paleosols to access extra water and
nutrients. Radiata pine now makes up about 92% of the
plantation forests in central North Island, with Douglas fir
comprising 4%.
12.7.4 Soil Erosion
Under native forest, the infiltration rate in Pumice Soils is
very high and generally exceeds rainfall rates. This means
12.7 Use and Management of Pumice Soils
195
John Filmer, were working on the equivalent problem to
bush sickness (known as ‘enzootic marasmus’) in Western
Australia. The breakthrough came in June 1935 when from
systematic trials, involving different groups of elements,
Underwood and Filmer concluded that ‘enzootic marasmus
is due to a deficiency of cobalt in the food’, and that ‘cobalt
must be regarded as an essential element in animal nutrition’.
In South Australia, Ted Lines reported almost simultaneously (in May, 1935) that tiny quantities of cobalt had
successfully treated the disease in sheep.
The South Australian success was reported in the journal
Nature on 28 September 1935. It was picked up by Hugh
Ramage in the UK, who had developed a new method for
measuring trace elements including cobalt. In New Zealand,
D.F.S. (Sandys) Wunsch (also known as Wunsh), who
managed a dairy factory at Edendale in Southland, and local
farmers, had begun trying to find a cure for Morton Mains
disease. They used ‘Whangarei’ limonite (unsuccessfully)
along with soils from Nelson and Bluff (successfully). In
1935, they obtained analyses from Ramage who found that
the Nelson and Bluff soils both contained nickel and cobalt,
but their local Southland soil did not. Wunsch and the
farmers, armed with the South Australian findings and
Ramage’s analyses, set about testing cobalt’s efficacy in
1935–36. Wunsch reported that ‘the results obtained have
been so spectacular that almost magical properties have been
ascribed to it [cobalt]’ and that it was ‘difficult to believe…
that traces of cobalt so minute’ were so effective.
In 1948, vitamin B 12 (cobalamin) was discovered and the
crucial role of cobalt in its formation was identified in 1950.
Vitamin B 12 is essential in ruminants (and humans) for
various functions including red blood cell production, the
development and functioning of brain and nerve cells, and
DNA synthesis. Thus cobalt deficiency may be more accurately described as a vitamin B 12 deficiency.
Soil surveyors related the tephra layers to cobalt levels
and so soil maps could be used to help identify areas of
cobalt deficiency, providing confidence in farm development
in the central North Island. On the pumice deposits (and
similar high-silica materials), cobalt was evidently an inherited deficiency. The amount of cobalt in Pumice Soils is
around 1 to 5 ppm, whereas similarly young soils on basaltic
tephras (Rangitoto Tephra and Tarawera Scoria) have about
100 ppm. In other (non-pumice-mantled) areas that had
displayed the symptoms of bush sickness, strong leaching
had removed most cobalt that had been present, and thus the
soils developed an acquired deficiency of cobalt. For
example, an Allophanic Soil at Waihi (with annual rainfall
*2000 mm yr
−1 ) contained only about 3 ppm of cobalt.
Ken McNaught developed a new method in 1938 for
assessing the cobalt content of pasture and found that
herbage on Pumice Soils contained on average <0.04 ppm,
whereas that from healthy areas averaged about 0.11 ppm.
Besides cobalt, the Pumice Soils are generally also deficient in boron, copper, molybdenum, iodine, and selenium.
There are low reserves of nutrient elements, with sulphur,
potassium, nitrogen, phosphorus, and magnesium usually
required for agricultural or horticulture crops. Reserve
potassium is low and exchangeable magnesium is very low,
particularly in subsoils.
12.7.3 Establishment of Plantation Forestry
Including Pinus radiata
Prior to the cause of bush sickness being established, with
livestock farming unsuccessful, exotic plantation trees such
as larch, Douglas fir, and eucalypts were planted to supplement the native-tree based forestry industry. Pinus radiata, the Monterey pine from California, was observed to
grow well. Initial plantings were made from 1898 at
Whakarewarewa (3250 ha, 17 million trees) and then near
Waiotapu from 1901 (3000 ha). A Royal Commission on
Forestry was established in 1913, and a proposal to plant
trees on the Kaingaroa Plains was developed in 1915. World
War I prevented any planting until 1923 when an extensive
planting campaign of P. radiata (‘radiata pine’) on the
Pumice Soils of the tussock-dominated Kaingaroa Plains
began, with 42 500 ha planted by the late 1920s.
Government-funded planting continued into the depression years from 1928 to 1933, partly to create work for
people desperate for employment. Smaller scale, but nevertheless extensive, pine forests were planted in the Tokoroa
plateau area from 1923 by private companies, and by 1930
included 47 700 ha of P. radiata (11.8 million trees) and
230 660 ha of P. ponderosa.
The radiata-dominated pine forestry became a success
story on the Pumice Soils with radiata able to be harvested at
about 25 years old and so many areas are now into fourth
and fifth rotations (crops) of trees. Pinus radiata is largely
tolerant of low fertility soils (boron deficiency aside) and it
has a long growing season. The low bulk densities of the
pumice deposits permit tree roots to penetrate deeply (up to
3–6 m) into buried paleosols to access extra water and
nutrients. Radiata pine now makes up about 92% of the
plantation forests in central North Island, with Douglas fir
comprising 4%.
12.7.4 Soil Erosion
Under native forest, the infiltration rate in Pumice Soils is
very high and generally exceeds rainfall rates. This means
12.7 Use and Management of Pumice Soils
195