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| As iodine is readily leached from soils, low iodine levels are likely in
coarse – textured, freely drained soils. At present, there does not appear to be a
really satisfactory extractant for measuring available iodine in soils. The one we use is
the best available and is better than a herbage test but it serves mainly as a guide to
possible low pasture iodine. Animals should be treated directly rather than using soil
application which will be readily leached from the soil. |
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| Low Zn can affect pasture establishment and reduce N uptake thus
decreasing yield. It also affects hoof and hair health in animals. |
| Zn deficiency is most likely on sandy soils with high pH. A soil test
below 2mg 1-1 is considered low for mineral soils. |
| (B) Arable |
| The trace element deficiencies which occur most frequently in tillage
crops are boron, copper, manganese and zinc. |
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| Deficiencies occur in beets, swedes and oil seed rape. Soil analysis is a
reliable means of predicting a risk of boron deficiency prior to growing susceptible
crops. |
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| It is essential for plants, animals and humans. In Ireland, cereal crops
are frequently affected by shortage. Low copper areas are largely associated with soil
formed from granite, sandstone and peat. Soil analysis is useful to determine available Cu
for arable crops. |
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| Deficiency is common in many crops especially beet, cereals and peas. It
occurs mostly in sandy and organic soils at high pH, but it can occur on most soils when
overlimed. Leaf analysis is a more reliable means of diagnosis than soil analysis but the
easily reducible (ER) soil manganese test together with pH is of some use in predicting
manganese deficiency. |
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Studies on the zinc content of Irish soils commenced only in the
1980’s as in the past it seemed that zinc deficiency of crops was not a problem here.
Potential zinc deficient soils include sandy soils with low soil Zn levels and high lime
soils. Several cases of zinc deficiency in cereals have been confirmed on sandy soils with
high pH. |
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