Bell, R.W. (1999) Boron. In: Peverill, K., Sparrow, L. and Reuter, D.J., (eds.) Soil Analysis An Interpretation Manual. CSIRO Publishing, Melbourne, pp. 309-317.
Whilst on a global scale boron (B) deficiency is one of the most prevalent micronutrient deficiencies, in Australia there are relatively few reports of B deficiency and fewer studies that have derived critical ranges for B concentration in soils. However, B deficiency is found on sandy soils on the slopes of the Great Dividing Range from Queensland through to Victoria, and has been reported on sandy soils in Western Australia. Generally, soil analysis gives a reasonable prediction of B deficiency when tests are calibrated for particular soil groups and crop species. Both hot water and hot 0.01 M CaCI2 extractants are used for soil B analysis in Australia. In soils with low B, the two extractants remove similar amounts of B and correlate well with plant response. Most values of the critical concentration for deficiency range from 0.15 to 0.5 mg B/kg soil. In very sensitive crops and in alkaline clay soils these values can double.
Boron toxicity is a widespread constraint to cereal and legume crop and pasture production in southern Australia. Elsewhere in the world, irrigation water high in B is the main cause of B toxicity. In southern Australia, however, high B is often found below 10-30 cm depth in soils developed on argillaceous sediments and is often associated with sodicity. On such soils, the incidence and severity of B toxicity varies from year to year, depending on rainfall distribution and quantity. Extractable B in the sub-soil can be used to predict potential B toxicity, but for practical reasons B concentration in the grain has been used to map the occurrence of B toxicity in southern Australia. Values of >3 mg B/kg are predictive of areas at risk of B toxicity.
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|Murdoch Affiliation:||School of Environmental Science|
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