Brown, heart in swedes: a Cumbrian survey

Abstract

1. A survey was made of swede fields in Cumberland and it was found that more than half the gross acreage was affected with Brown Heart to a greater or lesser extent.2. The water-soluble boron content of soils from affected and non-affected fields was determined. In general the boron content of fields showing Brown Heart was less than 0·30 parts per million.3. There is a close association between soil texture and the incidence of boron deficiency, a greater proportion of cases occurring on light soils.4. Recent liming rather than the actual pH. level of the soil appears to be correlated with the occurrence of Brown Heart in the field.5. It would appear that some prediction of the possibility of Brown Heart occurring might be made from a knowledge of the ‘available boron’ content of the soil taken in conjunction with such factors as the soil-texture and liming history of the field concerned.

Colorimetric Determination of Trace Quantities of Boric Acid in Biological Materials

“…A. Absorbance reading at 575 µ. 3 Accuracy limits (2 X standard error of estimate) will include about 95% of the results, PROCEDURE A 0.10-gram sample of lithium carbonate is weighed into a clean platinum crucible. Two milliliters of the fluid (or an appropriate weight of tissue sample) containing not more than 30 y of boron are transferred into the crucible and, if necessary, excess water is removed by evaporation on the steam bath.…”

“…More promising results were obtained by investigating the numerous colorimetric methods reported in the literature (1, [3][4][5][6]11). Of these, the quinalizarin procedure (1) appeared to be reported most frequently.…”