Summary
This long-term study of the Park Grass Experiment analysed archived soil and herbage samples spanning 132 years to investigate how farming practices and soil chemistry affect iodine and selenium retention and plant uptake. Liming was shown to reduce soil iodine and selenium retention compared to unlimed plots, with differences of 1660 μg/kg for iodine and 92 μg/kg for selenium after 105 years. The findings suggest that in intensively managed grassland with soil pH control, herbage alone may not meet the iodine requirements of grazing animals.
UK applicability
As the study was conducted at Rothamsted Research in the United Kingdom using UK soil and management conditions, the findings are directly applicable to UK pastoral farming and soil management practices. The conclusion that intensive agriculture with soil pH control may not meet grazing animal iodine requirements has direct relevance to UK livestock nutrition and grassland management policy.
Key measures
TMAH-extractable selenium and iodine concentrations in soil (0–23 cm) and herbage; soil-to-plant transfer factors; herbage yield; growing season rainfall
Outcomes reported
The study measured historical trends in iodine and selenium concentrations in soil and herbage samples from 1876 to 2008, and assessed how soil amendments, rainfall, crop yield and soil chemistry changes affected retention and bioavailability of these micronutrients.
Topic tags
Dig deeper with Pulse AI.
Pulse AI has read the whole catalogue. Ask about this record, its theme, or how the findings apply to UK farming and policy — every answer cites the underlying studies.