D4 exemption allows you to deposit diseased crops where they were grown, when a Plant Health Notice has been issued, to reduce the risk of spreading plant diseases or pests.
Source
https://www.gov.uk/guidance/d4-waste-exemption-depositing-agricultural-waste-consisting-of-plant-tissue-under-a-plant-health-noticeCanonical document at the regulator. Always cite this URL — not the Vantage detail page — in compliance evidence.