Francis John Richards FRS (1 October 1901 – 2 January 1965) was an English plant physiologist who specialized in quantitative studies on the mineral nutrition requirements of crops.
Under the direction of R. H. Yapp, Richards studied salt marsh ecology and led surveys of Dovey estuary.
There, he worked with F.G. Gregory to quantitatively define the effect of minerals such as nitrogen, potassium, and phosphorus on cereal crop growth, using barley as a model.
[6] Through factorial experiment design, he found significant interactions between potassium, carbohydrate, and water content which he speculated to explain previously reported discrepancies in the literature regarding the control of leaf succulence.
He also studied amino acid distribution in leaves under various mineral deficient conditions and found that putrescine accumulated during growth of barley seedlings lacking potassium.
Following the retirement of Gregory in December 1958, Richards became director of the new Unit of Plant Nutrition and Morphogenesis at Rothamsted, moving to Wye College in 1961.
He was known by his colleagues to hold a wide variety of hobbies, including archaeology, photography, number theory, and natural history.