IN THE 36 years she worked at Rothamsted agricultural research station, in Hertfordshire, Katherine Warington carried out investigations into the weed species that grow in wheat and the nutritious properties of boron that are valued to the present day, and form the basis of modern experiments in Britain and overseas. Warington was the first person to demonstrate that boron, in the form of boric acid, is essential to the healthy growth of broad beans.
Katherine Warington was born in Harpenden in 1897 and lived there for 90 years. Her father, Robert Warington, worked at Rothamsted with Sir John Lawes. She obtained an Honours Degree in Botany at Royal Holloway College (as it then was) and joined the staff of the Botany Department at Rothamsted in 1921 under Winifred Brenchley.
Warington's first piece of research showed that boron in very low concentrations was essential for healthy growth of broad beans in water culture. Making up and maintaining a boron-free solution to provide a standard of comparison and the basis for solutions of varying concentrations, starting from as little as five parts per million of boron, required careful planning and meticulous attention to detail throughout the life of the plants. All reagents used to make up the nutrient solution were re-tested for the presence of traces of boron, and everyone entering the glasshouse had first to wash their hands in the preparation room, even if they were not going to handle the plants. This work earned Warington a PhD from London University, and world-wide recognition from scientists interested in plant nutrition. She went on to investigate the response of other crops to boron, and later she used similar techniques to investigate other so-called 'minor elements' or trace elements, eg manganese and molybdenum.
Warington also helped Brenchley to maintain routine field survey records of weeds on Rothamsted's classical experiments, especially Broadbalk (continuous winter wheat since 1843) and Park Grass, started in 1856 to investigate the manuring of permanent grassland for hay.
Brenchley's investigations into weed species growing in the wheat had already been extended to taking soil samples for estimating the weed- seed content. The soil from different plots was placed in pans in a cold glasshouse and kept watered to allow the seeds to germinate so the seedlings could be identified and counted. This work had shown that most species had distinct patterns of germination in a year, some germinating in autumn, some in spring, some in both, a few in summer and a very few all the year round. Warington tested the effect of seasonal and diurnal fluctuations in temperature on germination by keeping some pens in a cellar at a constant temperature of about 50F. Very few seeds germinated at that temperature, but when the pans were transferred to the glasshouse there was a flush of seedlings, most species being represented regardless of their periodicity.
While she worked at Rothamsted, Warington exchanged reprints of articles with scientists all over the world and maintained an extensive card-
index of references. Many research workers visited her to see her experiments in progress and to discuss methods and results. Early in her career she studied for a time at the University of Lund in Sweden, where research on minor elements was being done. Later she was invited to speak about her methods and results at various scientific conferences in England and overseas, but she never sought publicity.
Warington was respected by all who met her professionally, but she was a quiet and modest person and consequently almost unknown to colleagues who did not have to consult her about their work - except in her early years, when she played tennis. Her name appears among the winners of the Russell Cup of the Rothamsted Tennis Club.
The few people privileged to become her friends admired her greatly for her strength of character and fortitude in adversity, based on a deep and abiding Christian faith. While she lived in Harpenden she worshipped regularly at the parish church, St Nicholas, and after her retirement she did volunteer clerical work in the parish office. Eventually she became too frail to live alone and moved to a residential home in St Albans.
She spent her last years enjoying visits from friends, reading, watching television programmes on art exhibitions, historic houses, Wimbledon tennis, promenade concerts and the Chelsea Flower Show. She was delighted and touched to receive a visit from a much younger research worker who had read and appreciated her papers on boron. She was then over 90 years old, and had been retired for over 30 years, yet she was fully mentally alert and able to sustain a prolonged and detailed scientific consultation.