Douglas Archibald Campbell was born in Dunedin on 13 December 1906 to Archibald Campbell, a poultry expert, and his wife, Louise Shepard. He attended Dunedin Technical School and Southland Technical College. He then studied at Canterbury College, graduating BSc in 1929, and at Canterbury Agricultural College, gaining first-class honours, winning the Sir James G. Wilson Prize for agriculture, and playing in the First XV. He graduated MAgrSc in 1931, having taken up the position of agricultural master at Rangiora High School the year before. While at Rangiora he co-authored a chapter on agricultural education in Agricultural organization in New Zealand (1936) and developed agricultural training courses. A keen deerstalker, he saw at first hand the severity of the erosion problem and was a foundation member of the North Canterbury Tree Planting Association, which aimed to combat soil erosion.
On 18 December 1936 Douglas Campbell married Marjory McIntosh at Rangiora. They settled in Hawke’s Bay, where Douglas taught agricultural courses at Napier Boys’ High School (1936–44). While teaching he also researched rates of run-off under various conditions for a PhD with the University of New Zealand. After the 1938 Esk Valley floods, as secretary of the Hawke’s Bay Erosion Control Committee he lobbied for national action and legislative reform. In 1940 he published a lengthy report in the local press outlining land use problems and their solutions. His thesis, submitted in 1942, was never successfully revised, and he did not graduate PhD, but his field research was published in a series of articles in the New Zealand Journal of Science and Technology in 1945 and 1950. Campbell pressed for improved soil conservation legislation. In 1942 the Soil Conservation and Rivers Control Council was established, and in 1944 he moved to Wellington and became their first technical officer, responsible for information and publicity.
As such, he produced a series of booklets with evocative titles, pictures and prose, all intended to heighten general awareness of the erosion problem in New Zealand. Critics felt he was representing only the worst aspects of erosion, but Campbell succeeded in his objective. By 1946 he was senior soil conservator with the Ministry of Works. He also began making documentary films to promote more widely measures preventing soil erosion; these were shown in a mobile cinema unit to thousands of people over a 20-year period. To demonstrate practical soil conservation techniques to farmers, he acquired demonstration farms and experimental areas. This brought him into conflict with the Department of Agriculture, which regarded soil conservation as a part of their farm extension activities (the soil conservators remained part of the Ministry of Works until their transfer to Agriculture in 1955). Campbell also clashed on occasions with prominent soil conservationist Lance McCaskill.
Subsequently, Campbell chaired the Soil Conservation and Rivers Control Council Advisory Committee on Agricultural Aviation. In October 1948 at Ōhakea air base he initiated the first aerial top-dressing trial. This proved successful and Campbell became an enthusiastic advocate of aerial top-dressing; it offered a means of combating erosion and also of increasing production. In 1950 he presented the results of aerial top-dressing work to the International Congress of Soil Science in Amsterdam. Visits to the United States, Canada and the United Kingdom, where he conducted that country’s first aerial top-dressing trials, demonstrated to him the special character of some of New Zealand’s erosion problems. In 1953 he developed aerial dropping of patented lightweight fencing materials and in 1956 an aerial fire-fighting system. He attended international soil science conferences in Pakistan (1952) and Australia (1968). In 1953 he convened the meeting that led to the formation a year later of the New Zealand Institute of Agricultural Science. He was the first secretary, later president, of the institute and for nine years edited its proceedings.
In 1965 Douglas Campbell received a Rockefeller Foundation fellowship to visit the United States to speak on the role of aircraft in soil conservation and pastoral improvement in New Zealand. While there he gave lectures at several universities. Various awards followed, including an honorary fellowship of the New Zealand Institute of Agricultural Science and honorary membership of the Aviation Industry Association of New Zealand. In 1968 he was made an ISO for services to soil conservation and awarded the Bledisloe Medal for services to farming. Shortly before the Water and Soil Conservation Act 1967 was passed, and after the soil conservators were transferred back to the new Soil and Water Division at the Ministry of Works, he retired. Campbell continued to work as an agricultural consultant until his death in Christchurch on 7 March 1969. He was survived by Marjory, three daughters and two sons.
Douglas Campbell brought great energy and practical imagination to his soil conservation work, enjoying the field more than the office. He was determined, bold and persistent. A contemporary noted that ‘few public servants had so many opponents and so few enemies’.