DSIR Soil Survey
In 1933 a Soil Survey Division was set up within the Department of Scientific and Industrial Research (DSIR), led by Les Grange. After a reconnaissance soil map of western Taranaki, Grange, with Norman Taylor and Charles Sutherland, began a survey of Waipā County. This established a format and set the standard for subsequent detailed surveys in Northland and Hawke’s Bay. The local names of the Waikato soils became widely accepted by farmers and researchers.
In 1936 the Soil Survey Division became a separate branch of the DSIR, under Les Grange. The growing group of soil scientists undertook surveys to assist agriculture or horticulture in regions such as Kerikeri, Whāngārei and Hawke’s Bay.
Although there had been a number of detailed surveys by the outbreak of the Second World War in 1939, there were still large areas that had not been studied. In 1940–41 almost all the resources of the Soil Survey Division were used for an emergency project to produce a survey of North Island soils at a scale of 4 inches to one mile (about 1:250,000). Soils were mapped as sets, defined by similar profiles. The maps were available by 1942, and were used to set priorities for agriculture and horticulture, and the use of scarce fertiliser.
A number of other surveys identified agricultural areas for strategic purposes – for example, to find suitable sites for military airfields and flax production.
DSIR Soil Bureau
In 1946 the Soil Survey Division became the DSIR Soil Bureau, with four groups: survey, chemistry, physics and biology. An influx of young graduates and trainees increased research in the field and in the laboratory.
Types of survey
By this time, there were three types of survey:
- general (mapping in soil sets; scale about 1:250,000)
- district (mapping in soil types; scale about 1:125,000)
- detailed (soils mapped in relation to farm boundaries; scale about 1:35,000).
Norman Taylor developed the widely used genetic classification of New Zealand soils, based on processes. It highlighted the weathering of soils and climatic factors, and emphasised that soils developed in sequences (known as a soil suite). Based on factors that affected plant growth, the system brought order, and was used for many years by farmers, soil scientists and others in primary industries. In 1948 the classification was used as the legend for the first national soil map, at a scale of 1:2 million.
A stone in the soil
After fighting on the Somme battlefield in 1917, Les Grange met sex hygiene campaigner Ettie Rout while on leave in Paris. She cared for him while he was ill. Over 30 years later, while undertaking a soil survey in the Cook Islands, Grange discovered that she had been buried in an obscure grave in Rarotonga. He arranged for a new headstone – the closest that Rout came to having a memorial for her war services.
Debate about soil erosion
In the late 1930s and early 1940s there was growing concern about soil erosion on land cleared for farming. The government ordered a commission of enquiry and then passed the Soil Conservation and Rivers Control Act 1941. To put the study of erosion on a sound footing, Grange set up studies of erosion-prone areas, including the high country of the South Island and the southern part of the North Island.
But there was controversy over the extent and significance of erosion. A royal commission on sheep farming denounced the DSIR report on the high country as anti-farming propaganda. After 1948, the DSIR’s study of erosion was halted. This decision had unfortunate consequences for many years, because engineering works went ahead without the support of soil erosion research.