75 Years of Soil Science.

Geology was more or less born at the beginning of the nineteenth century and the scientific study of soils started some 50 years after geology was established as a scientific discipline. There were essentially two groups that studied soils. A large group worked in the laboratory and they were called agro-chemists, who were mainly found in Western Europe where little land for extending the farm was available. Research interests had to focus on improving soil conditions of existing agricultural fields. Agricultural chemists dominated soil science for most of the nineteenth century. A smaller group of scientists studied soils in the field and they were mostly trained as geologists; they were agro-geologists. In the Russian Empire, large areas of land were available for agricultural expansion and there was a need for soil mapping and a better understanding of the soil concept. It is in the Russian Empire and later on in the USA, that soil survey and cartography developed. Agro-geologists and agro-chemists operated in different laboratories and continents. There was relatively little interaction at the time, possibly because so little was understood about soils and there was widespread disagreement and lack of consensus on almost all aspects of soil research. Soil science became a solid scientific discipline once the agro-geologists and agro-chemists joined their research capacities and organised joint meetings since 1909. Soil research in tropical regions started later than in the temperate regions and its scope has not changed much. The feeding of the ever increasing population, land degradation and the maintenance of soil fertility are still important research themes. The amount of research in environmental protection, soil contamination and ecosystem health is relatively small. More is known about the soil resources in the temperate regions than in the tropical regions despite the fact that one-third of the soils of the world are in the tropics and these support more than three-quarters of the world population. Soil science greatly expanded in the first half of the twentieth century. Since the Second World War, soil science has greatly benefited from new instrumentation and developments in other sciences. Many subdisciplines and specializations have been formed and soil science has broadened its scope in the temperate regions. Soil science had its zenith in the decades after World War II when the provision of food for growing populations became a key area of research. Soil research has made enormous contributions to the increase in agricultural production and in those times most soil scientists viewed soil as the foundation for agriculture. This changed in the 1970s, when soil science became linked to environmental concerns, like soil pollution, eutrophication and ground water contamination and soils were also viewed as stores and filters of contaminants. Climate change and soils came on to the global agenda in the 1980s.