Film ID: YFA 5407 THE PRECIOUS SOIL 1971 Visitor TabsDescription This is a documentary sponsored by ICI explaining the importance of, and methods for, good soil management for agriculture. The film is narrated by Richard Baker (unaccredited). The film begins showing flowers, fruit and various agricultural produce, and fields of wheat being ploughed. The commentary explains that in order to meet future needs, the soils needs to be made more productive. All the factors in this are listed. The film then works its way through these factors, starting with the kinds of land that the soil rests on, explaining their advantages and disadvantages: soft limestone, clay, coarse sand, upland gravel, river gravel and soft chalk. Next, the different soil types are explained, with their properties being dependent on levels of clay, silt and sand; again explaining how they differ in relation to roots being able grow, with the use of diagrams. This describes what makes for good or bad soil. A man measures soil structure using a gamma probe which measures porosity. He explains what can happen with a lack of air getting into the soil. Soils of different water retention capacities are demonstrated, as well as the effects this has on crops. It shows the effects of irrigation and drainage. A pipeline is laid in a field, cutting a trench with a large cutter. Then the effects of temperature and light are explained, as are those of different kinds of nutrients. Manure is spread on a field. Other chemical nutrients are also explained. How much nutrients are used up is shown, in grams per hectare. The effects nutrient deficiencies in the soil, such as copper, are explained, showing with the symptoms for the crops. Then there are experiments showing the effects of different rates of pH. levels on plants. A farmer takes samples of soil for analysis to a laboratory, where the process of analysis is shown for all the different minerals. Fields are shown being ploughed in various different ways, such as being chisel ploughed. Drawings are made of the shapes made by different types of ploughing. Then the way in which straw is broken down, producing humus, is explained. Lime and fertilizer are sprayed over a ploughed up field, showing the ways that fertilizers can be applied on a Yorkshire Pennine farm. 300 meters above sea level, explaining how the soil has been transformed through the right management. End Credits For their cooperation in making this film ICI thanks: Edinburgh University Dept. of Soil Science Ministry of Agriculture Fisheries and Food Etc. Scientific Advisor A James Low Film Editor Howard Lamming Photography Roger Thomas Directed by Gerald Fisher Produced by Agricultural Division Film Unit ICI Agriculture Division, Billingham, Teeside, England.