Soil and Food Production
What Is Soil?
Only since man began cultivating plants and domesticating animals has soil been known as we know it: primarily a means of food provision. Agricultural, cultivated land is largely an artificial system that had not existed naturally prior to the early farmers. Man has had to enter large quantities of energy and various substances into this half-natural substrate in order to keep it stable and productive in the long run. The amount of soil on Earth is defined by the surface area of the landmasses. Of the entire surface area of planet Earth (approx. 510 million square kilometres) only a little over 45 million km2 is agricultural land, of which only about 15 million km2 is intensively farmed. The rest – about two-thirds – comprises pastures, meadows and irregularly farmed land.
By tilling, hoeing, fertilising, draining or irrigating it, among other types of work, man has not only changed the natural structure of soil, but also significantly influenced its physical and chemical properties and soil fauna. The constant effort to improve the harvest, often at any cost, has not always resulted in improved cultivation conditions: often they have deteriorated, even the soil horizon (fertile layer of the ground) has degraded and humus has been lost. Large areas of farmland are threatened by erosion. Overgrazing, soil disintegration by cattle hooves, unsuitable crops and lack of both organic and industrial fertilisers in arid regions have resulted in both erosion and the parching of the surface soil layer. Both the primary building material – the soil particles of the mother rock – and the humus component are carried away from the soil horizon. Soil is thus gradually transforming into desert in certain semidesert and steppe regions of the world.
Water used for irrigation always contains many salts. In over-irrigation in warm regions, where a considerable proportion of the irrigation water evaporates, their concentrations increase over time and are deposited in the soil. Gradual soil salinisation is therefore a frequent consequence of over-irrigation in the desert and semidesert regions. Many cultivated crops either will not grow or will yield substantially reduced harvests in soils with altered chemical properties.
Over-fertilisation with industrial fertilisers, the use of pesticides, and the penetration of certain inorganic and organic toxins frequently exert a significant influence on nutrient circulation, changing the chemical reactions and reducing the vitality of soil organisms. Two kinds of danger result from the chemical contamination of soil: firstly, it is the accumulation of noxious substances in the plants that enter the human body either directly or via farm animals; secondly, there is the risk of intoxication of soil fauna and flora, which play a vital role in the decomposition of organic matter, aeration and nutrient circulation. “Acid rain” also affects the chemical properties of soil significantly.
Soil is compacted by heavy farming machinery, changing soil structure and permeability. The ‘flexible’ and absorbing humus component is gradually lost. Lacking humus and with the soil cavities compacted, such soil does not retain water. The original crumbly structure of the soil disintegrates in the process of being compacted into larger numbers of fine particles, which are more easily eroded by water and wind.
Vast tracts of farmland or virgin soil are occupied irreversibly by human settlements, industrial facilities, roads and large-scale open-cast mines and quarries. Land is thus consumed by humans.
Changes in soil quality and soil loss affect both nature and society hugely. Man has always acquired land for farming to the detriment of natural ecosystems by adapting former steppes, broad-leaved and mixed forests of the temperate zone, later on to encroach on the semideserts and even the tropical rainforest. The tropical rainforest zone is now undergoing the most drastic change of all. Rainforest vegetation comprised about 30% of the dry land surface before 1950. This type of vegetation only covered 6-7% (approx. 7.5 million km2) in the mid 1990s. Given that 160-200 thousand km2 disappear each year, tropical rainforest may not exist on planet Earth just 40-50 years from now.
Misguided soil management, farming methods and contamination may have far-reaching consequences for humans: above all, lower fertility, meaning reduced agricultural production. Hunger and further social problems result from soil degradation in many regions of the world. The reduced production also forces humans to apply larger quantities of fertilisers, pesticides and irrigation water. That may have the secondary effect of food contamination and pollution of other environmental components, the rock environment, water and air.
Modern methods of food procurement and human nutrition differ from the methods of our distant ancestors: humans choose their food according to their taste and custom; food selection is defined largely by familial and socio-cultural customs; we cook most food before eating, season our food and take it at specific times of day (breakfast, lunch, dinner). Local as well as imported ingredients are used as food; even artificial nutrition exists. Humans not only gather and hunt for food, but also produce their own; humans also preserve, store and transport food over long distances.
All the above characteristics make great requirements on work capacities, organisation, technologies, raw material acquisition, and of course the environment. Food production is a very complex process, in which soil plays a crucial but not the sole role.
In terms of environmental use (and risk), the food production process comprises four interconnected principal components, without which any modern food production would be impossible. These are:
- Primary resources – soil, seeds, climate, and labour.
- Technologies – farming machinery, raw material processing, storage, and breeding for improvement.
- Natural environment – source of irrigation water, fertilising materials; also capacity and room for agricultural waste disposal.
- Institutions – organisations, management methods, legislation, government regulations, subsidies, politics.
Supposing that the global population will grow and that it will need sufficient food supply, one or more of the above components will have to improve. The weakening of any of the components, on the other hand, implies decreasing food production. The potential for improvement varies across the world’s regions. Paradoxically, there is more hope for improvement in the industrialised rich countries than in the poor developing ones. For example, improved output can be expected in Europe, Canada and the USA, where breeding methods and technologies are particularly advanced. Increased food production in certain countries already suffering from shortage is unlikely. The problem is not only the difficulty in acquiring additional land easily, but also poor institutional security, technologies and access to additional resources. Yet the total global food production may still increase substantially over the coming decades. The current average harvest is still below the level of the most productive countries, and some countries are still not using all their potential arable land.
However, production increases will probably be lower than the population growth in the respective regions; moreover, such agricultural expansion will be very costly, particularly when having to double or triple to meet the requirement for improved nutrition for several billion people. The soil currently used for food production is of superior quality to that which has not yet been cultivated. Likewise, irrigation systems have been constructed in the most suitable areas. In addition, water is ever scarcer in many countries because households, industries and agriculture compete for it with growing intensity (see below). As a consequence, any increase in food production is more costly than any previous one. It is all the more so considering the environmental protection costs, which are currently not included in the prices of agricultural products. The environmental damage caused by what can be referred to with some exaggeration as ‘turning the planet into a large-scale human eatery’ may be beyond reckoning. The expansion of the agricultural sector, which will have to cater for the improved nutrition of a growing population, will likely result in deforestation, soil erosion, pesticide and fertiliser contamination in proportion to the amount of land given up to production purposes. It is possible to reduce the environmental impacts, but it is costly, and it will probably be easier if population growth slows down.
Even though there are many ways of treating agricultural land sparingly, applying fertilisers, pesticides and irrigation water appropriately, and cultivating highly productive crops, food production and the related activities (storage, preservation, raw material processing, transportation) will, without a doubt, be one of the crucial problems of humanity in the coming decades, and a cause of environmental devastation particularly in regions where the population is growing, climatic conditions are unfavourable, agriculture is poorly organised, and very few funds are available for machinery, fertilisers and pesticides. Farmland will therefore mostly be acquired by cutting down tropical forests and other natural and quasi-natural ecosystems.