Edaphology (from Greek ἔδαφος, edaphos, "ground",-λογία, -logia ) is one of two main divisions of soil science, the other being pedology. Edaphology is concerned with the influence of soils on living things, particularly plants. Edaphology includes the study of how soil influences humankind's use of land for plant growth as well as man's overall use of the land. General subfields within edaphology are agricultural soil science (known by the term agrology in some regions) and environmental soil science. (Pedology deals with pedogenesis, soil morphology, and soil classification.)
The ancient Greek language includes the forms of Greek used in Ancient Greece and the ancient world from around the 9th century BCE to the 6th century CE. It is often roughly divided into the Archaic period, Classical period, and Hellenistic period. It is antedated in the second millennium BCE by Mycenaean Greek and succeeded by Medieval Greek.
-logy is a suffix in the English language, used with words originally adapted from Ancient Greek ending in -λογία (-logia). The earliest English examples were anglicizations of the French -logie, which was in turn inherited from the Latin -logia. The suffix became productive in English from the 18th century, allowing the formation of new terms with no Latin or Greek precedent.
Soil science is the study of soil as a natural resource on the surface of the Earth including soil formation, classification and mapping; physical, chemical, biological, and fertility properties of soils; and these properties in relation to the use and management of soils.
In Russia, edaphology is considered equivalent to pedology, but is recognized to have an applied sense consistent with agrophysics and agrochemistry outside Russia.
Agrophysics is a branch of science bordering on agronomy and physics, whose objects of study are the agroecosystem - the biological objects, biotope and biocoenosis affected by human activity, studied and described using the methods of physical sciences. Using the achievements of the exact sciences to solve major problems in agriculture, agrophysics involves the study of materials and processes occurring in the production and processing of agricultural crops, with particular emphasis on the condition of the environment and the quality of farming materials and food production.
Xenophon (431–355 BC), and Cato (234–149 BC), were early edaphologists. Xenophon noted the beneficial effect of turning a cover crop into the earth. Cato wrote De Agri Cultura ("On Farming") which recommended tillage, crop rotation and the use of legumes in the rotation to build soil nitrogen. He also devised the first soil capability classification for specific crops.
Xenophon of Athens was an ancient Greek philosopher, historian, soldier, mercenary, and student of Socrates. As a soldier, Xenophon became commander of the Ten Thousand at about 30, with noted military historian Theodore Ayrault Dodge saying of him, “the centuries since have devised nothing to surpass the genius of this warrior.” He established the precedent for many logistical operations and was among the first to use flanking maneuvers, feints and attacks in depth. He was among the greatest commanders of antiquity. As a historian, Xenophon is known for recording the history of his time, the late-5th and early-4th centuries BC, in such works as the Hellenica, which covered the final seven years and the aftermath of the Peloponnesian War, thus representing a thematic continuation of Thucydides' History of the Peloponnesian War.
Cato the Elder, born Marcus Porcius Cato and also known as Cato the Censor, Cato the Wise, and Cato the Ancient, was a Roman soldier, senator and historian known for his conservatism and opposition to Hellenization. He was the first to write history in Latin.
De Agri Cultura, written by Cato the Elder, is the oldest surviving work of Latin prose. Alexander Hugh McDonald, in his article for the Oxford Classical Dictionary, dated this essay's composition to about 160 BC and noted that "for all of its lack of form, its details of old custom and superstition, and its archaic tone, it was an up-to-date directed from his own knowledge and experience to the new capitalistic farming." Cato was revered by many later authors for his practical attitudes, his natural stoicism and his tight, lucid prose. He is much quoted by Pliny the Elder, for example, in his Naturalis Historia.
Jan Baptist van Helmont (1577–1644) performed a famous experiment, growing a willow tree in a pot of soil and supplying only rainwater for five years. The weight gained by the tree was greater than the weight loss of the soil. He concluded that the willow was made of water. Although only partly correct, his experiment reignited interest in edaphology.
Jan Baptist van Helmont was a chemist, physiologist, and physician from the Spanish Netherlands. He worked during the years just after Paracelsus and the rise of iatrochemistry, and is sometimes considered to be "the founder of pneumatic chemistry". Van Helmont is remembered today largely for his ideas on spontaneous generation, his 5-year tree experiment, and his introduction of the word "gas" into the vocabulary of science.
Agricultural soil science is the application of soil chemistry, physics, and biology dealing with the production of crops. In terms of soil chemistry, it places particular emphasis on plant nutrients of importance to farming and horticulture, especially with regard to soil fertility and fertilizer components.
Soil chemistry is the study of the chemical characteristics of soil. Soil chemistry is affected by mineral composition, organic matter and environmental factors.
Plant nutrition is the study of the chemical elements and compounds necessary for plant growth, plant metabolism and their external supply. In 1972, Emanuel Epstein defined two criteria for an element to be essential for plant growth:
Horticulture has been defined as the culture of plants, mainly for food, materials, comfort and beauty. According to American horticulturist Liberty Hyde Bailey, "Horticulture is the growing of flowers, fruits and vegetables, and of plants for ornament and fancy." A more precise definition can be given as "The cultivation, processing, and sale of fruits, nuts, vegetables, and ornamental plants as well as many additional services". It also includes plant conservation, landscape restoration, soil management, landscape and garden design, construction and maintenance, and arboriculture. In contrast to agriculture, horticulture does not include large-scale crop production or animal husbandry.
Physical edaphology is strongly associated with crop irrigation and drainage.
Soil physics is the study of soil's physical properties and processes. It is applied to management and prediction under natural and managed ecosystems. Soil physics deals with the dynamics of physical soil components and their phases as solid, liquids, and gases. It draws on the principles of physics, physical chemistry, engineering, and meteorology. It is especially important in this day and age because most farmers require an understanding of agroecosystems. Soil physics applies these principles to address practical problems of agriculture, ecology, and engineering.
Irrigation is the application of controlled amounts of water to plants at needed intervals. Irrigation helps to grow agricultural crops, maintain landscapes, and revegetate disturbed soils in dry areas and during periods of less than average rainfall. Irrigation also has other uses in crop production, including frost protection, suppressing weed growth in grain fields and preventing soil consolidation. In contrast, agriculture that relies only on direct rainfall is referred to as rain-fed or dry land farming.
Drainage is the natural or artificial removal of a surface's water and sub-surface water from an area with excess of water. The internal drainage of most agricultural soils is good enough to prevent severe waterlogging, but many soils need artificial drainage to improve production or to manage water supplies.
Soil husbandry is a strong tradition within agricultural soil science. Beyond preventing soil erosion and degradation in cropland, soil husbandry seeks to sustain the agricultural soil resource though the use of soil conditioners and cover crops.
Environmental soil science studies our interaction with the pedosphere on beyond crop production. Fundamental and applied aspects of the field address vadose zone functions, septic drain field site assessment and function, land treatment of wastewater, stormwater, erosion control, soil contamination with metals and pesticides, remediation of contaminated soils, restoration of wetlands, soil degradation, and environmental nutrient management. It also studies soil in the context of land-use planning, global warming, and acid rain.
Arable land is, according to one definition, land capable of being ploughed and used to grow crops. In Britain, it was traditionally contrasted with pasturable land such as heaths which could be used for sheep-rearing but not farmland.
Crop rotation is the practice of growing a series of dissimilar or different types of crops in the same area in sequenced seasons. It is done so that the soil of farms is not used for only one set of nutrients. It helps in reducing soil erosion and increases soil fertility and crop yield.
Soil retrogression and degradation are two regressive evolution processes associated with the loss of equilibrium of a stable soil. Retrogression is primarily due to soil erosion and corresponds to a phenomenon where succession reverts the land to its natural physical state. Degradation is an evolution, different from natural evolution, related to the local climate and vegetation. It is due to the replacement of primary plant communities by the secondary communities. This replacement modifies the humus composition and amount, and affects the formation of the soil. It is directly related to human activity. Soil degradation may also be viewed as any change or ecological disturbance to the soil perceived to be deleterious or undesirable.
Pedology is the study of soils in their natural environment. It is one of two main branches of soil science, the other being edaphology. Pedology deals with pedogenesis, soil morphology, and soil classification, while edaphology studies the way soils influence plants, fungi, and other living things. The quantitative branch of pedology is called pedometrics.
Agronomy is the science and technology of producing and using plants for food, fuel, fiber, and land reclamation. Agronomy has come to encompass work in the areas of plant genetics, plant physiology, meteorology, and soil science. It is the application of a combination of sciences like biology, chemistry, economics, ecology, earth science, and genetics. Agronomists of today are involved with many issues, including producing food, creating healthier food, managing the environmental impact of agriculture, and extracting energy from plants. Agronomists often specialise in areas such as crop rotation, irrigation and drainage, plant breeding, plant physiology, soil classification, soil fertility, weed control, and insect and pest control.
A renewable resource is a natural resource which will replenish to replace the portion depleted by usage and consumption, either through natural reproduction or other recurring processes in a finite amount of time in a human time scale. Renewable resources are a part of Earth's natural environment and the largest components of its ecosphere. A positive life cycle assessment is a key indicator of a resource's sustainability.
Sustainable agriculture is farming in sustainable ways based on an understanding of ecosystem services, the study of relationships between organisms and their environment. It is a long-term methodological structure that incorporates profit, environmental stewardship, fairness, health, business and familial aspects on a farm setting. It is defined by 3 integral aspects which are: economic profit, environmental stewardship and social responsibility. Sustainability focuses on the business process and practice of a farm in general, rather than a specific agricultural product. The integrated economic, environmental, and social principles are incorporated into a “triple bottom line” (TBL); when the general impacts of the farm are assessed. Unlike a traditional approach where the profit-margin is the single major factor; Agriculture sustainability is also involved with the social and environmental factors.
Agrology is the branch of soil science dealing with the production of crops. The use of the term is most active in Canada. Use of the term outside Canada is sporadic but significant. The term appears especially well established in Russia and China, with agrologists on university faculty lists and agrology curricula.
Soil fertility refers to the ability of soil to sustain agricultural plant growth, i.e. to provide plant habitat and result in sustained and consistent yields of high quality. A fertile soil has the following properties:
Land degradation is a process in which the value of the biophysical environment is affected by a combination of human-induced processes acting upon the land. It is viewed as any change or disturbance to the land perceived to be deleterious or undesirable. Natural hazards are excluded as a cause; however human activities can indirectly affect phenomena such as floods and bush fires.
Agroforestry is a land use management system in which trees or shrubs are grown around or among crops or pastureland. This intentional combination of agriculture and forestry has varied benefits, including increased biodiversity and reduced erosion. Agroforestry practices have been successful in sub-Saharan Africa and in parts of the United States.
Soil conservation is the prevention of soil loss from erosion or prevention of reduced fertility caused by over usage, acidification, salinization or other chemical soil contamination.
In agriculture, tile drainage is a type of drainage system that removes excess water from soil below its surface. Whereas irrigation is the practice of providing additional water to soil when it is naturally too dry, drainage reduces the moisture in soil and thereby increases the amount of air in its pores so as to augment conditions for optimal growth of crops. While surface water can be drained by pumping, open ditches, or both, tile drainage is often the most prudent practice for draining subsurface water.
Agricultural soil science is a branch of soil science that deals with the study of edaphic conditions as they relate to the production of food and fiber. In this context, it is also a constituent of the field of agronomy and is thus also described as soil agronomy.
Soil health is a state of a soil meeting its range of ecosystem functions as appropriate to its environment. Soil health testing is an assessment of this status. Soil health depends on soil biodiversity, and it can be improved via soil conditioning.
Soil biodiversity refers to the relationship of soil to biodiversity and to aspects of the soil that can be managed in relation to biodiversity. Soil biodiversity relates to some catchment management considerations.
The environmental impact of agriculture is the effect that different farming practices have on the ecosystems around them, and how those effects can be traced back to those practices. The environmental impact of agriculture varies based on the wide variety of agricultural practices employed around the world. Ultimately, the environmental impact depends on the production practices of the system used by farmers. The connection between emissions into the environment and the farming system is indirect, as it also depends on other climate variables such as rainfall and temperature.
Soil management is the application of operations, practices, and treatments to protect soil and enhance its performance. It includes soil conservation, soil amendment, and optimal soil health. In agriculture, some amount of soil management is needed both in nonorganic and organic types to prevent agricultural land from becoming poorly productive over decades. Organic farming in particular emphasizes optimal soil management, because it uses soil health as the exclusive or nearly exclusive source of its fertilization and pest control.
Soil compaction, also known as soil structure degradation, is the increase of bulk density or decrease in porosity of soil due to externally or internally applied loads. Compaction can adversely affect nearly all physical, chemical and biological properties and functions of soil. Together with soil erosion, it is regarded as the "costliest and most serious environmental problem caused by conventional agriculture."