Reference
- SoilA mixture of inorganic matter derived from weathered rocks and organic components resulting from decay of prior vegetation. Eight elements are present in the inorganic component in excess of 1% (oxygen, silicon, aluminum, iron, calcium, potassium, magnesium, and sodium), most in the ionized state. Water and air are also present, either in the voids between the particles or adsorbed on their surfaces. Many other elements occur in lower percentages, including trace elements in concentration of less than 1000 ppm. Some of these, e.g., boron (about 20 ppm), are essential for plant nutrition. Both nitrogen and phosphorus are associated with the organic content. The concentration of these is a fraction of 1% of each, but they play a vital part in plant and animal life. The pH of soils varies widely with location; some soils are as low as pH 4.5 (very acid) and others as high as pH 10 (strongly alkaline). For most crops the pH ranges around the neutral point (6.5–7.5). Texturally, soils are classified on the basis of their content of sand, silt, and clay. Those having 45–50% sand and 20–28% clay are called loams, those with more than 50% sand are called sandy, and those with more than 28% clay are in the clay group. Technologists consider soil as being made up of layers, known as horizons, each having a characteristic composition and physical properties; the spectrum of these horizons is called the soil profile. Organic matter is usually excluded from the profile.
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Websites
- Natural Resources Conservation Service SoilsSoils is part of the National Cooperative Soil Survey, an effort of Federal and State agencies, universities, and professional societies to deliver science-based soil information.
- Soil Data AccessSoil Data Access is the name of a suite of web services and applications whose purpose is to meet requirements for requesting and delivering soil survey spatial and tabular data that are not met by the Web Soil Survey and Geospatial Data Gateway websites.
- soilSHOP ToolkitCommunity and urban gardening offer numerous benefits. Some gardens and outdoor play areas may have harmful substances like lead in the soil. The Agency for Toxic Substances and Disease Registry (ATSDR) promotes health education and outreach events called “soilSHOPs” to help people learn if their soil is contaminated with lead, and how to reduce exposures to contaminated soil and produce. The name soilSHOP stands for Soil Screening, Health, Outreach and Partnership. ATSDR developed this toolkit to help communities and other groups plan their own soilSHOP events.
Streaming Media
- Living Soils: Bacteria and FungiJust as humans cannot grow without our supportive microbiome, neither can plants. Plant roots, bacterial sheathes, and long filaments of fungus all function together to support the plant's growth, enhancing the uptake of water and nutrients and improving soil structure. But what happens to this crucial symbiosis when you add unnecessary fertilizers?
- Soil Analysis: What Makes Soil Great?Unless you live in a completely undeveloped area, chances are your home garden soil is not native. Learn what makes a "great" soil and how to determine your own approximate amounts of clay, silt, and sand; texture; nutrients; pH; and more - before you purchase that "must have" soil addition from the gardening store.
- Soil Preparation and ProtectionDon't plant before you fertilize! Chances are you've heard that admonishment more than once. But gardening science has revealed that many popular practices - including fertilizing every time you plant - are neither necessary nor sustainable. Learn about a more natural way to add organic material to your garden to protect soil structure and nourish your plants.
Perspectives
Soil Microbiology and Sustainable Crop Production
Soils into which crop plants root and from which they obtain essential minerals and water contain huge arrays of microbes. Many have highly beneficial effects on crop growth and productivity, others are pathogens causing diseases and losses to yield and quality, a few microbes offer protection from these pathogenic forms and others have little or no effect. These intimate and often complex inter-relationships are being explored with increasing success providing exciting opportunities for increasing crop yields and quality in sustainable harmony with the populations of beneficial soil microbes and to the detriment of pathogens. This book explores current knowledge for each of these aspects of soil microbiology and indicates where future progress is most likely to aid in increasing crop productivity by means which are environmentally benign and beneficial.
Soil Biology and Agriculture in the Tropics
The relationships between soils, microbes and humans are of crucial relevance in the tropics, where plant stress and microbial activity are exacerbated. This volume of Soil Biology presents the living component of tropical soils, showing how it is shaped by environmental conditions and emphasizing its dramatic impact on human survival and well-being. Following an introduction to the specificities of tropical soils and of their microbial communities, the biological aspects of soil management are examined, dealing with land use change, conservation and slash-and-burn agriculture, the restoration of hot deserts, agroforestry and paddy rice cultivation. As they are of particular relevance for tropical agriculture, symbioses of plants and microbes are thoroughly covered, as are the biodegradation of pesticides and health risks associated with wastewater irrigation. Lastly, traditional soil knowledge is discussed as a key to our sustainable presence in this world.
Soil Health and Climate Change
"Soil Health and Climate Change" presents a comprehensive overview of the concept of soil health, including the significance of key soil attributes and management of soil health in conventional and emerging land use systems in the context of climate change. Starting with a review of the physical, chemical and biological indicators of soil health and their significance for monitoring the impacts of climate change, this book then focuses on describing the role of soil structure, pH, organic matter, nitrogen, respiration and biota in sustaining the basic functions of soil ecosystems, and their anticipated responses to climate change. Further topics include the management of cropping, pastoral, and forestry systems, and rehabilitated mine sites, with a focus on mitigation of and adaptation to climate change impacts. Finally, the opportunities and potential risks of organic farming, biochar and bioenergy systems, and their ability to sustain and even enhance soil health, are discussed.
Soil and Culture
SOIL: beneath our feet / food and fiber / ashes to ashes, dust to dust / dirt!Soil has been called the final frontier of environmental research. The critical role of soil in biogeochemical processes is tied to its properties and place--porous, structured, and spatially variable, it serves as a conduit, buffer, and transformer of water, solutes and gases. Yet what is complex, life-giving, and sacred to some, is ordinary, even ugly, to others. This is the enigma that is soil. Soil and Culture explores the perception of soil in ancient, traditional, and modern societies. It looks at the visual arts (painting, textiles, sculpture, architecture, film, comics and stamps), prose & poetry, religion, philosophy, anthropology, archaeology, wine production, health & diet, and disease & warfare. Soil and Culture explores high culture and popular culture--from the paintings of Hieronymus Bosch to the films of Steve McQueen. It looks at ancient societies and contemporary artists. Contributors from a variety of disciplines delve into the mind of Carl Jung and the bellies of soil eaters, and explore Chinese paintings, African mud cloths, Mayan rituals, Japanese films, French comic strips, and Russian poetry.
Life in the Soil
Leonardo da Vinci once mused that "we know more about the movement of celestial bodies than about the soil underfoot," an observation that is as apt today as it was five hundred years ago. The biological world under our toes is often unexplored and unappreciated, yet it teems with life. In one square meter of earth, there lives trillions of bacteria, millions of nematodes, hundreds of thousands of mites, thousands of insects and worms, and hundreds of snails and slugs. But because of their location and size, many of these creatures are as unfamiliar and bizarre to us as anything found at the bottom of the ocean. Lavishly illustrated with nearly three hundred color illustrations and masterfully-rendered black and white drawings throughout, Life in the Soil invites naturalists and gardeners alike to dig in and discover the diverse community of creatures living in the dirt below us. Biologist and acclaimed natural history artist James B. Nardibegins with an introduction to soil ecosystems, revealing the unseen labors of underground organisms maintaining the rich fertility of the earth as they recycle nutrients between the living and mineral worlds. He then introduces readers to a dazzling array of creatures: wolf spiders with glowing red eyes, snails with 120 rows of teeth, and 10,000-year-old fungi, among others. Organized by taxon, Life in the Soil covers everything from slime molds and roundworms to woodlice and dung beetles, as well as vertebrates from salamanders to shrews. The book ultimately explores the crucial role of soil ecosystems in conserving the worlds above and below ground. A unique and illustrative introduction to the many unheralded creatures that inhabit our soils and shape our environment aboveground, Life in the Soil will inform and enrich the naturalist in all of us.