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Pedotransfer Function
In soil science, pedotransfer functions (PTF) are predictive functions of certain soil properties using data from soil surveys. The term ''pedotransfer function'' was coined by Johan Bouma as ''translating data we have into what we need''. The most readily available data comes from a soil survey, such as the field morphology, soil texture, structure and pH. Pedotransfer functions add value to this basic information by translating them into estimates of other more laborious and expensively determined soil properties. These functions fill the gap between the available soil data and the properties which are more useful or required for a particular model or quality assessment. Pedotransfer functions utilize various regression analysis and data mining techniques to extract rules associating basic soil properties with more difficult to measure properties. Although not formally recognized and named until 1989, the concept of the pedotransfer function has long been applied to estimate so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Science
Soil science is the study of soil as a natural resource on the surface of the Earth including soil formation, soil classification, classification and Soil survey, mapping; Soil physics, physical, Soil chemistry, chemical, Soil biology, biological, and fertility properties of soils; and these properties in relation to the use and Soil management, management of soils.Jackson, J. A. (1997). Glossary of Geology (4. ed.). Alexandria, Virginia: American Geological Institute. p 604. The main branches of soil science are ''pedology'' ― the study of formation, chemistry, morphology, and classification of soil ― and ''edaphology'' ― the study of how soils interact with living things, especially plants. Sometimes terms which refer to those branches are used as if synonymous with soil science. The diversity of names associated with this discipline is related to the various associations concerned. Indeed, engineers, agronomy, agronomists, chemists, geologists, physical geography, phys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field Capacity
Field capacity is the amount of soil moisture or water content held in the soil after excess water has drained away and the rate of downward movement has decreased. This usually occurs two to three days after rain or irrigation in pervious soils of uniform structure and texture. The nominal definition of field capacity (expressed symbolically as θfc) is the bulk water content retained in soil at −33 kPa (or −0.33 bar) of hydraulic head or suction pressure. The term originated from Israelsen and West and Frank Veihmeyer and Arthur Hendrickson. Veihmeyer and Hendrickson realized the limitation in this measurement and commented that it is ''affected by so many factors that, precisely, it is not a constant'' (for a particular soil), ''yet it does serve as a practical measure of soil water-holding capacity''. Field capacity improves on the concept of moisture equivalent by Lyman Briggs. Veihmeyer & Hendrickson proposed this concept as an attempt to improve water-use efficiency f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Functions
Soil functions are general capabilities of soils that are important for various agricultural, environmental, nature protection, landscape architecture and urban applications. Soil can perform many functions and these include functions related to the natural ecosystems, agricultural productivity, environmental quality, source of raw material, and as base for buildings. Six key soil functions are: #Food and other biomass production #Environmental Interaction #Biological habitat and gene pool #Source of raw materials #Physical and cultural heritage #Platform for man-made structures Food and other biomass production Soil acts as an anchor for plant roots. It provides a hospitable place for a plant to live in while storing and supplying nutrients to plants. Soil also functions by maintaining the quantity and quality of air by allowing to escape and fresh to enter the root zone. Pore spaces within soil can also absorb water and hold it until plant roots need it. The soil also mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nonlimiting Water Range
The non-limiting water range (NLWR) represents the range of water content in the soil where limitations to plant growth (such as water potential, air-filled porosity, or soil strength) are minimal. John Letey (1985) from UC Riverside introduced the NLWR concept in an attempt to integrate several physical properties associated with plant or root growth to refine the concept of available water capacity. Alvaro Pires da Silva, Bev Kay, and Ed Perfect (University of Guelph, Ontario) (1994) refined the concept and termed it ''least limiting water range'' (LLWR). The upper limit (wet end) of LLWR is determined not only by water content at field capacity (FC), but also the capability of providing adequate aeration for plant roots (usually taken as a minimum air filled porosity of 10%). The upper limit is then defined as: min q . Rather than air-filled porosity at 10%, LaoSheng Wu from UC Riverside proposed moisture content where Oxygen gas diffusion rate ODR value of 0.2 micro-g/cm2/m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moisture Equivalent
Moisture equivalent is proposed by Lyman Briggs and McLane (1910) as a measure of field capacity for fine-textured soil materials. Moisture equivalent is defined as ''the percentage of water which a soil can retain in opposition to a centrifugal force 1000 times that of gravity''. It is measured by saturating sample of soil 1 cm thick, and subjecting it to a centrifugal force of 1000 times gravity for 30 min. The gravimetric water content after this treatment is its moisture equivalent. This concept is no longer used in soil physics and has been replaced by field capacity. Lyman Briggs and Homer LeRoy Shantz (1912) found that: Moisture Equivalent = 0.02 sand + 0.22 silt + 1.05 clay Note: The volume of water stored in the root zone is equal to the depth of water in the root zone (Vw=Dw) See also * Available water capacity * Field capacity * Nonlimiting water range * Pedotransfer function * Permanent wilting point Permanent wilting point (PWP) or wilting point (WP) is de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Inference System
Inference is a process of deriving logical conclusion from the basis of empirical evidence and prior knowledge rather than on the basis of direct observation. Soil inference system (SINFERS) is the term proposed by McBratney et al. (2002) as a knowledge base to infer soil properties and populate the digital soil databases. SINFERS takes measurements with a given level of certainty and infers data that is not known with minimal uncertainties by means of logically linked predictive functions. These predictive functions, in a non-spatial context are referred to as pedotransfer functions. The basic assumption underlying SINFERS is that if one knows or is able to predict the basic fundamental properties of a soil, one should be able to infer all other physical and chemical properties using PTFs. Pedotransfer functions relate basic soil properties to other more difficult or expensive to measure soil properties by means of regression and various data mining tools. Crucial to the operation o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Neural Network
In machine learning, a neural network (also artificial neural network or neural net, abbreviated ANN or NN) is a computational model inspired by the structure and functions of biological neural networks. A neural network consists of connected units or nodes called '' artificial neurons'', which loosely model the neurons in the brain. Artificial neuron models that mimic biological neurons more closely have also been recently investigated and shown to significantly improve performance. These are connected by ''edges'', which model the synapses in the brain. Each artificial neuron receives signals from connected neurons, then processes them and sends a signal to other connected neurons. The "signal" is a real number, and the output of each neuron is computed by some non-linear function of the sum of its inputs, called the '' activation function''. The strength of the signal at each connection is determined by a ''weight'', which adjusts during the learning process. Typically, ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Agriculture
The United States Department of Agriculture (USDA) is an executive department of the United States federal government that aims to meet the needs of commercial farming and livestock food production, promotes agricultural trade and production, works to assure food safety, protects natural resources, fosters rural communities and works to end hunger in the United States and internationally. It is headed by the secretary of agriculture, who reports directly to the president of the United States and is a member of the president's Cabinet. The current secretary is Brooke Rollins, who has served since February 13, 2025. Approximately 71% of the USDA's $213 billion budget goes towards nutrition assistance programs administered by the Food and Nutrition Service (FNS). The largest component of the FNS budget is the Supplemental Nutrition Assistance Program (formerly known as the 'Food Stamp' program), which is the cornerstone of USDA's nutrition assistance. The United Stat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Texture Classification
Soil texture is a classification instrument used both in the field and laboratory to determine soil classes based on their physical texture. Soil texture can be determined using qualitative methods such as texture by feel, and quantitative methods such as the hydrometer method based on Stokes' law. Soil texture has agricultural applications such as determining crop suitability and to predict the response of the soil to environmental and management conditions such as drought or calcium (lime) requirements. Soil texture focuses on the particles that are less than two millimeters in diameter which include sand, silt, and clay. The USDA soil taxonomy and WRB soil classification systems use 12 textural classes whereas the UK-ADAS system uses 11. These classifications are based on the percentages of sand, silt, and clay in the soil. History The first classification, the international system, was first proposed by Albert Atterberg in 1905 and was based on his studies in southern Swed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Soil Organic Matter
Soil organic matter (SOM) is the organic matter component of soil, consisting of plant and animal detritus at various stages of decomposition, cells and tissues of soil microbes, and substances that soil microbes synthesize. SOM provides numerous benefits to soil's physical and chemical properties and its capacity to provide regulatory ecosystem services. SOM is especially critical for soil functions and quality. The benefits of SOM result from several complex, interactive, edaphic factors; a non-exhaustive list of these benefits to soil function includes improvement of soil structure, aggregation, water retention, soil biodiversity, absorption and retention of pollutants, buffering capacity, and the cycling and storage of plant nutrients. SOM increases soil fertility by providing cation exchange sites and being a reserve of plant nutrients, especially nitrogen (N), phosphorus (P), and sulfur (S), along with micronutrients, which the mineralization of SOM slowly rele ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Available Water Capacity
Available water capacity is the amount of water that can be stored in a soil profile and be available for growing crops. It is also known as available water content (AWC), profile available water (PAW) or total available water (TAW). The concept, put forward by Frank Veihmeyer and Arthur Hendrickson, assumed that the water readily available to plants is the difference between the soil water content at field capacity () and permanent wilting point (): :θa ≡ θfc − θpwp Daniel Hillel criticised that the terms FC and PWP were never clearly defined, and lack physical basis, and that soil water is never equally available within this range. He further suggested that a useful concept should concurrently consider the properties of plant, soil and meteorological conditions. Lorenzo A. Richards remarked that the concept of availability is oversimplified. He viewed that: the term availability involves two notions: (a) the ability of plant root to absorb and use the water with whi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulk Density
In materials science, bulk density, also called apparent density, is a material property defined as the mass of the many particles of the material divided by the bulk volume. Bulk volume is defined as the total volume the particles occupy, including particle's own volume, inter-particle void volume, and the particles' internal pore volume. Bulk density is useful for materials such as powders, granules, and other "divided" solids, especially used in reference to mineral components (soil, gravel), chemical substances, pharmaceutical ingredients, foodstuff, or any other masses of corpuscular or particulate matter ( particles). Bulk density is not the same as the ''particle density'', which is an intrinsic property of the solid and does not include the volume for voids between particles (see: density of non-compact materials). Bulk density is an extrinsic property of a material; it can change depending on how the material is handled. For example, a powder poured into a c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
