![]() ![]() An ideal soil has a bulk density of about 1.25 g cm -3. A high BR generally indicates higher soil microbial activity, however, not biological efficiency.īulk Density (ρ b): The mass (weight) of unit soil divided by the total volume occupied. Soil respiration is a direct and sensitive assessment of soil antecedent biological activity. conventionally tilled) soils because they are generalist feeders that prefer aerobic (oxygenated) conditions, and survive in small soil pore spaces (micropores).īasal Respiration (BR): Respiration, or oxygen used, by soil microbes to decompose organic matter or any crop residues as a food and energy source and released as carbon dioxide into the soil atmosphere. Bacteria are active in the soil for decomposing organic matter, recycling nutrients, and detoxification of contaminants. Bacteria are important for functioning of biochemical properties and/or processes. Typically a few micrometers in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals. Anaerobesis of soil is also responsible for widespread soil-borne diseases.īacteria: A large group of single-celled microorganisms lacking chlorophyll and are prokaryotic (lacking a nucleus). Soils that are heavy textured (clay), compacted, wet or flooded tend to be anaerobic because they have less oxygenated air to carry out oxidative reactions. Carbon dioxide and N2O are greenhouse gases that are normally present in the atmosphere, but at higher levels may contribute to global warming.Īnaerobic: Absence of oxygen or growing in the absence of oxygen. These pollutants can harm field crops, public health, birds and other animals, and the environment, and cause property damage. N2O), radon, and emitted heavy metal dusts. ![]() The common air pollutants are ground-level ozone, carbon monoxide, sulfur dioxide, nitrogen oxide (e.g. Soil aggregates are usually greater than ten millimeters in diameter and formed by natural forces (such as alternate wetting-drying) and organic substances derived from root exudates, roots, soil animals and microbial by-products which cement primary particles into smaller aggregates or smaller aggregates into larger particles, such as macroaggregates.Ī ir Quality: Defined as a measure of the amount or concentration of pollutants emitted into the atmosphere and the dispersion potential of an area to dilute those pollutants. Aerobic soils have plenty of oxygenated air to carry out oxidative reactions, such as soil organic matter decomposition and nutrient cycling.Īggregates: Primary soil particles (sand, silt, and clay) held together in a single mass or cluster, such as a crumb, block, prism or clod using organic matter as cementing material. ![]() Active carbon would include simple polysaccharides and glucose equivalent reduced sugars, amino acids and proteins, soluble and extractable carbon, and microbial biomass carbon, etc.Īerobic: Aerobic means in the presence of oxygen or growing in the presence of oxygen. The half-life of active carbon ranges from a few days to a few years. These soil microorganisms generally resemble fungi and have branched mycelium.Īctive Carbon (AC): The portion of total soil organic carbon (matter) that is relatively easily metabolized or utilized by microorganisms. The terms are listed in alphabetical order.Īctinomycetes: A large group of rod-shaped or filamentous bacterium that includes some that cause diseases and some that are the sources of antibiotics. The terms below are used to describe these biologically efficient and economically viable agricultural production systems. One of the goals of sustainable agriculture is to work with the natural cycles of the terrestrial ecosystems, especially with the soil biology to enhance the efficiency of agricultural management practices. With higher costs for labor, seed, fuel, fertilizer, and pesticides, agricultural producers are looking for more economical ways to improve crop production and maintain ecosystem sustainability. Sustainable agriculture and soil quality are terms that are increasingly important to modern farming. Understanding the terms defined in this fact sheet will help farmers understand relationships between tillage, crop rotation, cover crops, carbon sequestration, organic matter pool, agricultural sustainability, and soil and water quality. New concepts and terminology are being used to describe these changes. The increasing use of conservation tillage, no-till, and cover crops is changing the way we view the soil and the environment. ![]()
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