The science of soil management and crop production.

Ammoniacal nitrogen is a measure for the amount of ammonia, a toxic pollutant often found in landfill leachate and in waste products, such as sewage, liquid manure and other liquid organic waste products.

NH4+ is the ammonium ion. It has a positive charge and a molecular weight of 18g/mol. NH3-N represents the Nitrogen content of the ammonia, NH4-N is the nitrogen content of the ammonium ion. This is used when people wish to track nitrogen through the treatment process.

The breakdown of animal manure and other organic material in the absence of oxygen, (methane producing bacteria are most active in two temperature ranges, 95 to 105°F and 130 to 135°F. This is a living system and must be treated as such. The organic material is decomposed by acid formers into fatty acids and then into biogas by methane formers or methanogens.

The California Department of Food and Agriculture (CDFA) is responsible for ensuring the state's food safety, the protection of the state's agriculture from invasive species, and promoting the California agricultural industry.

A type of micro-irrigation system that has the potential to save water and nutrients by allowing water to drip slowly to the roots of plants, either from above the soil surface or buried below the surface. The goal is to place water directly into the root zone and minimize evaporation.

Effluent is an outflowing of water or gas to a natural body of water, from a structure such as a wastewater treatment plant, sewer pipe, or industrial outfall.

Engineering, procurement, and construction (EPC) contracts are the most common form of contract used to undertake construction works by the private sector on large-scale and complex infrastructure projects.

Environmental, social, and governance (ESG) criteria are a set of standards for a company’s operations that socially conscious investors use to screen potential investments. Environmental criteria consider how a company performs as a steward of nature. Social criteria examine how it manages relationships with employees, suppliers, customers, and the communities where it operates. Governance deals with a company’s leadership, executive pay, audits, internal controls, and shareholder rights.

In relatively large amounts, the soil supplies nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur; these are often called the macronutrients. In relatively small amounts, the soil supplies iron, manganese, boron, molybdenum, copper, zinc, chlorine, and cobalt, the so-called micronutrients.

 Methane and nitrous oxide are two important greenhouse gases. Important anthropogenic sources of biogenic methane are wet rice fields, cattle, animal waste, landfills and biomass burning. Important anthropogenic sources of biogenic nitrous oxide are land-use change, fertilizer production and use and manure application.

Macronutrients are essential for plant growth and a good overall state of the plant. The primary macronutrients are Nitrogen (N), Phosphorus (P), and Potassium (K). Nitrogen is essential for plant development, since it plays a fundamental role in energy metabolism and protein synthesis.

Microbial respiration is a measure of microbial activity that integrates the effects of microbial biomass accumulation over time, community composition, and environmental factors such as temperature and nutrient availability.

Nitrification is the biological oxidation of ammonia to nitrite followed by the oxidation of the nitrite to nitrate occurring in separate organisms or direct ammonia oxidation to nitrate in comammox bacteria. The transformation of ammonia to nitrite is usually the rate limiting step of nitrification.

NPK stands for "nitrogen, phosphorus, and potassium," the three nutrients that compose complete fertilizers.. Also implied is a percentage symbol after each number because each of the three numbers represents the percentage of that nutrient in the makeup of the fertilizer.

Organic pathogen means any organic irritant or contaminant including, but not limited to, “fungus”, wet or dry rot, bacteria, virus or other microorganisms of any type, and their by-products such as spores or mycotoxins.

A bacterium, virus, or other microorganism that can cause disease.

The interface between terrestrial and aquatic ecosystems. It may also include the areas bordering rivers, other bodies of surface water and adjacent vegetation that can influence both the aquatic system and the terrestrial-aquatic interface.

TKN (Total Kjeldahl Nitrogen) is the total concentration of organic nitrogen and ammonia. Today, TKN is a required parameter for regulatory reporting at many plants but is also used to provide a means of monitoring plant operations.

In agriculture, the yield is a measurement of the amount of a crop grown, or product such as wool, meat or milk produced, per unit area of land. The seed ratio is another way of calculating yields.