Agro-ecological zone (AEZ): FAO defines and delineates AEZs on the basis of the average annual length of growing period for crops, which depends on, inter alia, precipitation and temperature.
Agroforestry: Any type of multiple-cropping land use that entails complementary relations between tree and agricultural crops and produces some combination of food, fruit, fodder, fuel, wood, mulches or other products.
Available nutrients: The amount of plant nutrient in chemical forms within the soil that is accessible to plant roots, or compounds likely to be convertible to such forms during the growing season.
Biological nitrogen fixation (BNF): The fixation by bacterial cells of atmospheric nitrogen gas into organic compounds useful for life. Nitrogen-fixing bacteria exist in the soil and in association and symbiosis with plants and fungi.
Cation exchange capacity (CEC): A measurement of the ability of a soil to bind positively charged ions (cations), which include many important nutrients (calcium, magnesium and potassium). It depends on the amount and type of clay and on the amount and humification of organic matter in soil.
Compost: Mixed decayed and decaying organic matter which is a useful source of plant nutrients.
Denitrification: Reduction of nitrogen oxides (usually nitrate and nitrite) to molecular nitrogen or nitrogen oxides with a lower oxidation state of nitrogen by bacterial activity (denitrification) or by chemical reactions involving nitrite (chemodenitrification).
Fallow: Arable land not under a rotation of crops that is set aside for 1-5 years before being cultivated again, or land usually under permanent crops, meadows or pastures that is not being used for that purpose for at least one year. It includes arable land normally used for temporary crops but temporarily under grazing.
Farming system: Population of individual farm systems that have broadly similar resource bases, enterprise patterns, household livelihoods and constraints, and for which similar development strategies and interventions would be appropriate. Depending on the scale of the analysis, a farming system can encompass a few dozen or many millions of households.
Fertilizer: Any organic and inorganic material of natural or synthetic origin (other than liming materials) that is added to a soil to supply one or more plant nutrients essential to plant growth.
Food security: A situation that exists where all people at all times have physical, social and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life.
Integrated nutrient management (INM): Judicious manipulation of nutrient stocks and flows in order to arrive at a satisfactory and sustainable level of agricultural production at minimum environmental cost.
Macrolevel: A large scale level that corresponds to the continental or national level.
Manure: The excreta of animals, with or without an admixture of bedding or litter, fresh or at various stages of further decomposition or composting.
Mesolevel: An intermediate scale level that corresponds to the farming-system, region or district level.
Microlevel: A small scale level that corresponds to the village or farm level.
Nutrient balance: The difference between the sums of nutrient inputs and outputs on agricultural land.
Nutrient flow: Flux of nutrients from one unit to another unit. This study defines the principal unit as the soil of agricultural land to the depth of root growth.
Nutrient stocks: Amount of nutrients of a certain unit, e.g. soil or dunghill.
Soil fertility: The quality of a soil that enables it to provide adequate amounts of nutrients in a proper balance for the growth of specified plants or crops.
Soil management: The sum total of all tillage and planting operations, cropping practices, fertilizer, lime, irrigation, herbicide and insecticide application, and other treatments conducted on or applied to a soil for the production of plants.
Sustainable agriculture: Agricultural and agrifood systems that are economically viable and meet society’s need for safe and nutritious food, while conserving or enhancing natural resources and the environment for future generations.
Volatilization: The transformation of non-gaseous substances in a defined system and the loss of such gas from the defined system. For example, the loss of ammonia gas from a nitrogen-fertilized soil.
