Definition: Organic matter in soil which has reached a point of stability, where it will break down no further and might, if conditions do not change, remain essentially as it is for centuries, or millennia.
Definition: A group of hydrous aluminium phyllosilicate (phyllosilicates being a subgroup of silicate minerals) minerals (see clay minerals), that are typically less than 2micrometres in diameter. Clay consists of a variety of phyllosilicate minerals rich in silicon and aluminium oxides and hydroxides which include variable amounts of structural water.
Definition: Oak, mixed deciduous and conifer open forests of warm regions in the cool-temperate nemoral zone of Central and Southern Europe and in the supramediterranean belt of the Mediterranean, Asia Minor and Middle East
Definition: Of plant duration, a plant whose life span extends over more than two growing seasons, c.f. annual, biennial, ephemeral, of flowering with respect to architecture, hapaxanthic, monocarpic, pleonanthic
Definition: Of life span, a plant which lives for more than one but less than two years after germination, c.f. annual, ephemeral, perennial, of flowering with respect to architecture, hapaxanthic, monocarpic, pleonanthic.
Definition: substance or combination of substances that may be administered to human beings (or animals) for treating or preventing disease, or with the intent to make a medical diagnosis or to restore, correct or modify physiological functions.
