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Glossary for agroforestry

Compiled and edited by Peter Huxley and Helen van Houten, International Centre for Research in Agroforestry - 1997

C3 plant

    A plant in which the first product of carbon fixation is the 3-carbon compound phosphoglyceric acid. This plant group includes many dicotyledons and all woody perennial trees. C3 plants show observable photorespiration, but they are not necessarily less productive than C 4 plants. The sunflower (Helianthus annuus) is an example of a C 3 plant.

C4 plant

    A plant in which the first product of CO2 fixation is the 4-carbon compound oxaloacetic acid. C4 plants include many tropical grasses, corn, sugarcane and some weed species. Some genera, for example, Atriplex, include both C3 and C4 plants. C4 plants often show high rates of assimilation when incoming radiation is high and saturation deficits are low and thus may grow better than C3 plants in subtropical regions. C4 plants do not show observable photorespiration. See also carbon assimilation

calcareous soil

    Soil containing sufficient CaCO3, often with MgCO3, to effervesce visibly when treated with cold dilute HCl.

callus

    In a cell culture, a mass of thin-walled undifferentiated cells, developed as a result of wounding or culture on nutrient media.

calorie

    The traditional unit of measurement for content of food energy and for daily energy requirement. When used in terms of Pcal% (protein calories percentage) and Fcal% (fat calories percentage), cereal calories percentage, or sugar calories percentage, it implies the proportion of the daily total calories coming from these dietary components. See also digestible energy

calorific value

    Strictly, the heat released from a substance in total combustion. Measured in kcal-1 or Mcal kj–1 (1 calorie = 4.187 joules); 1 tonne of air-dry wood provides approximately 15 GJ, but individual tree species vary in calorific value. See also metabolizable energy

CAM plant

    A plant (usually succulent and growing in arid climates) with 'crassulacean acid metabolism'. Carbon dioxide is fixed by the enzyme PEP into malic acid at night, and during the day when the stomata are closed to conserve water, it is released and refixed through the normal photosynthetic carbon reduction (C3) cycle.

cambium

    A lateral meristem in a shoot.

canonical analysis

    A numerical technique for ordination of data sets involving the study of correlation between sets of attributes. Also called 'canonical correlation analysis'. See also multivariate analysis

canonical coordinate analysis

    A form of canonical analysis in which data sets are separately mapped using principal coordinate analysis and the resulting 'gower vectors' are canonically analysed.

canopy

    The assemblage or volume of leaves of all ages supported by branched stems that form the photosynthetic layers of a tree or crop. See also crown, stratified

carbon assimilation

    Carbon dioxide assimilation. In C3 (Calvin cycle) plants, carbon reduction starts with the carboxylation of ribulose biphosphate (Rubisco) and with a first product (phosphoglyceric acid) being reduced to a 3-carbon sugar. In C4 plants, CO2 is assimilated into the 4-carbon oxaloacetic acid by the enzyme PEP carboxylase, decarboxylation takes place and the liberated CO2 is refixed through the normal Calvin cycle in bundle sheath chloroplasts. Succulents have a malate-based CAM cycle.

carbon fixation

    See carbon assimilation

carbon nitrogen ratio

    Ratio of weight of organic C to weight of total N in soil or in organic matter. Obtained by dividing the percentage of organic C by the percentage of total N.

carrier

    The liquid or solid material added as a diluent to a chemical to facilitate its application.

carrying capacity

    1. Amount of animal life, human life or industry that can be supported indefinitely with available resources on a given area.

    2. In wildlife management, the optimum population density that a given environment or range is capable of sustaining permanently.

case study

    An example of a research problem, usually described by a representative unit of the population. The data presented in a case study result from collecting primary and secondary data. Thus a case study is a second-order abstraction that integrates data sets to demonstrate relationships among multiple factors that may be generalized to the research problem.

cash cropping

    Growing crops for sale either to a market or to agents, or at the 'farm gate'. See also subsistence farming

catch crop

    1. An alternate crop planted after the regular crop has failed or when other circumstances make its success doubtful; usually a short-season crop.

    2. A crop produced incidental to the main crop of the farm and usually occupying the land for a short period; also a crop grown to replace a main crop that has failed.

catchment area

    The land surface on which rain falls. Sometimes called a 'water catchment'. When referring to particular streams or rivers, it is the land surface from which water (rain) flows into them, sometimes through tributaries (feeder streams).

catchment basin

    See watershed

catena

    1. A sequence of soils of similar age, derived from similar parent material and under similar climate but with different characteristics because of relief and natural drainage. A soil catena is generally observed for a single slope from crest to valley base. See also toposequence

    2. A topographical unit used to describe a commonly occurring sequence of soil types in close spatial association ('to be connected like the links of a chain').

cation

    A positively charged ion. See also anion

cation adsorption capacity

    See cation exchange capacity

cation exchange capacity

    1. The number of negatively charged sites in a soil that can react with, and hold, cations. It is high for clays and humus and low for sand.

    2. The total amount of exchangeable cations that a soil can adsorb; also called 'total exchange capacity', 'base exchange capacity', and 'cation-adsorption capacity'. It is expressed in milli-equivalents per 100 g of soil or other adsorbing material such as clay. Determined values depend somewhat upon the method employed.

caulescent

    More or less stemmed or stem bearing, having an evident stem above ground.

cauliflory

    Production of flowers on the large branches and trunk.

cereal crop

    A member of the monocot grass family grown for its edible seed, for example, wheat, oats, barley, rye, rice, maize, grain sorghum and millet. Buckwheat, although a dicot and therefore not a member of the grass family, is commonly included among the cereals.

certified seed

    1. Seed from plants of proven genetic superiority produced to assure genetic identity, as defined and attested by a recognized certifying agency (syn:'elite seed'). Compare selected seed and source-identified seed. See also foundation seed

    2. Seed used for commercial crop production produced from foundation or registered seed, or seed that has been certified under the regulation of a legally constituted agency.

chaff

    The glumes, lemmas, paleas and lighter plant tissue fragments released in threshing.

chamaephyte

    A self-supporting woody plant or herbaceous evergreen perennial whose mature branch or shoot system remains perennially within 25–50 cm above ground level, or a plant that grows taller but whose shoots die back periodically to that height limit.

chemotaxonomy

    The classification of plants on the basis of the presence and concentration of certain specific chemical compounds in them.

chemotropism

    The growth (movement) of a plant organ in response to an external chemical stimulus (for example, pollen tube growth down a style).

chernozem

    A group of soils with a thick, nearly black, organic-rich A horizon, high in exchangeable calcium, underlain by a lighter coloured transitional horizon that is above the zone of calcium carbonate accumulation. It occurs mainly in cool humid climates under tall grass.

chestnut soils

    A group of soils with a moderately thick, dark brown A horizon over a lighter coloured horizon.

chilling requirement

    The requirement of many temperate crop plants, commonly fruit trees, for specific periods of cool temperatures needed to cause the plants to break dormancy and initiate floral development. See vernalization

chimera

    A plant composed of two or more genetically different tissues. Includes 'periclinal chimera', in which one tissue lies over another as a glove fits a hand, and 'sectorial chimera', in which the tissues lie side by side. Also spelled 'chimaera'.

chitted seed

    1. A general term for pre-germinated seeds.

    2. A method of storing and dispatching seed of short viability (such as Quercus and Castanopsis spp). The acorns or chestnuts are placed in trays between layers of leaf litter or peat moss and kept moist.

chlorosis

    1. Pathological condition of a plant caused by a deficiency of chlorophyll, shown by yellowing.

    2. A condition in which the leaves are yellow and small and plant growth and vigour decline.

C horizon

    A mineral horizon generally beneath the soil solum that is relatively unaffected by biological activity and pedogenesis and is lacking properties diagnostic of an A horizon or a B horizon. See also soil horizon

chromosome

    A small, elongated, deeply staining body found within the nucleus, consisting primarily of DNA and a protein sheath, and containing the genes or factors responsible for most hereditary traits.

cladode

    A flat stem looking like a leaf and photosynthetic, for example, as found in Australian acacias (syn: phyllode).

classification

    1. The ordering of a data set or data sets so as to define the nature of the classes and the methods of search to be used to recover data; a pattern- seeking method. See also pattern analysis

    2. A specified arrangement of related objects; in biology, ideally based on natural relationships.

clay

    A mineral soil separate consisting of particles < 0.002 mm diameter.

clay pan

    A horizon of accumulation of a stratum of dense, compact and relatively impervious clay. A clay pan is not cemented but is hard when dry and plastic or stiff when wet. Its presence, like that of a true hardpan, may interfere with water movement or root development.

clay soil

    A soil textural class. In engineering, a fine-grained soil with a high plasticity index.

clear cutting

    1. Strictly, the removal of an entire standing crop of trees. In practice, may refer to exploitation that leaves much unsaleable material standing. Also termed 'clear felling'.

    2. An area from which the entire timber stand has been cut. Removal of the entire stand in one cut. Reproduction is then obtained with or without planting or artificial seeding.

clearing

    [noun] A relatively small area within a forest that has no trees.

    [verb] To dispose of undergrowth and vegetational debris (slash) that is left after trees have been felled and trimmed. Sometimes done by a burn. Clearing is also done by removal or controlled burning around forests, villages, homes or trees to act as a firebreak.

cleistogamy

    Self-pollination within a flower, usually the result of a closed flower.

climax

    The final stage of succession that continues to occupy an area as long as climate and soil conditions remain unchanged. A plant community that has reached a relatively stable condition in which it is able to reproduce itself indefinitely and under existing conditions. A mature plant community. See also plant succession

climax species

    See shade-bearing trees

cline

    1. A geographic gradient exhibited by plants usually assumed to be genetically controlled.

    2. Continuous character variations (genetically based) that are related to environmental gradients. However, the term cline is not a taxonomic category.

clod

    1. A mass of soil produced by disturbance.

    2. A compact coherent mass of soil, 5–250 mm diameter. Often produced artificially by ploughing when soils are too wet or too dry for tillage.

clone

    1. All parts (ramets) regenerated asexually from a common ancestor (ortet) and having identical genotypes. Named clones are given non-Latin names preceded by the abbreviation 'cl'.

    2. A group of organisms descended by mitosis (the division of vegetative cells) from a common ancestor.

    3. A group of individual plants derived from a single stem by agamic (non-sexual) propagation. See also preclone

    4. A group of genetically identical plants produced asexually from a single individual, the ortet.

closed community

    A plant community whose components are so completely utilizing the site as to exclude further entrants. An 'open community' is therefore one not so excluding further entrants. See also community

closed forest

    Forest where trees are the dominant life form and the canopy is closed.

closed system

    A system that does not exchange matter with the surroundings (but may exchange energy with the surroundings).

clump

    The aggregate of stems issuing from the same root, rhizome system or stool, with particular reference to bamboos and the larger grasses. See also woody clump

clumpwood

    A plant community dominated by woody clumps.

clustering

    The process of classifying data points into groups, often done hierarchically so that small groups area djoined to form larger ones.

C : N ratio

    See carbon nitrogen ratio

coarse fragment

    A rock or mineral particle > 2 mm in diameter. Fragment names are dependent on size, shape and material. Group includes chert, cobblestones, stones.

codominant trees

    Trees with crowns forming the general level of the crown cover and receiving full light from above but comparatively little from the sides, usually with medium-sized crowns and more or less crowded on the sides.

cohesion

    'Holding together'. The force holding a solid or liquid together by attraction of similar molecules. for example, a 'cohesive soil'.

coincident cropping

    A cropping sequence in which two or more species with similar crop duration are grown together on the same unit of land.

collar

    The transition zone between stem and root, sometimes recognizable in trees and seedlings by the presence of a slight swelling.

colloid

    A substance that, when apparently dissolved in water, does not diffuse (or, if it does, diffuses only very slowly) through a semi-permeable membrane. It has little or no effect on freezing point, boiling point or the osmotic pressure of the solution.

colluvial soil

    Soil material that has moved downhill and accumulated on lower slopes and at the bottom of the hill. Colluvial material is moved downhill by the force of gravity and to some extent by soil creep, frost action and local wash (syn: colluvium).

colluvium

    1. A heterogeneous mixture of material that, as a result of gravitational action, has moved down a slope and settled at its base.

    2. Soil materials with or without rock fragments that accumulate at the base of steep slopes by gravitational action.

combining ability

    1. General combining ability is the average performance of a strain in a series of crosses. Specific combining ability is the deviation from performance predicted on the basis of general combining ability.

    2. The relative ability of an organism to transmit genetic superiority to its offspring.

commensalism

    1. 'Eating at the same table'. In biology, applied to animals or plants that live as tenants of others and share their food. See also symbiotic

    2. A relationship between two living beings, A and B, where B has a positive effect on A and A no effect on B, for example, a support tree for a climbing vine.

community

    1. Any assembly of organisms living together in a common area, no particular ecological status being implied; also closed community and 'open community'. See also biocoenosis

    2. A group of plants growing together (syn: stand), or all of the plants and animals of an area (syn: ecosystem).

community forestry

    Forestry developed in areas marginal to agriculture, with many members of the community being landless or small-scale farmers, often characterized by ecological and cultural diversity and the employment of traditional technologies. Communal land development is basic to this type of forestry. See also social forestry

companion crop

    A crop that is grown with another crop. Usually applied to small grain crops with which forage crops are sown. The small grain crop may also be known as a 'nurse crop', but companion crop is the term prefered by agronomists. It may also apply to others such as maize and soybeans when grown together.

compartment

    1. The basic territorial unit of a forest estate, permanently defined for purposes of location, description and record, and as a basis for forest management. Commonly a subdivision of a block. There is also a subcompartment, which is a temporary subdivision.

    2. An area of woodland delineated on a map, and by features on the ground, which forms a convenient division of a forest for managing it.

competition

    Used to refer to the processes, and also sometimes the outcome, of direct interactions between proximal plants (for example, allelopathy) or, more commonly, indirect interactions over a resource that must be shared or because of a shared enemy (pest). See also interference

complementarity

    In intercropping, a net positive outcome for a crop mixture of the interactions such as competition and facilitation, that occur between plant components growing simultaneously (spatial complementarity) or a mixture whose components, growing at different times, improve the capture of environmental reosurces (temporal compelenmtarity)

component

    An identifiable unit within a system. It may be capable of independent physical existence or may be an entirely conceptual entity.

component technology

    The cultural techniques used in the management of a crop or cropping pattern. Component technology includes variety, planting methods, tillage operations, fertilizer and water management, pest management, harvesting.

composite

    A mechanical mixture of strains bred and selected to provide a suitable range of genotypes giving a similar product but possessing a broader set of characteristics (for example, adaptability, disease resistance) than would otherwise be the case.

compost

    1. In plant nursery work, a mixture of inorganic and organic materials, perhaps with some soil of a particular suitable kind, in which seeds can be readily germinated or seedlings or young plants grown. Particular composts are made for particular purposes, and fertilizers are often added. See also synthetic variety

    2. A pile of decomposing organic matter of plant or animal origin. Soil and other amendments such as lime, nitrogen and phosphorus may be mixed with the organic matter.

    3. Organic residues, or a mixture of organic residues and soil that have been made into a pile and allowed to undergo biological decomposition.

compound bud

    A bud containing both vegetative and floral primordia; also called a 'mixed bud', as distinct from a simple bud.

compound land utilization type

    A land utilization type consisting of more than one kind of use or purpose, either undertaken in regular succession on the same land, or simultaneously undertaken on separate areas that are treated as a single unit for evaluation.

concomitant cropping

    A cropping sequence where two or more species, one of which has a shorter crop duration than the other(s), are grown together on the same unit of land.

concretion

    1. For soil, a local mass of solid particles of a chemical compound such as CaCO2 or iron oxides, in the form of aggregates or nodules of various sizes, shapes and colours.

    2. Small, hard, local concentration of material such as calcite, gypsum, iron oxide or aluminium oxide. Usually spherical or subspherical, but may be irregular in shape.

confounding

    In the statistical sense, when the differences arising from a treatment cannot be distinguished from some other source of variation.

conifers

    Trees that usually but not always have needle leaves or scale leaves and that bear separate male and female cones. They are usually, but not always, evergreen. Some, for example, larch, are deciduous. Conifers belong to the class Gymnospermae.

conservation

    The protection, use and improvement of natural resources according to principles that will assure their highest economic and social benefits.

constraint

    1. A requirement that a system must satisfy if outputs are to be maximized, or, in human terms, optimized.

    2. Exogenous factors limiting system performance that are situated at suprasystem level.

contact herbicide

    A herbicide that affects only that part of the plant with which it comes into contact, as opposed to a systemic (that is, translocated) herbicide.

contiguous

    Touching or closely adjoining, as in experimental plots.

continuous cropping

    The growing of crops in succession without a seasonal fallowing.

continuous model

    A model that portrays continuous processes, in contrast to a 'discrete' model, which includes discontinuous or abrupt phenomena.

continuous succession

    See crop succession

continuous variable

    A measured characteristic in which no distinct classes are recognizable, any class limits being arbitrarily drawn. See also discontinuous variable

continuum

    The occurrence of, for example, a tree species in a region in a continuously shifting series of combinations with a definite sequence or pattern, the result of a limited floristic complement acted upon by a limited range of abiotic factors. Such a gradient in a community is called a 'vegetative continuum'.

contour

    Linear demarcation of the land surface that indicates places of equal elevation; the lines on a map that connect these points. See also topography

contour cropping

    Sowing a crop in rows or strips so that these follow along a contour.

contour furrow

    A furrow ploughed on the contour on pasture or rangeland to prevent soil loss and so as to allow water to penetrate the soil; sometimes used in planting trees and shrubs on the contour.

contour tillage

    The cultivation of land along the lines of uniform elevation, or contour lines, to reduce erosion.

control

    A treatment in an experiment that is used as a baseline for comparisons or contrasts. For example, zero application of a fertilizer may be the control for an experiment on the effects of fertilizer. In agroforestry there is often more than one control, for example, 'crop only' and 'tree only'.

controlled burn

    See burn, fire

coppice

    1. A method of cutting certain species of trees to encourage them to regrow from the remaining stump. A tree that coppices readily does not require frequent replanting and is, therefore, useful for producing fuel and poles.

    2. Shoot developed from a dormant bud on a main trunk.

    3. A small wood regularly cut over for regrowth. Also called a copse. See also woodlot

coppice shoot

    1. Any shoot arising from an adventitious or dormant bud near the base of a woody plant that has been cut back. See also epicormic shoot. Also called 'sap shoot', 'stool shoot', 'water shoot' or 'water sprout'.

    2. Any shoot arising from the base of a woody plant that has recently been cut back.

coppice stand

    A crop of coppice shoots.

coppicing

    Cutting broadleaved trees close to ground level to produce sprouts or regrowth. Trees are also coppiced if they are damaged. See also pollarding

copse

    See coppice

cord

    A unit of gross volume measurement for stacked round or cleft wood, based on external dimensions. A 'standard cord' contains 128 stacked cubic feet, that is, 4 x 4 x 8 ft (1.22 x 1.22 x 2.43 m).

cork

    An external secondary tissue impermeable to waterand gasses. It is often formed in response to wounding or infection.

corm

    A specialized part of a stem; a short, enlarged base of a stem where food is stored. May be used as a propagule

correlative inhibition

    See apical dominance

costs

    In economics, goods and services (inputs) that reduce the income of families or firms, or reduce the national income of the society.

cotyledon

    An embryonic leaf. The cotyledons store food reserves, or digest and eventually absorb the food stored in the endosperm. In epigeal germination the cotyledons are raised above the ground and function photosynthetically. Alternatively, in hypogeal germination, the cotyledons remain underground.

covariance

    When two variables, say x and y, are measured on each of a number of sampling units, their covariance is the mean of the cross-products of the centred data. The ith cross-product is (xi x) (yi  – y) where x and y are the means of the x's and y's. Covariance is a measure of the interrelation between the variables.

covariance analysis

    Extension of the analysis of variance, where the dependent variable being analysed is a function of one or more independent variables not controlled in the experimental design but which have been observed at each value of the dependent variable.

cover

    For vegetation, that proportion of the ground overlain by the canopy of the plants growing on it (the vertical projection).

cover crop

    1. A crop grown to reduce soil erosion, conserve nutrients and provide organic matter. Cover crops are grown between the rows of a main crop or during the season when a cash crop is not being grown.

    2. In experimentation, a crop grown before an experiment to reduce soil variability. See also uniformity trial

creeper

    A trailing shoot that takes root mostly through its length. Sometimes applied to a tight-clinging vine.

critical value

    In land evaluation, a value of a diagnostic factor that forms the boundary between classes of a land-suitability rating.

crop

    A plant that is harvested for use by people or livestock. See also companion crop

crop calendar

    A list of the standard crops of a region in the form of a calendar giving the dates of sowing and various stages of their growth in years of normal weather.

crop growth rate

    The increase of crop material (dry weight) per unit area of ground covered by the canopy of the crop per unit time. Expressed, for example, as an absolute increment in kilograms per hectare per week, or grams per metre squared per week. Crop growth rate = net assimilation rate x leaf area index.

crop intensification

    The concept, approach, method and process of growing more crops per year either sequentially or simultaneously.

cropping intensity

    Percentage of net area available for cropping that is actually cropped.

cropping pattern

    The yearly sequence and spatial arrangement of crops, or crops and fallow, on any given area.

cropping season

    The period during the year when the environment is favourable for the growth of agricultural crops. In regions that have bimodal rainfall, there will be two such seasons. Trees may grow at other, less favourable, times. See also growing season

cropping sequence

    The time course of events among crop components utilizing the same unit of land. Cropping sequence can be coincident, concomitant, interpolated or overlapping.

cropping system

    1. The cropping patterns used on a farm and their interaction with farm resources, other farm enterprises and available technology. See also crop system

    2. The crop production activity of a farm. It comprises all cropping patterns grown on the farm and their interaction with farm resources, other household enterprises, and the physical, biological, technological and social economic factors or environments.

    3. A land-use unit comprising soils, crops, weeds, pathogens and insect subsystems, which transforms solar energy, water, nutrients, labour and other inputs into food, feed, fuel and fibre. The cropping system is a subsystem of the farming system.

crop productivity

    A measure of efficiency, that is, output (production) per unit of input over time, for example, grams of biomass per square metre per day, or crop yield expressed in tonnes per hectare per season. Can also be expressed in terms of labour or financial inputs, solar energy inputs, and so forth.

crop residue

    The portion of a crop after main product has been harvested. See also stover, straw

crop rotation

    The growing of different crops in recurring succession on the same land.

crop rooting zone

    Depth of soil in which crop roots are found.

crop succession

    The crop occupancy of the land and the successive ways in which the land is planted or sown. Crop succession can involve occupancy of land 'intermittently' or 'continuously'.

crop system

    An arrangement of crop populations that transform solar energy, nutrients, water and other inputs into useful biomass. The crops in the crop system can be different species and varieties, but they constitute one crop system only if they are managed as a single unit. The crop system is a subsystem of the cropping system.

crown

    1. A tree canopy, the upper part of a tree or other woody plant carrying the main branch system and foliage, and surmounting at the crown base a more or less clean stem.

    2. The branches and foliage of a tree. The upper portion of a tree. The leaves as foliage are an outgrowth of the vascular system and are mainly concerned with photosynthesis. The branches join the stem or other branches.

crown class

    Any class into which the trees forming a crop or stand may be divided on the basis of both their crown development and their crown position relative to the crowns of adjacent trees and the general canopy.

crown density

    The thickness, both spatially (that is, depth) and in closeness of growth (that is, compactness) of an individual crown.

crown diameter

    A mean figure derived from two (or more) measurements of the maximum and minimum spread of the crown.

crown height

    Of a standing tree, the vertical distance from ground level to the base of the crown, measured either to the lowest live branch-whorl (upper crown height) or to the lowest live branch excluding epicormics (lower crown height).

crown spring

    The point at which the stem of a tree breaks up into branches so that the main stem can no longer be distinguished.

crude fibre

    The components remaining after protein, soluble and easily decomposable carbohydrates, and fats have been chemically removed from a sample of plant material by appropriate methods. May be used in animal feed. See also crude protein

crude protein

    The estimated protein content of plant material. Obtained by analysing the nitrogen content of feed, assuming that all nitrogen is present as protein and that all proteins contain 16% nitrogen. Hence it is obtained by multiplying the percentage of the nitrogen content by 6.25.

culling

    See roguing

culm

    The stem of grasses and bamboos, usually hollow except at the swollen nodes.

cultivar

    1. An assemblage of cultivated plants, clearly distinguished by some characters (morphological, physiological, cytological, and so forth) and which when reproduced either sexually or asexually retains its distinguishing characteristics.

    2. A cultivated variety. It is given a non-Latin name, and designated 'cv.' (as distinct from 'var.' for a variety). A cultivar is any clone, race or product of breeding deemed worthy of cultivation and of a separate name.

cultivated variety

    A clone or seedling population with enough favourable characteristics to warrant cultivation and to be given a non-Latin name. There are no formal rules governing the description and naming of cultivated varieties. Cultivar names are fairly constant for the most commonly planted horticultural crops. They are much less constant for forest trees, a cultivar often being known by several names. See cultivar, variety

cultural practices

    Crop care practices including land preparation, seed selection, weed control, fertilizer and insecticide application, and water control in the field.

cumulative

    The accumulated temperature above a given standard for the total temperature days (or hours) since a given date during which the temperature was above the standard. See also base temperature, degree day, thermal time

current annual

    In forestry, for a particular stand, the annual increment of wood for increment the current year. See also mean annual increment and yield class

cut-off drain

    See diversion

cutting

    A detached part of a plant (for example, stem, root or leaf) that is placed in suitable conditions to promote rooting and the subsequent production of a new leafy shoot. Stem cuttings can be 'hardwood' (secondarily thickened from previous seasons' tissue), 'semi-hardwood' (mature current or last season's tissue) or 'softwood' (young tissue from the current season). They can be cut nodally or internodally. See also propagule

cyclophysis

    Process of maturation of the apical meristem, generally irreversible. See also periphysis, topophysis

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