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Terminologies used in Agronomy




  • Terminologies used in Agronomy

    Written and compiled by:

    Ahmad Mahmood, Department of Agronomy, Pir Mehr Ali Shah-Arid Agriculture University, Rawalpindi.

    Email: ahmadmahmood91@gmail.com

    What is Agronomy? : Agronomy is the science of crop production. It incorporates the basic sciences (Biology, Chemistry, Physics, Geology, Microbiology, etc.) into an applied science which is the foundation for most agriculture.

    Absorption Losses: Loss of water from a canal or a reservoir by capillary action and percolation and in case of canal during the process of delivery.

    Acid soil: A soil which is deficient in available bases, particularly Ca and which give an acid reaction when tested by a standard method.

    Acre foot water: The amount of water that would cover an area of land to a depth of one foot assuming no seepage evaporation and run off.

    Acre inch day: Term used principally in irrigated section of united state for measuring quantity of flow of water. It is equal to a flow which will cover one acre to a depth of one inch in a 24 hours period or 0.042 cubic feet per second.

    Acre inch: It is a measure of quantity of flow of water and is equal to the flow which will cover one acre to a depth of one inch.

    Acre :( 43560 sq. ft) an area of land about 220 feet long and 198 feet wide.

    Adiabatic: A condition in which heat is neither gained nor dissipated.

    Adobe soil: These soils are formed by the broken material of rocks transported by both wind and water.

    Agar: A substance made from seed weed and used in the solid culture.

    Agriculture: It is an art, science and business of raising crops and rearing of animals through exploring the natural resources with the coordination of socio economic infrastructure to meet the basic necessities of life .i.e. .food, feed, fiber and shelter.


    Allelopathy: Phenomenon involving the release of certain chemicals from plant parts into the environment which may when present in sufficient amounts, inhibit or suppress the germination or growth of the plants in the neighborhood. Alluvial soil: These are the soils which are formed by the deposition of broken material of rocks transported and deposited by water of streams and rivers.

    Altitude: Height from sea level

    Application losses: Water losses through percolation or run off.

    Arable farming: The term arable farming refers to system in which only crops that require cultivation of the soil are grown.

    Arboriculture: Intensive cultivation of individual trees possibly for fruits gums and resins.

    Arid region: The region where total rain fall is less than natural evapo – transpiration rate.

    Aridity: It is the characteristic of a region where there is low average rain fall or 100% available water. It is permanent feature of region.

    Available water: The water retained in a soil which represents the difference between field capacity and the permanent wilting percentage is called available water.

    Barani soil :When the source of irrigation to crop is only the rain water that is known as Barani soil.

    Base period: Period of time in days from the first watering of crop before sowing and the last watering before harvesting.

    Basic seed :Is the progeny of pre – basic seed produced so as to maintain genetic purity and identity.

    Basin : Flat area of land surrounded by low ridges or bunds

    Biological yield :It is the total dry matter produced by a plant as a result of photosynthesis and nutrient uptake minus that lost by respiration.

    Blind hoeing :Hoeing before a crop germinates.

    Botanical variety :When a group of plant occurring in nature is different from the general species originally described and the botanical binomial name is not enough to identify it is called as botanical variety.

    Broadcasting :Manual spreading of seed in the field and mixing of the spread seed by ploughing or planking the field.

    C3 plants :Plants which fix CO2 in three C molecule and do not use temperature and water as efficiently as C4 plant. e.g wheat, rice, cotton.

    C4 plant :: Plants which fix CO2 in to a four C molecules .e.g sugarcane, maize, sorghum.

    Capillary Water :It is the soil water in excess of hygroscopic water. This exists in the pore space of the soil by surface tension or molecular attraction against gravitational forces. It is only water available for plant growth and development.

    Capillary Water :It is that water which is held by surface forces (adhesion, cohesion, surface tension) or films around the particles in angles between them and in capillary pores.

    Catchment’s Area :The area which drains the rain water falling on it, via streams and rivers, eventually to the sea or into a lake.

    Cereal Crops :: A cereal is defined as crop grown for its edible seed. These crops are also known as grain crops e.g. wheat , Rice, Maize etc.

    Certified Seed :It is the progeny of basic seed and is produced by registered growers of seed producing agencies.

    Clayey Soil :A soil is known as clayey which contain at least 30% clay particles and in most cases not less than 40% ,usually it contain 45% clay , 30% silt and 25% sand.

    Climate :Aggregate of atmospheric condition over a long period of time.

    Clone : A cultivar propagated by vegetative method is called a clone.

    Colluvial Soil :Are those which are form from the material transported by the force of gravity.

    Command Area :Area which can be economically irrigated by an irrigation system.

    Commercial Farming System :In this type of farming system, crops are raised on a commercial scale for marketing.

    Companion Crops :The two crops grown together are called companion crops. e.g. Berseem and barley.

    Condiment Crops :Crops which are grown and consumed as condiments e.g. coriander, mint.

    Conidia :One celled asexual spores in certain fungi.

    Consumptive Use of Water :Evapo-transpiration plus the water assimilated by various plant metabolic processes. As the water consumed in plant metabolism is very small, consumptive use and evapo-transpiration are considered almost equal.

    Cover Crops :The crops, which are planted to cover the ground and to reduce the soil erosion and nutrients losses by leaching. e.g grasses and rye.

    Crassulation Acid Metabolism (CAM) Plants :CAM plants fix CO2 in four carbonic acid as do the C4 plants e.g pine apple.

    Critical Period of Competition :During the crop period there is a certain time when crop plants are most sensitive to competition by weeds, this time is known as the critical period of competition.

    Critical Threshold Level (CTL) : A weed, insect pest density capable of causing significant damage to crop is termed as critical threshold level.

    Crop Rotation :Is the strategy of raising crops from a piece of land in such an order or succession that the fertility of land suffers minimally and the farmer’s profits are not reduced.

    Crop Water Requirement :The amount of water required to raise a crop to maturity with in a given period of time.

    Crop :A crop is a community of plants grown under field condition for its economic value.

    Cropping Intensity :The term cropping intensity refers to the ratio of actual cultivated area to total farm area over a year.

    Cropping Pattern :It is a general cropping system followed or practiced by the farmers in an ecological zone.

    Cropping Scheme :Allocation of an area to different crops being grown on a particular farm in a year.

    Cultivator :Which only cut and stirr the soil.

    Define Necrosis :Death of organs of a plant, either as blight or death of tissue in localized areas, usually inside fruit and stems or die back or death of stems or branches.

    Define Olericulture :Branch of horticulture which deals with cultivation of vegetables.

    Delta of Water :The depth of irrigation water required for the full crop period.

    Determinate Plants :Those plant which initiate their reproductive stage after completing vegetative growth, e.g. wheat, barley.

    Dicots :Dicots have two cotyledons and reticulate leaf venation.

    Diversified Farming :This is an expanded type of farming system in which varieties of crops are produced and many types of animals are reared.

    Dobari Crops :A crop grown on residual moisture after the harvest of rice.

    Dormancy :Seed dormancy is the state of inhibited germination of seeds with viable embryos in condition conducive to plant growth.

    Drainage :It is the removal of excess surface or ground water from the root zone of a crop by means of surface or sub – surface drains.

    Dry farming: In which crops and livestock are raised on land which does not receive sufficient rainfall for water intensive crops and no irrigation  facilities are available fall into this category.

    Duty of water: The relationship between irrigation water flow and its commanded area where crops mature fully with that amount of water within a base period is called duty of water.

    Earthing up: The operation of pulling up soil from the center of crop rows to the bottom of the plants, this helps in uprooting weeds and supporting to plants.
    Economic yield: The economically important part for which a particular crop is grown.
    Effective rainfall: It is the part of the rainfall which forms a portion of the water requirement of a crop or which can be used by crop.
    Eolian soil: The soil which is formed by the material transported by winds from one place to another is called eolian soil.
    Epigeal germination: It is derived from two words epi “above” and geas “earth”. In this type of germination the cotyledons come out above the soil surface and generally turn green and act as first foliage leaves. e.g. bean,cotton.
    Evapotranspiration:It is the total loss of water due to its evaporation from land, plant and water surfaces and transpiration by vegetation per unit area per unit time.
    Exhaustive crops: Crops, which feed heavily on the soil and deplete soil nutrients e.g. sorghum, tobacco.
    Extensive farming: In this type of farming large areas are used with minimum expenditure or attention to efficient use of other resources.
    Fiber crops: The crops, which are grown for their fiber and are used in making textiles, ropes. e.g. jute, sun hemp, cotton.
    Field capacity: The amount of water retained by soil after drainage of saturated soil by gravitational force is called field capacity.
    Field carrying capacity: It is the field capacity. It is also called normal moisture capacity.
    Forage crops: Those crops, which are grazed by animals and harvested      for green chop, hay, silage are classified as forage crops e.g. maize and sorghum.
    Fruit farming: In which orchards are planted and the objectives are to maximize fruit production, enhance quality and increase income.
    Functional Allelopathy: It is the case when the chemicals are toxic after being transformed by microorganism.
    Garden crops: Vegetable crops, which are grown for their edible leaves, shoots, flowers, fruit and seed. e.g cabbage and okra.
    Germination: Is the emergence and development from the seed embryo of those essential structures which, for the kind of seed provided, indicate    the ability to produce a normal plant under favourable conditions.
    Grassland farming: These systems are mainly concerned with growing grasses for consumption by livestock kept for milk or meat production.
    Gravitational potential: It is produced by gravitational forces operating on soil water.
    Gravitational water:Is the water in excess of hygroscopic and capillary water that percolates through the soil under the action of gravity if favourable conditions for water drainage are provided.
    Green manure crops: Some crops are grown and ploughed in the soil in green form in order to improve soil fertility e.g. Berseem , Guara,Dhaincha etc
    Hard pan: A hard semi impervious layer usually developed due to continuous ploughing to a depth of about 15 cm, with cultivators, or with continuous deposition of salts due to soil or surface irrigation water.
    Herbaceous: Plants with soft and easily vulnerable body parts.
    Herbs: Are plants of small to medium height and canopy.
    Hydrophyte: Plant which grows in water, or which loves water.
    Hygroscopic water:Water attached to soil particles by loose chemical bonds and does not move by the action of gravity or capillary force.
    Ideotype: An ideal plant type developed through breeding.
    Indeterminate plants:In these plants, the vegetative and reproductive stages continue simultaneously e.g. okra, tomato. Soybean is the only crop, which has determinate and indeterminate as well as semi – determinate growing types.
    Inoculant: The bacteria containing material used to introduce N – fixing Rhizobium bacteria into soil.
    Integrated weed management: The concept of IWM involves the planned use of all possible direct and indirect measures rather than relying on a single method to combat weeds.
    Inter cropping: Growing of two or more crops together on the same field, where one crop (main crop) planted in rows first and then another crop (intercrop) is planted in between the rows. These crops remain in association for a shorter time. These crops may or may not be planted and harvested at the same time e.g in Sugar cane planting of onion, garlic etc
    Interception: When the drops of rainfall or precipitation are intercepted by plant leaves it is called interception.
    Irrigated soil: The soil, which receives irrigation water from well and tube wells, are known as irrigated or chahi soil.
    Irrigation efficiency: It is a term used to indicate how efficiently the available water supply is being used for crop production.
    Irrigation scheduling: It refers to the number of irrigations for a crop and their timing.
    Irrigation water requirement: The quantity of water required for successful crop production exclusive of precipitation, ground water and other natural resources.
    Irrigation: Irrigation is the artificial application of water to soil or crop plants to assist crop production.
    Kera: Manual sowing of seeds in lines in furrows.
    Kharif crops: Those crops, which are planted in the summer month from the March to July and harvested in autumn and winter, are called Kharif crops e.g. rice and cotton.
    Lacustrine soil: When the material transported by streams and river, if deposited in lakes the soils are called Lacustrine soil.
    Latitude: The angular distance north or south of earth equator.
    Line: A cultivar propagated by seed is called a line.
    Livestock and poultry farming: This category includes farming system in which various kinds of livestock are reared for meat, milk, wool and    eggs.
    Loamy soil: The soil is more or less than midway clay and sandy soil and ideal loam soil may defined as a mixture of sand , silt and clay particles which shows the properties of sandy, silt and clayey in equal proportion.
    Lodging: The bending or breaking over of a plant before harvesting.
    Long day plants: Plants which change vegetative to reproductive stage by producing flowers and fruits, when the days become longer. e.g. Carrot, Radish etc.
    Matric potential: It is produced by capillary and surface forces.
    Maximum potential soil moisture deficit: Is the greatest value of potential soil moisture deficit attained during the growth of a crop.
    Monocots: These plants have one cotyledon and parallel leaf venation.
    Muck soil: If the quantity of organic matter exceeds 20 % but less than 50% are called muck soil.
    Mulch: Any material or practice which is used to check the loss of water by evaporation is called mulch.
    Multiple cropping: It is growing of two or more crops in a year from the same piece of land
    Narcotic or drug crops: This category includes those crops, which have some narcotic and drug value e.g. poppy, tobacco.
    Natural erosion: The erosion of the soil under natural condition.
    Natural soil: Strictly speaking a soil having pH of 7, in practice a soil having PH 6.6 and 7.3.
    Net plot: Area from which  yield and other characteristics are measure. It is also known as the net area of the plot.
    No tillage crop(zero tillage crop): Crop grown with out any tillage to prepare seed bed or      row.
    Node A slightly enlarge portion of stem where leaves and bud arises and  where branches originate.
    Nucleus seed: Seeds obtained from selected individual plants of a particular variety which needs to be purified and multiplied in such a way as to maintain its genetic purity.
    Nut cycle: The regeneration/cycling of nutrients.
    Nutrients budget: A quantitative data of the major nut flowing to retained within the discharge from the system.
    Nutrients: The food for microbial and plant life mainly composed of            nitrogen and phosphorous but also of potassium , Mg , Fe , Ca ,Co ,Cu , Zn and others elements.
    Oil seed crops: These are the crops, which are grown for the purpose of extracting oil from their seed e.g. mustard and groundnut.
    On – farm water management: The planned use of irrigation water              at the farm level or more efficient utilization in agriculture.
    Osmotic potential: It is also called solute potential. It is produced by           various solutes in soil water.
    Peat soil: If the quantity of organic matter is more than 50% is called peat soil.
    Percolation: Downward movement of water with in the soil profile.
    Permanent wilting percentage: The soil water content at which plants can no longer extract sufficient water from the soil for their growth is called permanent wilting percentage.
    Plant development: Plant development is the progress of plant from germination to maturity through a series of stages.
    Plant growth: It is the increase in the dry weight of a plant over time mainly as a consequence of photosynthesis.
    Plough pan: A dense, compacted layer about 5 to 7 cm thick formed beneath the surface soil by repeated ploughing in the same path.
    Plough: Its function is to cut, stirr, invert, and pulverize the soil.
    Pore space: It is a space between soil particles occupied by air and water; it is largely controlled by the texture of soil.
    Potential Evapotranspiration: Is defined as the amount of evaporation occurring from an extensive area of a short, green growing crop completely covering the ground and well supplied with water.
    Potential soil moisture deficit: It is the difference between a crop potential evapotranspiration and the amount of rainfall received by a crop plus the quantity of water delivered to it in irrigation.
    Pre – basic seed: It is the progeny of nucleus seed, and is handled so as to maintain specific genetic purity and identity as completely as possible.
    Pressure potential: It is produced by actual hydrostatic pressure.
    Puddling: Ploughing in standing water to create a shallow hard pan at a 10 to 15 cm depth, which helps to increase water-holding capacity and reduce moisture losses by percolation.
    Pulses or grain legumes: The crops belonging to Leguminoseae family are grown for their edible seed e.g chick pea, lobia.
    Rabi crops: These crops are planted in winter from October to December    and harvested in summer from March to May e.g. wheat,
    Readily available water The portion of the available water that is most easily extracted by a plant is called readily available water.
    Regular and trade winds e.g. monsoon winds
    Relay crops: A relay crops is one which is planted as a second crop after the first crop has reached its reproductive stage of growth but before it is ready for harvest. e.g. planting of sugar cane in sugar beet.
    Relief: When rising ground or mountains running at right angle to the prevailing wind.
    Root and tuber crops: These are vegetable crops grown for their under ground parts like roots, bulbs, rhizomes, corms and stem tubers e.g. carrot and onion.
    Rumber: The process in which planker or leveler is used to conserve moisture at watter condition before the preparation of land after rauni.
    Run off: When water flows out the field by breaking the bunds of the field or flows to the sloppy areas from the high level is called run off..
    Sandy soil: the soil which contains 2.00 to 0.2 mm diameter soil particles ,   it contain 85% sand , and >15% , silt and clay. These soils are poor in plant material.
    Saturation capacity:This term refers to the amount of water present in the soil when it is completely saturated with water.
    Scarification: Any physical or chemical treatment that makes the seed coat permeable is known as scarification.
    Seed certification: Is the process to secure, maintain and make available    high quality seed and propagating materials of superior crop varieties, so grown and distributed as to ensure desirable standards of genetic identity, physical purity and quality attributes.
    Seedling A young plant that has grown from a seed
    Seeling: Mechanical weeding process carried out by ploughing with bullocks or tractors.
    Seepage: Losses through the beds and banks of canals and water channels               take place mainly by unlined canals.
    Sett: A piece of seed cane with two – four buds(eyes).
    Short day plants: Plants which changes from vegetative to reproductive stage and produces flowers and fruits , when the days become shorter.
    Shrubs: Are bushy plants with medium to tall height and canopy.
    Silage crops: Those crops, which are harvested when still green and succulent and are fed directly to animals with out curing, are called silage crops. e.g. Berseem, Shaftal, maize.

    Soil: A natural body developed from variable mixtures of broken and weathered minerals and decaying organic matter which covers the earth crust in thin layers and supplies proper amount of nutrients and air water  and mechanical support to plants.
    Stratification: Is the practice of exposing imbibed seeds to cool temperature conditions for a few days prior to germination in order to break their dormancy.
    Subsistence farming: In which basic necessities like food, clothing, and shelter are produced for the family to live on.
    Sugar crops: These are the crops, which are grown for sugar purposes. e.g. sugar cane and sugar beet.
    Tell the share of wheat crop in total cropped area of Pakistan:                                                      37.01% under wheat.
    Temporary wilting percentage: Soil water content at which plants wilt during the hot windy part of the day but regain turgidity during the cooler part of the day is called TWP.
    Tillage: It is usually defined as the mechanical manipulation of the soil aimed at improving its physical condition.
    Tiller: To put forth shoots other than the mother shoot from roots axis.
    Tilth: The physical condition of soil is called Tilth.
    Topping: Topping in tobacco is the removal of the terminal bud with or without some of the small top leaves just before or after the appearance of the flower head.
    Transpiration ratio:It is the ratio of the weight or volume of water transpired by the plant during its growth period to the weight of dry matter produced by the plant.
    Transpiration: It is the process of loss of water from living plants.
    Truck farming: It refers to the system in which the bulk of the out puts are produced and marketed.
    True Allelopathy: When the allelochemical is toxic in their original form is called true Allelopathy.
    Variety: In general the term variety has been used to refer to a group of similar plant with in a particular species that is distinguished by one or more then one character and given the name.
    Vernalization and chilling: Many biennials and temperate annuals, as well as certain fruit trees, require exposure to cold temperature before they can flowers. This is known as Vernalization requirement for annuals and biennials and chilling requirement for fruit trees.
    Vines: Are plants, which have tender stems, and requires some support for upward growth.
    Water holding capacity: Ability of soil to retain water.
    Water potential: Refers to the chemical potential of water.
    Watter: Describes the condition when soil moisture level is suitable for cultivation.
    Weather: It is a state of atmosphere at any time; it is combined effect of many things such as heat, cold.
    Weed: any plant growing out of its proper place.
    Harvest index
    It is the ratio of economic yield to biological yield. It is expressed in percentage in
    H.I.          =              economic yield x 100 / Biological yield

    Biological yield
    It is the total dry matter produced by the crops after synthesis minus respiration losses.
    Economic yield
    That part of the crop for which crop is grown e.g. stem in sugarcane, root in the case of sugar beet.
    Monocropping
    Raising of only one crop in a year when there is seasonal supply of water is called Monocropping, monoculture or specialized farming.
    Multiple cropping
    Raisingof two or more crops in the same field or in a year is called diversified multiple cropping or simple multiple cropping.
    Tilth
    It is the final condition of soil when all the tillage operations are carried.
    What  is composite variety? A mixture of genotype from general sources maintained by normal pollination.
    What are the compounds which act as buffer in soil? Clay organic matter and such compounds as carbonates and phosphates which make the soil to resist appreciable change in pH value.
    What is arid? A term applied to land that is dry also means deficient in rainfall.
    What is compost? A manure derived from decomposed plant remains usually made by fermentation, waste plant material under controlled conditions. Compost usually used in green houses to enrich the soil either dungs as surface.
    What is contact herbicide ? Which kill only those parts of plant with which they come into contact and used mostly to control annual weeds when seedling, they have little residual effect.
    What is crop rotation ? A definite succession of crops following one an other in a specific order.
    What is drought resistance? Characteristics of plants which are suitable for cultivation in dry condition regardless of the inherent mechanism that provides resistance.
    What is effective rainfall? Precipitation which falls during the growing period of the crop and is available to meet the Evapotranspiration requirements of crops .
    What is Gibberellins ? Plant growth stimulating chemicals which are able to induce a number of effects on plants.
    What is harvest index? The  ratio of grain weight to total plant weight in    a cereal crop.
    What is hybrid vigour ? Qualities  in a hybrid not present in either parent.
    What is malathion ? An Organophosphorus insecticide and acaricide available either alone or in mixture used in liquid or dust form.
    What is meant by autotrophe? Organism able to manufacture their own food from inorganic materials. Using energy from outside sources.     Most green plants are completely autotrophe.’
    What is meant by bolting? Formation of elongated stem or seed stalk, it     is usually takes place during the second season of the growth in biennial    plants.
    What is meant by cropping intensity ? Refers to the no. of crops which are raised during the year.
    What is meant by F1 and F2 generation? Genetic terms for the off spring generations produced by a parental generation of plants or animals.

    What is meant by layerage? Methods of plant propagation by asexual       means in which a portion of stem, shoot or branch has covered with soil or some other medium in which root can develop , after which the rooted portion get detached from the parent plant.
    What is meant by soiling crops? Crops harvested when green and succulent condition are fed to animals shortly after cutting , it is neither dried nor stored for future feeding.
    What is organic farming? System of farming which avoid the use of artificial fertilizers , pesticides or herbicides, and concentrate on methods     of crop rotation and the use of home growth feed , organic fertilizer.
    What is pasteurization? Process of killing organisms in a product, commonly milk by heating to a controlled temperature.
    What is pedology? The study of soil.
    What is planker? Implement used to crush clods on land where a roller can be used consisting of  number of fixed over lapping plates, showed with iron bars along the working edges which is pulled over the land.
    What is seed certification? Refers to the system of maintaining the genetic purity and quality of seed.
    What is seed dressing? The chemical treatment of seeds particularly cereals, with fungicides and some time insecticides to protect them against soil and seed borne disease and pest.
    What is truch gardening ? Growing of crops like potato onion and cabbage on large scale for distinct market.
    What is trench layering ? An asexual reproductive method of plant propagation involving laying down the whole stem, the new shoots are thus forced to push their way through a layer of soil which prevents the bark from coloring and favors root formation.
    What is weathering? The process by which soil disintegrates and decomposes, eventually producing soil particles by exposure to the physical and chemical effects of atmospheric agents.
    Wilting point: The point at which the water content of a soil reaches such a level that it is firmly held by soil and unavailable to plant roots, so that the plants wilt permanently and die.
    Zaid Kharif crops: These are the crops, which are planted in August to September and harvested in December to January e.g. toria.                
    Zaid rabi crops: These are crops, which are planted in February and harvested in May-June e.g. tobacco.

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