41 Agriculture Important terms & definitions For Competitive Exam Part-1

Agriculture terms & definitions

Agriculture terms & definitions

1. Allelochemicals

It is a substance produced by members of one species that influences the behaviour or growth of members of another species.

Allelochemicals can be divided into several categories like

1. Kairomones which benefit the receiving organism but cause disadvantage to the producer.

2. Allomonesthat benefit the producer but have no effect on the receiver.

Synomones are beneficial to both producer and recipient.

2. Micro irrigation

  • Microirrigation is a broader term that is used to cover all forms of small emission devices including individual emitters, rowcrop tubing, spray strakes, and micro-sprinklers.
  • All of these devices were developed for water distribution to small crop area, frequently to individual plants.
  • This micro irrigation system encompasses several ways of water application to plants such as drip, spray, subsurface and bubbler irrigation.

(Agriculture terms & definitions)

3. Pressurized irrigation

  • It is a system that relies on water pressure for the system to work to supply required quantity of water to the roots.
  • The main variations of pressurized irrigation systems are drip irrigation and sprinkler irrigation.
  • These systems have the potential to avoid the water loss related to surface irrigation with efficiency in the range of 75% 95%.

4. Drip irrigation

  • Drip irrigation sometimes called as trickle irrigation, involves dripping water onto the soil at very low rates from a system of small diameter plastic pipes fitted with outlets called emitters or drippers.
  • Water is applied close to plants so that only part of the soil in which the roots grow is wetted, unlike surface and sprinkler irrigation which involves wetting the whole soil profile.
  • The advantages are high water application efficiency, lower labour costs, minimised fertiliser/nutrient loss andability to irrigate irregular shaped fields.

(Agriculture terms & definitions)

5. Sprinkler irrigation

  • Sprinkler irrigation system allows application of water under high pressure with the help of a pump.
  • It releases water similar to rainfall through a small diameter nozzle placed in the pipes.
  • Water is distributed through a system of pipes, sprayed into air and irrigates in most of the soil type due to wide range of discharge capacity.

Advantages of sprinkler irrigation are

o Reducing water loss due to conveyance

o Suitable in all types of soil except heavy clay

o Best suited for fields with high plant population per unit area.

o Reduces soil compaction.

o Saves land as no bunds required. o Reduces labour cost.

6. Salinity of soil

  • Soil salinity is a term used to describe the salt content within soil. 
  • Salt is a naturally occurring mineral within soil and water that affects the growth and vitality of plants.
  • Soil salinity can be influenced through several different factors ranging from human influence to environmental causes.
  • If the salt content becomes high, the soil becomes known as sodic soil and can present many difficulties when used as a growing medium.

(Agriculture terms & definitions)

7. Alkalinity of soil 

  • Alkaline soil is any soil that falls above 7 on the pH scale which is the unit of measure for acidic versus alkaline soil.
  • The pH scale is a numeric system between 0 and 14 used to test the acidity or alkalinity of soil with a measurement of 7 being completely neutral.
  • Soils with a high pH tend to contain higher levels of sodium, calcium and magnesium. 
  • The availability of nutrients is often limited and plants can become stunted in alkaline soils because they’re not as soluble as acidic soils.
  • Alkaline soil may also be known as sweet soil.

8. Acidity of soil

  • Acid soil is any soil that falls below 7 on the pH scale.
  • Acid soil can be caused by many things and can occur naturally in areas with high rainfall amounts and by geological factors. 
  • Soils high in minerals and clays tend to fall on the acidic side, but acid soil can also be caused by other factors like nitrogen from fertilizers.
  • Acidic soil effects particularly the subsurface which will restrict root access to water and nutrients.

(Agriculture terms & definitions)

9. Deep tillage

  • Deep tillage means performing tillage or ploughing operations below the normal tillage depth to modify the physical or chemical properties of a soil.
  • Deep ploughing turns out large sized clods, which are baked by the hot sun when it is done in summer.
  • These clods crumble due to alternate heating and cooling and due to occasional summer showers.
  • This process of gradual disintegration of clods improves soil structure and kills pests’ larvae due to exposure to hot sun.

10. Kharif season crops

  • The Kharif cropping season is from July to October during the south-west monsoon.
  • The crops sown in this season includes rice, maize, sorghum, pearl millet/bajra, finger millet/ragi (cereals), arhar (pulses), soyabean, groundnut (oilseeds), cotton etc.
  • These crops are dependent on the quantity of rainwater as well its timing, as too much or too little or at wrong time waste’s the whole year’s efforts.

(Agriculture terms & definitions)

11. Rabi season crops 

  • Rabi cropping season is from October to March during the winter months. 
  • The Rabi crops include wheat, barley, oats (cereals), chickpea/gram (pulses), linseed,
  • mustard (oilseeds) etc.
  • These crops are grown either with rainwater that has percolated into the ground, or with irrigation and not dependent on rain as too much water can be harmful for these crops.

12. Zaid season crops 

  • Zaid cropping season is from March to May during the summer season.
  • These are crops grown on irrigated lands that do not have to wait for monsoons.
  • They require warm dry weather for major growth period and longer day length for flowering.
  • The main produce are seasonal fruits and vegetables.
  • Some Zaid crops are Water melon, cucumber, muskmelon, sunflower, sugarcane, etc.

(Agriculture terms & definitions)

13. Crop rotation

  • Crop rotation is the systematic planting of different crops in a particular order over several years in the same growing space.
  • This process helps maintain nutrients in the soil, reduce soil erosion, and prevents plant diseases and pests.
  • There is no universally accepted rotation schedule as the types of plants in a particular farm or garden depend on the local soil, climate, and resources available.
  • The length of rotation time between different plants will also vary depending on the needs of the farmer.

14. Crop diversification

Crop diversification refers to the addition of new crops or cropping systems to agricultural production on a particular farm taking into account the different returns from value-added crops with complementary marketing opportunities.

Major advantages of crop diversification are

o Increasing income on small farm holdings

o Withstanding price fluctuation

o Balancing food demand

o Improving fodder for livestock animals

o Conservation of natural resources

o Minimising environmental pollution

o Increasing community food security

(Agriculture terms & definitions)

15. Symbiotic association

  • Symbiosis describes a close association of two organisms that benefits at least one of the organisms.
  • At times, these close relationships evolve, some beneficial relationships may go sour, while destructive relationships persist to the point of benefiting both species. 
  • Changes in genes or behaviour that improve reproductive chances transfers to offspring, while any trait detrimental to an organism’s survival generally decreases in frequency in descendant populations until that characteristic dies out altogether.

16. Mutualism

  • Mutualism is a symbiotic relationship between individuals of different species in which both individuals benefit from the association.
  • In this type of symbiosis, both organisms of different species rely on one another for nutrients, protection and other life functions, hence, they are usually found living in close proximity.
  • It can be thought of as a form of “biological barter” since the species trade resources (for example carbohydrates or inorganic compounds), or services such as gamete or offspring dispersal, or protection from predators.

(Agriculture terms & definitions)

17. Nitrification 

  • Nitrification is the process of oxidation of ammonium compounds in dead organic material into nitrates and nitrites by soil bacteria, which makes nitrogen available to plants.
  • It also pertains to the conversion of nitrogen from inorganic to organic by nitrate bacteria, which effectively recycles the substance so that it can be used again by plants via root uptake.
  • Natural nitrification is a biological occurrence performed by nitrifying bacteria or due to lightening, but Nitrogen can also be fixed artificially.

18. Ammonification

  • Ammonification is the process by which the organically bound nitrogen of microbial, plant, and animal biomass is recycled after their death.
  • It is carried out by a diverse array of microorganisms that perform ecological decay services, and its product is ammonia ion.
  • Ammonium is a suitable source of nutrition for many species of plants, especially those living in acidic soils.
  • However, most plants cannot utilize ammonium effectively, and they require nitrate as their essential source of nitrogen nutrition.

(Agriculture terms & definitions)

19. Biological Nitrogen fixation

  • Biological nitrogen fixation is an important factor in any sustainable agriculture program.
  • It is a process in which nitrogen is taken from its relatively inert molecular form (N2) in the atmosphere and converted into nitrogen compounds useful for building plant protein. 
  • The best known nitrogen fixing plants are legumes which contain symbiotic rhizobia bacteria within nodules in their root systems, producing nitrogen compounds that help to fertilize the soil.

20. De-nitrification

  • This is the reverse process of nitrification, during which nitrates are reduced to nitrites and then to nitrogen gas and ammonia.
  • Thus, reduction of nitrates to gaseous nitrogen by microorganisms in a series of biochemical reactions is called “denitrification”.

The overall process of denitrification is as follows:


Nitrate –> Nitrite –> Nitric Oxide –> Nitrous Oxide –> Nitrogen gas

  • When naturally occurring, this process is wasteful as available nitrogen in soil is lost to atmosphere.
  • Nowadays, denitrification is seen as a remedy for decreasing acidity of soil which has surplus nitrogen due to application of excessive fertilizers.

(Agriculture terms & definitions)

21. Volatilization 

  • Volatilization is the process of converting a liquid or solid ammonium in soil to gaseous ammonia.
  • Other terms used to describe the same process are vaporization, distillation, and sublimation.
  • Several factors that affect volatilization of ammonia are – soil pH, type of fertilizer, soil temperature & moisture, crop residue, etc.

22. Organic inputs 

  • Organic inputs are raw materials such as fertilizers, seeds, land, water etc. which are unaltered or unaffected by synthetic products.
  • The use of organic inputs have come into prominence as the concept of organic and sustainable farming is sprouting.
  •  All land friendly and sustainable practices use organic manure, non GM seeds, and other inputs which are derived organically.

23. Blanket recommendation 

  • Blanket recommendation is made by the higher authority like government to the farmers for using certain kinds of fertilizers or organic inputs to bring change in the production of agricultural products.
  •  Example: Government ordered for all fertilizers to be Neem coated, which will disintegrate slowly, requiring less fertilizers and also avoid leaching of fertilizers into the water table.

(Agriculture terms & definitions)

24. Herbicides

An herbicide is a chemical substance used to control or manipulate undesirable vegetation, especially weeds in agricultural farms.

They areclassified into two categories –

o Selective herbicides kill specific unwanted plants while leaving desirable vegetation relatively unharmed.

o Non-selective herbicides (total weed killers) kill all or most plant species.

Herbicides are applied to maximize crop production by diminishing the development of unwanted plants.

They are also applied in ponds and lakes to control aquatic plants, in forests to prepare logged areas for replanting, and to golf courses, lawns, parks, and other areas to clear out unwanted vegetation.

25. Saprophytes

  • Saprophytes are living organisms that feed on dead and decaying organic matter, unlike parasites that live on living organisms.
  • They are considered extremely important in soil biology as they break down dead and decaying organic matter into simple substances that can be taken up and recycled by plants.
  •  Examples of Saprophytes are fungi and some bacteria.

(Agriculture terms & definitions)

26. Evapo-transpiration loss

  • Evapotranspiration (ET) is the loss of water to the atmosphere by the combinedprocesses of evaporation and transpiration.
  • Evaporation occurs when waterchanges to vapour on either the soil or plant surfaces.
  • Transpiration refers to the water lost through plant tissue.
  •  ET is a good indicator of how much water plantsare losing on a daily basis, and the rate of ET varies with different plants.
  • Someplants retain moisture longer than others, even in very dry conditions and this is whysome plants are more drought tolerant than others.

27. Leaching 

Leaching is the process of water carrying soluble substances or small particles through soil or rock. 

It is actually two important actions occurring simultaneously

1. Chemical interactions with surfaces

2. Physical movement of water.

Leaching creates is an important balance between preventing salt accumulation and removing nutrients from soil.

But excessive leaching removes crucial nutrients from the soil and it also affects the ground water table which is an important source of drinking water.

(Agriculture terms & definitions)

28. Soil horizon

  • Soil horizon is a layer generally parallel to the soil crust, whose physical characteristics differ from the layers above and beneath.
  • Each soil type usually has three or four horizons defined physical features such as colour and texture.
  • The differentiation of the soil into distinct horizons is largely the result of influences, such as air, water, solar radiation and plant material, originating at the soil-atmosphere interface.
  • Since the weathering of the soil occurs first at the surface and works its way down, the uppermost layers have been changed the most, while the deepest layers are most similar to the original parent material.

29. Soil Profile 

  • A soil profile is a vertical cross section of the soil.
  • When exposed, various soil horizons, or layers of soil, become apparent. 
  • The profile is made up of layers, running parallel to the surface, called Soil Horizons.
  • Each horizon of soil may be different from the other horizons in physical or chemical ways.
  •  The differences are developed from the interaction of such soil-forming factors as parent material, slope, native vegetation, weathering, and climate.

(Agriculture terms & definitions)

30. Irrigation efficiency 

  • Irrigation efficiency (IE) is the ratio of the amount of water consumed by the crop to the amount of water supplied through irrigation.
  • The water applied by the irrigation system and not being made available to be taken up by plant roots is wasted and reduces irrigation efficiency.
  • The term irrigation efficiency expresses the performance of a complete irrigation system or components of the system.
  • The major causes for reduced irrigation efficiency include storage losses, conveyance losses and field application losses.
  • In India, overall irrigation efficiency of major irrigation projects ranges between 35-40%. 71. Basal application of fertilizers
  • Basal application of fertilizers is one of the Broadcasting techniques.
  • The broadcasting of fertilizer refers to spreading fertilizers uniformly all over the field.
  • The main objective of basal application of the fertilizers at sowing time is to mix it with soil properly.
  •  Insoluble phosphatic fertilizers such as rock phosphate are used in this method of application.

The main disadvantages of application of fertilizers through broadcasting are:

1. Nutrients cannot be fully utilized by plant roots as they move laterally over long distances.

2. The weed growth is stimulated all over the field.

3. Nutrients are fixed in the soil as they come in contact with a large mass of soil.

31. Integrated nutrient management

Integrated Nutrient Management refers to the maintenance of soil fertility and of plant nutrient supply at an optimum level for sustaining the desired productivity.

It is achieved through optimization of the benefits from all possible sources of organic, inorganic and biological components in an integrated manner. 

The concept of Integrated Nutrient Supply includes

1. Regulated nutrient supply for optimum crop growth and higher productivity.

2. Improvement and maintenance of soil fertility.

3. Zero adverse impact on agro – ecosystem quality by balanced fertilization of organic manures, inorganic fertilizers and bio- inoculants.

It improves and sustains the physical, chemical and biological functioning of soil.

(Agriculture terms & definitions)

32. Bulky organic manures 

  • Manures are grouped, into bulky organic manures and concentrated organic manures based on concentration of the nutrients.
  • Bulky organic manures contain small percentage of nutrients and they are applied in large quantities.
  • Farmyard manure (FYM), compost and green-manure are the most important and widely used bulky organic manures.
  • Farmyard manure refers to the decomposed mixture of dung and urine of farm animals along with litter and left over material from roughages or fodder fed to the cattle

Use of bulky organic manures has several advantages:

1. They supply plant nutrients including micronutrients

2. They improve soil physical properties

3. They increase the availability of nutrients

4. Carbon dioxide released during decomposition acts as a CO2 fertilizer

5. Plant parasitic nematodes and fungi are controlled

33. GM crop 

  • A Genetically Modified or transgenic plant is a plant that has a novel combination of genetic material obtained through the use of modern biotechnology.
  • A transgenic crop plant contains a gene or genes which have been artificially introduced instead of the plant acquiring them through pollination.
  • These genes are introduced with a view to expressing a novel trait which is not normally found normally in the given species.
  • Bt Cotton is the best example of GM crop.

(Agriculture terms & definitions)

34. Soil Tilth

  • Soil Tilth is the term used to express soil condition resulting from tillage.
  • A soil is said to be in good Tilth when it is soft, friable & properly aerated.
  • The Tilth is the physical condition of the soil brought out by tillage that influences crop emergence, establishment, growth and development
  • It is a loose, friable, airy, powdery granular & crumbly structure of the soil with optimum moisture content suitable for working & germination or sprouting seeds & propagates.
  • An ideal soil tilth is not the same for all types of crops & all types of soils.
  • For instance: small seeded crops like bajara, ragi, lucerne, Sesamum, mustard require a much finer seedbed, while Jowar & cotton require a moderately compact & firm seed bed.

35. Concentrated organic manure 

  • Concentrated organic manures have higher nutrient content than bulky organic manure.
  • The important concentrated organic manures are oilcakes, blood meal, fish manure etc.,
  • These are also known as organic nitrogen fertilizer.
  • These organic fertilizers are relatively slow acting, but they supply available nitrogen for a longer period.

36. Transplantation

  • Transplanting is the process of moving a fully germinated seedling (or mature plant) and replanting it in a permanent location for the growing season.
  • Transplanting is also called as replanting.
  • Transplanting is a kind of Indirect Planting.
  • A plant that has been recently transplanted is referred to as a transplant.
  • Transplants can be more resistant to insect and other pest pressure, because they are more mature and stronger when they are replanted in the crop area.

(Agriculture terms & definitions)

37. Thinning

  • Thinning denotes the removal of some plants, or parts of plants, to make room for the growth of others.
  • It is the selective removal of flowers, fruits, shoots, and seedlings or young plants to allow adequate space for the remaining organs/plants to grow efficiently.
  • The Benefits of Thinning include increased growth, improved utilization of resources, reducing vulnerability to insects and pests and fire prevention.

39. Weeding 

  • Weeding is an important control method practiced.
  • Weeding is a valueless plant growing wild, especially one that grows on cultivated ground to the exclusion or injury of the desired crop.
  • The removal of weeds is useful because these unwanted plants compete with the crop for space, water and nutrients.
  • Weeds can be controlled mechanically or by using chemicals (herbicides).

40. Micro propagation

  • Micropropagation is the rapid vegetative propagation of plants under in vitro conditions of high light intensity, controlled temperature and a defined nutrient medium.
  • It refers to the production of whole plants from cell cultures derived from explants (the initial piece of tissue put into culture) or meristem cells.
  • Micro-propagation is widely used in forestry and in floriculture.
  • Micro-propagation can also be used to conserve rare or endangered plant species.
  • It is a best methodology available for rapid multiplication and production of quality seed free of any disease and pest which ensure maximum production, potential or varieties.

(Agriculture terms & definitions)

41. Genetic Engineering

  • Genetic transformation is the heritable change in a cell or organism brought about by the uptake and establishment of introduced DNA.
  • Genetic engineering allows the use of several desirable genes in a single event and reduces the time to merge novel genes into elite background.
  • Genetic engineering has a number of useful applications, including scientific research, agriculture and technology.
  • In plants, genetic engineering has been applied to improve the resilience, nutritional value and growth rate of crops such as potatoes, tomatoes and rice.
  • Selective breeding is not considered a form of genetic engineering.

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