Absolute Humidity

Absolute Humidity is the absolute or actual quantity of water vapour by weight present in given volume of air.

Acre-foot

The volume of water that would cover one acre to a depth of one foot.

Artificial Insemination

Impregnating an animal through artificial means, not through natural breeding.

Annual

Any plant which completes its entire life cycles and dies within one year or less.

Aboricide

A chemical used for killing trees or woody shrubs.

Acedophilies

The plants which can grow in acidic soils (pH range 4.5-6.5).

Acid Forming Fertilizer

A term applied to commercial fertilizers which leave an acid residue in the soil. The amount of calcium carbonate required to neutralize the acid residue is referred as its equivalent acidity.

Actinomycetes

A non-taxonomic term applied to a group of organisms with characteristics intermediate between the simple bacteria and the true fungi.

Active Ingredient

It is that part of a chemical formulation which is directly responsible for the herbicidal effects. In some herbicides the entire molecule is considered as the active unit. Thus, if the chemical is 95 per cent pure it will be considered as having 95 per cent active ingredient. In others, the herbicidal activity is more accurately calculated on an acid equivalent basis.

Adjuvant

An additive ingredient that facilitates or modifies the action of the principle ingredient.

Adsalt Sugarcane

Sugarcane that takes 18 months for harvesting usually planted in July.

Agricultural Statistics

It concerns with scientific methods for collecting, organizing, summarizing, presenting and analyzing data generated from agricultural experiments as well drawing valid conclusion and making reasonable decision on the basis of such analysis.

Agriculture

An activity of man, primarily aimed at the production of food, fibre, fuel etc. by optimum use of terrestrial resources.

Agrihorticulture

Agrihorticulture is a form of agroforestry where fruit trees are the tree components. This system provides for a higher income per unit area, with the additional income being generated from fruit yield. It also serves as an option to the farmer even in case of crop failure. Sometimes, well maintained and well established orchard bring even higher returns than the field crops. Fruit trees also provide protection to degraded lands. The species of fruits to be grown depend largely on the amount of rainfall. Porous, aerated and deep soils are good for fruit growing. These systems require high initial investment and care.

Agroclimatic Region

The grouping of different physical areas within the country into broadly homogenous zones based on climatic and edaphic factor.

Agroecological Zone

A major area of land that is broadly homogenous in climatic and edaphic factors, but not necessarily continuous, where a specific crop exhibits roughly the same biological expression.

Agroecology

The holistic study of agroecosystem, including all environmental agricultural crops and human elements, their interrelationships and the process in which they are involved.

Agrometeorology

The branch of meteorology relevant to problems of agriculture. It is concerned, in particular, with the surface layer of the atmosphere and with condition with the variations of the meteorological element like rainfall, humidity, temperature, sunshine, wind velocity, atmospheric pressure etc.

Agronomy

The word has been derived from the Greek word ‘agros’ means fields and ‘nomos’ means management. It is a specialized branch of agriculture dealing with crop production and soil management.

Allelopathy

Direct/indirect harmful effect that one plant has on another or manually on each other through the production of chemical compounds that escape into the environment.

Alley Cropping

A farming system in which arable crops are grown in alley formed by trees or shrubs, established mainly to hasten soil-fertility reiteration and enhance soil productivity. Annual crops are grown in spaces between rows and trees or shrubs, often leguminous one that tolerate heavy and regular coppicing. The leafy and woody material of the trees and shrubs is used as mulch in the crop(s) and also often as fodder, timber, fuel etc. Also referred to as venue cropping and hedgerow cropping.

Allogamy

In allogamy, pollen grains from flowers of one plant pollinate the flowers of other plants (Syn., cross-pollination).

Alluvial Soil

A soil developed from recently deposited by alluviam (running water of streams and rivers) and exhibiting essentially no horizon development or modification of the recently deposited materials. This is the most important soil group in India, derived from the deposition from tributaries of the Ganga, Brahmaputra and Indus. Despite a great deal of variations, alluvial soils, coastal alluviam and coastal sands. Geologically the alluvium is divided into khaddar or the newer alluviam which is sandy,generally light coloured and less stony (kankari)in composition, and bhangar or the older alluvium which is dark, more clayey and full stones (kankar). The soils range from drift sand to loams and from fine silts to stiff clays. Occasional pebbles are also present. The drawbacks of these soils are- presence of impervious clays in part obstructs drainage and promotes accumulation of injurious salts of sodium and magnesium making these soils less fertile. Formation of hard pan at alleviation of finer soil is sometimes observed.

Alternative drying and wetting (rice)

Frequent draining and reflooding (aerobic and anaerobic cycle ) in rice fields.

Aquatic weeds

Weeds are found in lakes and ponds.