Tamil Nadu HSE First Year Agricultural Science flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Agriculture definition

The art, science and business of producing crops and raising livestock for human use, including agronomy, horticulture, forestry, animal husbandry, fishery and agricultural engineering.

Tamil Nadu agro-climatic zones

Tamil Nadu has seven agro-climatic zones: Northeast, Northwest, Western, Cauvery Delta, Southern, High Rainfall and Hilly zones, each differing in rainfall and cropping pattern.

Northeast monsoon

The main rainy season in Tamil Nadu, occurring from October to December, supplying the larger share of the state's annual rainfall of about 900 mm.

Soil profile horizons

Vertical layers of soil: O organic litter, A humus-rich topsoil, E eluviation, B illuviation, C weathered parent material and R bedrock.

Bulk density

Oven-dry soil mass divided by total soil volume, expressed in g/cm3; it indicates compaction and helps calculate porosity.

Cation exchange capacity

The ability of soil to hold exchangeable cations, measured in cmol(+)/kg; clay and humus raise CEC and improve nutrient retention.

Lime versus gypsum

Lime (calcium carbonate) is applied to correct acidic soils, while gypsum (calcium sulphate) is applied to reclaim alkaline or sodic soils.

Essential plant nutrients

Sixteen to seventeen elements needed by plants; N, P, K are primary macronutrients, Ca, Mg, S secondary, and Fe, Mn, Zn, Cu, B, Mo, Cl micronutrients.

Cropping intensity

Gross cropped area divided by net sown area, multiplied by 100; values above 100 percent indicate multiple cropping on the same land.

Fertilizer nutrient content

Urea contains 46% N, diammonium phosphate 18% N and 46% P2O5, muriate of potash 60% K2O, and single super phosphate 16% P2O5.

IW/CPE ratio

Irrigation water depth divided by cumulative pan evaporation; it guides irrigation scheduling, with ratios near 0.8 to 1.0 used for many crops.

Plant population formula

Plants per hectare equals 10,000 divided by the product of row spacing and plant spacing in metres; it converts spacing into plant density.

Asexual propagation

Propagation by cutting, layering, grafting, budding or tissue culture, producing plants genetically identical to the parent and true to type.

Scion and rootstock

In grafting, the scion is the fruiting upper portion and the rootstock is the rooted lower portion that supplies water and nutrients.

Tapioca propagation

Cassava is propagated by stem cuttings, and Tamil Nadu is the leading Indian producer, mainly in Salem, Namakkal and Erode districts.

Fertigation

Application of soluble fertilizers through a drip or micro-irrigation system directly to the root zone, improving nutrient and water use efficiency.

Economic threshold level

The pest population density at which control measures are justified to prevent economic loss; it lies below the economic injury level.

Disease triangle

A plant disease develops only when a susceptible host, a virulent pathogen and a favourable environment occur together; removing one factor prevents disease.

Koch's postulates

Four steps proving a pathogen causes a disease: constant association, pure culture isolation, inoculation reproducing symptoms, and re-isolation of the same organism.

Rice blast symptoms

Caused by Magnaporthe oryzae, producing spindle-shaped lesions with grey centres and brown margins on rice leaves, reducing yield.

Ruminant stomach

A four-chambered stomach of cattle, sheep and goats: rumen, reticulum, omasum and abomasum, where microbes ferment cellulose and synthesize protein.

Kangayam breed

An indigenous draught cattle breed of Tamil Nadu, known for strength and endurance, used for ploughing and cart work.

Oestrous cycle in cattle

The reproductive cycle of about 21 days in cattle, with gestation lasting about 280 to 285 days after successful artificial insemination.

Newcastle disease

A viral disease of poultry, also called Ranikhet disease, causing respiratory and nervous signs; vaccination is the main control measure.

Primary tillage implements

Mouldboard and disc ploughs break and invert soil, while secondary implements such as cultivators, harrows and rotavators pulverize and level the seedbed.

Tractor horsepower conversion

One horsepower equals 0.746 kilowatts; tractor and engine power ratings are commonly expressed in horsepower.

Drip versus sprinkler irrigation

Drip applies water slowly at the root zone and saves water, while sprinkler irrigation sprays water like rain and suits undulating land.

Benefit-cost ratio

Total benefits divided by total costs of an enterprise; a ratio above one indicates that the activity is profitable.

Law of diminishing returns

As more units of a variable input are added to fixed inputs, marginal product eventually declines, guiding optimal input use.

Extension methods

Individual methods include farm visits, group methods include demonstrations and field days, and mass methods include radio, television, print and social media.

Adoption process stages

The five stages a farmer passes through: awareness, interest, evaluation, trial and adoption, with innovators and early adopters leading.

Integrated Nutrient Management

Combining organic manures, chemical fertilizers and biofertilizers such as Rhizobium and Azospirillum to maintain soil health and crop yields.