Tamil Nadu HSE First Year Agricultural Science key terms

The science and practice of cultivating soil, growing crops, and raising livestock for food, fibre, and other products. It combines farming activity with knowledge of soils, plants, animals, and markets.

The number of crops grown on the same piece of land in one agricultural year, expressed as a percentage of the net sown area. Growing two crops gives 200 per cent.

The period from the late 1960s when high-yielding cereal varieties, irrigation, and fertilisers sharply raised food grain output in India. It made Tamil Nadu and Punjab major rice producers.

The vertical arrangement of successive layers, called horizons, from the surface down to the parent rock. Each horizon differs in colour, texture, and organic matter content.

The relative proportion of sand, silt, and clay particles in a soil. It governs water holding, drainage, aeration, and workability, and is described by a textural class name.

A measure of the acidity or alkalinity of soil, on a scale from 0 to 14, where 7 is neutral. It controls nutrient availability and the choice of crops and amendments.

The detachment and removal of topsoil by wind or water. It reduces fertility, silts up tanks, and is checked by contour bunding, terracing, mulching, and vegetative cover.

Supplying crop nutrients through a balanced combination of chemical fertilisers, organic manures, biofertilisers, and green manures. It sustains yield while protecting soil health and reducing cost.

A crop such as daincha or sunhemp grown and then ploughed into the soil while still green. It adds organic matter and nitrogen, improving structure and fertility.

The branch of agricultural science dealing with field crop production and soil management. It covers choice of varieties, sowing, spacing, irrigation, nutrition, and harvesting practices.

Growing different crops in a planned sequence on the same land over successive seasons. It breaks pest cycles, balances nutrients, and improves soil structure.

The quantity of seed required to sow one hectare of a crop at the recommended spacing and germination. It is expressed in kilograms per hectare.

Raising seedlings in a nursery and then moving them into the main field at the correct age and spacing. Common in rice, it improves establishment and weed control.

A managed area where seedlings or planting material are raised under care before field planting. It allows uniform, healthy planting stock and better use of costly seed.

Joining a scion, the desired shoot, onto a rootstock so they unite and grow as one plant. It is used to propagate fruit trees and to gain disease-resistant roots.

A propagation method in which a stem is induced to form roots while still attached to the parent plant, then separated. Air layering is widely used in guava and citrus.

The deliberate removal of plant parts such as branches, shoots, or roots to shape growth, improve light entry, and regulate bearing. It is routine in orchards and plantations.

A strategy that combines cultural, mechanical, biological, and chemical methods to keep pests below damaging levels. Pesticides are used only when monitoring shows they are needed.

The pest population at which control measures are justified to prevent the loss from exceeding the cost of treatment. It guides spraying decisions in integrated pest management.

Suppressing pests using their natural enemies such as predators, parasitoids, and pathogens. Examples include Trichogramma cards against stem borer and neem-based preparations.

An abnormal condition caused by pathogens such as fungi, bacteria, viruses, or nematodes, or by environmental stress. It shows as symptoms like wilting, spots, or blights.

An animal with a multi-chambered stomach that ferments plant feed with microbes, such as cattle, buffalo, goat, and sheep. It digests roughage efficiently.

A daily feed allowance that supplies all required nutrients in correct proportion and quantity for a given animal and production level. It combines roughage and concentrate economically.

Mating animals of two different breeds to combine desirable traits, such as the high milk yield of exotic breeds with the hardiness of local breeds. Progeny are crossbreds.

A self-propelled power unit used to pull, mount, or drive farm implements and machinery. Its power is rated in horsepower and delivered through the drawbar or power take-off.

A shaft on a tractor that transmits engine power to driven implements such as rotavators, threshers, and pumps. It runs at a standardised speed, usually 540 rpm.

The replacement of manual and animal power with machines for field operations, irrigation, and post-harvest work. It reduces drudgery and timeliness losses but needs capital and skills.

The total expenditure incurred in raising a crop on one hectare, including seed, fertiliser, labour, irrigation, and machinery. It is the basis for computing profit.

The total value of output from a farm enterprise, obtained by multiplying yield by price. Deducting the cost of cultivation from it gives the net income.

The science of organising and operating a farm to maximise profit through efficient use of land, labour, capital, and management. It involves planning, budgeting, and record keeping.

A voluntary association of members who pool resources for shared economic benefit, such as marketing produce or supplying inputs. Earnings are shared according to member participation.

The process of educating farmers through demonstrations, field days, and advisory visits so they adopt improved practices. It links research stations with villages.

A small group of villagers, often women, who save regularly, lend among themselves, and later access bank credit. SHGs are a major channel for rural development in Tamil Nadu.

Covering the soil surface with crop residues, plastic film, or other material to reduce evaporation, suppress weeds, and moderate soil temperature. It also limits erosion.

Cultivation without synthetic fertilisers and pesticides, relying instead on organic manure, compost, biofertilisers, and biological pest control. Certification is needed for premium markets.

A preparation containing living microorganisms such as Rhizobium, Azospirillum, or phosphate-solubilising bacteria that improve nutrient availability to crops. It supplements chemical fertiliser.

A collection of dried, pressed, and labelled plant specimens used for study and identification. In practical work it trains students in plant collection and record keeping.

A supervised trip to a farm, research station, or market so students observe real practices and record findings. It links classroom theory with field conditions.