Introduction to Agriculture Flashcards

A set of vocabulary flashcards covering the core principles of agriculture, soil science, crop and livestock management, meteorology, and genetics based on the SAE 101 lecture notes.

Agriculture

Derived from the Latin words 'Ager' (field) and 'Cultura' (cultivation), it is the science, art, or occupation concerned with cultivating land, raising crops, and feeding, breeding, and raising livestock.

Soil

A dynamic, natural body of mineral and organic constituents differentiated into horizons, developed as a result of pedogenic processes during and after weathering of rocks.

Surface soil

The immediate uppermost loose layer of the earth (generally $0-15\,cm$ deep) consisting of organic matter and soil organisms suitable for plant growth, also known as furrow slice soil.

Soil minerals

The largest portion of soil volume ($45\%-49\%$), consisting of primary minerals (similar to parent material) and secondary minerals (formed from weathering, like silicate clay).

Soil water availability

The capacity of a particular soil to hold water for plant use, which is largely dependent on soil texture and the affinity of organic matter for water.

Permanent wilting point

Also called the 'wilting coefficient,' it is the point where water is held so tightly by soil particles that plants cannot extract it.

Humus

Decayed organic matter recycled by microorganisms into a form that is rich in readily available plant nutrients.

Soil profile

A vertical section through different layers of the soil, where each layer differs in texture, color, depth, and chemical composition.

A-Horizon

Often referred to as topsoil or the root zone, this surface layer is where organic matter accumulates and is characterized as a zone of eluviation where minerals are leached downward.

B-Horizon

Commonly known as subsoil or the zone of illuviation, it is the area of maximum accumulation of substances like iron and aluminum oxides leached from upper horizons.

Solum

The combined section of the A, E, and B-horizons where most plant roots exist.

Soil texture

The percentage of sand, silt, and clay in a soil, specifically referring to mineral particles less than $2\,mm$ in diameter.

Sand (Particle Size)

Soil particles with a diameter of $0.05-2\,mm$ that feel gritty and do not feel plastic or sticky when moist.

Silt (Particle Size)

Soil particles with a diameter of $0.002-0.05\,mm$ that feel smooth and are non-sticky and non-plastic when moist.

Clay (Particle Size)

Soil particles with a diameter of less than $0.002\,mm$ that are very sticky when wet and form hard lumps when dry.

Mulching

The practice of covering the soil surface with organic materials (dry grass, leaves, sawdust) or artificial materials (polyethylene plastics) to conserve water and minimize weeds.

Crop rotation

The process of planting different crops (e.g., non-legumes followed by legumes) on the same land in a specific sequence to maintain soil fertility and avoid disease.

Multiple cropping

Growing two or more crops together in the same field so that the products and waste from one crop assist the growth of the other.

Taxonomy

The branch of science focused on naming, describing, and classifying organisms into groups based on morphological, reproductive, and anatomical characteristics.

Binomial nomenclature

A two-part naming method developed by Carl Linnaeus where botanical names consist of a Genus and a species name (e.g., Genus species).

Horticulture

Derived from the Latin 'hortus' (garden) and 'colere' (cultivate), it is the branch of agriculture dealing with the production of fruits, vegetables, flowers, and ornamental plants.

Tilling (Ploughing)

The process of loosening and turning the soil to improve air circulation, root penetration, and water retention capacity.

Broadcasting

A method of sowing seeds where they are sprayed or scattered manually across the field instead of being placed in specific furrows.

Irrigation

The periodic supply of water to plants in the fields from sources like rivers, reservoirs, or wells, essential for stages like seedling, flowering, and grain filling.

Threshing

The process of separating grains from the harvested crop (chaff or husk), often done by trampling with animals or using a motorized machine.

Winnowing

The use of wind to separate lighter chaff from heavier grains by tossing the mixture into the air.

Weeds

Undesirable plants that grow alongside crops and compete for sunshine, water, space, and nutrients.

Pest

Organisms, mostly insects and their larvae, that feed on and damage food crops, but can also include mites, slugs, snails, and larger animals like rats.

Complete metamorphosis

An insect life cycle (holometabolous) involving four stages: egg, larva, pupa, and adult, where immature stages look different from adults.

Pathogens

Disease-causing organisms including fungi, bacteria, nematodes, viruses, viroids, and phytoplasmas.

Livestock

A broad term covering all domestic animals (quadrupeds, poultry, insects like bees) regardless of age or purpose, excluding non-domesticated animals not in captivity.

Artiodactyla

A sub-order of mammals consisting of cloven-hoofed animals with compounded stomachs, which is the major group of herbivorous livestock.

Chevon

The specific term used to describe the meat of a goat.

Highlands Halfbred

A sheep breed in Papua New Guinea produced by crossing Priangan (tropical) sheep with temperate Corriedale and Perendale breeds.

Weather

The day-to-day state of the atmosphere and its short-term variation in a given place at a given time.

Climate

The sum of prevailing weather conditions of a place over a long period of time, influenced by rainfall, temperature, and humidity.

Lapse rate

The regular rate at which temperature falls as altitude increases, specifically $0.5\,^{\circ}C$ for every $100\,m$ (or $5\,^{\circ}C$ per $1000\,m$) in PNG.

Mitigation

Human interventions intended to reduce the sources or enhance the sinks of greenhouse gases to address climate change.

Allele

Alternative forms of a gene that occurs in pairs; the uppercase version is dominant while the lowercase is recessive.

Genotype

The genetic makeup or gene combination of an individual for a given trait (e.g., $RR$, $Rr$, or $rr$).

ACGT

An acronym for the four types of bases found in a DNA molecule: adenine (A), cytosine (C), guanine (G), and thymine (T).

Mechanical Advantage (M.A.)

The ratio of the force delivered by a machine (the load, W) to the force applied to operate it (the effort, F), expressed as $M.A. = \frac{W}{F}$.