feeding a hot, hungry world - agriculture in the face of climate change
Glossary
bluetongue. A virus spread by Culicoides midges, which causes fever, haemorrhaging in the mouth and nose and excessive saliva production. The animal’s lips, tongue and lower jaw may become swollen. Despite the disease’s name, the blue tongue that can occur is relatively rare. The animal can also become lame. Death occurs about six days after the appearance of symptoms. For more information see the Queensland Government Department of Agriculture, Fisheries and Forestry website.
coleoptile. A sheath that contains and protects the first leaves of a plant as they sprout upwards and emerge from the soil.
conservation farming. A multifaceted approach to sustainable farming that revolves around maximising water use, minimising soil disturbance, keeping crop residues to provide mulch, reduce erosion and increase soil organic matter and minimising soil compaction by reducing traffic on paddocks.
cyanide. A toxic substance that can exist as hydrogen cyanide gas (HCN), cyanogen chloride (CNCl) or as crystals of sodium cyanide (NaCN) or potassium cyanide (KCN). Cyanide shuts down cell respiration, causing cells to die. People affected by cyanide poisoning can suffer from breathing problems, convulsions and coma. Exposure to lower doses can result in giddiness, weakness, headaches, breathing problems and a loss of consciousness.
cyanogenic glycoside. A chemical found in a number of plants and foods, including cassava (also known as manioc, yucca and tapioca), almonds, lima beans, butter beans, stone fruits and bamboo shoots. This chemical can react to form cyanide, which is highly toxic to humans and animals.
fallow. Describes a cultivated field where nothing is grown in order for the soil to recover and replenish nutrients.
fusarium head blight. A fungal disease affecting grasses. Crops that can be affected include wheat, durum and barley. The effects of the disease are floret sterility, which results in major yield losses, production of small shrivelled grains and seed discolouration. Fungal toxins may also be produced, making the grain unsuitable for some end uses.
herbicide. A chemical used to kill plants or inhibit their growth. Herbicides can
be selective (kills some plants but not others) or non-selective. They
can affect the whole plant, or only part of a plant, at particular
stages of development.
leaf rust. A fungal disease that can affect wheat. Leaf rust forms orange-brown pustules on the leaves that can be rubbed off the leaf. Rusts can be transmitted from one season to the next via living plants, but cannot survive on crop stubble, soil or seed.
microbe. A single-celled microscopic organism.
no-till. A farming method where soil is not ploughed or cultivated. Crop residues are retained on the soil surface and soil disturbance is minimised to help maintain soil structure.
pasture. Areas of land vegetated with grasses or other plants suitable for grazing by livestock.
phenol. Also known as carbolic acid, this is a poisonous chemical compound, sometimes found in the essential oils of plants. In industry, phenols are used to make plastics, detergents and antiseptics.
phenology. The study of life cycle events, and how they relate to seasonal or climatic changes.
photosynthesis. The biochemical process in which green plants (and some microorganisms such as algae) use energy from light to synthesise carbohydrates from carbon dioxide and water. Photosynthesis can be shown as:
CO2 + H2O + energy → [CH2O] + O2
powdery mildew. A fungal disease that can affect a wide range of plants. Powdery white spots appear on the stems and leaves of plants. This fungus requires a living host to survive the winter, and be transmitted from one crop to the next.
rangelands. Various landscapes including woodlands, grasslands, wetlands and deserts, and areas of native vegetation used for livestock.
ruminant. An animal which chews regurgitated food (cud) and usually has a stomach divided into four compartments, one of which is the rumen. Partially digested food is returned from the stomach to the mouth and chewed, allowing further digestion. Ruminants include cows, sheep, goats, deer and giraffes. Their digestive system allows them to digest fibrous plant material which would be indigestible to other animals.
stem rust. A fungal disease that mainly affects wheat, but can also occur on barley, triticale and some grasses. Stem rust is rare, but can be devastating to crops. Reddish-brown oblong pustules form on the plant stems and leaves. Rusts can be transmitted from one season to the next via living plants, but cannot survive on crop stubble, soil or seed.
stripe rust. A fungal disease that can cause large yield losses in wheat crops. Stripes of yellow pustules form on the leaves. Rusts can be transmitted from one season to the next via living plants, but cannot survive on crop stubble, soil or seed.
Posted May 2013.