Time-Domain Refractometry (TDR)

A method used by a soil moisture meter to measure soil moisture content. It measures the time for electrical signals to travel the length of a sensor-probe and return to determine the volumetric water content of the soil. The progress of the electrical pulse varies according to the moisture content encountered; a higher recorded voltage indicates higher moisture content.

  Tolerance

The ability of an organism to withstand, without significant detriment to itself, the effects of an undesirable condition. For example, some plants are more tolerant of saline conditions than others.

  Toxic

A situation in which one or more substances or conditions are harmful to an organism, having a significant impact on its health and development, often resulting in weak and poor growth, and where the organism is unable to tolerate the impact then death will typically occur. The overapplication or excessive presence of many micro-nutrients can lead to a deficiency of other nutrients, with a common response being a reduction in the unit weight and resilience of a plant.

  Toxicity

A measure of how poisonous and harmful a substance is.

  Trailed Gang Mower

A cylinder mower which is towed behind a power unit such as a tractor. The number of units will typically be 3 or 5 but can be more. A range of manufacturers make trailed gang mowers. A typical 3 gang mower will have a cutting width of 2.13m and have a cutting performance of 1.5 hectares per hour at a speed of 10 kilometres per hour; whilst a 5-gang mower will have a cutting width of 3.5m and have a cutting performance of 2.5 hectares. Trailed gang mowers are typically powered by the motion of their side wheels, which are usually either steel wheels or having pneumatic tyres.

  Transpiration

Water which is lost by a plant as water vapour. Water moves into the plant via the root hairs, which are mostly located towards the apical (or tip) region. Water moves through the outer cells that surround the xylem within the root and into the xylem ready for further movement within the plant. The xylem consists of two key features: tracheids, which have perforated sides, and vessels, which have perforated sides as well as perforated ends. This network of interconnected cells provides the means by which water is moved up through a plant. Water is lost, as water vapour, through the stoma

Continue reading about this

  Tricarboxylic Acid Cycle

This is another name for the Krebs Cycle.

  Tropisms

The response of plants to stimuli, resulting in growth taking place being towards or away from the stimuli. The main tropisms are Phototropism; Gravitropism; and Thigmotropism.

  Uneven Cut

An uneven cut which will typically produce a ridged type of appearance, with one side of the mower being set to a different height than the other side.

  Uniformity

Plant Breeders have rights of protection over plant varieties with uniformity being assessed for all characteristics used to establish Distinctness and 'A variety can be considered sufficiently uniform after two years of tests'.