There is no single agreed definition of the term drylands. Two of the most widely accepted definitions are those of FAO and the United Nations Convention to Combat Desertification (UNCCD, 2000). FAO has defined drylands as those areas with a length of growing period (LGP) of 1–179 days (FAO, 2000a); this includes regions classified climatically as arid (Plate 1), semi-arid and dry subhumid. The...

In hydrological models, evaporation from interception is often disregarded, combined with transpiration, or taken as a fixed percentage of rainfall. In general interception is not considered to be a significant process in rainfallrunoff modelling. However, it appears that on average interception can amount to 20–50% of the precipitation. Therefore, knowledge about the process of interception is...

A recursive claim that there is a ’scarcity of global data on evaporative partitioning’ is used to justify the development of the STEAM model (see e.g. pg. 206, L23). However, over the last decade, there have been numerous efforts to derive the separate components of the terrestrial evaporative flux at the global scale, not just from land surface models and climate reanalyses, but also by combi...

In both Australia and Swaziland large areas of sugarcane rely on irrigation to produce a viable crop or to improve rainfed productivity. Matching water supply to crop demand is essential for productivity and sustainability in any irrigation scheme. Historically Class-A pan evaporation was used as a basis for determining sugarcane water demand or evapotranspiration (ETc). ETc is now frequently o...

Methods for the precise control of drought stress have been a holy grail of plant biology research. Here we describe a five-container growth chamber system and a 16-container greenhouse system, each of which uses load cells to monitor and control the mass of a soil/plant system. The calibration and signal conditioning necessary to quantify transpiration over 10 minute intervals is described. Ev...

In this research, amount of evaporation and transpiration and water requirement of wheat plant for Marvdasht town (representation station: Zaraghan) during 17-years statistical duration from 1989-2005 and properties of plant and soil are calculated using CROPWAT software. At the first, trends of dry and wet periods for mentioned station were determined using long-term average of climatic data (...

In this research, amount of evaporation and transpiration and water requirement of wheat plant for Marvdasht town (representation station: Zaraghan) during 17-years statistical duration from 1989-2005 and properties of plant and soil are calculated using CROPWAT software. At the first, trends of dry and wet periods for mentioned station were determined using long-term average of climatic data (...

Plant transpiration, a process of water movement through a plant and its evaporation from aerial parts especially leaves, consumes a large component of the total continental precipitation (≈48%) and significantly influences global water distribution and climate. To date, various chemical and/or biological explorations have been made to tune the transpiration but with uncertain environmental ris...