Evapotranspiration rates (ET) and consumptive water use (CWU) were measured for three desert turfgrasses using weighing lysimeters with a calcined clay growth medium. Water use rates were compared over a two-year study for 'Sea Isle I' seashore paspalum (Paspalum vaginatum) and A138 desert saltgrass (Distichlis spicata), along with 'Tifway' bermudagrass (Cynodon dactylon x Cynodon transvaalensis). Saltgrass showed elevated leaf canopy temperatures for extended periods before exhibiting visible wilt symptoms while 'Tifway' bermudagrass and seashore paspalum wilted readily, even at relatively high soil water contents. Saltgrass transpired for 11.9 d on average before drought stress was observed. Seashore paspalum maintained leaf turgor, on average 5.6 d without irrigation, whereas 'Tifway' bermudagrass averaged 4.0 d before requiring irrigation. The two-year average Kc values for three grasses before self-imposed drought was expressed by visible leaf wilting were 0.85, 0.79, and 0.74, for A138 saltgrass, 'Sea Isle I' seashore paspalum, and 'Tifway' bermudagrass, respectively.

Water availability is a common concern in semi-arid regions, such as Southern Arizona, USA. Hydroponic greenhouse crop production greatly reduces irrigation water use, but the study of water use by evaporative cooling has been limited.This project investigated water use by two evaporative cooling systems: pad-and-fan and high-pressure-fog with fan ventilation. All studies were performed in a double-layer polyethylene film-covered greenhouse (28 x 9.8 x 6.3 m) with mature tomato plants (2.9 plants m-2). Water use efficiency (WUE, kg yield per m3 water use) was calculated daily according to ventilation rate, as well as for a 6-month croppipng period, which used temperature-controlled pad-and-fan cooling.Pad-and-fan water use was 3.2, 6.4, 8.5, and 10.3 L m-2 d-1 for ventilation rates of 0.016, 0.034, 0.047, 0.061 m3 m-2 s-1, respectively. High-pressure-fog water use with a single central, overhead line was 7.9, 7.4, and 9.3 L m-2 d-1 for ventilation rates of 0.01, 0.016, 0.034 m3 m-2 s-1, respectively. For pad-and-fan ventilation rates less than 0.034 m3 m-2 s-1, total greenhouse WUE (20 - 33 kg m-3) was similar to field drip irrigation. For the temperature-controlled high-pressure-fog system, total greenhouse WUE (14 - 17 kg m-3) was similar to field sprinkler irrigation.For the 6-month crop cycle, combining water use by closed irrigation and pad-and-fan systems produced a total WUE of 15 kg m-3. Pad-and-fan WUE increased during monsoon conditions due to lower water use rates.Evaporative cooling water use and air temperature were well-predicted by the energy balance model. Predictions of air temperature improved when outside climate the measured conditions at one greenhouse location. Wind tunnel and full-scale studies of natural ventilation demonstrated the value of knowing airflow patterns when designing and operating a high-pressure-fog systemIt is possible for greenhouse tomato production to have a higher WUE than field production, if ventilation rates are not excessive, if closed irrigation is used, and if control methodologies are improved. Water use can be minimized by knowing how the evaporative cooling system affects greenhouse climate and plant responses.

Afforestation and reforestation programs utilizing available fields for biofuel production, carbon sequestration, and other uses linked to climate change are looking to tree physiologists to identify species and genotypes best-suited to their purposes. The ideal poplar genotype for use in Canadian programs would be drought-resistant, cold-climate adapted, and fast-growing, thus requiring an understanding of links between a variety of physiological traits linked to growth and productivity. This study examined the basis for variations in water-use efficiency within four selected populations of Populus trichocarpa and Populus balsamifera (2 provenances each). Each species included both a northern and a southern provenance. Correlations between water-use efficiency, nitrogen-use efficiency, ¹³C/¹²C isotope ratio, stomatal conductance, and overall productivity were evaluated. Gas exchange variables measured included net photosynthesis, transpiration rate, stomatal conductance, and intercellular CO₂ content. Water-use efficiency and ¹³C content across all genotypes were highly correlated. Results suggested that variation in water-use efficiency was primarily related to variation in stomatal conductance across all genotypes. Whereas differences in net photosynthesis in this study were not significant between species, P. balsamifera did reveal a higher average stem volume overall. Although variation in stomatal conductance was the major determinant of differences in water-use efficiency, positive correlations were found between ¹³C isotope abundance and net photosynthesis in both P. balsamifera provenances. In this regard, results for the northern P. balsamifera provenance are the most consistent across all gas-exchange and growth trait correlations, in terms of meeting expectations for sink-driven water-use efficiency. The findings in this study suggest the possibility of identifying poplar genotypes with an absence of trade-off between water-use efficiency and nitrogen-use efficiency, notably among genotypes from the northern P. balsamifera provenance, near Gillam.

In cities throughout Africa, domestic water is widely used for small businesses. The amount of water used depends on the size of the business and the individuals involved in these businesses are mostly women. However, many of these businesses do not have a direct connection to the city’s water network and the business owners often travel a far distance to purchase water at high prices. To explore this problem, the research titled “Analysis of Domestic Water Use for Livelihood Activities among the Poor in Alajo and Sabon Zongo Communities of Accra, Ghana” was undertaken. The main objectives of the study were two-fold: to measure the extent of domestic water use for livelihood purposes by both men and women in sub-urban communities of Accra and its contribution to their livelihoods, and enhance access of poor women to water to improve their water-dependent livelihoods and thus reduce poverty in Accra. The study also addressed issues relating to health and sanitation and explained that poor water quality in this community is as a result of damaged pipes and dirty storage tanks. The study was carried out using qualitative approach of investigation: interviewing, focus group discussions (FGDs), and direct observation. Statistical Packages for Social Sciences (SPSS) was used to analyze data collected. The study found that income generated from water related businesses contribute either all or more than half of the household income of water-related business operators. Water prices in these communities are ten times the regulated prices charged by the water utility, which have great impact on the profit margins of these small businesses and are often the stronghold of women. The highest level of education attained by most of the water related business owners is Junior Secondary School (Grade 8), which gives a basis for the explanation of their low income and high poverty levels. The study posed some recommendations including the possibility of government’s provision of water to every household in the communities. Furthermore, the implication of this recommendation was discussed, as it eliminates the business of water sellers and obstructs the income generated to support their households. Other livelihood activities that can be carried out by these water-related business owners were stated to include internet café business, grocery store operation, and boutique store operation. Certain limitations of this study have also been identified as its scope was limited to some extent. Areas of further research have also been identified.

In cities throughout Africa, domestic water is widely used for small businesses. The amount of water used depends on the size of the business and the individuals involved in these businesses are mostly women. However, many of these businesses do not have a direct connection to the city’s water network and the business owners often travel a far distance to purchase water at high prices. To explore this problem, the research titled “Analysis of Domestic Water Use for Livelihood Activities among the Poor in Alajo and Sabon Zongo Communities of Accra, Ghana” was undertaken. The main objectives of the study were two-fold: to measure the extent of domestic water use for livelihood purposes by both men and women in sub-urban communities of Accra and its contribution to their livelihoods, and enhance access of poor women to water to improve their water-dependent livelihoods and thus reduce poverty in Accra. The study also addressed issues relating to health and sanitation and explained that poor water quality in this community is as a result of damaged pipes and dirty storage tanks. The study was carried out using qualitative approach of investigation: interviewing, focus group discussions (FGDs), and direct observation. Statistical Packages for Social Sciences (SPSS) was used to analyze data collected. The study found that income generated from water related businesses contribute either all or more than half of the household income of water-related business operators. Water prices in these communities are ten times the regulated prices charged by the water utility, which have great impact on the profit margins of these small businesses and are often the stronghold of women. The highest level of education attained by most of the water related business owners is Junior Secondary School (Grade 8), which gives a basis for the explanation of their low income and high poverty levels. The study posed some recommendations including the possibility of government’s provision of water to every household in the communities. Furthermore, the implication of this recommendation was discussed, as it eliminates the business of water sellers and obstructs the income generated to support their households. Other livelihood activities that can be carried out by these water-related business owners were stated to include internet café business, grocery store operation, and boutique store operation. Certain limitations of this study have also been identified as its scope was limited to some extent. Areas of further research have also been identified.

Afforestation and reforestation programs utilizing available fields for biofuel production, carbon sequestration, and other uses linked to climate change are looking to tree physiologists to identify species and genotypes best-suited to their purposes. The ideal poplar genotype for use in Canadian programs would be drought-resistant, cold-climate adapted, and fast-growing, thus requiring an understanding of links between a variety of physiological traits linked to growth and productivity. This study examined the basis for variations in water-use efficiency within four selected populations of Populus trichocarpa and Populus balsamifera (2 provenances each). Each species included both a northern and a southern provenance. Correlations between water-use efficiency, nitrogen-use efficiency, ¹³C/¹²C isotope ratio, stomatal conductance, and overall productivity were evaluated. Gas exchange variables measured included net photosynthesis, transpiration rate, stomatal conductance, and intercellular CO₂ content. Water-use efficiency and ¹³C content across all genotypes were highly correlated. Results suggested that variation in water-use efficiency was primarily related to variation in stomatal conductance across all genotypes. Whereas differences in net photosynthesis in this study were not significant between species, P. balsamifera did reveal a higher average stem volume overall. Although variation in stomatal conductance was the major determinant of differences in water-use efficiency, positive correlations were found between ¹³C isotope abundance and net photosynthesis in both P. balsamifera provenances. In this regard, results for the northern P. balsamifera provenance are the most consistent across all gas-exchange and growth trait correlations, in terms of meeting expectations for sink-driven water-use efficiency. The findings in this study suggest the possibility of identifying poplar genotypes with an absence of trade-off between water-use efficiency and nitrogen-use efficiency, notably among genotypes from the northern P. balsamifera provenance, near Gillam.

Thesis (PhD) -- University of South Australia, 1999

This project investigated the physiological responses of grapevine to deficit irrigation strategies including partial rootzone drying (PRD) and regulated deficit irrigation (RDI). The principle objectives of the project were to (1) establish if the response to partial rootzone drying (PRD) is as a consequence of irrigation amount or a unique vine physiological response to PRD; (2) to investigate the effect of limiting environmental conditions on vine responses to PRD and deficit irrigation; (3) to investigate the effect of PRD and deficit irrigation on berry metabolism and maturation; and (4) effect of PRD and deficit irrigation on vine water-use. The experiment used field-grown Shiraz grapevines in a commercial vineyard in the Strathbogie Ranges in north-eastern Victoria. The experiment ran from season 2001/2002 through to 2003/2004 in a medium vigour, warm climate vineyard, with soils of low water holding capacity. (For complete abstract open document)

Thesis (M. Env. St.) -- University of Adelaide, 2000. / Bibliography: leaves 97-99.

Thesis (Ph.D.)--Murdoch University, 2004. / Thesis submitted to the Division of Science and Engineering. CD-ROM contains appendices. Bibliography: leaves 289-305.