<p>This paper deals with relationship between irrigation and agriculture and conflicts within an irrigation system and as well between other stakeholders concerning the water. Irrigated lands are up to 2.5 times more productive compared to rain-fed agriculture. They are important element in the agriculture sector in Sub-Saharan Africa, and have been favoured by governments and donor agencies for their high rate of return. Without proper technical equipments or support negative impacts on the environment are linked to irrigation activities. Furthermore, a case study was made in Tanzania, Kiru Valley, regarding the tension between big scale and small-scale farmers as result from the water decline. The results demonstrate that the institutions do not have the power to solve the conflict. It is difficult to define the different stakeholders and the boundaries of the area that affect the amount of water in the valley.</p>

A greenhouse experiment was conducted at the University of Arizona, Tucson, Arizona, to study the effects of liquid sewage sludge loading rates on the vegetative growth, yield, and quality of barley grain and straw. Vegetative growth, grain yields, and straw yields were similar whether barley was grown with inorganic N or equivalent amounts of plant-available N from sewage sludge. Sewage sludge loading rates higher than three times the recommended plant-available N rate decreased barley stands in the seedling stage. The loss of stand was compensated for by higher tillering later in the season. High sludge loading rates tended to delay maturity, increase tillering and increase straw yield; however, they did not affect grain yield. Concentrations of cadmium (Cd), copper, (Cu), lead (Pb), nickel (Ni), and zinc (Zn) in barley grain and straw and the amounts of heavy metals recovered in the soil following each harvest were similar to the control for all sewage sludge treatments.

Attempts to characterize nitrogen (N) status of irrigated spring wheat by using basal stem nitrate - N (NO₃⁻N) tissue tests have shown contradictory results, due to the wide range of agronomic conditions existing in Arizona. Seven N fertility trials were conducted at the Maricopa and Safford Agricultural Centers over the 1985-88 crop years to examine the effects of N rate, N fertilizer form, residual soil N, soil texture and contrasting varieties on basal stem NO₃⁻N concentrations, yield and quality of irrigated durum wheat. Fertilizer N treatments were broadcast at planting then at the 5-6 leaf, boot and anthesis growth stages to simulate fertigation in conjunction with the first four basin irrigation events. Stem tissue samples were taken from all plots at the 3-4 leaf 5-6 leaf joint, boot and anthesis growth stages for NO₃⁻N analysis with a nitrate electrode. Diagnostic levels for durum wheat basal stem tissue NO₃⁻N tests at these growth stages are presented.

Collecting additional data to calibrate and refine current guidelines for interpreting soil and plant test values is an ongoing need in Arizona. An experiment was conducted at the Safford Agricultural Center during the 1987 -89 crop years to evaluate the response of 'Aldura' durum wheat to a range of residual soil and fertilizer P levels. Maximum grain yields exceeding 5,500 lbs./A were obtained by banding 50 lbs. P₂O₅/A as triple superphosphate with the seed at planting in 1988. Residual P front phosphorus fertilizer applications up to 80 lbs. P₂O₅/A had no significant effect on grain yields of the succeeding wheat crop. Basal stem PO₄-P tissue analysis seemed reliable in monitoring P nutrition of durum wheat during the vegetative growth period. Observed critical levels of POD P in basal stem tissue for durum wheat at the 3-4 leaf, joint and boot growth stages were 2000, 1200 and 500 ppm, respectively.

A field experiment was conducted on a Pima clay loam at the Safford Agricultural Center to: 1) determine the optimum rates of late season N needed to achieve optimum yield and quality of irrigated durum wheat in conjunction with varying rates of early season N; and 2) evaluate the usefulness of stern NO₃-N analysis in predicting the late season N rates which optimize grain production but minimize the potential for nitrate pollution of groundwater. The application of 75, 175 and 350 lbs. N/a during vegetative growth resulted in wheat with deficient, sufficient and excessive N status at the boot stage, as indicated by stem NO₃-N analysis. The application of 60 lbs. N/a at heading to N- deficient wheat and 15-20 lbs. N/a to N-sufficient wheat resulted in grain protein levels above 14 %, but the applications had little effecton grain yield. Applications of N at heading to wheat which had previously received excessive N did not affect grain yield or quality. The use of stein NO₃-N analysis appears to be a useful tool in predicting the minimum N rate to be applied during the early reproductive period to insure acceptable levels of grain protein at harvest.

Wheat irrigations were scheduled using two computer models and an infrared thermometer, using three critical threshold values. Yields from these plots were compared with plots scheduled by the farm manager. The highest yield was obtained by the computer model using evapotranspiration data taken from the local AZMET station; this corroborates results from the previous year. The crop coefficients and the irrigation model that have been developed over the past several years are very accurate for this area. The two lower threshold infrared treatments were second and third in yield and had lower water use efficiencies.

The economic impact analysis contained in this book shows how irrigation farming is particularly susceptible when applying certain water management policies in the Australian Murray-Darling Basin, one of the world largest river basins and Australia’s most fertile region. By comparing different pricing and non-pricing water management policies with the help of the Water Integrated Market Model, it is found that the impact of water demand reducing policies is most severe on crops that need to be intensively irrigated and are at the same time less water productive. A combination of increasingly frequent and severe droughts and the application of policies that decrease agricultural water demand, in the same region, will create a situation in which the highly water dependent crops rice and cotton cannot be cultivated at all. / Die ökonomische Folgenanalyse in diesem Buch zeigt, dass insbesondere Landwirte, die stark auf Bewässerung angewiesen sind, von Wasserregulierungsstrategien im Australischen Murray-Darling Becken betroffen sind. Dieses Gebiet ist eines der größten Flussbecken weltweit und zugleich Australiens fruchtbarste Region. Durch den Vergleich von verschiedenen Preisstrategien und anderen Ansätzen konnte mit Hilfe des Water Integrated Market Models herausgefunden werden, dass die Auswirkungen auf hochgradig wasserabhängige Feldfrüchte mit geringeren Wasserproduktivitäten am stärksten sind. Die Kombination von häufigeren und intensiveren Trockenzeiten und einer Regulierungspolitik mit dem Ziel, die Nachfrage nach Wasser zu verringern, führt dazu, dass in ein und derselben Region hochgradig wasserabhängige Feldfrüchte wie Reis und Baumwolle mit geringeren Wasserproduktivitäten nicht mehr angebaut werden können.

The approach to water management worldwide is currently in transition, with a shift evident from purely centralised infrastructure to greater consideration of decentralised technologies, such as rainwater harvesting (RWH). Initiated by recognition of drivers including increasing water demand and increasing risk of flooding, the value of RWH is beginning to filter across the academic-policy boundary. However, in the UK, implementation of RWH systems is not straight forward; social and technical barriers, concerns and knowledge gaps exist, which currently restrict its widespread utilisation. Previously, these issues have been examined independently. The research described in this thesis highlights the need for interdisciplinary working to lower the barriers and resolve the concerns. Consequently, a combination of social and engineering research perspectives, methods and analysis is utilised to achieve the aim of the research: the production of a strategic framework to support the implementation of RWH in the UK. The framework is the culmination of empirically derived social and technical evidence bases including: surveys with householders and architects; interviews with small to medium enterprises (SMEs); a design and performance evaluation of a non-domestic RWH system; non-domestic water closet (WC) monitoring to develop a demand profile and a water quality study and health impact assessment (HIA) of a non-domestic RWH system. Results indicate that householders were willing but not able to implement RWH, due to financial constraints and perceived maintenance burdens. For SMEs 5 ‘implementation deficit categories’ were identified, which undermined their ability to implement. The use of continuous simulation tools, with appropriate data, need to be promoted and the non-domestic demand profile derived was distinctly different to the well-established domestic profile, yielding implications for system design. The non-domestic RWH system was able to achieve an average water saving efficiency of 97% for the period monitored and the HIA quantified the risk to health as being within the recognised screening level. Triangulation of the results into an integrated socio-technical evidence base facilitated the identification of three core strategy aims, their corresponding actions and actors (stakeholder groups). The overall strategic framework is presented in the form of a Venn diagram. It is unlikely the comprehensive nature of the strategic framework would have been achieved, if the interdisciplinary process had not been undertaken. Therefore adoption of a socio-technical approach to implementation is vital, if RWH in the UK is to transition from novel to mainstream.

This paper looks at economic factors and water rights quantification on 95 Native American reservations economies in the western United States (U.S.). The study looks at the issues in two parts: (1) the characteristics of reservations quantifying their water rights compared to those who do not and (2) the effects of water rights quantification on reservation economic characteristics. Data was compiled from the U.S. Census Bureau, USDA, water specialists, court decrees, news articles, and scholarly papers. Results found that tribes who operate casinos and have higher revenues from agricultural goods are more likely to have quantified their water rights. Tribes with quantified water rights also had increased income levels. This study can help tribes design policies to create sustainable water management policies and economies on tribal reservations.

Digital river network dataset is an important source of information in any aspect of water management decision making. It is also a base for modelling or scientific research in many different fields. Development of the dataset in the Czech Republic had been fragmented in a past and as a result three different datasets have been developed that cover the whole of the state's territory. The datasets contain different geometries, different and often conflicting attributes and serve different purposes. Today the time has come that water management decision makers have realised that the situation is no longer sustainable and make effort to merge the datasets into one. The task brings in several technical issues and a potential for severe legal consequences. The aim of this study is to develop a methodological approach to merging the existing datasets into one. This methodological approach to decision which of the conflicting or different attributes should be adopted is based on assumption that the existing datasets will be merged into one consisting the best of all. Comparison of features in the existing dataset will inevitably lead to many conflicts when it will be necessary to decide which of the considered features should be adopted to the resulting dataset. The study considers the main purposes which...