Inaug.-Diss.--Heidelberg. / Vita. Bibliography: p. 237-242.

As the shortage of fresh water becomes more and more critical, alternative sources are being sought. The reuse of wastewater has become a viable option, particularly for agriculture and landscaping. However, the possible presence of the enteric pathogens, especially viruses, in wastewater has created concern about potential health risks associated with this practice. If wastewater is used for irrigation it may contaminate vegetable crops which are commonly eaten raw. Also, it may contaminate grass used for golf courses, school yards, and playgrounds where more people may be exposed. Rotaviruses may be of particular concern since they are a cause of infantile diarrhea and gastroenteritis in adults and have been a cause of waterborne disease outbreaks. No information, however, is available about the dissemination and survival of rotaviruses on uncooked food and landscaped areas. This information is necessary in developing criteria for determining safe uses of wastewater for crop irrigation. A method was developed for recovery of rotavirus from the surface of vegetables. The simian rotavirus SA-11, adsorbed onto the vegetable surfaces and effects of various eluents, pH, and exposure time, was evaluated to optimize recovery. The maximum recovery of rotavirus occurred with a solution of 3% beef extract at pH 8.0 after 5 minutes of exposure. Survival of rotavirus SA-11 on lettuce, radishes, and carrots stored at 4°C and room temperature was evaluated. Rotavirus SA-11 was able to survive up to 30 days at refrigeration temperatures and up to 25 days at room temperatures. Rotavirus survived longest on lettuce. The survival of coliphage and enteric viruses on grass was studied during winter and summer outdoors. Coliphage, poliovirus, and rotavirus SA-11 survived on two types of grass during winter and summer from 8 to 40 hours. Human rotavirus survived longer than the other enteric viruses, however, coliphage was more sensitive to inactivation. The occurrence of rotaviruses and enteroviruses in the secondarily treated sewage (activated sludge) was evaluated over a one year period. Total coliforms, pH, and turbidity were also determined. Rotavirus concentrations peaked during Spring and Winter while concentrations of enteroviruses peaked during May, September, and December. No correlation was found between the concentrations of total coliforms, rotaviruses and enteroviruses.

No description available.

Project Completion Report, OWRT Project No. A-050-ARIZ. / Agreement No. 14-31-0001-5003 / Project Dates: July 1974 - June 1976. / The work upon which this publication was based was supported in part by funds provided by the Office of Water Research and Technology (A-050-ARIZ), U.S. Department of the Interior, Washington, D.C., as authorized by the Water Research and Development Act of 1978. / INTRODUCTION: The use of treated sewage effluent by the Buckeye Irrigation Company began with 800 acre -feet in 1962 and had increased to 40,000 a.f. by 1968. The effluent was diverted by the Buckeye Irrigation Company from the Gila River approximately seven miles below the City of Phoenix 91st Avenue treatment plant, as it became available at their diversion point. Natural streamflow, used in earlier years, had virtually stopped due to upstream development except in heavy runoff years such as 1941. The ground water in the district of the Buckeye Irrigation Company is relatively high in dissolved solids. The quality of the treated effluent is better. In 1971 the company signed a 40 -year contract with Phoenix to assure its use of 30,000 a.f. of effluent per year. The effluent is mixed with native ground water to bring the total water applied on the 18,000-acre district up to approximately 90,000 a.f. (Halpenny, 1973). The treated effluent use by the Buckeye Irrigation Company is the largest in the State of Arizona and one of the largest land applications of treated effluent in the United States. It is unique in that it is being utilized by an irrigation district. Most other uses have been by city operated farms or private farms under a single ownership. In spite of its uniqueness the effects of effluent use by the Buckeye Irrigation District had not, prior to this research, been well documented. This documentation was made in order to improve the general knowledge needed to extend this type of use to other areas in the state and nation. "Widespread consideration and utilization of land application cannot be made until such time as adequate information concerning the technique involved is made available. The experience gained by those who have successfully utilized this wastewater management should be used... specific evaluation of established systems in the various climatic zones would appear to be more fruitful than new research installations for determining long term effects on soils, vegetation, ground water and the indigenous ecology..." (Sullivan, et al., 1973). During the two year research period most of the initial objectives were achieved. The original specific objectives were: 1. To identify changes during an extended period of application of treated wastewater to irrigated fields in: a. irrigation practices b. cropping patterns c. fertilization practices d. crop yield response and quality e. quality of irrigation water, and f. soil properties. 2. To make a preliminary evaluation of the effects of the use of effluent on ground-water conditions. 3. To make a preliminary evaluation of changes in water costs and farm profits.

This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Revised; Originally Published: 2009 / 4 pp. / Proper water management involves two basic considerations: when and how much irrigation water to apply. The timing of an irrigation event (the when) involves utilizing information on plant needs and soil water conditions. How much depends primarily on the soil’s water holding capacity, the depletion level and the rooting depth of the crop. Once you have calculated how much water to apply, how can you be sure that you have accurately applied that amount? Or, if you miss your target amount, how do you determine how much water you actually applied? The amount of water applied to a field is a function of time, flow and area. The time of an irrigation is easily recorded. The amount of area irrigated is also easily calculated. However, estimating flow rate in an open ditch is often guess work, at best. In this bulletin we shall discuss ways to measure water flow in an open ditch.

Over-irrigation and poor internal drainage of soils in the Indus basin of Pakistan have resulted in waterlogging and salinity problems, severely affecting agriculture. These problems may be solved by subsurface drainage or more efficient irrigation water management. Since drainage system installation is relatively expensive Pakistan, efficient irrigation management practices e.g., irrigation scheduling and on-farm water management are cheaper alternatives. / A soil water simulation model, SWAP93, was used to evaluate the effects of water stress on crop yield, water use efficiency (WUE) and crop water use in sugarcane [Saccharum officinarum L.]. This information was used to determine water management practices, which can reduce salinity and waterlogging / Drainage fluxes and evapotranspiration simulated by the model were compared with those measured in drainage lysimeters (water tables controlled at 1.5 m and 2.25 m from the soil surface) for 1989 and 1990. Drainage fluxes were overestimated, and evapotranspiration underestimated. The model's original grass-based evapotranspiration (ET) was changed to an alfalfa-based one, resulting in a better estimation of drainage fluxes and ET. / The effects of soil water balance, simulated by the SWAP93, on the crop yield, WUE and crop water use were assessed using twelve irrigation treatments consisting of four irrigation amounts (1800, 1650, 1200 and 900 mm) factorially combined with three irrigation intervals (7, 10 and 15 days) for seven years of climatic data. / Crop yields increased linearly with irrigation of 1200 mm during the growing season, Crop yield, ET and WUE were not significantly different for irrigation amounts ranging from 1200 to 1800 mm. When the total applied water was above 1400 mm, the crop yield showed a plateau. This maximum yield was reached because irrigation water was remained in the soil profile or percolated into deeper layers at high levels of irrigation application. / For a 7-day irrigation interval, the 1200 mm treatment showed water deficits during the middle of the growing season, whereas for 10- or 15-day irrigation intervals, water deficits were negligible. / A 3rd degree polynomial relationship between cumulative irrigation amount and drainage fluxes was developed, allowing a daily estimation of irrigation amount for a given percolation or capillary rise. This relationship can be used to optimize irrigation amounts, and evaluate their impacts on percolation losses. / From the results of this simulation study, it was predicted that the 1200 mm---15 irrigation application treatment (15 day interval) was best for irrigation scheduling to reduce salinity and waterlogging.

No description available.

A field lysimeter experiment was conducted on a sandy loam soil during the growing seasons of 1989 and 1990. The experiment tested the effects of four water table treatments on soybean (Glycine max) yields. The water table depths were 40, 60, 80, and 100 cm in depth. / Yields were measured in terms of: total seed mass per plant, number of seeds per plant, number of pods per plant, number of seeds per pod, and speed protein content at harvest. / The water management simulation model DRAINMOD, was used to develop irrigation and drainage strategies for soybean production. Three water table management methods were tested with each of three water table depths. The methods were conventional drainage, controlled drainage, and subirrigation, and the water table depths were 40, 60, 80, and 100 cm. / It was shown that for the driest year highest yields are obtained with subsurface irrigation and a weir setting of 40 cm. For the average year, highest yields are obtained with subirrigation and a 60 cm weir setting. For the wet years, best results are found when controlled drainage is used with 80 cm weir setting. It was found that in all but the driest and wettest years controlled drainage improved yields by 10% or more.

Surface runoff is one of the most important problems which occur with moving sprinkler irrigation systems: it is particularly severe in centre pivot systems operated at low pressure. The consequences of surface runoff are waste of water, lower irrigation efficiency, soil erosion and removal of fertilizers from the field. An obvious indicator of the potential for runoff to occur during sprinkler irrigation is the appearance of surface ponding. Indeed, results from a stationary "time to ponding" test (using a minimum set of three constant water application rates) carried out on the farm, is commonly used to determine the irrigation rate in moving systems. This practice sometimes leads to the occurrence of runoff under moving systems, particularly centre pivot systems. / The primary aim of the investigation was to explore the phenomenon of soil surface ponding in stationary "time to ponding" tests (using constant water application rate) and in moving sprinkler irrigation systems (using variable water application rate), and to discover the relationship between these two sets of conditions, in order to improve the design and managements of these systems and avoid runoff. / A vital component of the investigation was the development of a laboratory rig which incorporated certain characteristics and properties, including: A special soil test bed containing 355mm depth of a loamy sand soil, together with a system continuously measuring and monitoring soil moisture content. The rig also included heating and suction systems to reduce and establish target soil moisture conditions before each test, and an efficient drainage system. Ponding was identified in 15 circular depressions on the soil surface. A water application simulator capable of being operated in both stationary and moving modes at different speeds, applying different constant and variable irrigation rates to the soil test bed with very small droplets. The nature of the supply closely approximated that of field installations. A continuous water application measurement device capable of measuring instantaneous water application rate and pattern as well as irrigation depth applied to the soil test bed. / Certain parameters, of necessity, were fixed for the investigation: these included the soil, the type of variable application pattern (parabolic), the range of speeds of the moving simulator (10% to 100% of maximum speed which was 345mm/minute) and the range of initial soil moistures (3% up to field capacity). Initial tests were carried out to determine a suitable water application rate: this was set as 103mm/h (average). The main set of tests was carried out using this average application rate under constant ("time to ponding") and variable ("onset of ponding") irrigation conditions at different soil moisture contents. / The main outcome of the research was that the maximum irrigation depth that can be applied by a moving system (variable pattern) without the appearance of ponding for any set value of initial soil moisture, is significantly less than the maximum irrigation depth which must be applied to produce ponding in a stationary system (constant pattern), operated with the same initial soil moisture and same average application rate. Therefore, the results obtained from a “time to ponding” test, if applied directly, overestimate the optimum water application rate and also the maximum irrigation depth which can be applied in moving irrigation systems, if they are to operate efficiently. / A relationship was established between the two sets of outcomes for corresponding soil and water application rate and pattern conditions. The apparatus and the method can be used for further research to discover similar relationships for different soil types and different water application rates and patterns in order to provide a general model. This model can be used to modify the optimum water application rate (obtained directly from stationary "time to ponding" tests) and, also, the maximum irrigation depth (through choice of speed appropriate to the initial soil moisture) in moving sprinkler irrigation systems, particularly in centre pivot systems. / Thesis (PhDCivilEngineering)--University of South Australia, 2005.