In the developed world most of domestic sewage is treated by the activated sludge process, which results in large volumes of sludge or biosolids being produced. This results in millions of tons of biosolids produced each year in the United States, which must either be disposed of or recycled in some manner. Land application is seen as the most economical and beneficial way of handling biosolids. Although the United States Environmental Protection Agency supports and regulates the land application of biosolids, more research is needed to ensure its safe.The Appendix study A assessed the potential of Salmonella regrowth in Class A biosolids pellets and compost after land application. No Salmonella growth occurred in any of the soil/biosolids mixtures regardless of inoculum size or moisture content. While regrowth of Salmonella in biosolids may occur under saturated conditions it does not occur after Class A biosolid land application at typical agronomic rates. The Appendix B study evaluated the sensitivity of BGM and PLC/PRF/5 cell lines for detection of viruses as well as the occurrence and concentration of adenoviruses. The PLC/PRF/5 cell line was more sensitive for the detection of adenovirus and other enteroviruses in raw and Class B biosolids. The Appendix C study determined the potential of regrowth of Salmonella typhimurium in vermicompost and Class A biosolids alone and after addition to soil. In summary, no regrowth of Salmonella was observed, and the die-off of Salmonella was not different in soil, biosolids or vermicompost.

Site preparation effects on growing season soil water regimes were investigated on three clearcut, grass-dominated sites in the Interior Douglas-fir (IDFdk), Montane Spruce (MSxk) and Engelmann spruce-Subalpine fir (ESSFxc) Biogeoclimatic Subzones, near Kamloops, British Columbia. The response of newly planted Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and lodgepole pine (Pinus contorta Dougl.) to these treatments was determined at the IDFdk site. Soil water regimes were measured in scalped, ripped and herbicide site preparation treatments and in an untreated control using a neutron moisture meter, a two-probe gamma-density gauge, tensiometers and thermocouple psychrometers. At the IDFdk, seedlings were spring planted in each of the treatments and control to determine whether microclimate modification by site preparation would improve seedling water relations, growth and survival during the first growing season. Root zone soil water content was most limited at the low-elevation site (IDFdk) and least limited at the high-elevation site (ESSFxc). The different site preparation treatments provided similar increases in root zone soil water content, profile water storage and drainage at each site. This resulted in substantial increases in soil water supply at the lowest two sites. Site preparation resulted in increased Douglas-fir and lodgepole pine stomatal conductance (gs), transpiration (E), leaf area, root egress, root collar basal area and dry matter production. Survival of both species was high in the control and in all site preparation treatments. Both species had similar seasonal patterns of gs and E in the control. In the site preparation treatments, lodgepole pine had greater gs, and by late summer, greater E than Douglas-fir. Although lodgepole pine had substantially higher twig xylem pressure potentials and lower soil-plant liquid flow resistances than Douglas-fir, both species appeared well adapted to survive drought. First growing season stomatal responses of both species to environmental conditions, including normalized vapor pressure deficit at seedling height (Ds/P), solar irradiance (Rs) and root zone extractable water (Φe), were similar when normalized against annual maximum conductance (gsmax ). A multiplicative model with non-linear least squares optimization (NLLS) of response functions to Rs, Ds/P and Φe provided a simple, reasonably accurate description of gs/gsmax for both species, and accounted for differences in gs between the control and ripped treatment. In most cases, the NLLS models developed for a given species and year resulted in relatively precise (R²>0.60) and unbiased estimates of gs /gsmax, and yielded estimates of mean daily stomatal conductance (Gs ) and total daily transpiration (T) within 20% of measured values, for the same species in other years. / Land and Food Systems, Faculty of / Graduate

The Monument Valley UMTRA Site is a former uranium mining site that is located in Cane Valley, Arizona. The mining that occurred there from 1943 to 1968 created a groundwater contaminant plume that consists of nitrate, sulfate, and uranium. There are only a few viable methods for remediation of these types of contaminants occurring in large, deep plumes. Monitored natural attenuation is a popular approach because it is a green and low-cost alternative. However, it is often ineffective without some form of supplemental enhancement. In-situ biosequestration is one method of enhanced attenuation, which involves injecting an electron- donating substrate that will promote microbial activity and sequester contaminants by bioprecipitation, biomineralization, and enhanced adsorption. Prior tests conducted at the Monument Valley site in the center of the plume using ethanol as the electron donor proved effective in the treatment of nitrate, sulfate, and uranium. Subsequent pilot scale tests are being conducted in the source zone of the Monument Valley Site to further investigate the feasibility and effectiveness of using in-situ biosequestration for treatment of uranium contaminated groundwater. The preliminary results of these tests are discussed.

The hydrological components of land surface climate models have increased greatly in complexity over the past decade, from simple bucket models to multilayer models including separate and distinct soil water and ground water components. While the parameterizations included in these models have also increased in complexity, the fundamental ability of the numerical solution for the vertical movement of soil water in the Community Land Model (or other land surface models) to simply maintain the hydrostatic solution of the original partial differential equation has yet to be determined.Also, the ability of current generation reanalysis products to simulate near surface quantities as gauged by flux tower measurements has yet to be determined.This study demonstrates that the numerical solution as used in CLM3.5 cannot maintain the hydrostatic state. An alternate form of the equation, titled the Modified Richards equation is presented so that the numerical solution maintains steady statesolutions. Also, an improved and simple bottom boundary condition is derived that itself doesn't destroy hydrostatic initial conditions. The new solution is demonstrated to be as accurate as proven numerical solutions while being one to three orders more computationally efficient. The Modified Richards equation together with the new bottom boundary condition is shown to improve the ability of CLM to simulate soil water, water table depth, and near surface turbulent fluxes.Comparison with flux tower observations shows that ERA-Interim better simulates near surface temperature and wind speed than other current generation reanalysis products. Reanalysis products are able to reproduce the flux tower observations on monthly timescales, and the errors between the products and the measurements are primarily due to biases. However, at six hourly timescales the errors are not only larger but also caused primarily by a lack of correlation with the observations.

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No description available.

The measurement of water in soil on a potential, gravimetric or volumetric basis is considered, with studies concentrating on the measurement of water by dielectric and neutron moderation methods. The ability of the time-domain reflectometry technique to measure water content simultaneously at different spatial locations is an important advantage of the technique. The reported apparent dielectric by the TRASE� time-domain reflectometer and Pyelab time-domain reflectometry systems is sensitive to change in extension cable length. In some soil, e.g. a commercial sand, the response to increasing extension length of extension cable is linear. For other soil a linear response occurs for certain lengths of cable at different moisture contents. A single model accounting for clay content, extension cable length, time-domain reflectometry system, probe type and inherent moisture conditions explained 62.2 % of variation from the control (0 m extension) cable. The extension cable causes a decrease in the returning electromagnetic-wave energy; leading to a decline in the slope used in automatic end-point determination. Calibration for each probe installation when the soil is saturated, and at small water contents is recommended. The ability of time-domain reflectometry, frequency-domain and neutron moderation techniques in measuring soil water content in a Brown Chromosol is examined. An in situ calibration, across a limited range of water contents, for the neutron moderation method is more sensitive to changing soil water content than the factory supplied 'universal' calibration. Comparison of the EnviroSCAN� frequency-domain system and the NMM count ratio indicates the frequency-domain technique is more sensitive to change in soil water conditions. The EnviroSCAN� system is well suited to continuous profile-based measurement of soil water content. Results with the time-domain reflectometry technique were disappointing, indicating the limited applicability of time-domain reflectometry in profile based soil water content measurement in heavy-textured soil, or soil with a large electrical conductivity. The method of auguring to a known depth and placement of the time-domain reflectometry probe into undisturbed soil is not recommended. A time-domain reflectometry system is adapted for in situ measurement of water in an iron ore stockpile. The laboratory calibration for water content of the processed iron ore compares favourably to a field calibration. In the field study, the 28 m extension cable used to connect the probes to the time-domain reflectometry affected the end-point determination of the time-domain reflectometry system. To account for this, 0.197 should be subtracted from the reported apparent dielectric before calculation of volumetric moisture content.

The estimation of evapotranspiration (ET), a key process within the Earth's surface water and energy balance, remains an important challenge for a wide range of disciplines such as surface hydrology, irrigation management and meteorology. However, notwithstanding the considerable progress recently made in our understanding of the physical and biological processes governing ET, the accurate quantification of ET is very tricky to achieve, even at a limited spatial scale. In this study, we combine field measurements with numerical experiments to tackle issues related to the quantification of ET and the associated uncertainties for a maize cropped field using two different approaches, i.e. the agro-hydrological modelling and the soil water balance approach. For the agro-hydrological modelling, we mainly focus on the estimation of field-scale soil water content and on the identification of root water uptake parameters. With regard to the field-scale soil water content, we put forward that the within-field variability is large and that the maize crop plays a non-negligible role in the development of the soil water content patterns both at the field and at the maize row scale. For deriving root water uptake parameters (RWUP), we develop and test two different approaches, i.e. the simplified soil water balance and the inverse modelling approach. Using numerical experiments, we show that the simplified soil water balance approach produces quite accurate RWUP. On the other hand, the inverse modelling approach is only successful for some soils and for some conditions due to instability and nonuniqueness issues. For the soil water balance approach, we show that the accuracy of the local ET estimate is strongly dependent on the estimation method used to derive the bottom fluxes and that the use of pedotransfer functions is of little interest. For field-scale ET estimates, we show that the variability of ET is large both at the field scale (due to the variable crop growth) and at the maize row scale (due to the maize row layout). To produce accurate field-scale ET estimates, we suggest to scale up maize row scale ET estimates using the concept of temporal stability or using a covariant such as the Leaf Area Index. The results of our study suggest that the estimation of water fluxes or associated state variables for a row cropped field requires a two-step upscaling strategy, from the local scale to the row, then from the row to the field scale.

The feed production cost in tilapia diets is driven by the prices of its ingredients such as fishmeal (FM) and soybean meal (SBM). Fishmeal and soymeal combined with other ingredients provides fish with the nutrients required for growth and sustaining life. Soybean meal is used as an alternative to fishmeal, but prices for this traditional ingredient have increased significantly in recent years as a result of high market demand from other industries. Consequently, there has been an increase interest by tilapia nutritionists and feed manufacturers to find less expensive, alternative feedstuffs for use in tilapia diets. Camelina (Camelina sativa) is an oil seed crop grown in higher latitudes especially along the US - Canada border, northern China and northern Europe. Camelina after removal of most of the edible oil has been proposed as a fish feed ingredient. A sixty-day feeding trial was conducted and diets were formulated to contain various levels of camelina inclusion (0, 5, 10, 15, 20 and 25%) for the "camelina meal" while the "camelina oil" was formulated to contain one level (4.7%) of oil and was divided as "raw" and 4.7 "wash". The results indicated that that fishes fed diets containing camelina ingredients had growth performance and feed utilization results that were similar to fish fed the commercial diet (P>0.05). There were significant differences (P<0.05) for body organ indices and body composition. The 15% camelina meal diet was the lowest cost experimental diet per kilogram gain and therefore, this alternative ingredient might be a potential replacement for soymeal in a more cost effective feed formulation. The fatty acid composition of tilapia fillets was also analyzed at the end of the feeding trial. The inclusion of camelina meal and oil in tilapia diets resulted in significant increases in the Omega-3/Omega-6 ratio in fillets when compared to the control. The 15% camelina meal provided the best results of the experimental diets yielding significantly higher polyunsaturated fatty acid (PUFA) and lower saturated fatty aid (SFA) than the control diet. On a commercial scale, tilapia commercial feeds differ in both formulated nutrient levels and ingredient composition. In intensive system culture, natural food is limited making it important that all nutrients are supplied through a complete pelleted diet. An advantage to feeding a pelleted diet is that the pellet-type feed enables the farmers, feed formulators and manufactures to design a diet that provides an optimal nutritional mix for tilapia. Precise levels in the protein and lipid percentages of tilapia diets can reduce feed costs and also reduce the amount of underutilized protein and lipids stored as fat in tilapia. Feed comprises of over 60% of the variable cost in the intensive aquaculture operation; if feed prices were to increase, it would be a substantial amount for tilapia producers to absorb. Therefore an improved diet formulation designed for tilapia can increase profitability. Results indicated that the experimental diets (28% Crude Protein (CP)-Amino Acid (AA), 28% CP and 40% CP) performed similar to the control diet (32% CP) as it relates to fish growth. The experiment conducted on a commercial scale at an operating farm found that feeding tilapia the lowest protein level diets (28% CP) resulted in higher biomass gain per raceway, biomass gain per fish and significantly higher protein efficiency ratio (PER) when compared to the control diet (32% CP). The 28% CP diet also had the second best FCR value and most importantly higher returns based on its FCR when compared to the control diet (32% CP).

ABSTRACT The TDR measures soil water content by measuring the travel time of an electromagnetic step pulse through a wave guide embedded in the soil. Damage during insertion and retrieval of the probe makes it unsuitable for repeated use. A multilevel-TDR probe with adequate protection for cable was designed and tested to overcome this problem. Each section of the multilevel-TDR probe was constructed by embedding a 60 mm centre rod and a 63 mm outer loop in grooves on the outer wall of a 200 mm section of PVC pipe. Fifteen such probes were tested in the laboratory and the field by comparing it with the weighing method. Regression analysis between TDR-ϴv and weighing method-ϴv showed good correlation with an R2 of 0.97 and 0.98 during two laboratory experiments and 0.51 during the field experiment. This multilevel probe is cost effective, reusable and can measure soil water content at different depths.