The effects of different concentration of flaxseed gum (FG) (0.1–0.5%, w/w) on the stability of soybean oil emulsion were studied by particle size, rheological properties, creaming stability and nuclear magnetic resonance (NMR). Results showed that emulsion particle size decreased significantly with the increase in FG concentration. Rheological measurements showed FG exhibited thickening and gelling properties. Viscosity, storage modulus, and loss modulus increased accordingly with the increase in FG concentrations, and emulsions with 0.5% FG looked like a viscoelastic solid. Emulsions with a higher FG concentration exhibited better creaming stability and structure. With the increase of FG concentration, the ¹H and ¹³C NMR spectra line widths in high field also increased, which confirms that the interaction between FG and oil molecules is enhanced. These results show that FG can substitute for other emulsifiers or stabilizers in emulsions, and is beneficial to the stability of emulsions.

In the southwestern United States, precipitation in the high mountains is a primary source of groundwater recharge. Precipitation patterns, soil properties and vegetation largely control the rate and timing of groundwater recharge. The interactions between climate, soil and mountain vegetation thus have important implications for the groundwater supply. This study took place in the Sacramento Mountains, which is the recharge area for multiple regional aquifers in southern New Mexico. The stable isotopes of oxygen and hydrogen were used to determine whether infiltration of precipitation is homogeneously distributed in the soil or whether it is partitioned among soil-water ‘compartments’, from which trees extract water for transpiration as a function of the season. The results indicate that “immobile” or “slow” soil water, which is derived primarily from snowmelt, infiltrates soils in a relatively uniform fashion, filling small pores in the shallow soils. “Mobile” or “fast” soil water, which is mostly associated with summer thunderstorms, infiltrates very quickly through macropores and along preferential flow paths, evading evaporative loss. It was found that throughout the entire year, trees principally use immobile water derived from snowmelt mixed to differing degrees with seasonally available mobile-water sources. The replenishment of these different water pools in soils appears to depend on initial soil-water content, the manner in which the water was introduced to the soil (snowmelt versus intense thunderstorms), and the seasonal variability of the precipitation and evapotranspiration. These results have important implications for the effect of climate change on recharge mechanisms in the Sacramento Mountains.

In Irapuato, Guanajuato, Mexico, strawberry crops represent an important source of jobs for many people, particularly women. Traditionally, the crop is fertilized with high a rate of N (350-500 kg N ha(-1)). Thus, the objectives in this study were 1) to quantify the nitrogen uptake derived from fertilizer by the crop through the 15N isotopic technique, and 2) to quantity the water productivity. A strawberry crop cv. Chandler was transplanted to the field and fertilized with 300 kg N ha(-1) as ammonium sulphate 1% 15N atoms excess. The fertilization was split in three applications of 100 kg N ha(-1) at 30, 91 and 157 days after transplanting (dat). The lowest N-efficiency occurred in the period 0-64 dat (7%). The berries always showed the lowest N-efficiency (< 1%). The N-efficiency occurred in stage 64-91 dat. The highest N uptake from fertilizer occurred during the periods 64-91, 128-157, and 188-219 dat. In relation to water, the results indicate "poor" water productivity. The highest value observed occurred between 157-188 dat and is directly related to peak biomass accumulation. The calculated value of water productivity is 1.6 m3 kg(-1) fruit. Our data illustrate the need to continue with studies focused on the optimization the N-fertilizer and water.

Little is known of the interactions between groundwater and surface water on deeply weathered landscapes of low relief in the Great Lakes Region of Africa (GLRA). The role of groundwater in sustaining surface-water levels during periods of absent rainfall is disputed and groundwater is commonly excluded from estimations of surface-water balances. Triangulated piezometers installed beside lake gauging stations on Lake Victoria and Lake Kyoga in Uganda provide the first evidence of the dynamic interaction between groundwater and surface water in the GLRA. Stable isotope ratios (2H:1H, 18O:16O) support piezometric evidence that groundwater primarily discharges to lakes but show further that mixing of groundwater and lake water has occurred at one site on Lake Victoria (Jinja). Layered-aquifer heterogeneity, wherein fluvial-lacustrine sands overlie saprolite, gives rise to both rapid and slow groundwater fluxes to lakes which is evident from the recession of borehole hydrographs following recharge events. Darcy throughflow calculations suggest that direct contributions from groundwater to Lake Victoria comprise <1% of the total inflows to the lake. Groundwater/surface-water interactions are strongly influenced by changing drainage base (lake) levels that are controlled, in part, by regional climate variability and dam releases from Lake Victoria (Jinja).

The geochemical and isotopic composition of surface waters and groundwater in the Velenje Basin, Slovenia, was investigated seasonally to determine the relationship between major aquifers and surface waters, water–rock reactions, relative ages of groundwater, and biogeochemical processes. Groundwater in the Triassic aquifer is dominated by HCO₃–, Ca²⁺, Mg²⁺and δ¹³CDICindicating degradation of soil organic matter and dissolution of carbonate minerals, similar to surface waters. In addition, groundwater in the Triassic aquifer has δ¹⁸O and δD values that plot near surface waters on the local and global meteoric water lines, and detectable tritium, likely reflecting recent (<50 years) recharge. In contrast, groundwater in the Pliocene aquifers is enriched in Mg²⁺, Na⁺, Ca²⁺, K⁺, and Si, and has high alkalinity and δ¹³CDICvalues, with low SO₄²–and NO₃–concentrations. These waters have likely been influenced by sulfate reduction and microbial methanogenesis associated with coal seams and dissolution of feldspars and Mg-rich clay minerals. Pliocene aquifer waters are also depleted in¹⁸O and²H, and have³H concentrations near the detection limit, suggesting these waters are older, had a different recharge source, and have not mixed extensively with groundwater in the Triassic aquifer.

A medium-term forecast of the challenges and needs of agriculture at global and regional levels shows that to achieve significant increases in agricultural productivity in the developing countries not only intensification, diversification and specialization of agricultural production systems will be needed but also sustainable use and conservation of the natural resources. In response to this situation, the Joint FAO/IAEA Programme through its Soil and Water Management & Crop Nutrition sub-program, promotes the development and adoption of integrated soil, water and nutrient management practices in well-defined agro-ecosystems and cropping systems through the use of nuclear and related techniques. In the Latin American region there is an operational IAEA Technical Co-operation Project carried out in the frame of the regional program ARCAL (Regional Co-operative Agreement for the Promotion of Nuclear Science and Technology in Latin America and the Caribbean). The main features, activities and outputs/achievements of the project ARCAL XXII "Plant Nutrition, Soil and Water Management" are described. The results obtained in the regional network of field trials illustrate the use of nuclear techniques to generate technologies of integrated and efficient use of water, fertilizers, and alternative nutrient sources and their contribution to increasing agricultural productivity. A logical continuation of the ongoing project will be the formulation of a new one on sustainable management of agricultural production systems and conservation of land resources in Latin America.

The Lake Connewarre Complex is an internationally protected wetland in southeast Australia, undergoing increasing environmental change due to urbanisation. Stable isotopes of water (δ¹⁸O and δ²H) and other geochemical indicators were used to assess sources of water and salinity in the shallow groundwater and surface-water systems, and to better understand groundwater/surface-water interactions. While much of the shallow groundwater is saline (from 1.27 to 50.3 g/L TDS) with overlapping salinities across water groups, stable isotopes allow clear delineation of two distinct sources of water and salinity: marine water with δ¹⁸O between −1.4 and +1.3 ‰ and ion ratios characteristic of seawater; and meteoric water with δ¹⁸O between −6.1 and −3.6 ‰ containing cyclic salts, probably concentrated by plant transpiration. Groundwater bodies in shallow sediments beneath the wetlands have salinities and stable isotopic compositions intermediate between fresh wetland surface water and a marine water end-member. This marine-type water is likely relict seawater emplaced when the wetlands were connected to the estuary, prior to modern river regulation. Freshwater input to underlying groundwater is a recent consequence of this regulation. Future predicted changes such as increased stormwater inflow, will increase rates of freshwater leakage to shallow groundwater, favouring the proliferation of exotic reed species.

Correct understanding of groundwater/surface-water (GW–SW) interaction in karst systems is of greatest importance for managing the water resources. A typical karst region, Fangshan in northern China, was selected as a case study. Groundwater levels and hydrochemistry analyses, together with isotope data based on hydrogeological field investigations, were used to assess the GW–SW interaction. Chemistry data reveal that water type and the concentration of cations in the groundwater are consistent with those of the surface water. Stable isotope ratios of all samples are close to the local meteoric water line, and the ³H concentrations of surface water and groundwater samples are close to that of rainfall, so isotopes also confirm that karst groundwater is recharged by rainfall. Cross-correlation analysis reveals that rainfall leads to a rise in groundwater level with a lag time of 2 months and groundwater exploitation leads to a fall within 1 month. Spectral analysis also reveals that groundwater level, groundwater exploitation and rainfall have significantly similar response periods, indicating their possible inter-relationship. Furthermore, a multiple nonlinear regression model indicates that groundwater level can be negatively correlated with groundwater exploitation, and positively correlated with rainfall. The overall results revealed that groundwater level has a close correlation with groundwater exploitation and rainfall, and they are indicative of a close hydraulic connection and interaction between surface water and groundwater in this karst system.

Stable isotopes (δ¹⁸O, δD), dissolved silica (DSi) concentration and major ion composition were used to indicate groundwater/surface-water interaction between the aquifers, the rivers and a lake in the high-latitude Lake Pyhäjärvi catchment in Finland. Significant differences were recorded in water chemistry between the groundwater and surface waters, especially in the stable isotope composition and DSi concentrations, which could thus be used as tracers. The baseline data on isotopic patterns and hydrogeochemistry in the hydrological cycle were provided by a 1-year monitoring survey in this snow-type catchment area. The proportions of groundwater in the rivers, the lake inshore area and in a groundwater abstraction plant were calculated using stable isotopes and DSi. Two inflowing rivers had distinct differences in their water chemistry. DSi has potential as a tracer in the river environment, whereas stable isotopes were more applicable in the lake environment. Locally, near the shoreline, the effect of discharging groundwater on the lake-water quality could clearly be observed. Furthermore, infiltration of the lake water into the aquifer could be observed near the pumping wells onshore. This infiltration presents a potential risk for the water quality of water supply (intake) wells. Frequent sampling is needed as part of the evaluation of the level of groundwater/surface-water interaction in snow-type catchments in order to estimate the magnitude of seasonal variation. In groundwater/surface-water interaction studies, spring thaw and high-precipitation events could be problematic, in terms of both sampling and interpreting results.

Isotope hydrological studies carried out since 1987 in Haiti have proven to be effective in improving conceptual models of the principal aquifers in this Caribbean island nation. However, many of these studies have been limited and are mostly unpublished. It is, therefore, important to share the available datasets with scientists and water managers to support further studies and guide decision-making. Eleven datasets were compiled in a unique database for continued advancement and application. This dataset now contains 248 δ¹⁸O and δ²H results from water samples collected at 190 locations throughout the country. δ¹⁸O and δ²H values range, respectively, from –3.8 to –8.95‰ and –67.4 to –16.8‰ for precipitation (n = 5), 0.9 to 2.76‰ and 8.8 to 18.4‰ for lakes (n = 4), –2.61 to 4.98‰ and –26.63 to 28.2‰ for rivers (n = 11), –5.11 to –2.6‰ and –29.8 to –6.9‰ for springs (n = 82) excluding hot springs, and –5.1 to –1.37‰ and –29.4 to –2.9‰ for boreholes (n = 142). The overall presentation of the available data is complemented with an overview of the studies in which stable isotope data acquisition was performed. The global dataset is presented under three primary contexts: (1) elaboration of a local isotope meteoric water line of equation δ²H = 7.2δ¹⁸O + 8.8 supported with data predominately from the Ouest jurisdictional department, (2) spatial variability analysis of the dataset, and (3) definition of the altitude gradient (per 100 m) using freshwater springs of the Plaine du Cul-de-Sac/Massif de la Selle area of –6.67‰ for δ²H and –0.09‰ for δ¹⁸O.