Instantaneous Water Research Articles

Nitrogen nutrition effects on triticale photosynthesis and assimilate translocation under late-season water stress conditions

In this study, photosynthesis and assimilate translocation and their contribution to improving grain yield and harvest index (HI) of triticale under different N sources and irrigation regimes in an arid climate were evaluated. There were two levels of water regimes: normal irrigation (IRN) and deficit irrigation (cutting irrigation after anthesis stage - IRD). Four N sources: Azospirillum brasilense (Bio), Azospirillum brasilense + 75 kg N ha−1 as urea (Bio + N75), 150 kg N ha−1 as urea (N150) and control unfertilized (N0) plots were used. Results showed the highest net photosynthesis rate (Pn ) was observed in Bio + N75 (24 and 20 µmol CO2 m−2 s−1 at the milking and soft dough stages, respectively) under IRN. The IRD decreased Pn in all N sources, however, the highest reduction was observed in N150 and the lowest in Bio and Bio + N75 treatments. Similar trends were observed in other photosynthetic traits and assimilate remobilization, except for the instantaneous water use efficiency (IWUE), which increased by IRD when bio-fertilizer was applied. The highest grain yield was found by N150 under IRN, which was not significantly different from Bio + N75 treatment. In contrast, application of Bio + N75 resulted in the highest grain yield compared to the other N sources under IRD. Overall, since the lowest reduction in photosynthetic traits, assimilate remobilization, and grain yield of triticale under IRD conditions occurred when bio-fertilizer was applied, this N fertilizer regime could be recommended for the arid areas where water shortage occurs frequently.

Divergent Leaf Morpho-Physiological and Anatomical Adaptations of Four Lettuce Cultivars in Response to Different Greenhouse Irradiance Levels in Early Summer Season.

Lettuce (Lactuca sativa L.) is a winter-spring leafy vegetable, but the high demand for fresh products available year-round requires off-season production. However, the warm climate of the Mediterranean areas can impair the summer production of lettuce, thus requiring the adoption of genotypes tolerant to high irradiance as well as useful agronomic strategies like shading net installations. The aim of our research was to assess the leaf morpho-physiological and anatomical changes, in addition to productive responses, of four lettuce cultivars (‘Ballerina’, ‘Maravilla De Verano Canasta’, ‘Opalix’, and ‘Integral’) grown under shading and non-shading conditions to unveil the adaptive mechanisms of this crop in response to sub-optimal microclimate (high irradiance and temperature) in a protected environment. Growth and yield parameters, leaf gas exchanges, chlorophyll fluorescence and morpho-anatomical leaf traits (i.e., leaf mass area, stomatal density and epidermal cell density) were determined. Under shading conditions, the fresh yields of the cultivars ‘Ballerina’, ‘Opalix’ (‘Oak leaf’) and ‘Integral’ (‘Romaine’) increased by 16.0%, 26.9% and 13.2% respectively, compared to non-shading conditions while both abaxial and adaxial stomatal density decreased. In contrast, ‘Canasta’ under non-shading conditions increased fresh yield, dry biomass and instantaneous water use efficiency by 9.6%, 18.0% and 15.7%, respectively, while reduced abaxial stomatal density by 30.4%, compared to shading conditions. Regardless of cultivar, the unshaded treatment increased the leaf mass area by 19.5%. Even though high light intensity and high temperature are critical limiting factors for summer lettuce cultivation in a protected environment, ‘Canasta’ showed the most effective adaptive mechanisms and had the best production performance under sub-optimal microclimatic conditions. However, greenhouse coverage with a white shading net (49% screening) proved to be a suitable agricultural practice that ensured an adequate microclimate for the off-season growth of more sensitive cultivars ‘Ballerina’, ‘Oak leaf’ and ‘Romaine’.

Alternative Water Heating Technologies Replaced Instantaneous Water Heater in Hotel Sector – a SWOT-AHP Analysis

In pursue of energy-efficient alternative water heating options, a SWOT-AHP analysis was accomplished for Solar Water Heater (SWH) and Heat Pumps (HP) against instantaneous water heaters (IWH). The results show that the energy consumption and bills saving are dominant in strength of both HP and SWH. Financial and technological aspects seem to play a relatively significant role. Additionally, HP and SWH are more convenient for the energy consumption in water heating technology in hotel sector of Thailand. Finally, we can say that HP and SWH are more convenient for water heating system as compare to IWH.

Yield Comparisons between Cotton Variety Xin Nong Mian 1 and Its Transgenic ScALDH21 Lines under Different Water Deficiencies in a Desert-Oasis Ecotone

Water scarcity is the major limiting factor for oasis-desert agricultural production of cotton. It is necessary to improve cotton for drought tolerance and minimize drought-related crop losses, and the transgenic approach is efficient for cotton improvement. In order to evaluate the value of ScALDH21 transgenic cotton (G. hirsutum L.), it was tested in the main cotton region of south Xinjiang, in an environment of extreme drought around the desert. Transgenic cotton, overexpressing aldehyde dehydrogenase gene (ScALDH21) from the desiccation-tolerant moss Syntrichia caninervis in cotton variety Xin Nong Mian 1, was field-tested under six treatments based on three irrigation schedules and two irrigation levels (full (FI) and deficit (DI) irrigation) as follows: root zone model-simulated forecast irrigation (F) (FFI and FDI), soil moisture sensor-based irrigation (S) (SFI and SDI), and flood irrigation based on experience estimates (E) (EFI and EDI) to evaluate growth and yield performances. The results revealed that plant height and leaf area increased significantly in ScALDH21-transgenic cotton genotypes under all treatments. Physiological parameters such as chlorophyll content, net photosynthesis rate, and instantaneous water use efficiency were not significantly highly in transgenic lines compared to non-transgenic plants (NT). However, transgenic lines showed significantly improved yield and superior fiber quality than NT plants regardless of irrigation. The results demonstrate that ScALDH21-transgenic lines were excellent compared to NT plants under different water deficiency conditions. The study also provides guidelines for optimal irrigation protocol and minimum water requirements for the use of the ScALDH21-transgenic cotton lines in arid zones.

Foliar application of H2O2 as salt stress attenuator in ‘BRS Rubi do Cerrado’ sour passion fruit

Irrigation with saline water causes a reduction in yield, especially in semi-arid regions. Cultivation strategies have been developed to mitigate salt stress on plants, such as the use of hydrogen peroxide. The objective of this study was to evaluate the attenuating effect of hydrogen peroxide on the gas exchange and growth of ‘BRS Rubi do Cerrado’ sour passion fruit cultivated under irrigation with saline water. The design was completely randomized in split-plot plots, with water salinity levels ECw (0.6, 1.2, 1.8, 2.4, and 3.0 dS m-1) considered the plots and the concentrations of hydrogen peroxide H2O2 (0, 15, 30, and 45 μM) considered the subplots, with three replicates. Gas exchange (stomatal conductance, transpiration, CO2 assimilation rate, intercellular CO2 concentration, instantaneous water use efficiency, and instantaneous carboxylation efficiency), and absolute and relative growth rates in stem diameter were evaluated. An increase in irrigation water salinity from 0.6 dS m-1 reduced gas exchange, and exogenous application of hydrogen peroxide did not promote a significant effect on gas exchange. However, foliar application of hydrogen peroxide at 15 μM increased the growth of ‘BRS Rubi do Cerrado’ sour passion fruit.

Biochar application rate does not improve plant water availability in soybean under drought stress

Biochar, a form of porous pyrogenic carbon, has been shown to influence soil physicochemical properties and increase crop yield. However, it is unclear whether biochar application at different rates will improve crop performance in a clay soil under drought conditions through increasing plant water uptake. Here, we examined performance of soybean after amendment with biochar (pyrolysed at ~400 °C for 5 h) at four application rates (0, 25, 50 and 100 t ha−1) and grown under three moisture regimes (40%, 60% and 80% of field capacity). The instantaneous plant water content was determined periodically by recording relative water content, water retention capacity, and water uptake capacity in leaves while the cumulative water stress and water use efficiency (WUE) were determined from aboveground δ13C signatures and amount of water applied, respectively. The yield and yield attributes were also recorded. Results showed that across all drought treatments, biochar application significantly enhanced crop growth rate and increased total biomass production with a doubling in yield in the 100 t ha−1 biochar application. However, the seed yield did not increase with biochar application. Although biochar application improved WUE (biomass produced per unit of water applied), it most likely did not improve plant water uptake, since none of the measured plant water status indicators were affected by biochar. Instead, the enhanced biomass production may have been caused by an improvement in plant nutrition. Possibly, biochar application increased N acquisition through biological nitrogen fixation as there was a significant relationship between nitrogen (N) concentration in aboveground biomass and total biomass production. Moreover, application of biochar increased soil available potassium (K), and enhanced K uptake may have increased stress tolerance in soybean. Therefore, our findings show that biochar could improve plant performance in a clay soil by improving nutrient supply rather than by increasing water uptake.

Unsaturated Flow Processes and the Onset of Seasonal Deformation in Slow‐Moving Landslides

AbstractPredicting rainfall‐induced landslide motion is challenging because shallow groundwater flow is extremely sensitive to the preexisting moisture content in the ground. Here, we use groundwater hydrology theory and numerical modeling combined with five years of field monitoring to illustrate how unsaturated groundwater flow processes modulate the seasonal pore water pressure rise and therefore the onset of motion for slow‐moving landslides. The onset of landslide motion at Oak Ridge earthflow in California’s Diablo Range occurs after an abrupt water table rise to near the landslide surface 52–129 days after seasonal rainfall commences. Model results and theory suggest that this abrupt rise occurs from the advection of a nearly saturated wetting front, which marks the leading edge of the integrated downward flux of seasonal rainfall, to the water table. Prior to this abrupt rise, we observe little measured pore water pressure response within the landslide due to rainfall. However, once the wetting front reaches the water table, we observe nearly instantaneous pore water pressure transmission within the landslide body that is accompanied by landslide acceleration. We cast the timescale to reach a critical pore water pressure threshold using a simple mass balance model that considers variable moisture storage with depth and explains the onset of seasonal landslide motion with a rainfall intensity‐duration threshold. Our model shows that the seasonal response time of slow‐moving landslides is controlled by the dry season vadose zone depth rather than the total landslide thickness.

Effect of applying a calcined kaolin-based particle film on the photosynthetic capacity and growth of young eucalyptus plants

In scenarios of climatic change when increased global temperatures can be expected, it is essential to search for technologies that favor sapling survival and growth after planting and increase yield in the field. Kaolin-based particle films (KBPF) have been applied as barriers against the deleterious effects of high levels of solar radiation. The objective of the present study was to assess the effects of applying purified calcined kaolin-based particle film to young eucalyptus plants. Five treatments were carried out: 0% (just water), 3%, 5%, 7%, and 10% calcined kaolin applied to the adaxial part of the leaves. A complete randomized block design was used with five treatments and ten replicates. The plants were assessed for height, diameter at ground level, gas exchanges (net photosynthetic CO2 assimilation, stomatal conductance and transpiration), instantaneous (WUE) and intrinsic water use efficiency (IWUE), chlorophyll a fluorescence (maximum quantum yield of photosystem II (PSII) (Fv/Fm), concentration of active reaction centers in relation to the quantity of photons absorbed (RC/ABS) and the maximum ratio of quantum yields of photochemical and concurrent non-photochemical processes in PSII (Fv/F0), SPAD reading and leaf ontogeny. The 3% KBPF concentration showed the best responses in biometric assessments 80 days after planting (DAP) and were corroborated by the responses of the leaf, stem and shoot dry matter production as a whole. The leaf ontogeny assessments showed positive responses following KBPF application when considering leaf development, with 7% KBPF concentration resulting in the highest mean values. The mean specific leaf mass had negative response to high KBPF concentrations. At 60 DAP, the gas exchange variables during both assessment periods declined with an increase in KBPF concentration. Significant differences as a result of KBPF applications were found only at the start of the assessments (34 DAP) for both WUE and for IWUE. Leaf ‘greenness’ (SPAD reading) at 47 days showed a quadratic relationship in both periods. The variables of chlorophyll fluorescence showed a linear response at 34 DAP and a quadratic response 60 DAP. KBPF application increased height and diameter growth in plants treated with 3% KBPF but this response was not associated with photochemical efficiency and photosynthetic carbon assimilation values on a single-leaf basis. The best performance among the variables was provided by 3% KBPF application.

Economic and environmental performance of instantaneous water heating system for craft beer production

While microbrewery has become very popular, energy efficiency is a great challenge to microbrewers which causes low profitability margins and poor environmental performance. With a high heating rate, instantaneous water heating system (IWHS) is a potential alternative to steam boiler for beer brewing. This study developed an integrated techno-economic analysis (TEA) and life cycle assessment (LCA) to, for the first time, evaluate the economic and environmental consequences of IWHS implementation in a microbrewery. Results showed that labor, packaging and raw materials were the major variable costs of craft beer. The net present value and internal rate of return calculated indicated that the investment in IWHS was not profitable to the microbrewery with its current productivity. Raw material production and beer processing were the environmental hotspots of craft beer. Due to reduced gas use for mashing and cleaning, IWHS decreased the global warming potential of craft beer by approximately 22.4%. Besides justifying the IWHS investment, enlarging the production scale of the microbrewery can reduce the environmental footprint of its beer. This study provided microbrewers with a holistic tool with clear indicators to evaluate the economic and environmental feasibility of alternative hot water supply systems for a more sustainable craft beer production.

Free surface flow over square bars at different Reynolds numbers

Large-eddy simulations of free surface flow over bed-mounted square bars are performed for laminar, transitional and turbulent flows at constant Froude number. Two different bar spacings are selected corresponding to transitional and k-type (reattaching flow) roughness, respectively. The turbulent flow simulations are validated with experimental data and convincing agreement between simulation and measurement is obtained in terms of water surface elevations and streamwise velocity profiles. The water surface deforms in response to the underlying bed roughness ranging from mild undulation for transitional roughness to distinct standing waves for k-type roughness. The instantaneous water surface deformations increase with an increase in Reynolds number. Contours of the mean streamwise and wall-normal velocities, the total shear stress and the streamfunction reveal the presence and extension of recirculation zones in the trough between two consecutive bars. The flow is governed by strong local velocity gradients as a result of the rough bed and the deformed water surface. The local Froude number at the free surface increases for low Reynolds number in the flow over transitional roughness and decreases for low Reynolds number in the flow over k-type roughness. The transitional and turbulent flows exhibit a very similar distribution of the pressure coefficient Cp in both cases, whilst Cp is generally lower for the laminar flow. Regarding the friction coefficient, Cf, it is significantly lower in the turbulent case than in the transitional and laminar cases. The bar spacing does not affect significantly the relative contribution of friction and pressure forces to the total force, neither does the Reynolds number. The friction factor is greater for transitional roughness and decreases with increasing Reynolds number.

Calcium improves the leaf physiology of salt treated Limonium stocksii: A floriculture crop

Calcium acts as a signaling molecule in many plants to improve resistance during unfavorable environments. Limonium stocksii (Boiss.) Kuntze seedlings were grown in 0 and 600 mmol L−1 NaCl (with and without additional 15 mmol L−1 Ca2+) for 15 d. The effects of these treatments were studied on plant growth, leaf water relations, malondialdehyde (MDA) content, ion-flux, Na+ secretion rate and photosynthesis. Plant biomass declined by 50% and MDA content increased by 50% in plants treated with 600 mmol L−1 NaCl for 15 d. Leaf water content (WCFM) and relative water content declined and sap osmolality increased after 3 d of 600 mmol L−1 NaCl treatment. Leaf Na+, Na+/K+ ratios and Na+ secretion rate were increased in salinity treatment. Decrease in photosynthesis was coupled with lower stomatal conductance and intercellular CO2, however, instantaneous water use efficiency was improved under salinity treatment. Efficiency of PSII, relative electron transport rate, photochemical quenching and non-photochemical quenching were reduced by salinity treatment compared to non-saline control. The Ca2+ application yielded 25% higher fresh mass at enhanced water contents while lowers tissue osmotic potential and membrane damage in plants exposed to high salinity. The Na+ accumulation in the leaf was reduced, while the secretion was increased in the presence of additional Ca2+. However, Ca2+ application did not improve either the photosynthetic gas exchange or light reactions of photosynthesis under saline conditions. Our results indicated that L. stocksii decreases its growth, water content, photosynthesis and dark respiration under increased leaf Na+ concentrations. Whereas, application of Ca2+ enhanced plant salinity resistance by improving water balance, Na+-secretion and membrane integrity.

Grafting Enhances Pepper Water Stress Tolerance by Improving Photosynthesis and Antioxidant Defense Systems.

Currently, limited water supply is a major problem in many parts of the world. Grafting peppers onto adequate rootstocks is a sustainable technique used to cope with water scarcity in plants. For 1 month, this work compared grafted peppers by employing two rootstocks (H92 and H90), with different sensitivities to water stress, and ungrafted plants in biomass, photosynthesis, and antioxidant response terms to identify physiological–antioxidant pathways of water stress tolerance. Water stress significantly stunted growth in all the plant types, although tolerant grafted plants (variety grafted onto H92, Var/H92) had higher leaf area and fresh weight values. Var/H92 showed photosynthesis and stomata conductance maintenance, compared to sensitive grafted plants (Var/H90) and ungrafted plants under water stress, linked with greater instantaneous water use efficiency. The antioxidant system was effective in removing reactive oxygen species (ROS) that could damage photosynthesis; a significant positive and negative linear correlation was observed between the rate of CO2 uptake and ascorbic acid (AsA)/total AsA (AsAt) and proline, respectively. Moreover, in Var/H92 under water stress, both higher proline and ascorbate concentration were observed. Consequently, less membrane lipid peroxidation was quantified in Var/H92.

An IoT Based Water Quality Testing Device: An Approach to Modelling a Geographical Map Based on Water Quality Data and Decision Support System

According to the World Health Organization, 30% people lack access to safe water. Normally water quality is evaluated in a scientific laboratory which is expensive, time-consuming and impractical for real-time implementation. Thus, researchers have introduced different electronic devices to test water quality in real-time. However, these methods focused only on testing device development rather than disseminating resultant information for real-life applications. Moreover, these devices did not have any correlation with mobile decision support system and notification. To address these limitations, an integrated decision support system has been developed for instantaneous water quality detection by hardware configuration, smartphone application and web-based mapping. The evolved device automatically calculates six types of water parameter values, while the smartphone application categorizes water quality and notifies its consumption suitability by decision support system. The smartphone application also stores the GPS location of the water source and water quality data and also sends to the server for generating geographical map concerning its quality. Smartphone application’s stored data and central stored data are synchronized based on location. The smartphone also generates notification even without any access to the internet when a user enters into a lowerwater quality region. This package of solutions can be implemented all over the world for ensuring safe water.

Growth and physiological responses of cotton plants to salt stress

AbstractThe objective of this study was to investigate the growth and physiological responses cotton plants to salt stress. At seven leaf stage, cotton plants were subjected to two treatments; 0 mM NaCl as the control and 150 mM NaCl as the salt stress treatment, respectively. The effect of salt stress on leaf gas exchange rates, leaf nitrogen concentration, chlorophyll content, leaf K+ and Na+ concentrations, plant water status, endogenous phytohormone concentrations, dry matter accumulation and partitioning in plant organs was evaluated. The results showed that salt stress significantly decreased plant growth, water consumption, leaf water relations characteristics and leaf gas exchange rates as compared to the control. Under salt, photosynthetic rate was reduced to less extend than did stomatal conductance (gs) and transpiration rate, resulting in greater intrinsic and instantaneous water use efficiencies compared to the control plants. gs decreased linearly with decreasing leaf water potential and leaf hydraulic conductance under salt. Salt‐stressed plants possessed a significant higher concentration of abscisic acid ([ABA]leaf), while a significantly lower concentrations of gibberellic acid ([GA3]leaf) and zeatin riboside ([ZR]leaf) in leaf than those grown under control. Negative linear relationships were found between gs and [ABA]leaf, ratio of [ABA]leaf to [GA3]leaf, ratio of [ABA]leaf to ([GA3]leaf+[ZR]leaf), respectively. Salt stress significantly decreased leaf K+ concentration, the ratio of K+/Na+ in leaf, shoot growth and biomass partitioning into leaf and stem, whereas increased leaf chlorophyll content, leaf nitrogen concentration and biomass partitioning into boll. Although the water use efficiency of plant biomass was unaffected, the water use efficiency of boll biomass was significantly enhanced by salt stress. Collectively, salt‐induced changes in both hydraulic and chemical properties were involved in mediating the leaf gas exchange response to salt stress, and the enhanced leaf nitrogen concentration and biomass partitioning into boll may lead to a sustained yield with less water consumption in cotton plants grown under moderate salinity stress.

Effects of K+ and Ca2+ supplement during fertigation on leaf gas exchange and salt tolerance of cotton at full and deficit irrigation regimes

Modulation of K+ and Ca2+ levels could enhance salt tolerance in crops, yet the underlying mechanisms remain largely elusive. The objective of this study was to investigate the effects of K+ and Ca2+ supplement during fertigation on leaf gas exchange in cotton plants subjected to salt stress and deficit irrigation regime. The leaf gas exchange parameters, leaf nitrogen concentration, chlorophyll content, plant water status, abscisic acid concentration in leaf ([ABA]leaf), K+ and Na+ concentration in leaf, as well as water use efficiency were evaluated. The results showed that: stomatal conductance (gs), transpiration rate (Tr) and net photosynthetic rate (An) were significantly decreased by 150 mM NaCl stress, whereas K+Ca treatment significantly alleviated the negative impact of salt under full irrigation. The relative water content and leaf water potential (Ψ1) was significantly decreased by salt stress. At full irrigation, K+Ca treatment further decreased Ψ1 in the salt-stressed plants than the non-K+Ca treatment. K+ and Ca2+ addition had a more positive effect on gs and Tr than on An, resulting in significantly lowered intrinsic and instantaneous water use efficiencies in salt-stressed plants at full irrigation. K and K+Ca treatments significantly increased the content of K+ and the ratio of K+/Na+ in leaf under salt stress and deficit irrigation. Salinity induced-reduction in gs was associated with high [ABA]leaf and a lower Ψ1, whereas, the alleviation of gs and An in the salt-stressed plants at full irrigation upon K+ and Ca2+ addition could be attributed to osmoregulation and increased concentration of K+ and the ratio of K+/Na+ in leaf. In conclusion, at full irrigation, K+Ca treatment notably alleviated the salinity-induced depression in gs and An, ameliorating plants performance under salt stress condition. These results provide useful information for better irrigation and fertilization management in a future water-limited and salinity-affected soil environment.

Predictive control strategies for optimizing temperature stability in instantaneous hot water systems

Domestic hot water production is responsible for a significant part of domestic energy consumption; instantaneous gas heating devices are widely used because they don’t require reservoirs, therefore have a competitive use/consumption ratio compared to other technologies. However, users' perception of comfort is severely affected by sudden changes in temperature outside the desired temperature. The instability of the water temperature with overshoots and undershoots is the most common disadvantage, which occurs mainly due to sudden changes in the water flow requested by users and the response delays inherent to the heating system. Traditional heat cell power controllers have difficulties in responding to these problems in a timely manner, as they don’t have the capacity to anticipate the effects of sudden variations in water flowrate. In this work, predictive control strategies were developed which, due to its predictive nature, allows anticipating and correcting the negative effects of sudden variations of water flowrate in the temperature. A comparative analysis of model based predictive controllers (MPCs), with and without adaptive function, with traditional controllers used in the tankless gas water heaters (TGWHs) was carried out. Tests in a simulated environment demonstrated better performances in the stabilization of temperature during sudden changes in water flowrates.

On Inflow to a Tunnel in a Fractured Double-Porosity Aquifer.

Inflow to a tunnel is a great public concern and is closely related to groundwater hydrology, geotechnical engineering, and mining engineering, among other disciplines. Rapid computation of inflow to a tunnel provides a timely means for quickly assessing the inflow discharge, thus is critical for safe operation of tunnels. Dewatering of tunnels is another engineering practice that should be planned. In this study, an analytical solution of the inflow to a tunnel in a fractured unconfined aquifer is obtained. The solution takes into account either the spherical or slab-shaped matrix block and the unsteady state interporosity flow. The instantaneous drainage water table and anisotropic hydraulic conductivities of the fractures network are also considered. Both uniform flux and uniform head boundary condition are considered to simulate the constant head boundary condition in the tunnel. The effects of the hydraulic parameters of the fractured aquifer on the inflow variation of the tunnel are explored. The application of the presented solution to obtain the optimum location and discharge of the well to minimize the inflow to a tunnel is illustrated.

Effects of water-nitrogen coupling on photosynthetic characteristics, yield, water and nitrogen use efficiency for mountain apple trees under surge-root irrigation in Northern Shaanxi area of China.

Taking 7-year-old apple trees (Hanfu) as the test material, an experiment with three irrigation levels including high water (W1, 85%-100%θf, θf was the field water holding capacity), medium water (W2, 70%-85%θf) and low water (W3, 55%-70%θf), and three nitrogen application levels, high (N1, 600 kg·hm-2), medium (N2, 400 kg·hm-2) and low (N3, 200 kg·hm-2), was conducted to investigate the effects of water and nitrogen coupling on photosynthetic characteristics, yield and water and nitrogen utilization of apple trees in mountainous areas under surge-root irrigation (SRI). The results showed that the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (gs), intercellular CO2 concentration (Ci), leaf instantaneous water use efficiency (WUEi) of apple trees leaves decreased with decreasing nitrogen application rates under the same irrigation amount, but Ci increased. Under the same nitrogen application rate, foliar Pn, Tr, gs and WUEi decreased with decreasing irrigation amount, but Ci increased. The daily average values of Pn and Tr under W1N1 treatment were the largest, while W2N2 treatment had the largest WUEi. Apple yield, irrigation water use efficiency (IWUE) and nitrogen partial productivity (NPFP) were significantly affected by irrigation and nitrogen application. The W2N2 treatment had the highest yield (26761 kg·hm-2). IWUE increased significantly with the decreasing irrigation and the increasing nitrogen application, while NPFP increased significantly with the increases of irrigation and the decreases of nitrogen application. Results of the regression analysis showed that the combination of irrigation and nitrogen application was closest to W2N2 treatment when yield and IWUE got the optimal solution. Therefore, W2N2 treatment was the best combination mode of water and nitrogen application for apple under SRI in Northern Shaanxi mountain area.

Safety for Electric Shower Water Heater installation in Indonesia

Death casualties due to electrocution when showering using electric shower water heater (ESWH) have been reported. The cases included the use of either water heater with storage system or the instantaneous water heater. There are three factors that may contribute to the event, namely, the improper installation including the grounding and wiring systems, the equipment factor, and the human error. The first two factors are the most dominant. This paper presents scenarios when one may experience an electrocution during showering, the current safety regulations in Indonesia regarding the installation of the electric shower water heater, and the mitigations to avoid casualties. The additional of ELCB (Earth Leakage Circuit Breaker) may increase the safety factor as it protects the user from an electrical shock in shorter duration than the common Main Circuit Breaker (MCB). A successful ELCB depends also on the correct installation of protection earth wiring and grounding.

Application of Fractions of Crop Evapotranspiration Affects Carbon Partitioning of Grapevine Differentially in a Hot Climate

Majority of viticulture regions are located in mid-latitudes characterized by weather variability and stressful environments relying on irrigation for mitigating environmental stress during the growing season and to ensure a profitable yield. The aim of this study was to characterize the response of grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) to different applied water amounts based on the replacement of fractions of crop evapotranspiration (ETc) during two growing seasons with contrasting precipitation patterns. The experiment consisted of three irrigation treatments based on the weekly replacement of 25, 50, and 100% of ETc. Grapevine stem water potential decreased during the growing season reaching its lowest value (-1.5 and -1.2 MPa, respectively) at harvest in the more stressed vines (25 and 50% ETc). Leaf gas exchange variables were measured during the two seasons and 100% ETc had the highest rates of photosynthesis and stomatal conductance and better instantaneous water use efficiency, also resulting in higher leaf chlorophyll and carotenoid content. Mineral nutrient content for nitrogen and potassium increased linearly with the increase in applied water. At harvest, no differences were observed in the number of clusters per vine; however, the 25% ETc had the lowest berry size and yield per vine with no difference in sugar content of berry. Conversely, sugar allocation to reserve organs was highly affected by applied water leading to different shoot to root biomass partitioning, where shoot:root ratio, leaf non-structural carbohydrates, and photosynthetic pigments increased with greater applied water. Likewise sucrose:N ratio and root non-structural carbohydrates decreased with the lower applied water. Altogether, carbon allocation between the source and sink organs likely controlled the response of grapevines to water deficits in a hot climate, and replacing 50% ETc was sufficient to sustain the grapevine performance given the enhancement of sugar transport, which could slow down the detrimental effect of water deficits on yield.