Low Water Treatment Research Articles

Inoculation with arbuscular mycorrhiza did not affect growth, root traits or gas exchange of grafted almond saplings when exposed to drought stress

Very little is known about potential benefits of using AM inoculation as a tool to alleviate drought stress of trees grown under nursery conditions. There is some evidence that benefits of mycorrhiza on gas exchange parameters and growth of trees are proportionally greater when trees are subjected to drought stress. We hypothesized that inoculation with mycorrhiza would increase growth, nutrition, stem water potential and gas exchange of containerized almond (Prunus dulcis (Mill.) D.A. Webb) when young trees are grown under low water availability.In the spring of 2015 and 2016, forty containerized almond trees (Nonpareil scion grafted on Hansen 536, a peach/almond hybrid rootstock) were either inoculated or not with a commercially available arbuscular mycorrhizal inoculum and kept well-watered for 60 days in 2015 and 54 days in 2016, after which half of the plants were exposed to gradually reduced water availability over 38 days in 2015 and 61 days in 2016. Measurements included growth metrics, stem water potential, stomatal density, leaf NPK concentration, light saturated photosynthesis, and parameters calculated from CO2 response curves (Vcmax, J, TPU, Rd, gm, and stomatal limitation).The low-water treatment decreased stem water potential and reduced trunk diameter growth, light saturated photosynthesis (A), stomatal conductance (gs), Vcmax, J, TPU, gm, specific root length, leaf N and K concentration and total leaf N, P, and K content. Inoculation decreased root mass, increased leaf mass fraction, and decreased root mass fraction in 2015, but not in 2016. Neither stem water potential nor gas exchange were significantly altered by inoculation. Inoculation decreased leaf stomatal density, and slightly elevated leaf N and P concentrations in the low water treatments, although not consistently across years. Contrary to expectations we did not find substantially greater benefits from mycorrhizal inoculation in young drought stressed almond trees and conclude that the potential for mycorrhizal inoculant to alleviate drought stress in containerized trees is minimal.

Effect of Subsurface Drainage in Regulating Water on Desalinization and Microbial Communities in Salinized Irrigation Soils

In order to achieve water conservation and salt control in saline irrigation areas and improve the soil ecological environment of farmland in irrigation areas, this study carried out a field trial in 2020–2021 on edible sunflowers planted in saline subsurface farmland in the Hetao Irrigation District. Three irrigation level treatments and a control setup under subsurface drainage were compared. The control was with no drainage and local conventional irrigation levels (the spring irrigation amount is 240 mm and the bud stage irrigation amount is 90 mm, CK); and the three irrigation levels were conventional irrigation (the spring irrigation amount is 240 mm and the bud stage irrigation amount is 90 mm, W1), medium water (the spring irrigation amount is 120 mm and the bud stage irrigation amount is 90 mm, W2), and low water (the spring irrigation amount is 120 mm and there is no irrigation in the bud stage, W3). The results showed that soil desalinization was best in the conventional irrigation (W1) treatment and lowest in the low-water treatment (W3) under subsurface drainage. The desalinization rate was 13.54% higher in the subsurface drainage than in the undrained treatment with the same amount of irrigation water. Under subsurface drainage, the medium-water treatment (W2) increased the diversity of soil microorganisms and the relative abundance of dominant phyla such as Ascomycetes, Chlorobacterium, Acidobacterium, and Ascomycetes among soil bacteria and Ascomycetes and Tephritobacterium amongst fungi. The average sunflower yield in the treatments under subsurface drainage increased by 32.37% compared with the undrained treatment, and the medium-water treatment (W2) was the most favorable for protein and essential amino acid synthesis. Structural equation modeling indicated that desalinization rate, irrigation water utilization efficiency, bacterial Chao1 abundance and Shannon diversity, and fungal Chao1 abundance and Shannon diversity were the major influences on sunflower yield. Based on the entropy weight method TOPSIS model, 15 indicators such as soil desalinization rate, soil microbial diversity, water and nitrogen utilization rate, and sunflower yield and quality were evaluated comprehensively for each water treatment of subsurface drainage farmland. It was found that the irrigation volume under tile drainage of 210 mm (W2) had the highest comprehensive score, which could improve the soil microenvironment of the farmland while realizing water conservation and salt control in salty farmland, increase the production of high-quality crops, and be conducive to the sustainable development of agriculture; it was the optimal irrigation treatment for the comprehensive effect. The results of this study are of great significance for the realization of efficient water conservation and salt control and the protection of food security and ecological safety in the Hetao Irrigation District.

ZnFe2O4-infused hierarchically porous carbon nanofiber electrode for enhanced capacitive deionization

Highly porous carbon materials with abundant active adsorption sites are desirable for capacitive deionization (CDI). However, their limited salt adsorption capacity, slow desalination rate, and sensitivity to salt concentrations hinder practical applications in low salinity water treatment. In this study, we successfully synthesized a hierarchically porous carbon nanofiber electrode infused with ZnFe2O4 prepared by electrospinning the FeⅢ-MOF-5/benzoxazine/polyacrylonitrile (FeⅢ-MOF-5/BA-a/PAN) system, followed by high-temperature curing, KOH activation, and carbonization processes. The activated electrode material exhibited remarkable characteristics, including an exceptionally high specific surface area of 2506.73 m2 g−1 and significantly enhanced mesoporosity. Results demonstrated pseudo-capacitive behavior with a specific capacitance of 149.3 F g−1 and excellent electrochemical cycling stability. Notably, the electrode showed significant adsorption capacities in a 1000 mg L−1 NaCl solution at applied potentials of 1.2 and 1.6 V, with values of 74.27 and 88.95 mg g−1, respectively. The adsorption process followed both the Freundlich isotherm and the pseudo-second-order kinetic models. These findings highlight the promising potential of the ZnFe2O4-infused porous carbon nanofiber electrode for efficient desalination and ion removal applications.

Estimating Cotton Canopy Temperature Artifacts in UAV-Based Thermal Measurements

Thermal sensors mounted on unmanned aerial vehicles (UAVs) have been used for crop evaluation. The assembly of multiple UAV images into a composite orthomosaic image that represents an agricultural field is common. The creation of these composite orthomosaic images is predicated on the assumption that the variable of interest, for example, plant height, does not change in the interval between the first image and the last image. Canopy temperature is continuously variable. Thus, in a composite thermal image, the temperature differences between any two points can include both the temperature differences of the two locations, as well as the temperature change occurring during the time the images were captured. A modeling approach was used to investigate these temporal thermal artifacts in cotton (Gossypium hirsutum L.). The objectives were to analyze the average amount of thermal variation that can occur across a field, identify times of maximum variation, and examine the magnitude of these thermal artifacts across the temporal scale of a typical drone mission. As the time between the first image and last image increased from 15 minutes to an hour, the temporal thermal distortion increased from 0.7 to 1.4 °C for a high-water treatment and from 0.9 to 2.8 °C for a low-water treatment. The simulated flights from 1030 to 1230 h had the largest variation and the 1230 to 1430 h and 1430 to 1630 h flights had less thermal variation. Depending on the application, the thermal distortion could range from negligible to potentially significant.

Responses of a common tropical epiphyte, Asplenium nidus, to changes in water and nutrient availability.

Epiphytes are highly dependent on atmospheric inputs of water and nutrients. Reductions in water availability associated with warming and climate change and continual atmospheric nitrogen (N) deposition can affect plant growth but few studies have evaluated the effects of changes in both water and nutrient availabilities on epiphytes. We experimentally tested whether epiphyte growth is more water- or nutrient-limited, if nutrient limitation was stronger for nitrogen or phosphorus, and whether nutrient limitation interacts with water availability. We applied watering (high and low) and nutrient addition (control, +N, +P, +N+P) treatments to greenhouse-grown Asplenium nidus, a common epiphytic fern found in many tropical and subtropical wet forests. We measured leaf area production and leaf elemental concentrations to assess how A. nidus growth and physiology respond to changes in water and nutrient availabilities. We found that leaf growth of A. nidus was more affected by water availability than nutrient addition and the effect of adding nutrients was not fully realized under low-water availability. Among the different nutrient treatments, +N+P had the greatest effects on A. nidus growth and physiology in both watering treatments. Watering treatment changed leaf elemental concentrations but not their ratios (i.e. C:N and N:P). Nutrient addition altered C:N and N:P ratios and increased the concentration of the added elements in leaves, with more pronounced increases in the high-watering treatment. We conclude that the growth of A. nidus is more water- than nutrient-limited. When nutrient limitation occurs (i.e. under high-water availability), nutrient co-limitation is stronger than limitation by N or P alone. This result taken together with studies of other epiphytes suggests greater water than nutrient limitation is likely widespread among epiphytic plants. The limited effects of nutrient addition in the low-water treatment suggest that the effect of atmospheric N deposition on epiphyte growth will be limited when water availability is low.

Effects of Water and Nitrogen Coupling on Yield, Quality, Water and Nitrogen Use Efficiencies of Greenhouse Muskmelon

The proficient supply of water and nitrogen is a key factor in facility agriculture. In order to pursue high yields, most farmers blindly irrigate and fertilize, leading to yield reduction, quality decline, soil salinization, and fertility destruction. A successive two-year greenhouse experiment was carried out on fruit quality, yield, irrigation water use efficiency (IWUE), and nitrogen use efficiency (NUE) of greenhouse muskmelon (Cucumis melo L.) under drip fertigation, which can provide a scientific basis for local muskmelon intensive production in Southeast China. The experiments were conducted in 2020 and 2021, with three irrigation levels 80% (W1), 100% (W2), and 120% (W3) of ETc and three N levels 60 (N1), 95 (N2), and 130 (N3) kg N ha−1. The amount of drip irrigation water was determined every 5 days based on crop evapotranspiration (ETc). The seasonal irrigation amount ranged from 209.77 mm to 298.86 mm in 2020 and from 201.22 mm to 286.04 mm in 2021. The highest muskmelon yield was obtained in the treatment of W3N3 with an average of 27.38 t ha−1 in 2020 and 27.10 t ha−1 in 2021. Although the yield was improved by increasing nitrogen supply, there was no significant difference between N2 and N3 treatment in two years under the irrigation level of W2 and W3. The highest irrigation water use efficiency was observed in the W1N3 treatment in 2020 and 2021. The NUE increased with decreasing N rates at the same irrigation level. Under the same nitrogen application level, TSS and Vc under low water (W1) were higher than that under medium water (W2) and high water (W3) treatment. The highest content of nitrate in low water and high nitrogen (W1N3) treatment was 55.41 µg/g in 2020 and 52.50 µg/g in 2021, respectively. The yield and quality of muskmelon are often incompatible, for instance, W2N2 treatment can obtain a higher yield, but W1N2 treatment maximizes Vc, TSS of muskmelon quality. Our findings suggest that the irrigation level of 1.0 ETc, nitrogen level of 95 N ha−1, and 3500 kg·ha−1 of decomposed organic fertilizer was recommended as the best combination, which can improve the yield, quality, IWUE, NUE of muskmelon under drip fertigation with soil mulching in the experimental site.

The Impact of Water Availability on the Discriminative Status of Nitrogen (N) in Sugar Beet and Celery Using Hyperspectral Imaging Methods

A pot experiment was conducted to determine the impact of water availability on the discriminatory status of nitrogen (N) in plants using hyperspectral imaging. Nitrogen deficiency causes a significant decrease in chlorophyll concentration in plant leaves regardless of water availability. Five different classification algorithms were used to discriminate between nitrogen concentrations in plants at different levels of water availability. Several statistical parameters, including kappa and overall classification accuracy for calibration and prediction, were used to determine the efficiency and accuracy of the models. The Random Forest model had the highest overall accuracy of over 81% for sugar beet and over 78% for celery. Additionally, characteristic electromagnetic wavelengths were identified in which reflectance correlated with nitrogen and water content in plants could be recorded. It was also noted that the spectral resolution between the N and High Water (HW)/Low Water (LW) treatments was lower in the short-wave infrared (SWIR) region than in the visible and near-infrared (VNIR) region.

Utility of anthesis–silking interval information to predict grain yield under water and nitrogen limited conditions

AbstractDelayed silking relative to pollen shed, measured as the anthesis–silking interval (ASI, the period between pollen shed and silking), is a good indicator of response to abiotic stresses in maize (Zea mays L.). This research was conducted to investigate how ASI is affected by nitrogen (N) and water availability and to assess the utility of ASI to indirectly predict grain yield (GY) under contrasting water and N treatments. Two experiments were conducted in Hancock, WI, in 2018 and 2019. One experiment (Diverse hybrids) included 302 hybrids resulting from the cross of diverse inbred lines by a single tester evaluated at four different treatment levels resulting from combining nonlimited and low N with nonlimited and low water treatments. The second experiment (NSS FAC) included a set of 408 hybrids derived from the cross of biparental doubled‐haploid lines from 13 factorial populations and evaluated under nonlimited and low N treatments. Anthesis and silk time in growing degree days, and GY (Mg ha−1) were measured. Genomic prediction was assessed using a genomic best linear unbiased prediction model, and predictive ability was calculated as the correlation between genomic predictions and adjusted means in the different treatments. Predictive ability ranged from .15 to .49 for NSS FAC and from .06 to .51 for Diverse hybrids across traits and treatments. The ASI was a good indicator of stress and showed higher heritability than GY in the limited treatments for both experiments; however, it did not improve yield predictability.

Catalysis-involved 3D N-doped graphene aerogel achieves a superior solar water purification rate and efficiency

Solar-driven water evaporation is a promising technology to address the water scarcity concern. While in the past years this research direction has initiated sizable progress in water purification, its application remains challenging due to the low water evaporation rate and treatment efficiency. Herein, a 3D cylinder evaporator (SMNG) with superior evaporation rate and excellent water treatment efficiency is developed through a unique 3D structural design by incorporating catalytic Ag-MnO2 nanostructure with N-doped graphene aerogel. The SMNG evaporator possesses an evaporation rate as high as 6.46 kg m−2 h−1 under one sun irradiation, with a photothermal conversion efficiency of 90.25 %. In addition, the SMNG also exhibits a remarkable desalination ability, with an evaporation rate of 6.15 kg m−2 h−1 and an ions rejection rate up to 99.9 % on seawater. In an outdoor environment, the SMNG can attain a maximum seawater evaporation rate of 8.57 kg m−2 h−1, demonstrating its promising practical applications. The SMNG evaporator also shows over 99.9 % efficiencies in purifying wastewater that contains organic dyes, heavy ions, formaldehyde, and E. coli.

Above- and below-ground plant traits are not consistent in response to drought and competition treatments.

Our understanding of plant responses to biotic and abiotic drivers is largely based on above-ground plant traits, with little focus on below-ground traits despite their key role in water and nutrient uptake. Here, we aimed to understand the extent to which above- and below-ground traits are co-ordinated, and how these traits respond to soil moisture gradients and plant intraspecific competition. We chose seedlings of five tropical tree species and grew them in a greenhouse for 16 weeks under a soil moisture gradient [low (drought), medium and high (well-watered) moisture levels] with and without intraspecific competition. At harvest, we measured nine above- and five below-ground traits of all seedlings based on standard protocols. In response to the soil moisture gradient, above-ground traits are found to be consistent with the leaf economics spectrum, whereas below-ground traits are inconsistent with the root economics spectrum. We found high specific leaf area and total leaf area in well-watered conditions, while high leaf dry matter content, leaf thickness and stem dry matter content were observed in drought conditions. However, below-ground traits showed contrasting patterns, with high specific root length but low root branching index in the low water treatment. The correlations between above- and below-ground traits across the soil moisture gradient were variable, i.e. specific leaf area was positively correlated with specific root length, while it was negatively correlated with root average diameter across moisture levels. However, leaf dry matter content was unexpectedly positively correlated with both specific root length and root branching index. Intraspecific competition has influenced both above- and below-ground traits, but interacted with soil moisture to affect only below-ground traits. Consistent with functional equilibrium theory, more biomass was allocated to roots under drought conditions, and to leaves under sufficient soil moisture conditions. Our results indicate that the response of below-ground traits to plant intraspecific competition and soil moisture conditions may not be inferred using above-ground traits, suggesting that multiple resource use axes are needed to understand plant ecological strategies. Lack of consistent leaf-root trait correlations across the soil moisture gradient highlight the multidimensionality of plant trait relationships which needs more exploration.

How are leaf carbon- and water-related traits coordinated acclimation to elevated CO2 by its anatomy? A case study in tomato

A fundamental behavior for plants will be to minimize transpirational water loss whilst maximize photosynthesis in order to acclimate complex growth conditions. However, elevated CO 2 is expected to result in photosynthesis acclimation, the primary limitations and mechanisms underlying the concerted changes of leaf photosynthesis and hydraulic conductance are not fully understood. To test the acclimation of photosynthetic carbon gain and transpirational water loss to elevated CO 2 concentration, we conducted a study in cherry tomatoes grown under two CO 2 levels with different water and fertilizer management. Leaf anatomical traits associated with photosynthesis and hydraulics were also measured. Tomato plants showed greater photosynthesis and lower hydraulic conductance under high CO 2 conditions. However, as durative high concentration of CO 2 injection, photosynthetic rate and hydraulic conductance significantly decreased in both high- and low-water treatments, yet the decrease could be mitigated by conducting fertilizer. Further quantitative analysis showed that mesophyll limitation (ML) and outside-xylem hydraulic resistance (R ox ) were the major contributors to photosynthetic and hydraulic acclimation under durative elevated CO 2 exposure. High water and fertilization treatments decreased the ML and R ox , which supported the higher photosynthetic rate and hydraulic conductance of plants grown under extended elevated CO 2 condition. The acclimation to durative elevated CO 2 concentration is partly attributed to the modification of leaf anatomy. The lower leaf vein length per area (VLA) or the mesophyll cell to cell connectivity (f cm ) which supported lower water transport conductivity of xylem and outside-xylem in elevated CO 2 and low-water treatments. Additionally, a reduction of mesophyll (S m ) and/or chloroplast (S c ) surface area adjacent to intercellular space in CO 2 gas-phase paths with the time of high CO 2 injection was also observed, which may responsible for lower g m , thus photosynthesis acclimation. Coordination of leaf photosynthesis and hydraulics was changed under durative elevated CO 2 condition. Only g m and K ox , the main contributor of photosynthesis and hydraulics, existed a coordinated relationship by modifying their common structural basis, as the volume fraction of the intercellular air space (f ias ) and mesophyll surface area adjacent to intercellular space (S m ). These results will be helpful for better understanding of plants acclimate to future CO 2 enriched condition and are of significance to agricultural management. • Tomato showed a lower hydraulic cost of photosynthesis under elevated CO 2 . • Coordination of leaf photosynthesis and hydraulics was changed under durative elevated CO 2 condition. • The coordination of g m and K ox influenced the photosynthetic carbon gain and hydraulics of tomatoes grown under elevated CO 2 . • Leaf morpho-anatomical traits drive the long-term acclimation to elevated CO 2 concentration.

Assessment of Moringa oleifera Seeds as a Natural Coagulant in Treating Low Turbid Water

This research examined the coagulating potential of Moringa oleifera seeds in treating low turbid water. The active ingredient of the seeds was extracted using Soxhlet Apparatus with hexane as the solvent, after which the coagulant was dosed from 0.03g/L to 0.4g/L and used to treat a water sample with a low Turbidity of 18.4NTU, yielding an optimum value of 4.90NTU, an optimum dose of 0.03g/L and a turbidity reduction of 100% when compared with the World Health Organization (WHO) standard which is 5NTU. The study affirms Moringa oleifera as an effective natural coagulant in low turbid water treatment and it is recommended for household water treatments. Keywords— Hexane, Low turbid water, Moringa oleifera, Natural coagulant, Soxhlet apparatus

Transgenerational Effects of Maternal Water Condition on the Growth, C:N Stoichiometry and Seed Characteristics of the Desert Annual Atriplex aucheri.

Water conditions directly affect plant growth and thus modify reproduction allocation. However, little is known about the transgenerational effects of water conditions on xerophytes. The desert annual Atriplex aucheri produces three types of seeds (A: dormant, ebracteate black seeds; B: dormant, bracteolate black seeds; C: non-dormant, bracteolate brown seeds) on a single plant. The aim of this study was to investigate the effects of low/high water treatment (thereafter progeny water treatment) on aboveground biomass, C:N stoichiometry, and offspring seed characteristics of A. aucheri grown from brown seeds whose mother plants were under low/high water treatment (thereafter maternal water treatment). Progeny water only affected shoot dry weight and seed allocation of type A. Under low progeny water treatment, plants from parents with low maternal water treatment had the lowest biomass. Maternal water did not significantly influence the C and N content, however high maternal water increased the C:N ratio. Maternal water treatment did not significantly affect seed number. However, plants under low maternal and progeny water treatments had the lowest weight for type B seeds. When progeny plants were under low water treatment, seed allocation of type A, type B, and total seed allocation of plants under high maternal water were significantly lower than those of plants under low maternal water. These results indicate that water conditions during the maternal generation can dramatically contribute to progeny seed variation, but the transgenerational effects depend on the water conditions of progeny plants.

Flow anodic oxidation: Towards high-efficiency removal of aqueous contaminants by adsorbed hydroxyl radicals at 1.5 V vs SHE

Electrochemical advanced oxidation processes (EAOPs) have emerged as a promising water treatment alternative but major breakthroughs are still needed in order for EAOPs to be competitive with traditional treatment technologies in terms of energy cost. Most existing studies have been conducted at high potentials to generate the powerful hydroxyl radical oxidant (aqueous •OH). While adsorbed hydroxyl radicals (OH*) may form at a much lower energy cost, their possible utilization is limited due to the poor mass transfer of this highly reactive species on solid electrodes. In this report, we describe a novel flow anode system using 4–16 μm Magnéli phase titanium suboxide particles as the anode material which enables the generation of a high steady state •OH concentration (5.4 × 10−12 mol m−2) at only 1.5 V (vs SHE) in a dilute electrolyte (5 mM KH2PO4). The energy cost of removal per order of selected water contaminants (tetracycline and orange II in this study) using the flow anode is 1.5-–6.7 Wh m−3, which is 1 – 4 orders of magnitude lower than that of existing techniques. The anode material used demonstrates great stability with the configuration readily scaled up. The results of this study provide new insight into a high efficiency, low cost water treatment technology for organic contaminant degradation.

Soil microbes and seed mucilage promote growth of the desert ephemeral plant Nepeta micrantha under different water conditions

Ephemeral plants, which can complete their life cycle in two to three months, play an important role in stabilizing sand dune surfaces from wind erosion in spring in the Gurbantunggut Desert, northwestern China. Soil microbes and seed mucilage could promote seedling growth of desert species via independent effects and / or interactions. However, it is uncertain whether both factors affect growth of adult ephemeral plants when exposed to different water regimes. Intact or demucilaged seeds of Nepeta micrantha were sown in sterile and non-sterile soil and exposed to three water regimes. The results indicated that plants under middle water treatment had higher dry mass accumulation as compared to that under low and high water treatments. Soil microbes and seed mucilage could significantly increase plant growth in all three water regimes. Their interactions showed positive effect on growth only under low water treatment. Nepeta micrantha plants had the highest biomass in the treatment of intact seeds in non-sterile soil and exposed to middle water regimes. Our study provides a better understanding of the growth regulation mechanism by which water, soil microbes and seed mucilage interactively promote growth of ephemeral plants in arid desert.

Eight generations of native seed cultivation reduces plant fitness relative to the wild progenitor population.

Native seed for restoration is in high demand, but widespread habitat degradation will likely prevent enough seed from being sustainably harvested from wild populations to meet this need. While propagation of native species has emerged in recent decades to address this resource gap, few studies have tested whether the processes of sampling from wild populations, followed by generations of farm cultivation, reduce plant fitness tolerance to stress over time. To test this, we grew the eighth generation of farm‐propagated Clarkia pulchella Pursh (Onagraceae) alongside seeds from two of the three original wild source populations that established the native seed farm. To detect differences in stress tolerance, half of plants were subjected to a low‐water treatment in the greenhouse. At the outset, farmed seeds were 4.1% heavier and had 4% greater germination compared to wild‐collected seed. At maturity, farmed plants were 22% taller and had 20% larger stigmatic surfaces, even after accounting for differences in initial seed size. Importantly, the mortality of farmed plants was extremely high (75%), especially in the low‐water treatment (80%). Moreover, farmed plants under the high‐water treatment had 90% lower relative fitness than wild plants due to the 1.3 times greater weekly mortality and a 3‐fold reduction in flowering likelihood. Together, these data suggest that bottlenecks during initial sampling and/or unconscious selection during propagation severely reduced genetic diversity and promoted inbreeding. This may undermine restoration success, especially under stressful conditions. These results indicate that more data must be collected on the effects of cultivation to determine whether it is a suitable source of restoration seed.

Evaporation of maize crop under mulch film and soil covered drip irrigation: field assessment and modelling on West Liaohe Plain, China

Due to existing problems related to drip irrigation under the conditions of mulching and the vigorous promotion of soil covered drip irrigation without film, drip irrigation experiments were conducted in 2017 and 2018 in order to explore the mechanism of water conservation. Three different irrigation treatments were adopted in this study: high, middle, and low irrigation quotas. In addition, two different experiment areas were selected: Taking mulching as an example, Zone I (film covered area) and Zone Ⅱ (bare soil area). For comparison, the division of zone with soil covered drip irrigation without film was the same as that with the mulching film. The two zones were designed to analyze soil evaporation regularity based on a calibrated SIMDualKc model under the conditions of both mulched drip irrigation and soil covered drip irrigation without film, respectively. The results showed that the SIMDualKc model could potentially be applied to simulate the soil water content and evaporation rates with a higher accuracy. The soil evaporation in high-water treatment was 13% higher than that in medium-water treatment, and that in low-water treatment was 5% lower than that in medium-water treatment under the soil covered drip irrigation without film conditions. The evaporation rates were only 0.67 mm and 36.18 mm in the Zone I and Zone II areas under mulched drip irrigation conditions, respectively. The water conservation had mainly occurred in the mulched area (Zone I) where mulched drip irrigation methods were utilized, and the evaporation was much less than that of the areas where soil covered drip irrigation without film methods were implemented. The results obtained in this study may provide a theoretical basis for future maize production under the conditions of both mulched drip irrigation and soil covered drip irrigation without film processes.

The combined effects of water and nitrogen on the relationship between a native hemiparasite and its invasive host.

Stem hemiparasites are dependent on their hosts for water and nitrogen. Most studies, however, have assessed the influence of one factor on parasite:host associations, thus limiting our mechanistic understanding of their performance in nature. We investigated the combined effects of water and nitrogen (N) availability on both a host (Ulex europaeus) and its parasite (Cassytha pubescens). Parasite infection significantly decreased host shoot biomass and shoot:root ratio more severely in high water than low water, irrespective of N supply. Parasite stem [N] was significantly higher in high water than low water treatments, regardless of N supply, but parasite biomass did not vary among treatments. Irrespective of water and N supply, infected plants had significantly lower total, root and nodule biomass, predawn and midday quantum yields, maximum electron transport rates, water potentials and nitrogen concentration [N]. Parasite δ13 C was significantly higher than that of the host. Our results suggested that stem hemiparasites can better extract resources from hosts when water availability is high, resulting in a greater impact on the host under these conditions. When hemiparasitic plants are being investigated as a biocontrol for invasive weeds, they may be more effective in wetter habitats than in drier ones.

Low cost bench scale community level water treatment system and adsorption method for removal of nitrate from groundwater

Nitrate contamination has gain significant research interest, since presence of nitrate in large quantity in drinking water, often causes health disorders. In present day situation, nitrate removal is important aspects of water treatment process. Prevailing process, conditional influence and various approaches play important role in nitrate remediation. Various physical and chemical methods are available to remove the nitrate from groundwater; these are effective in removal but expensive in operation. To overcome these limitations, low cost bench scale water system with suitable adsorption method is adopted. In the present study, a treatment system was developed for community level comprising of anoxic batch reactor; filtration unit and a chlorination unit. Adsorption method is extremely useful in nitrate removal for different dosages such as: 5 g/L, 7.5 g/L, 10 g/L, since it retains nitrogen within the root zone. From the experiment, it is found that, low cost bench scale treatment method was effective in nitrate removal as material used were cost effective and locally available. Adsorbent method such as fly ash shows prominent result compared to other adsorbent such as activated carbon for an optimized condition of 7.5 g/L. Hence it can be recommended compared to other methods.

Natural Products for Surface Water Coagulation: an Alternative Sustainable Solution for Rural Areas

This research aims at process optimization using response surface methodology (RSM) for coagulation of surface water by coagulants extracted from natural product. Apricot seeds extract (ASE), peach seeds extract (PSE) and mango seeds extract (MSE) were evaluated. The optimum operating conditions for ASE and PSE at initial turbidity of 27.5 NTU were pH 7 and coagulant dose of 45 mg/l. However, the optimum operating conditions for MSE at initial turbidity of 27.5 NTU were pH 5.5 and MSE dose of 45 mg/l. Under the optimum conditions, residual turbidity without filtration was 9.13, 10.3, 5.81 NTU for ASE, PSE and MSE, respectively. MSE could be used as secondary coagulant with the alum. At low turbidity surface water treatment, ratios of 20/80, 40/60 and 60/40 MSE/alum achieved residual turbidity of less than 1 NTU which comply with the Egyptian Standards. However, at medium turbidity surface water, ratio of 20/80 MSE/alum achieved residual turbidity of less than 1 NTU.