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The salinity of water and agricultural lands is a major environmental factor adversely affecting crop productivity. Strawberry plants have been found to be sensitive to salt stress conditions. Salicylic acid (SA) and Ca2+ are endogenous signal molecules involved in many metabolic processes, which can stimulate the plants defence mechanisms to biotic and abiotic constraints. The main objective of this work was to investigate the impacts of SA (0.25 mM) and calcium nitrate (5 mM) application, singly or in combination, on growth parameters as well as physiological and biochemical markers of strawberry plants (Fragaria ananassa Duch, var. Fortuna) exposed to saline conditions (80 mM NaCl). The results showed that high salinity reduces plant growth and photosynthetic pigment content. Salt stress also induced an accumulation of Na, a decrease in K and Ca concentrations, a reduction in the levels of sugars, total phenol, relative water content, photochemical efficiency (Fv/Fm), and stomatal conductance as well as a decrease in proline, proteins, enzyme activities (catalase, superoxide dismutase and peroxidase) and an accumulation of hydrogen peroxide and malondialdehyde. However, SA and calcium treatments enhanced the plants' tolerance to salt stress by improving the above-mentioned parameters. Additionally, the best results were obtained with combined treatment (Ca + SA) under both salinity conditions. These findings indicated that the combination of calcium supplementation with exogenous application of SA may provide an effective solution to improving the strawberry plant's tolerance to saline conditions. [ABSTRACT FROM AUTHOR]

Combatting subsoil acidity is a challenge as the incorporation of lime in subsurface layers may not be economically feasible. The use of nitrate to facilitate plant excess anion uptake has shown the potential to increase soil pH. A column experiment was carried out to demonstrate this root‐induced alkalization in various depths in an acid soil with pH 4.28 (0.01 M CaCl2). It consisted of two types of nitrogen (N) fertilizers (urea and Ca(NO3)2, both at 5 atom% 15N enrichment) banded at a depth of 0–10 cm, 10–20 cm or 20–30 cm, with phosphorus (P) fertilizer (NaH2PO4) at 150 mg P per column either applied to the N layers (N+P) or evenly mixed into the remaining layers without N addition (N‐P). Aluminium‐tolerant wheat (ET8) was used as test plants, receiving an initial N dose of 60 mg kg−1 soil at sowing and an additional dose of 30 mg kg−1 every 10 days from 40 days after sowing. Plants had a total N supply of 90 mg N kg−1 at 50 days and 180 mg N kg−1 at 80 days after sowing. The N+P treatments increased plant N uptake and increased rhizosphere and bulk soil pH. Nitrate placement increased pH of treated layers by up to 0.4 and 0.2 units in the rhizosphere and bulk soils, respectively, compared with the control at Day 80. Rhizosphere alkalization was greater with deeper N+P treatments as these encouraged the proliferation of deeper roots in the treated layer. The form of N and the application method of P fertilizer had no effect on shoot biomass over 80 days of growth. The N+P treatments had 7% higher 15N recovery of fertilizer in plants than the N‐P treatments. The current study also showed that P fertilizer enhanced rhizosphere alkalization induced by calcium nitrate. The results suggest that the use of nitrate fertilizer with P treatments can facilitate alkalization of acid subsoils. Highlights: Phosphorus facilitates amelioration of subsurface soil acidity with nitrate fertilizerPlacement of nitrate induces alkalization of acid soil at various depthsCombined addition of nitrate and P at depth enhances nitrate uptake by wheatBalanced nutrient supply enhances excess anion uptake and rhizosphere alkalization [ABSTRACT FROM AUTHOR]

Yield in cherimoya (Annona cherimola Mill.) is affected by various factors reducing fertilization and fruit production such as: the protogynous dichogamy of the flowers, deficient natural pollination, and low pollen quality. The objective of this study was to determine in vitro the differences in pollen quality of nine ecotypes and one cultivar of A. cherimola from pollen samples collected at the female and male phenological stages of flowering. The percentage of pollen germination and the length of pollen tubes was evaluated in vitro at 2 and 24 hours after incubation at 21°C, in two phenological stages of the flowers during bloom in 2018 and 2019 seasons. The germination medium contained: 10% sucrose, 1% agar, 0.005% boric acid, and 0.025% calcium nitrate. Fabulosa and Austro ecotypes and the Fino de Jete cultivar had the highest pollen germination in the male phenological stage, after 2 and 24 hours in both seasons. Fabulosa had the highest percentage of germination in the female stage in both seasons. The ideal phenological stage for pollen collection was at anther dehiscence. Austro and Fabulosa ecotypes had the longest pollen tubes after 2 and 24 hours, in both phenological stages for both seasons. Fabulosa and Austro ecotypes, and Fino de Jete cultivar, showed promising pollen characteristics for hand pollination of cherimoya. [ABSTRACT FROM AUTHOR]

This study was conducted to examine the effect of calcium nitrate (CaNO3) on berry shattering in and the fruit characteristics of the 'Cheongsoo' grape cultivar. The rate of berry shattering was reduced regardless of CaNO3 concentration when the detachment force of the abscission zone at the stalk-berry junction increased. When 0.8% CaNO3 was treated, the berry shattering rate decreased by approximately 40% compared to the control; this was the lowest value. Furthermore, fruit quality declined and side effects were not observed following the CaNO3 treatment although fruit firmness also increased by 57% compared to the control. These results indicate that treatment with CaNO3 can contribute to stable production of 'Cheongsoo' grapes. [ABSTRACT FROM AUTHOR]

Chill hour’s availability influence break dormancy, sprouting and production of temperate fruit trees in different regions. Chilling requirements for growing peaches in subtropical regions are limited during winter and some chemicals are necessary for overcoming dormancy and inducing budburst. Therefore, there is a necessity of more information about the use of these chemicals on inducing sprouting in peach trees. This study aimed to assess hydrogen cyanamide, nitrogen fertilizer and calcium nitrate to induce budburst in the ‘Douradão’ peach orchard, located in the subtropical region of São Paulo state, Brazil. Then, tree chemicals were evaluated: 0.6% hydrogen cyanamide; 2.5% nitrogen fertilizer + 4% calcium nitrate; 4% calcium nitrate and control to determine the budburst, flowering and fruit set percentage, flowering period, number of fruits, production per tree and yield. The experimental design was a randomized block, in a split plot arrangement. The plots were represented by inducing sprouting chemicals and subplots for two crop seasons. The hydrogen cyanamide increased, anticipated and concentrated the flowering of the plants; besides enhancing fruit set and production. Furthermore, nitrogen fertilizer + calcium nitrate also promoted budburst enhancing flowering, production per tree and yield. The spraying of the peach trees with only calcium nitrate presented a performance like the one observed in the control. The results allowed indicate the use of hydrogen cyanamide or nitrogen fertilizer + calcium nitrate, as an alternative for inducing budburst in peach trees of Douradão cultivar under subtropical conditions, depending on the adopting orchards system cultivation.

Phase equilibria in sections of the calcium-nitrate–glycerol–water system at temperatures from 0 to –47°C are studied by visual polythermal analysis. The ratio of calcium nitrate and glycerol in the sections varies from 3 : 1 to 1 : 3. It is found that all nitrate–glycerol compositions are characterized by good ice-melting capacity and form low-temperature eutectics. These compositions are promising for the development of new anti-icing agents on their basis. [ABSTRACT FROM AUTHOR]

The study was conducted in the Department of Horticulture, University of Mosul in 2019/2020. The experiment was conducted with two factors, the first factor was NPK fertilizer (20:20:20) with three levels (100, 150 and 200 mg.L-1), while the second factor was Calcium nitrate with three levels 1%,1.5% and 2%. Calcium nitrate increased the growth parameters significantly in leaves number, number of crown, number of fruit, fruit weight, fruit length, number of runners, total yield, number of distorted fruits, the area of one seedling, number of flower, the number of fruit set, leaf area, and chlorophyll content. The NPK recorded the highest rate in the studied traits leaves number, number of crown, Number of fruit, fruit weight and fruit length number of runners total yield, number of flowers, leaf area, leaf Chlorophyll content, the area of one seedling, and number of distorted fruits. The data were analyzed through the statistical analysis program (SAS) based on Duncan's polynomial test. [ABSTRACT FROM AUTHOR]

A study was undertaken to find out the sexual system, pollination syndrome and seed dispersal modes in Croton scabiosus, an endemic deciduous tree from the Southeastern Ghats of Andhra Pradesh, India. The standard field methods/observations were used to examine different aspects of the pollination ecology. The study revealed that C. scabiosus blooms and fruits throughout winter, summer and the early phase of the wet season. Sporadic flowering occurs during the late wet season, if soil environment is favorable. The species is monoecious, ambophilous, involving myrmecophily and thripsophily, and polychorous, involving diplochory and hydrochory. In vitro pollen germination studies with different nutrient media indicated that sucrose and boric acid had each good pollen germination and tube development, while sucrose together with boric acid showed stimulatory effect in maximizing pollen germination rate and pollen tube length at the optimal concentration. Calcium nitrate, potassium nitrate and magnesium sulphate had dual roles of regulation and enhancement of pollen germination, as well as pollen tube growth, depending on their concentrations. [ABSTRACT FROM AUTHOR]

Recently, calcium nitrate (CN) has been widely used in contaminated sediments remediation. However, the release of NO3−–N, NO2−–N, and Pb into the overlying water accompanying with the addition of CN may cause a toxic threat to the water ecosystem. Herein, this study investigated the effect of CN addition dosages on the sediment remediation, including oxidation-reduction potential (ORP), acid-volatile sulfide (AVS), phosphorus, nitrogen, and Pb. Results showed that, with the increase of CN addition ratio from 0.5× to 2.0× (from 0.5 to 2.0 times the theoretical CN dosage, based on autotrophic sulfide-driven denitrification), the ORP, AVS, and Fe (II) removal rates had a significant improvement. Moreover, due to the abundant Ca2+ and the oxidization of Fe (II), it would make O–P transformed to Ca–P and Fe/Al–P, which lead to the locking of phosphorus in sediments. However, this study indicated that the more CN added, the more NO3−–N, NO2−–N, and Pb2+ released in the overlying water. In addition, the increase of exchangeable Pb and oxidizable fraction Pb in sediments were characterized, which had a positive correlation with CN dosages (p < 0.01). Thus, secondary pollution needs to be considered for sediment remediation, and adding nitrate directly into sediments may not be suitable for natural water bodies. [ABSTRACT FROM AUTHOR]

Background: The content of stone cells in pears has a great influence on taste. Stone cells are formed by the accumulation of lignin. The treatment of exogenous calcium can affect the lignin synthesis, but this Ca-mediated mechanism is still unclear. In this study, the author performed a comparative transcriptomic analysis of callus of pears (Pyrus x bretschneideri) treated with calcium nitrate Ca (NO3)2 to investigate the role of calcium in lignin synthesis. Results: There were 2889 differentially expressed genes (DEGs) detected between the Control and Ca (NO3)2 treatment in total. Among these 2889 DEGs, not only a large number of genes related to Ca single were found, but also many genes were enriched in secondary metabolic pathway, especially in lignin synthesis. Most of them were up-regulated during the development of callus after Ca (NO3)2 treatment. In order to further explore how calcium nitrate treatment affects lignin synthesis, the author screened genes associated with transduction of calcium signal in DEGs, and finally found CAM, CML, CDPK, CBL and CIPK. Then the author identified the PbCML3 in pears and conducted relevant experiments finding the overexpression of PbCML3 would increase the content of pear stone cells, providing potential insights into how Ca treatment enhances the stone cell in pears. Conclusions: Our deep analysis reveals the effects of exogenous calcium on calcium signal and lignin biosynthesis pathway. The function of PbCML3 on stone cells formation was verified in pear. [ABSTRACT FROM AUTHOR]

Secondary salinization caused by the overaccumulation of calcium nitrate [Ca(NO3)2] in soils due to excessive fertilization has become one of the major handicaps of protected vegetable production. Brassinolide, a bioactive plant steroid hormone, plays an important role in improving abiotic stress tolerance in plants. However, whether and how brassinolide (BR) can alleviate Ca(NO3)2 stress remains elusive. Here, we investigated the effects of exogenous BR on hydroponically grown tomato (Solanum lycopersicum L.) plants under Ca(NO3)2 stress through proteomics combined with physiological studies. Proteomics analysis revealed that Ca(NO3)2 stress affected the accumulation of proteins involved in photosynthesis, stress responses, and antioxidant defense, however, exogenous BR increased the accumulation of proteins involved in chlorophyll metabolism and altered the osmotic stress responses in tomatoes under Ca(NO3)2 stress. Further physiological studies supported the results of proteomics and showed that the exogenous BR-induced alleviation of Ca(NO3)2 stress was associated with the improvement of photosynthetic efficiency, levels of soluble sugars and proteins, chlorophyll contents, and antioxidant enzyme activities, leading to the reduction in the levels of reactive oxygen species and membrane lipid peroxidation, and promotion of the recovery of photosynthetic performance, energy metabolism, and plant growth under Ca(NO3)2 stress. These results show the importance of applying BR in protected agriculture as a means for the effective management of secondary salinization. [ABSTRACT FROM AUTHOR]

[Objective] In the present work, potato cultivar Hermes was used as the plant material to investigate the effects of different calcium fertilizers on yield and the quality of potato tubers during storage based on field experiment. [Method] Calcium nitrate (A) and organic calcium of BRANDT Co., lid. (B) were applied to potatoplants at the seedling stage by drip irrigation, and the application amount was 400 g!hm2 (Al, Bl), 1200 g/hm2 (A2, B2), and 2000 g!hm2 (A3, B3), 2800 g!hm2 (A4, B4), respectively, with no calcium fertilizer applied as the control (CK) . [Result] Compared with the CK, the A3 and B3 treatments of calcium nitrate and organic calcium increased the yield by 52. 28% and 79. 54%, and the number of tubers per plant and the weight of tubers per plant increased by 16. 20 %, 61. 39% and 53. 06%, 79. 59%, respectively. Both calcium fertilizers increased the rate of large potatoes and commercial potatoes. The reducing sugar content of potato tubers was significantly lower than that of CK during the storage period under B2 and B3 treatments. After storage for 45 days, the crude protein content of tubers increased by 11. 30%, 21. 47% and 37. 85%, 35. 03% respectively compared with the CK under A2, A3 treatments of calcium nitrate and B2, B3 treatments of organic calcium. After storage for 90 days, the crude protein content of tubers was higher than that of the CK under different calcium fertilizer treatments; Tuber dry matter content increased 5. 50% and 15. 76% compared with the CK under A3, B3 treatment of calcium nitrate and organic calcium; Tuber hardness was 22. 04 %, 11. 14 % and 2. 63 %, 20. 94% higher than the CK under A2, A3 treatment of calcium nitrate and B2, B3 treatment of organic calcium. After 135 days of storage, the crude protein content of tubers was higher than the CK under different calcium fertilizer treatments; the starch content of tubers was increased by 24. 50% and 30. 66 % respectively compared with the CK under the A3 treatment with calcium nitrate and the B3 treatment with organic calcium; it showed the highest tuber hardness by L 27% increase compared with the CK under B3 treatment with organic calcium; [Conclusion] In summary, the two calcium fertilizers both promoted the increase in yield and improved the storage quality of tubers. Treatment with an organic calcium dosage of 1200 - 2000 g/hm2 is more conducive to improving yield and tuber storage quality. [ABSTRACT FROM AUTHOR]

Phase equilibria at 25°C in the KNO3–Ca(NO3)2–H2O system were studied by the isothermal sections method. The phase diagram of the system was found to feature six phase fields, three monovariant lines, and two invariant points, the latter corresponding to a eutonic solution saturated with KNO3 and KNO3⋅Ca(NO3)2⋅3H2O and to a peritonic solution in equilibrium with Ca(NO3)2⋅4H2O and KNO3⋅Ca(NO3)2⋅3H2O. The structure of the double salt was determined by X-ray structural analysis; its melting temperature and heat of melting were determined by differential scanning calorimetry (DSC) as ∆Нm = 132.2 kJ/kg, and Tm = 52.1°С. The density of salt melts was measured at 60, 80, and 85°C. The thermophysical parameters of the double salt allow us to regard it as a promising heat storage material. [ABSTRACT FROM AUTHOR]

In recent year, the demand for guava fruit has been increasing in domestic and international markets. However, guava fruit is extremely perishable due to the short shelf life and rapid over-ripening of the fruits suggesting the need for practical tools to extend their shelf-life. In the present study, the efficiency of calcium nitrate treatment was investigated on Golla guava fruit. Fruits were treated with different concentrations (0, 1%, 2%, 3% and 4%) for 12 days storage at ambient condition. Among the dipping treatments, 4% calcium nitrate significantly reduced fruit weight loss (FWL), decay percentage, and suppressed the increase of soluble solids content (SSC). Moreover, 4% calcium-treated fruits had higher total titratable acidity (TA), and lower ripening index (SSC: TA ratio) and pH during the storage period. Higher ascorbic acid, total phenolic content (TPC) and higher reducing, non-reducing and total sugars along with retained higher activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) enzymes were observed in (4%) calcium nitrate treated guava fruits. Calcium nitrate (4%) also exhibited higher aroma, taste and flavour among the other treatments. Generally, the pre-storage calcium nitrate dipping treatment of guava fruit-maintained fruit quality for up to 12 days at ambient storage condition and could be suggested as practical solution at commercial levels in extending the shelf life of fresh guava fruits. [ABSTRACT FROM AUTHOR]

Secondary soil salinization causes plant stress, which can be relieved by different ratios of red to far-red light (R:FR). Our study aimed to elucidate the role of low R:FR ratios treatments on photosynthesis and growth of tomato seedlings in salinized soils. Tomato seedlings were treated under three R:FR ratios and calcium nitrate was applied simultaneously. The results showed that the treatments under low R:FR ratios stimulated growth parameters of tomato seedlings under calcium nitrate stress, the best impact being achieved at the R:FR ratio of 0.7 in this experiment. Low R:FR ratios treatments increased proline content as well as PSII maximum efficiency, actual electron transport operating efficiency, and photochemical quenching of tomato seedlings under calcium nitrate stress but decreased the value of nonphotochemical quenching. Moreover, low R:FR ratios treatments promoted net photosynthetic rate and increased the expression of a Rubisco gene. In conclusion, low R:FR ratios treatments could improve the salt resistance of greenhouse tomato plants. [ABSTRACT FROM AUTHOR]

Jequitibá-rosa (Brazilian name) is a tree that can reach 30 to 50 meters in height, with valuable wood production and aptitude for artificial regeneration programs, but information on adequate fertilization in the seedling production process is still scarce. The objective of this work was to verify the effect of nitrogen sources and doses on the growth and quality of jequitibá-rosa seedlings. The seedlings were produced in red-yellow Latosol, in the region of Viçosa MG, in pots with a capacity of 1.5 dm³. The nitrogen (N) sources used were ammonium nitrate, ammonium sulfate and calcium nitrate, in five doses (0, 75, 150, 225 and 300 mg/dm³ of N) applied in installments at 25, 50, 75 and 100 days after subculture. The experimental design was in randomized blocks, in a factorial scheme (3 x 5), with four replications. At 125 days after subculture, the morphological characteristics of the plants were evaluated. The source x dose interaction was significant for all characteristics and indices evaluated. The sources with the highest averages were ammonium nitrate and ammonium sulfate, in N doses ranging from 70 to 225 mg/dm³. It is recommended for the production of jequitibá-rosa seedlings, an average dose of 170 mg/dm³ of N using ammonium nitrate as a source or 100 mg/dm³ of N through ammonium sulphate, split at 25, 50, 75 and 100 days after plant repotting. [ABSTRACT FROM AUTHOR]

Hydrodynamics control the movement of water and material within and among habitats, where time-scales of mixing can exert bottom-up regulatory effects on aquatic ecosystems through their influence on primary production. The San Francisco Estuary (estuary) is a low-productivity ecosystem, which is in part responsible for constraining higher trophic levels, including fishes. Many research and habitat-restoration efforts trying to increase primary production have been conducted, including, as described here, a whole-ecosystem nutrient addition experiment where calcium nitrate was applied in the Sacramento River Deep Water Ship Channel (DWSC) to see if phytoplankton production could be increased and exported out of the DWSC. As an integral part of this experiment, we investigated the physical mechanisms that control mixing, and how these mechanisms affect the strength and duration of thermal stratification, which we revealed as critical for controlling phytoplankton dynamics in the relatively turbid upper DWSC. Analysis of a suite of mixing mechanisms and time-scales show that both tidal currents and wind control mixing rates and stratification dynamics in the DWSC. Longitudinal and vertical dispersion increased during periods of high wind, during which wind speed influenced dispersion more than tidal currents. Thermal stratification developed most days, which slowed vertical mixing but was rapidly broken down by windinduced mixing. Stratification rarely persisted for longer than 24 hours, limiting phytoplankton production in the study area. The interaction between physical mechanisms that control mixing rates, mediate stratification dynamics, and ultimately limit primary production in the DWSC may be useful in informing habitat restoration elsewhere in the Delta and in other turbid aquatic environments. [ABSTRACT FROM AUTHOR]

Calcium nitrate supplementation has recently been suggested to provide potential benefits to sows and, in particular, their offspring when administered at a level of 1,200 ppm in feed shortly before farrowing through lactation. More specifically, nitrate supplementation has been suggested as one opportunity for improved placental and/or fetal blood flow and has been hypothesized in previous work to be important to the swine industry in light of the global trend toward larger litter sizes. The benefit is likely manifested through exposure to the nitrate moiety, but interestingly, nitrate has historically been considered a compound of concern for swine. High levels of nitrate once metabolized to nitrite can interfere with the oxygen-carrying capacity of hemoglobin, resulting in increased methemoglobin and, subsequently, methemoglobinemia (MetHb) if the animal is deprived of significant amounts of oxygen; however, the level of nitrate exposure necessary to induce MetHb in sows is not clearly defined. This work was undertaken to examine methemoglobin levels in sows and piglets exposed to the potentially beneficial levels of 1,200 and 6,000 ppm nitrate added to their diets over the course of the periparturient period. Other oxygen capacity blood variables were evaluated (e.g. hemoglobin, hematocrit, and various measures of hemoglobin and red blood cell volumes and concentrations), as well as performance endpoints (weight changes and feed intake) and general observations over the 27-d period. No evidence of treatment-related toxicity manifestation was observed at these supplemental levels. Nearly all oxygen-related variables were affected by time (independent of treatment), indicating adaptive general effects of farrowing. These findings support the hypothesis that MetHb is not a concern up to at least 6,000 ppm supplemental nitrate exposure, even in combination with additional nitrate in the sow's daily diet. This work is important to help swine producers understand that consideration of nitrate benefit should outweigh concern for risk of nitrate-induced toxicity. [ABSTRACT FROM AUTHOR]

The investigations of the effect of the Ca(NO₃)₂ dosage at different initial curing temperatures on the Portland cement hydration process and the physical and mechanical properties of Portland cement are presented in the paper. The results show that the Ca(NO₃)₂ admixture shortens the induction period of the hydration of the cement paste and reduces the maximal hydration temperature of the cement paste. The setting time of the cement paste with Ca(NO₃)₂ is about 1 hour shorter for 1% of Ca(NO₃)₂ in the cement paste. At 0 °C and 5 °C, the accelerating effect of the Ca(NO₃)₂ admixture is the most pronounced. At lower temperatures (-5 °C, -10 °C), only 3 % of the Ca(NO₃)₂ admixture can shorten the initial setting time by about 40 %. The most effective application of Ca(NO₃)₂ is achieved at -5 °C. For the 2 day-specimens cured at the lower initial temperatures (-5 °C, -10 °C), the higher Ca(NO₃)₂ dosages (2-3%) significantly improve the standard strength values of the concrete.

The effect of seed priming with calcium nitrate Ca (NO3)2 and potassium nitrate (KNO3) on germination and seedling vigour were studied in papaya varieties. Open pollinated local (gauty) papaya seeds were soaked in Ca (NO3)2 and KNO3 solutions (10000 ppm, 15000 ppm and 20000 ppm) up to 24 hours and germination percentage and seedling characteristics were recorded. The least number of days taken for seed germination (4.33 days), the highest germination percentage (82.56 % ), the highest shoot length (14.31 cm) the highest fresh biomass (1.36 g) and dry biomass (0.174 g) were recorded in 10000 ppm Ca(NO3)2 treatment. Further, seeds of papaya varieties viz., Arka Surya, Arka Prabhat and Madhu bindhu were treated with 5000 ppm, 10000 ppm and 15000 ppm Ca (NO3)2 and observed that Arka Prabhat seeds treated with 10000 ppm Ca (NO3)2 hadtaken the least number of days for germination (4.75 days) and also the highest shoot length (25.2 cm). The results of the experiment proved the significant effect of calcium ions over potassium ions on papaya seed germination and seedling vigour.

Jujube fruit quickly undergoes spoilage and normally has a short shelf life. Therefore, the effect of immersion treatment in different calcium salts on qualitative and biochemical characteristics of fresh jujube fruit was evaluated. Treatments included control (distilled water) and solutions of calcium chloride, calcium nitrate, and calcium sulfate at a concentration of 0.5 and 1%. Fruits were immersed in water or calcium salt solution for 5 min, air-dried and then cold stored at 4 °C for 50 days. The results showed that such treatment did not affect significantly the pulp color and the anthocyanin concentration in the fruit. However, the soluble solids in the treated fruits significantly decreased compared with the control. Interestingly, all levels of calcium salts, except 0.5% calcium nitrate, preserved the total antioxidant capacity in comparison with the control. Concentrations of 1% calcium nitrate, chloride, and sulfate significantly increased crispness compared with the control. The taste of fruit treated with calcium sulfate significantly deteriorated compared with the control and other treatments. In general, 1% calcium nitrate and 1% calcium chloride applied before storage preserved or strengthened the jujube fruit qualities after storage compared with control. It can be concluded that such treatment is recommended for practical application.

The main purpose of this study was to evaluate the effect of calcium fertilizer treatments on fruit quality and distribution of calcium in apple fruit (Malus domestica Borkh. cv. Idared). Four treatments were tested: application of calcium nitrate through the fertigation system, foliar application of calcium nitrate, application of calcium oxide through soil, and control treatment (without calcium fertilizer). In the experiment, freshly picked apples harvested in Gorazde region (eastern Bosnia) in September 2018 were analyzed. The highest impact to increase calcium content in apple had a treatment where calcium nitrate was added through the fertigation system. It was the result of the balance between calcium and nitrogen in the applied solution as well as the fertigation capacity to timely deliver nutrition to the main rooting zone. Calcium distribution was not uniform within the fruit: the highest content was found in the apple core, decreasing in the apple flesh, and rising again in the apple skin, regardless of fertilizer treatment. There was no difference among calcium fertilizer treatments in total soluble solids and titratable acidity of apple, indicating that these treatments were insufficient in order to improve the examined parameters of fruit quality.

Secondary salinization caused by the overaccumulation of calcium nitrate [Ca(NO3)2] in soils due to excessive fertilization has become one of the major handicaps of protected vegetable production. Brassinolide, a bioactive plant steroid hormone, plays an important role in improving abiotic stress tolerance in plants. However, whether and how brassinolide (BR) can alleviate Ca(NO3)2 stress remains elusive. Here, we investigated the effects of exogenous BR on hydroponically grown tomato (Solanum lycopersicum L.) plants under Ca(NO3)2 stress through proteomics combined with physiological studies. Proteomics analysis revealed that Ca(NO3)2 stress affected the accumulation of proteins involved in photosynthesis, stress responses, and antioxidant defense, however, exogenous BR increased the accumulation of proteins involved in chlorophyll metabolism and altered the osmotic stress responses in tomatoes under Ca(NO3)2 stress. Further physiological studies supported the results of proteomics and showed that the exogenous BR-induced alleviation of Ca(NO3)2 stress was associated with the improvement of photosynthetic efficiency, levels of soluble sugars and proteins, chlorophyll contents, and antioxidant enzyme activities, leading to the reduction in the levels of reactive oxygen species and membrane lipid peroxidation, and promotion of the recovery of photosynthetic performance, energy metabolism, and plant growth under Ca(NO3)2 stress. These results show the importance of applying BR in protected agriculture as a means for the effective management of secondary salinization.

Phase equilibria in the sections of the Ca(NO3)2–CO(NH2)2–H2O system and the deicing properties of calcium nitrate and carbamide mixtures with a ratio between the components ranging from 90 : 10 to 40 : 60 have been studied. Eutectic temperatures with ice, melting ability at a temperature of –5 and ‒10°C, and the character of interaction with water (the occurrence of an endothermic or exothermic effect) have been determined for these mixtures. Mixtures having the best anti-icing properties are revealed. [ABSTRACT FROM AUTHOR]

The effects of N source, fall fertilization, and preventive fungicides were evaluated in bermudagrass [Cynodon dactylon (L.) Pers.] artificially inoculated with Ophiosphaerella korrae and O. herpotricha, the most common spring dead spot (SDS) pathogens in the United States. The source of N applied to bermudagrass from May to August 2006–2008 had a significant effect on SDS symptoms appearing in the spring of 2007–2009. Ammonium sulfate [(NH4)2SO4] provided excellent suppression of O. herpotricha but had no effect on O. korrae, which was suppressed instead by calcium nitrate (CaNO3). More research is needed to determine the underlying mechanisms responsible for suppression of SDS with N sources and the potential role of Mn and Ca in development of the disease. Fall applications of K, S, gypsum, or dolomitic lime had no influence on SDS development. Preventive applications of propiconazole, propiconazole + azoxystrobin, tebuconazole, or fenarimol provided effective control of O. herpotricha but failed to provide significant suppression of O. korrae. The differential response of SDS pathogens to fertilization practices and preventive fungicide applications highlight the importance of pathogen identification in development of integrated management programs. [ABSTRACT FROM AUTHOR]

Bio-cementation is currently appraised to solidify sandy soils, but only few studies use it to cement loess soil particles. The effects of the addition of loess soils on bacterial growth, urease activity, and productive rates for calcium carbonate were studied. Moreover, bio-cementation tests were conducted to improve the collapsibility of loess soils. The results showed that adding increased loess soils increased the pH of supernatant, while the addition of loess soils slightly affected the growth and urease activity of Sporosarcina pasteurii. The productive rates for calcium carbonate in samples treated with calcium chloride and calcium acetate are larger than those treated with calcium nitrate. The optimum concentrations of calcium ions and urea in the cementation solution for bio-cementation tests were 0.75 M and 1.0 M, respectively. The coefficients of collapsibility of samples with various initial densities all decreased via bio-cementation, but the decreasing ratios were different. The productive rates for calcium carbonate were larger for the samples with larger densities. The coefficients of collapsibility decreased with the increase in treatment cycles. Moreover, there were larger increasing ranges of productive rates for precipitation from 4 to 6 cycles. Adding bacterial suspension and cementation solution together enabled better treatment effects for the samples with smaller densities, however, while adding them separately was more suitable for the samples with larger densities. [ABSTRACT FROM AUTHOR]

Effect of coating with calcium nitrate in three concentrations (0.0, 0.5, and 1.0 wt%) on chemical and mechanical properties, and impact behaviour of two apple cultivars (Golden Delicious (GD) and Red Delicious (RD)) during time (0, 2, and 4 months) was studied. Moisture content, pH, titratable acidity, °Brix, organoleptic properties, modulus of elasticity (E), yield stress, yield strain, and toughness were measured. The effect of impact loads was determined by measuring bruise volume (BV) and bruise susceptibility (BS). The results showed that pH and °Brix significantly increased, while titratable acidity, E, yield strain, toughness, and BV decreased during storage time. As Ca(NO3)2 concentration increased, titratable acidity, E, yield strain and yield stress increased and pH decreased (P < 0.05). Highest and lowest values for °Brix were observed in GD treated with 1.0% Ca(NO3)2 after four months (13.31) and GD treated with 0.5% Ca(NO3)2 at the first day (10.65), respectively. Maximum E was obtained in GD treated with 1.0% Ca(NO3)2 on the first day (2130 kPa) and this sample also showed the lowest BS after four months of storage (2.82 mL J−1), while the uncoated GD had the highest BS on the first day (7.11 mL J−1). [ABSTRACT FROM AUTHOR]

Ceramics consisting of anhydrous calcium sulfate, CaSO4, after firing in the range 800–1000°C have been prepared from calcium sulfate dihydrate (CaSO4⋅2H2O) powder synthesized using aqueous 1 M calcium nitrate (Ca(NO3)2) and ammonium sulfate ((NH4)2SO4) solutions. In the preparation of the powder, the precipitate was washed four times with distilled water to remove ammonium nitrate, NH4NO3, a reaction by-product and, after drying, the powder was disaggregated in acetone. The synthesized CaSO4⋅2H2O powder particles had an elongated prismatic shape both before and after disaggregation. After firing at 800, 900, and 1000°C, the microstructure of the ceramics based on the synthesized CaSO4⋅2H2O powder free of reaction by-products contained sintered elongated polycrystalline structures, confirming that the ceramics inherited the microstructure of the starting powder. Ceramics consisting of anhydrous calcium sulfate, CaSO4, can be recommended for the fabrication of implants for bone tissue defect repair by regenerative medicine methods because they are biocompatible and bioresorbable. [ABSTRACT FROM AUTHOR]

Enhanced use efficiency of fertilizer nitrogen (N) is paramount for sustainable pear fruit production. Sufficient fruit N content is a major factor for pear fruit storage potential, but fertilizer N use efficiency in pear fruit trees is generally low. The objective of this work was to test a methodology to quantify N uptake, partitioning and leaching loss as influenced by different calcium nitrate (Ca(NO 3) 2) fertilizer timings. To this end, 10-year-old 'Conference' pear trees (Pyrus communis L.) were transplanted and grown in soil-filled pallet boxes subjected to different timing of fertilizer addition. A fraction of the calcium nitrate was labelled with 15N and applied one month before full bloom, during summer and post-harvest. By sampling newly formed biomass (i.e., leaves, fruit and flower buds), temporal dynamics in the N fraction derived from calcium nitrate fertilization were determined. Simultaneously NO 3 − leaching derived from calcium nitrate fertilization was quantified. Our data suggest that spring application of N was most efficiently partitioned to leaves, fruits and buds at the time of harvest with a mean percentage of calcium nitrate derived N (Ndff) of 9.2%, 20.4% and 18.6%, respectively. Summer application of calcium nitrate was far less efficient at the time of harvest with Ndff of 0.56%, 0.89% and 1.4%, respectively, and substantially higher NO 3 − leaching was observed compared to spring fertilization. Post-harvest application showed even higher levels of leaching. Applying a split fertilization scheme with 60 kg N ha−1 evenly spread over spring, summer, and post-harvest, about 9, 15 and 30%, respectively, of the fertilizer N had leached out as NO 3 − at the end of the growing season. This experimental approach may offer potential for detailed N budget studies for various fruit tree studies. • Nitrogen applied during spring was most efficiently partitioned to the newly produced organs. • Summer fertilization is inefficient in adjusting nitrogen uptake of the respective growing season. • Summer and post-harvest fertilization result in high nitrate leaching. • Importance of fertilization observed since control group bared lower yield and pear nitrogen content. [ABSTRACT FROM AUTHOR]

[Objective] In order to provide theoretical basis for pollen viability identification, artificial pollination and cross breeding of large- fruited yellow passion fruit, the effects of different culture medium in vitro and storage conditions on pollen germination were analyzed. [ Method] Pollens were collected from newly blooming flowers of large-fruited yellow passion fruit The suitable concentrations of sucrose, boric acid, calcium nitrate and suitable pH for pollen in vitro culture were screened by Li, (5 4) onhogonal design. The effects of sampling time of flowers, storage humidity and temperature on pollen viability were studied by using the most suitable pollen culture medium. The suitable storage condition for pollen of large-fruited yellow passion fruit was determined. [Result] The results of onhogonal test showed that the order of influencing factors on pollen germination rate of large-fruited yellow passion fruit was calcium nitrate > sucrose > boric acid > pH. The optimum medium for pollen germination in vitro was 100. 00 g/L sucrose + 0. 02 g/L boric acid + 0. 40 g/L calcium nitrate, and the medium pH was 5. 0. The pollen germination rate in the optimum medium was 85. 55 % . The pollen germination rate of large-fruited yellow passion fruit was more than 80. 00% when the sampling time was from 11 :30 to 17 :30. The pollen viability was the highest in the third hour ( 16: 30) after flowering, which was significantly higher than the germination rate of pol- lens collected at other times except 13 : 30 and 15 : 30 (P <0. 05, the same as below). The results of storage test showed that, the pollen germination rate of natural air drying on sulfur paper treatment for 3 - 48 hours was significantly higher than that of sealed centrifugation tube storage at room temperature and storage in desiccator on sulfur paper for the same time, and the pollen germination rate of 48 h storage was still 34. 28%. The pollen germination rate was 61. 49% after natural air drying for 5 hours and sealed in centrifugal tube at 4 °C for 24 hours, which was significantly higher than that (55. 22%) after natural air drying for 5 hours and sealed in centrifuge tube at - 20 °C for 24 hours. [Conclusion] The optimum medium for pollen germination in vitro of large-fruited yellow passion fruit is 100. 00 g/L sucrose+ 0. 02 g/L boric acid+ 0. 40 g/L calcium nitrate, and pH is 5. 0. The best storage condition is that the pollens collected on the day are dried naturally for 5 hours and sealed in centrifuge tube at 4 °C [ABSTRACT FROM AUTHOR]

Ceramics consisting of anhydrous calcium sulfate, CaSO4, after firing in the range 800–1000°C have been prepared from calcium sulfate dihydrate (CaSO4⋅2H2O) powder synthesized using aqueous 1 M calcium nitrate (Ca(NO3)2) and ammonium sulfate ((NH4)2SO4) solutions. In the preparation of the powder, the precipitate was washed four times with distilled water to remove ammonium nitrate, NH4NO3, a reaction by-product and, after drying, the powder was disaggregated in acetone. The synthesized CaSO4⋅2H2O powder particles had an elongated prismatic shape both before and after disaggregation. After firing at 800, 900, and 1000°C, the microstructure of the ceramics based on the synthesized CaSO4⋅2H2O powder free of reaction by-products contained sintered elongated polycrystalline structures, confirming that the ceramics inherited the microstructure of the starting powder. Ceramics consisting of anhydrous calcium sulfate, CaSO4, can be recommended for the fabrication of implants for bone tissue defect repair by regenerative medicine methods because they are biocompatible and bioresorbable. [ABSTRACT FROM AUTHOR]

An urgent task at the present time is the disposal and processing of large-tonnage waste of titanium production of Ust-Kamenogorsk titanium-magnesium plant of the Republic of Kazakhstan. This work shows research on the development of sludge technology with the extraction of titanium dioxide and calcium nitrate, which will eliminate the formation and discharge of technological waste into the environment. Ammonium fluoride processing of cakes from sludge leaching made it possible to first isolate silicon fluorides in the form of fumes, and then sublimate titanium fluorides. Silicon and titanium fluorides were converted to silicon and titanium dioxides by alkaline hydrolysis. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, the effect of different calcium sources on calcium carbonate deposition by the ureolytic Paenibacillusfavisporus U3 was investigated. Calcium lactate, calcium nitrate, and calcium chloride were used as organic and inorganic calcium sources. In addition, the activity of urease and carbonic anhydrase enzymes required for calcium carbonate mineralization by U3 was determined. Results showed that the highest amount of CaCO.i was reached at lOOOmM CaCE concentration. Enzyme activity studies proved that U3 contains urease and carbonic anhydrase enzymes. Also, calcite and vaterite forms of calcium carbonate were produced by the U3 strain. The calcite and vaterite crystals of calcium carbonate were verified by XRD, XRF, CRS, EPMA, and FESEM-EDX. Lastly, P. favisporus U3 can precipitate large amounts of calcium carbonate by tolerating high CaCE concentration, demonstrating its potential for use in soils with high calcium chloride concentrations. [ABSTRACT FROM AUTHOR]

This study was conducted to utilise the effective self-healing system to regain the mechanical properties of the cementitious materials containing micro-cracks. Storing epoxy and calcium nitrate as healing agents was performed by microencapsulation in the urea–formaldehyde shell. The microcapsules were characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetric, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cementitious samples were prepared by mortar mixing with various amounts of microcapsules (0, 1, 3 and 6% w/w). The healing potential of microcapsules was analysed based on the recovery rate of the mechanical properties. The obtained microcapsules have an outer rough surface, suitable diameter (1–100 μm) and shell thickness (0.2–0.6 µm), and remarkable thermal stability (up to 260 °C). Mechanical test results exhibit that created micro-cracks were healed completely and regained the recovery rates over 100%. The prepared microcapsules besides enhancing thermal stability, demonstrate a high performance in microcracks sealing to improve durability of cementitious materials. [ABSTRACT FROM AUTHOR]

Foliar application of nutrient is more efficient than soil-applied. In this project the effect of calcium nitrate and potassium nitrate on qualitative and quantitative traits was investigated in seedless barberry (Berberis vulgaris L.). Seedless barberry shrubs with different reproductive statuses (ON and OFF) were treated with spraying of calcium nitrate (Ca(NO3)2) or potassium nitrate (KNO3) solutions at concentration of 0.5% and distilled water (as control) four times during different fruit growth and development stages. The results showed that foliar application of both chemical salts significantly increased the number of clusters per branch, the number of berries per branch and the number of berries per cluster in 2017. The highest and the lowest number of clusters per branch, and the number of berries per branch were obtained in KNO3 and control treatments, respectively in 2018. Also, the greatest number of berries per cluster was recorded in treated plants with Ca(NO3)2 in 2018. The nitrogen content of fruit was higher in Ca(NO3)2 treatment. The highest fruit calcium content was obtained in Ca(NO3)2 treatment in both seasons. Berries treated with distilled water (control) were redder, and the fruits treated with Ca(NO3)2 and KNO3 (0.5%) were brighter in the 2017 season. However, the quality of treated fruit with Ca(NO3)2 and KNO3 (0.5%) was higher than the control in both years. The results showed that foliar spraying with Ca(NO3)2 and KNO3 significantly improved the qualitative and quantitative characteristics of barberry fruit compared to the control. [ABSTRACT FROM AUTHOR]

In recent years, calcium nitrate addition has become a promising and usually used method for in situ sediment remediation. In this study, excess calcium nitrate was applied to column sediments to explore the coupling reactions of elements such as N, Fe, S, and P. Diffusive gradients in thin film (DGT) devices were used to collect labile substances at the sediment-water interface. Rhizon samplers were used to collect soluble substances in interstitial water. Results showed that nitrate addition turned the surface sediment into a more oxidized state, and mobile Fe, S, P, and As were removed in surface ~ 10-cm sediment. Due to different nitrate distributions in corresponding sediment depths, the consumption rates of NH3-N and soluble reactive P were faster in the surface sediment than that in deeper layers. Different from previous researches, the transient increase of soluble Fe was observed in this study, which was probably attributed to the solvation of FeS in the autotrophic denitrification process. According to our results, we suggest that a dosage of far less than 141 g N/m2 and slightly more than 45.3 g N/m2 can be used for the remediation of black and odorous sediment and control of internal P by calcium nitrate. [ABSTRACT FROM AUTHOR]

A two-year field experiment was carried out to investigate the effect of calcium nitrate (CN) application on the nutrients concentration and yield of Golab apple, Granny Smith apple, Beirut pear and Takdaneh cherry. A completely randomized design experiment was conducted with three factors including: trees (Golab Apple, Granny Smith Apple, Pear cultivar: Beirut and Cherry cultivar: Takdaneh), CN fertilizer treatments (T0: nil, T1: soil application, T2: soil test results application, and T3: soil and foliar application) and Year (First year and Second year) with four replications. Studied parameters included; the concentration of nitrogen (N), phosphorus (P), calcium (Ca) and magnesium (Mg), nutrient ratios, and fruits yield. The results of two-year experiments indicated that CN application significantly increased fruits Ca concentration. Regarding to results belonged to the second year, the highest Ca and Mg concentration was related to Granny Smith apple, while the highest N concentration was observed in cherry. Also results demonstrated that for all fruits the highest ratios of N/Ca and Ca/Mg was obtained in first and second years, respectively. CN fertilization through the second year, reduced N accumulation in all fruits and balanced the N/Ca ratio. The lowest ratio of N/Ca was observed in T2 and T3. In accordance with the results of the present study, it was found that soil application of CN increased fruits Ca concentration and Ca/Mg ratio and reduced the N/Ca ratio. Generally, increase in Ca uptake improved fruits quality of orchard products. [ABSTRACT FROM AUTHOR]

[Display omitted] • MDC was applied for the first time to obtain calcium nitrate crystals. • Hydrophobic PVDF/Span 85 membranes were prepared and used in the MD step. • Remarkably higher water contact angle was achieved by adding Span 85 to PVDF. • The permeate flux of the MD process was increased by adding Span 85 to PVDF. • The highest amount of crystals was obtained by adding 4 wt% Span 85 to PVDF. As an alternative to the energy-intensive evaporation-crystallization method, membrane distillation crystallization (MDC) was applied for the first time to obtain calcium nitrate crystals from its aqueous solution. Calcium nitrate solution was obtained through the reaction between calcium carbonate and nitric acid, and then it was concentrated in the membrane distillation (MD) process and further crystallized. The MD step was conducted using hydrophobic polyvinylidene fluoride (PVDF)/sorbitan trioleate (Span 85) membranes. Span 85 was incorporated into the membrane structure in various concentrations to improve the hydrophobicity of membranes, and the resultant membranes were characterized via different methods. In addition, the resultant calcium nitrate crystals were characterized by X-ray fluorescence (XRF) spectroscopy. The MDC results showed that the optimum amount of Span 85 in the polymeric solution was 4%, which led to the formation of a membrane with higher porosity (67.2%) and water contact angle (95.7°) compared to the neat PVDF membrane. The mentioned membrane exhibited the highest water flux in the MD process compared to the other membranes, and also it produced the highest amount of crystals due to its remarkably better performance in the MD step in terms of feed concentration. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Minerals & Processing / Huagong Kuangwu yu Jiagong is the property of Industrial Minerals & Processing Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Extrusion-based additive manufacturing imposes high requirements on the material stability right after the extrusion. Therefore, a thorough understanding of the chemical reactions that determine the early reduction in processability is necessary. Accelerators are especially considered here, which have a major influence on the early reaction. This study contributes to these issues by analyzing the influence of 0.1 wt% TEA (triethanolamine) and 2.0 wt% Ca(NO3)2 on the hydration of two CEM I 52.5 R. The hydration was analyzed by isothermal heat flow calorimetry and in-situ X-ray diffraction. Vicat needle penetration, a penetrometer of own design, and ultrasonic P-wave velocity development were used to monitor the early change in workability. The obtained results indicate that ettringite formation is the main factor influencing workability during the first 60 min of hydration. Afterwards, the influence of ettringite is exceeded by the formation of C–S–H. Ca(NO3)2 was shown to enhance C–S–H formation and had no significant effect on the workability during the first 60 min of hydration while rapidly decreasing workability during the induction period. TEA was shown to increase brownmillerite dissolution and ettringite formation and, consequently, promote the workability loss during the initial hydration period. The time of initial and final setting determined by the Vicat needle test depended mainly on the formation of C–S–H phases. [ABSTRACT FROM AUTHOR]

Global lithium salt price surges drive up costs for high-performance repair materials, creating demand for cost-effective alternatives. Calcium nitrate (CN), with its low production costs and capacity to enhance early cement strength, emerges as a preferred choice. Limited knowledge on combining calcium sulfoaluminate (CSA) cement and CN prompts further exploration for a potentially cost-effective solution in repair materials. This study investigated the impact of varied CN contents on fluidity, setting time, compressive strength, electrical resistivity, heat of hydration, hydration products, and pore structure of CSA cement. The results show that CN can enhanced fluidity, significantly reduced setting time, accelerated hydration process, shortened the hydration induction period, and promoted the nucleation and growth of ettringite. When CN content was 8%, the compressive strength of samples reached its peak at 40.8 MPa, 44.9 MPa, and 47.3 MPa at 3 d, 7 d, and 28 d, respectively. Exceeding 8% CN content will increase the cumulative heat release which reach the maximum of 314.5 J·g−1 at 72 h. The addition of CN will generate the NO 3 -AFm phase and improve the stability of ettringite, as well as refine the pore structure of the samples but increase their total porosity. • The hydration mechanism of CSA cement with high amounts of calcium nitrate (CN) was analyzed. • The optimal amount of CN to enhance the compressive strength of CSA cement samples was 8%. • Although high amounts of CN can refine the pores of CSA cement, it also led to an increase in its total porosity. • The presence of NO 3 -AFm in CSA cement samples affected its hydration process, promoting the stability and formation of AFt. [ABSTRACT FROM AUTHOR]

In recent years, the preparation of new microbial dust suppressants based on microbial induced carbonate precipitation (MICP) technology through enriched urease-producing microbial communities has become a new topic in the field of coal dust control. The deposition of CaCO 3 was the key to suppress coal dust. However, deposition characteristics in the field is not sufficient and the relationship between deposition characteristics and erosion resistance is not clear, which hinders the development of engineering application of new microbial dust suppressant. Therefore, based on X-CT technology, this paper observed and quantified micro-deposition of bio-consolidated coal dust with different calcium sources. Furthermore, a conceptual framework for deposition was proposed and its correlation with erosion resistance was revealed. The results showed that CaCO 3 induced by calcium chloride and calcium lactate was aggregate deposited. Aggregate deposited CaCO 3 was small in volume, showed the distribution of aggregation in the central area and loose outside, and mosaiced pores. CaCO 3 induced by calcium nitrate was surface deposition due to attached biomass. Surface deposition was mostly large volume CaCO 3 expanding from the inside out, which could cover coal dust to a high degree and completely cemented pores. In addition, the threshold detachment velocity of coal dust cemented by surface deposition was increased by 17.6–19.1% compared to aggregate deposition. This depended on the abundance and strength of CaCO 3 bonding between coal dust particles under different deposition. The two-factor model based on porosity and CaCO 3 coverage can well express relationship between erosion resistance and depositional characteristics. Those results will help the engineering application of MICP technology in coal dust suppression. • Different depositional property for different calcification condition. • Aggregate deposition formed "bridges" between particles. • Surface deposition formed calcite layer with a thickness of 6–7 μm. • Differences in deposition caused to 17.6–19.1% variation in TDV. [ABSTRACT FROM AUTHOR]

Nitrate leaching from agriculture can be reduced by the choice of fertilizer and a proper timing of its application. For permanent grassland grown under temperate conditions, nitrate leaching was hypothesized to be lower from dairy cattle slurry (CS) compared to synthetic fertilizer calcium ammonium nitrate (CAN), based on differences in chemical composition, consequential effects on nitrogen (N) conversion processes in soil, and resulting differences in synchronization of (nitrate) N availability and plant N uptake. We tested the hypothesis in a two-year field experiment on cut grassland on a leaching-sensitive sandy soil, fertilized each year with 320 kg ha−1 of plant-available N from either 100% top-dressed CAN or a combination of 40% from CAN and 60% from sod-injected CS, and measured effects on grass herbage yield, herbage N uptake, and nitrate concentration in pore water at 1.0 m depth. Our results show a comparable level of herbage N uptake for both treatments, allowing for a proper comparison of nitrate leaching at a similar level of plant-available N. Average nitrate concentration in pore water in the main leaching period (over winter) was after the first (dry) growing season 44% lower for CS + CAN (41 mg l−1) compared to CAN only (73 mg l−1), and after the second (wet) growing season 35% lower for CS + CAN (32 mg l−1) compared to CAN only (49 mg l−1). Nitrogen application increased nitrate concentration at 1.0 m depth not only in winter but also in the growing season. We conclude that for permanent grasslands in temperate regions, nitrate leaching from timely applied CS may be considerably lower than from CAN, which is different from previous assumptions. • Nitrate leaching from cattle slurry was lower than from fertilizer on grassland. • Leaching was 35–44% lower for slurry + fertilizer compared to fertilizer only. • Nitrate was not only leached in winter but also in the growing season. [ABSTRACT FROM AUTHOR]

Silicon (Si) and selenium (Se) can improve the tolerance of plants to NaCl-induced salt stress. However, few studies are available on their regulatory effects on plants' tolerance to calcium nitrate stress, which often occurs in protected facilities, causing secondary soil salinization. In this study, we report the effects of Si (6 mM) and Se (20 μM) applied separately or in combination on the growth, photosynthesis, oxidative damage, and nitrogen metabolism of tomato plants, as well as fruit quality under calcium nitrate stress. The results showed that applications of Si or Se alone or in combination improved the plant growth and photosynthetic performance and reduced oxidative damage of the stressed plants. Applications of Si and Se did not decrease the calcium accumulation in leaves of the stressed plants. Under calcium nitrate stress, the concentrations of NO 3 −, NO 2 − and NH 4 + in leaves were significantly increased, while the activities of nitrogen assimilation-related enzymes (including nitrate reductase, nitrite reductase, glutamine synthase, glutamine-2-oxoglutarate aminotransferase and glutamate dehydrogenase) were decreased. Applications of Si and Se, especially their combined treatment, decreased the NO 3 −, NO 2 −, and NH 4 + concentrations and enhanced the activities of nitrogen assimilation-related enzymes in the stressed plants. Applied Si and Se also decreased the nitrate and titratable acid concentrations and increased vitamin levels in tomato fruits under calcium nitrate stress. It is suggested that Si and Se improved the tomato plant growth and fruit quality under calcium nitrate stress by alleviating oxidative damage and promoting both photosynthesis and nitrogen assimilation. • Si and Se improved tomato growth and photosynthesis under calcium nitrate stress. • Si and Se addition alleviated the oxidative damage of tomato plants under stress. • Si and Se addition enhanced the nitrogen assimilation in tomato plants under stress. • Si and Se addition improved the fruit quality of tomatoes under stress. [ABSTRACT FROM AUTHOR]

• Nutrient deficiency decreased the vegetative growth of Phalaenopsis to ambient CO 2 levels. • Elevated CO 2 alters nutrient availability, improving plant growth and SPAD value with deficient CAN levels (CAN0). • Elevated CO 2 decreased the biomass and photosynthetic efficiency with high CAN levels (CAN2−3). • Elevated CO 2 can be effectively used for Phalaenopsis cultivation with optimal CAN supply. Phalaenopsis Queen Beer 'Mantefon' is an orchid species that absorbs CO 2 at nighttime due to its crassulacean acid metabolism. These orchids originated from nutrient–poor environments in tropical forest understories. However, elevated CO 2 at nighttime influences plant nitrogen utilization for growth. This study investigated the leaf growth and photosynthetic responses in Phalaenopsis Queen Beer 'Mantefon' to varying ambient and elevated CO 2 (400 and 800 μmol⋅mol−1, respectively) and four nitrogen−based calcium ammonium nitrate (CAN) levels over 20 weeks: calcium, ammonium, and nitrate levels by 0.00, 0.00, and 0.00 mmol⋅L−1 (CAN0, control), 0.90, 0.55, and 2.97 mmol⋅L−1 (CAN1), 6.73, 1.11, and 6.05 mmol⋅L−1 (CAN2), and 12.80, 1.72, and 9.13 mmol⋅L−1 (CAN3), respectively. The phosphate and potassium levels were consistent across all CAN levels at 2.74 and 4.37 mmol⋅L−1, respectively. Elevated CO 2 levels showed no significant impact on the number of leaves in CAN1−3 plants yet increased with those with CAN0. Leaf area significantly increased with elevated CO 2 levels by 44 % (CAN0) and 26 % (CAN1). Strong correlations emerged between the number of leaves and leaf area, as well as between leaf area and root−to−shoot dry biomass ratio (R/S). Increasing CO 2 levels heightened SPAD chlorophyll in CAN0 plants, and SPAD and F 0 showed a strong correlation with elevated CO 2 and increasing CAN levels. The total dry biomass decreased in plants with high CAN (CAN and CAN3) compared to those with CAN0, regardless of CO 2 levels, and F v /F m dropped below 0.616 with high CAN under elevated CO 2. Phalaenopsis Queen Beer 'Mantefon' demonstrated augmented leaf growth and R/S under limited CAN (CAN0) and elevated CO 2 conditions, indicating improved resource allocation potential. The results suggest that supplying CO 2 in a greenhouse can effectively improve Phalaenopsis vegetative growth with limited nutrient conditions, which differs from growth aspects under ambient CO 2 levels. [ABSTRACT FROM AUTHOR]

Mixing Portland cement (PC) and calcium sulfoaluminate (CSA) cement can provide several advantages for specific applications. However, the stability of ettringite has a significant impact on ettringite-rich cements properties. This study aims to investigate the impact of calcium nitrate (Ca(NO 3) 2 = CN) and calcium carbonate (CaCO 3 = CC) on the performance evolution and stabilization mechanism of PC-CSA-C$ systems. The experimental results demonstrate that the incorporation of CC and CN has a significant impact on the early hydration kinetics. A second exothermic peak appears indicates the depletion of the calcium sulfate, and its appearance time is related to the amount of CC and CN added. The blended system containing CN exhibited the highest early and late compressive strength, as well as excellent volume stability. Compared with CC, CN was confirmed to be more effective in stabilizing ettringite in the PC-CSA-C$ system and preventing its conversion into monosulfate. Furthermore, the analysis of the pore structure reveals a significant increase in the proportion of pores with diameters ≤50 nm in the systems containing CN. In particular, CN displays a stronger ability to stabilize ettringite to reduce chemical shrinkage and increase the content of C-(A-)S-H gel, and the 28-day compressive strength was approximately 10 MPa higher compared to the control group. [ABSTRACT FROM AUTHOR]

The implementation of extrusion-based 3D concrete printing (3DCP) in large-scale constructions is currently limited by concerns regarding rheology control and the sustainability of this process. To address these issues, this study presents an approach to develop limestone-calcined clay-based cementitious (LC3) materials accelerated by Ca(NO 3) 2 solution in an inline static mixer-based 3DCP setup. Using this approach, a printable mixture containing only about 275 kg/m3 of Portland cement was formulated that can exhibit a good buildability performance and a 28-day compressive strength of over 30 MPa. Additionally, the effects of adding Ca(NO 3) 2 solution on the initial setting time, structural build-up, inline buildability, early-age hydration, and compressive strength of LC3 materials were investigated and discussed. Results show that the addition of Ca(NO 3) 2 solution improved the buildability and accelerated initial setting as well as the structuration due to the promoted ettringite precipitation and C –S–H nucleation. Furthermore, compressive strength at 7 and 28 days was improved through increasing the Ca(NO 3) 2 dosage, which can be attributed to the formation of NO 3 -AFm and the increase in the amount of C –S–H gels. [ABSTRACT FROM AUTHOR]