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The chicken eggshell was applied as an alternative calcium source to produce calcium nitrate fertilizer. 12 g of eggshell waste was used as raw material for extraction into liquid calcium nitrate by a 100 mL of 10%(v/v) nitric acid solution. The liquid calcium nitrate fertilizer was encapsulated through the wet-extrusion process, in which calcium ions from liquid calcium nitrate as crosslinking agents and sodium alginate as an absorbent polymer. 73.57% of nitrate was absorbed by the droplet of 2%(w/v) sodium alginate, forming sphericallike gel structures. The optimal hardening time for bead gel formation was 120 min. The average size of wet bead gels was 4.29 ± 0.34 mm. The bead gels were oven-dried at 45◦C for 1 hour to maintain their shapes. Among other controlled release agents, pectin showed the slowest nitrate release from fertilizer bead gel. The chemical nature of bead gels characterized by FTIR indicated that nitrate was absorbed by alginate polymer incorporated with pectin, binding with the Ca2+ ions.

Extended Abstract Introduction Citrus decline is a significant deteriorating factor in citrus cultivation, imposing costly damages to many orchards worldwide, including in Iran. Key factors contributing to citrus decline include environmental stresses such as the physical and chemical conditions of the soil, soil nutritional status, soil moisture condition, and biotic stresses. Environmental stresses, particularly mineral deficiencies and water stress, appear to play a crucial role in citrus deterioration. The Jiroft region is one of the major agricultural centers in south of Iran. Despite its pivotal role in citrus production of the country, the region's orchards experience widespread deterioration, causing considerable annual losses. However, no research has yet explored the potential benefits of simultaneous use of management and nutritional treatments in these orchards. Therefore, this study aims to investigate the effect of management and nutritional treatments on alleviating both biotic and abiotic stresses and reducing citrus fruit deterioration. Materials and Methods The current study employed a randomized complete block design over two years in Jiroft, south of Iran, incorporating the following treatments: 1. Control: No intervention. 2. Optimal Management: This included timely irrigation, fertilization (chemical and organic amendments based on soil and leaf tests), and gardening practices (pruning, fruit thinning, and weed removal). 3. Optimal Management + Potassium Silicate: This treatment received optimal management plus potassium silicate fertilizer applied through irrigation water three times at a rate of 30 L ha-1 (as determined by soil test). 4. Optimal Management + Shading: This treatment consisted of optimal management with shading (integrated or individual) at approximately 25% during the hot season, along with plant mulch. 5. Optimal Management + Biocontrol & Fungicides/Nematicides: This treatment combined optimal management with Mycorrhizal and Trichoderma fungi, along with fungicides and nematicides. 6. Optimal Management + Calcium Nitrate Injection: Trees received calcium nitrate injection (30%) directly into the trunk twice a year. 7. Optimal Management + Calcium Nitrate Fertilizer & Foliar Spray: This treatment involved optimal management with calcium nitrate fertilizer applied three times (500 grams per tree, one-month intervals) through irrigation water supplemented by foliar sprays containing calcium chelate and micronutrients (zinc, manganese, iron, and copper) applied three times. Then, leaf samples (both 5–6-month-old leaves and new leaves) and fruits were collected and transported to the laboratory for analysis. This analysis included measurements of number of new leaves, leaf area (average surface area per tree leaf), yield, fruit length and diameter, and the concentration of specific macro- and microelements in the leaves.Results and Discussion The results revealed an inverse relationship between the average number of new leaves per tree and the severity of decay. Treatment-4 displayed a 1.5-fold increase in new leaves compared to the control (treatment-1). Additionally, the number of final shoots (spring and summer regrowth) was 191 in the treatment-4 and 76 in the control treatment. In the treatment-4, the mean leaf area was 41.8 cm2, compared to 29.4 cm2 in the control treatment, demonstrating an increase of 42.20%. Statistical comparisons of other responses also indicated a significant increase in treatment-4 compared to the others. Treatment-4 also exhibited the greatest improvements in fruit size. Fruit diameter and length increased by 35.5% and 33.9%, respectively, compared to the control. Treatment-4 resulted in the largest average leaf area (41.8 cm²) compared to the control (29.4 cm²). Fruit yield followed a similar trend, the lowest fruit yield (22.9 kg/tree) being observed in the control treatment. Conversely, treatment-4 (optimal irrigation management with shading and mulch) achieved the highest fruit yield (50.2 kg/tree), representing a significant increase of 119.2%, 45.9%, 52.5%, 2,100.0%, 95.3%, and 77.4% compared to control, treatment-2, treatment-3, treatment-5, treatment-6, and treatment-7, respectively. Treatment-4 also demonstrated the highest concentrations of zinc, manganese, and iron in the fruits. These elements increased by 1.50, 1.52, and 1.65 times, respectively, compared to the control. The results overwhelmingly favored treatment-4 compared to the control and other treatments. This superiority likely stems from the combined effects of shade mesh and mulch, which are unique to treatment-4. Shade mesh not only provides shade but also reduces radiation intensity, ultimately minimizing heat stress, sunburn, and water loss through evaporation and transpiration from the tree's foliage. Beneficial effects of Treatment-4 go beyond shade and mulch by ensuring optimal plant nutrition based on soil tests, addressing a crucial factor in citrus health. Inadequate nutrition can contribute to tree decline. By providing the necessary macro and micronutrients and adjusting environmental conditions like temperature and humidity, particularly around the roots, we can minimize disruptions in nutrient uptake and promote overall tree health. Conclusions Given the warm climatic conditions of Jiroft at Kerman's southern region, citrus decline arises from a combination of biotic and abiotic stresses. Consequently, solutions targeting either biotic or abiotic constraints are unlikely to provide a sustainable solution to the citrus decline question. An integrated approach, incorporating optimal irrigation and combined nutrient management, was found to be more effective. Therefore, implementing optimal irrigation and combined nutrition management, using plant mulch in the shaded area of the trees, and employing netting as a shade was proven to be a suitable solution to the citrus decline in the Jiroft at southern region of Kerman province, Iran.

Shrinkage of concrete during hardening is a serious problem in attempts to maintain the integrity of concrete structures. One of the methods of combating shrinkage is compensating for it using an expansive agent. The purpose of this work is to develop and study an expanding agent to concrete, including high-calcium fly ash and calcium nitrate as an expansion activator. The content of Ca(NO3)2 can be used to regulate the degree of expansion of the additive itself during hydration and, accordingly, to control shrinkage, thus obtaining shrinkage-free or expanding concrete. Shrinkage–expansion deformations of concrete can also be regulated by the amount of expanding additive replacing part of the cement. With the Ca(NO3)2 content of fly ash being 10% or more, concrete experiences expansion in the initial stages of hardening. The transition of deformation through 0 to the shrinkage region occurs depending on the composition and content of the additive after 8–15 days of hardening. It has been established that replacing cement with pure fly ash with a curing period of 90 days or more has virtually no effect on the strength of concrete, either in bending or in compression. The use of an expanding additive containing 5–15% Ca(NO3)2 reduces the strength of concrete by an average of 9%, despite the fact that calcium nitrate is a hardening accelerator.

The objective of this work to study the influence of foliar application of boric acid (0, 125, 250 and 500 ppm) and calcium nitrate (0, 1%, 2% and 3%) on fruit set and yield as well as fruit quality of Seewy date palm cultivar growing in El Dakhla Oasis, New Valley governorate during two successive seasons (2021, 2022), palms were treated with different rates of boric acid (zero, 125, 250 and 500 ppm) and sprayed with calcium nitrate at rates (zero, 1%, 2% and 4%). Results showed that all studied treatments had significant effect on fruit set and total yield compared with the control treatment in both experimental seasons. Spraying boric acid at 500 ppm with calcium nitrate at 2% in both seasons gave the best results of fruit set and total yield. In addition, this combination gave the highest T.S.S content, total sugars and reducing sugars; in contrast, the lowest values of total acidity in two studied seasons.

This study aimed to comprehensively investigate the properties of a binder based on high-calcium fly ash and silica fume with a complex additive consisting of calcium nitrate and magnesium chloride. The strength characteristics, the characteristics of the hydration process, and the phase composition of the hydration products of the binder were investigated. Silica fume was used to suppress the expansion of fly ash during hydration. A complex additive (CA) consisting of Ca(NO3)2 and MgCl2 provided a higher strength of binder than each of these salts separately. When testing a mortar with sand, the CA additive ensured that the strength of the specimens was 43.5% higher than the strength of the mortar with the addition of Ca(NO3)2 and 7.5% higher than the strength of the mortar with the MgCl2 additive. Calcium nitrate greatly accelerated the process of heat release in the first 60 min of binder hydration, and subsequently, conversely, slowed it down. The addition of MgCl2 gave a significantly greater thermal effect than Ca(NO3)2. When the two salts acted together, even a small fraction of magnesium chloride (0.2 of CA) compensated for the retarding effect of calcium nitrate and provided heat release for the binder that was almost as good as that of MgCl2.

A field experiment was conducted to investigate the effect of calcium nitrate and magnesium sulfate on the growth and tuber yield in potato (Solanum tuberosum L). Experiment was carried out in split-plot design comprising of nine calcium nitrate and magnesium sulfate treatments i.e.T1- Ca(NO3)2 @ 0.5%, T2- Ca(NO3)2 @ 1%, T3- Ca(NO3)2 @ 2%, T4- MgSO4 @ 0.5%, T5- MgSO4 @ 1%, T6- MgSO4 @ 2%, T7- Ca(NO3)2 @ 1% + MgSO4 @ 1%, T8- Ca(NO3)2 @ 2% + MgSO4 @ 2%, T9- Control on two potato varieties i.e. Kufri Jyoti and Kufri Chandramukhi. Data collected on different parameters were analyzed using CPCS1 software. Among all the calcium nitrate and magnesium sulfate treatments, application of Ca(NO3)2 @ 2% + MgSO4 @ 2% was found to be the best for most of the parameters studied and between the varieties Kufri Jyoti was found highly significant for the different parameters under study. Hence it can be concluded that commercial cultivation of potato in the central region of Punjab can be successfully supplemented with application of Ca (NO3)2 + MgSO4 and variety Kufri Jyoti.

Fly ash from Berezovskaya Thermal Power Plant, containing a lot of CaO, in combination with silica fume does not expand and exhibits the properties of a binder. However, the strength of this binder is low. The addition of Ca(NO3)2 significantly increases the strength of the binder. The work aims to study the effect of Ca(NO3)2 additive on the strength, heat of hydration, and phase composition of hydration products of the binder based on high-calcium fly ash and silica fume. The results of X-ray diffraction and Differential Thermal Analysis show that the main phases formed during the hydration of binder with the calcium nitrate additive in various dosages are lime, calcium hydroxide, ettringite, CSH(II) type silicates and calcium aluminosilicates, corresponding to such minerals as gismondine, yugavaralite, goosecreekite. When hardening in water, the residual amount of lime after 7 days is sharply reduced. An increase in the dosage of Ca(NO3)2 from 1.5 to 11.8 % leads to a decrease in the CaO content by almost 2 times. With an increase in the dosage of calcium nitrate, the content of portlandite noticeably decreases, and a significant increase in the amount of calcium hydroaluminosilicates, especially the composition of CAS2H4, is observed. A study of the heat release process showed that calcium nitrate greatly accelerates the process in the first 60 minutes of hydration. However, then the composition with the addition of Ca(NO3)2 is inferior in the rate of heat release to binder without the additive. When testing a mortar with polyfractional sand, the addition of Ca(NO3)2 more than doubled the compressive strength of the mortar.

ABSTRACT Nitrogen (N) fertilization effectiveness in onion depends on N source, as well as on soil type and management system. The aim of the study is to investigate the effect of N sources and doses applied as top-dressing on bulb yield, leaf N contents and on the postharvest conservation of onion bulbs grown under no-tillage (NTS) and conventional tillage (CTS) systems. Three experiments were carried out: two in Lebon Régis County-SC, under NTS; and one in Caçador County-SC, under CTS. The herein tested N sources comprised urea, ammonium nitrate, calcium nitrate and ammonium sulfate, in combination to N doses applied as top-dressing (70, 140, 210, 280 and 350 kg N ha-1) in addition to the control, without N. The N sources did not affect yield parameters, leaf N content and post-harvest onion losses. The maximum technical efficiency in bulb yield was observed at N doses of 195.8 and 258.4 kg ha-1 in the no-tillage system (NTS) and at 270.7 kg N ha-1 in the CTS. The NTS enabled maximum yield at N dose 47% lower than the officially recommended one. Maximum relative commercial yield was associated with 31.1 g kg-1 of leaf N.

In this study, a high-performance concrete based on calcium oxide-activated materials (HPC-CAM) was developed and studied. Calcium chloride and calcium nitrate additives were used to improve the microstructure of such concrete. In addition, different fibers including steel, recycled PET, basalt, glass, and modified synthetic macro fibers were used to overcome the brittleness of the HPC-CAM geopolymer matrix. Compressive, flexural, water absorption, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) tests were performed to evaluate the overall characteristics of the specimens thus prepared. The results showed that adding calcium chloride and calcium nitrate increased the compressive strength of HPC-CAM by 69% and 29%, respectively. All samples containing calcium chloride had flexural strengths that were 20% higher than those with calcium nitrate. HPC-CAM samples reinforced with recycled PET fibers and modified synthetic macro-fibers recorded flexural toughness values that were 8- and 6-fold greater than those for steel fibers. The highest calcium silicate hydrate gel (C–S–H) and Si–O-T (T = Si or Al) peaks were obtained in HPC-CAM containing calcium chloride.

In situ capping and biochemical oxidation are two of the most commonly used methods for internal phosphorus (P) control, but there are few studies on the combined use of these two methods. In this study, two lanthanum (La)-based materials, La-modified bentonite (LMB) and the La-modified attapulgite and chitosan composite (LMA&C), were combined with calcium nitrate (CN) to investigate the effect on sediment P control. Results showed that SRP removal rates by LMB+CN and LMA&C+CN were much higher than that by LMB, LMA&C and CN alone. LMB+CN and LMA&C+CN decreased DGT-labile P flux both in overlying water and surface 65 mm sediment, while LMB and LMA&C had an effect only on overlying water and surface 10~40 mm sediment, and CN was effective only on sediments. LMB and LMA&C transformed NH4Cl-P, BD-P, NaOH-SRP and NaOH-NRP in surface 20 mm sediment to HCl-P and Residual-P on day 60. CN transformed NaOH-SRP and NaOH-NRP to BD-P, resulting in the increase in NH4Cl-P. LMB+CN and LMA&C+CN sequestered P in the surface 20 mm mainly as HCl-P and Residual-P, and mainly as BD-P in −20~−60 mm. Results indicate that the combination of capping by La-based material and oxidation by CN is a promising method for sediment P control.

The article presents the results of research on the processing of such wastes of titanium-magnesium production as sludge from sludge dumps and fine dump dusts from the electric smelting of ilmenite concentrates. The results of nitric acid leaching of sludge with the transfer of calcium into solution and the production of calcium nitrate are given. Titanium-containing cake after nitric acid leaching of sludge and electric smelting dust cannot be returned to the technological process due to its high silica content, so the silicon impurity was removed from their composition. Silicon removal was performed by fluoroammonium processing with sublimation of hexafluorosilicate compounds. An amorphous silicon dioxide product was obtained, after ammonia hydrolysis of silicon-containing sublimations and appropriate treatment of the sediment. The residue from the sublimation of silicon fluorides consists mainly of titanium-containing phases and can be suitable for return for electrofusion after ammonia treatment.

Potato (Solanum tuberosum L.) is a widely consumed and essential food crop globally, making it an ideal food matrix for biofortification. Agronomic biofortification is one of the strategies used to enhance Ca content in edible parts of crops, considering the adverse health issues associated with Ca deficiency. This study aims to investigate the impact of Ca agronomic biofortification through four foliar applications after the beginning of tuberization on the yield of tubers of Solanum tuberosum L. (Picasso variety) produced in Lourinhã (Portugal) in 2018, focusing on the application of calcium chloride or, alternatively, calcium nitrate at different concentrations (calcium chloride—1, 3, 6 and 12 kg/ha or calcium nitrate—0.5, 1, 2 and 4 kg/ha). Control plants and plants subjected to the different Ca treatments were placed in plots of 20 × 24 m; the treatments were carried out in quadruplicate (compass 60–80 cm). As such, the Ca content in tubers was quantified by atomic absorption spectrophotometry in the different treatments. The Ca biofortification index with calcium chloride or calcium nitrate ranged between 5 and 40%, with the treatment with 6 kg/ha CaCl2 being the one which presented the highest Ca content in tubers at harvest and 1 kg/ha CaCl2 being the treatment with the lowest Ca biofortification index. However, 6 kg/ha CaCl2, despite presenting the highest Ca content, was not the treatment that presented the highest yield. Indeed, all the calcium nitrate treatments demonstrated a substantial increase in tubers yield, which varied between 2.3 (4 kg/ha Ca(NO3)2) and 24.3% (2 kg/ha Ca(NO3)2). Statistical analysis was carried out in all the analyses using one-way ANOVA to assess differences among treatments in Solanum tuberosum L. (Picasso variety), followed by Tukey’s analysis for mean comparison, with a 95% confidence level. Furthermore, these findings emphasize the potential of Ca biofortification, especially calcium nitrate treatments, in enhancing the yield of Solanum tuberosum L. tubers.

Continuous cropping can lead to an excessive accumulation of nitrate in facility-cultured soil. Excessive accumulation of nitrate gradually becomes the main reason for crop failure in vegetables and endangers human health. Therefore, the exploration of effective measures to decrease abundant nitrate accumulation in Chinese flowering cabbage is indispensable. In this study, a kind of plant growth regulator, fulvic acid (FA), was used to study its positive effect on alleviating the growth inhibition induced by excessive Ca(NO3)2 in Chinese flowering cabbage. Meanwhile, we conducted hydroponic cultivation and measured the growth indices, photosynthetic and oxidation-reduction characteristics of Chinese flowering cabbage with different treatments. After determining the optimal treatment concentration, we mainly designed four treatment groups, including Con, FA, Ca(NO3)2 and FA + Ca(NO3)2 cotreatment, to explore the regulatory mechanism by which FA alleviates Ca(NO3)2 stress in Chinese flowering cabbage. The results showed that FA can effectively alleviate the inhibitory effect of excessive Ca(NO3)2 on the growth of Chinese flowering cabbage seedlings. FA recovered the photosynthetic capacity of seedlings under Ca(NO3)2 stress. In addition, FA depressed the accumulation of O2·−, H2O2, malondialdehyde (MDA) and relative electrical conductivity, but increased the activity of antioxidant enzymes, including SOD, POD, CAT and APX, which finally enhanced the stress resistance of Chinese flowering cabbage to Ca(NO3)2. The expression of nitrate-related transporters, BcNRT1.1 and BcNRT1.5, was depressed by FA, which inhibited redundant nitrate absorption and restricted more nitrate from being stored in the roots instead of being transferred to the shoot. Ultimately, nitrate accumulation in the edible part was reduced in Chinese flowering cabbage seedlings. In general, exogenous FA may alleviate nitrate stress by improving oxidation resistance, photosynthetic capacity and redundant Ca(NO3)2 accumulation in Chinese flowering cabbage.

Georgia is a leading fresh market cabbage (Brassica oleracea var. capitata) producer. Current recommendations for bare-ground cabbage grown in the Coastal Plain of Georgia indicate 175 to 225 lb/acre nitrogen (N). Approximately one-third of N fertilizer is recommended at planting, with two or three additional side-dress applications during the season. Growers have begun banding liquid fertilizer between four and six times during the season to reduce N leaching and enhance productivity. To determine the validity of current recommendations as well as the efficacy of applying periodic liquid fertilizer throughout the growing season, field experiments were conducted in Tifton, GA in Fall 2016 and 2017 with the cabbage cultivar Cheers. Fertilizer N rates were 175, 200, 225, and 250 lb/acre N applied using equivalent preplant fertilizer (50 lb/acre N) with two posttransplant applications of a granular fertilizer (27–0P–0K–5Ca) or six applications of a liquid fertilizer (9N–0P–0K–11Ca). A factorial, randomized, complete block design was used. There were no interactions among fertilizer program, N rate, or year for cabbage yield or nutrient concentrations. Total yield was unaffected by the N rate. However, plants fertilized with the lowest N rate (175 lb/acre N) had the lowest yields from the first two harvests compared with the other N rates. Nutrient concentrations were affected by year, with 2017 having greater concentrations of most macronutrients compared with 2016. In conclusion, the application of 175 lb/acre N led to a potential delay in harvest, but all other N rates were equal. The application method did not impact yield or earliness, suggesting that current recommendations for fertilizer applications after planting cabbage in Georgia are adequate.

Rapid industrialization and over-use of agrochemicals may lead to cadmium (Cd) contamination in agricultural soil, posing serious threat to human health. In recent times, application of plant nutrients and other growth promoting substances, like, nanoparticles (nZVI), silicon, salicylic acid were reported to have ameliorated Cd toxicity, in this regard, nitrogen (N) amendment can be a promising technique to ameliorate Cd toxicity as, N is an essential macronutrient responsible for plant growth and development. In the present study, seven days old seedlings of Oryza sativa L. cv. Lalat were co-treated with 10 µM CdCl2 and two different nitrogen supplements (Calcium nitrate and Ammonium acetate) separately to evaluate its ameliorating potential. It was observed that, Cd stress impaired plant vigor, biomass, RWC, nitrogen-containing components and non-enzymatic antioxidants causing significant reduction in photosynthesis and N-assimilation, indicating sensitivity of the cultivar to Cd stress. Cd stress also enhanced lipid peroxidation, enzymatic-antioxidant activity, proline and non-protein thiol accumulation. N-supplementation to Cd stressed plants rescued plant growth, biomass, protein content and nitrogen containing compounds leading to the upregulation of photosynthesis and nitrogen assimilation. N amendment was found to downregulate lipid peroxidation, enzymatic antioxidant activity, proline and non-protein thiol content and upregulate non-enzymatic antioxidant. Agronomical parameters and yield also improved significantly by N supplementation as compared to Cd stressed plants. Supplementation with N salts also improved grain quality by enhancing grain nutrients and reduced grain Cd by decreasing bioavailable Cd in soil, thereby reducing daily Cd intake and cancer risk. Among the two N-supplements, ammonium acetate showed better ameliorating effect compared to calcium nitrate.

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.

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.

This study comprised of five different integrated fertilizers of calcium nitrate Ca(NO3)2 with ammonium sulphate (NH4)2SO4 ratios (0%:100%, 10%:90%, 20%:80%, 30%:70%, and 40%:60%) to enhance the physico-chemical properties, and the antioxidant and nutritional compounds of pomegranate fruits cv. ‘Wonderful’. The results discovered that the application of Ca(NO3)2:(NH4)2SO4 in different ratios significantly affected all measured parameters. Among integrated fertilizers, the 30%:70% combination showed an increment of 10.8% in fruit weight, 2.9% in fruit length, 11.8% in fruit volume, and 7.0% in fruit diameter. Similarly, total soluble solids, vitamin C, anthocyanin, total sugars, and reduced sugars, were also increased by 11.2%, 14.6%, 20.2%, 7.4%, and 5.2%, respectively. Likewise, values of both color variations from green to red (a*) and from blue to yellow (b*), and chroma, were also increased by 13.8%, 16.6%, and 14.4%, respectively. Moreover, the application of Ca(NO3)2:(NH4)2SO4 at a ratio of 40%:60% showed 25.1% decrease in titratable acidity, and 45.4% and 27.0% increase in maturity index and peel luminosity, respectively. Additionally, the 30%:70% combination showed an increment of 30.9% in total phenolic content, 70.5% in total tannin content, and 43.6% in total flavonoid content. Additionally, it showed 25.8% and 1.7% decrease in pH and moisture content, respectively. Moreover, P, K, Ca, Mg, Na, Fe, Mn, Zn, Cu, and Ni in fruit increased by different increments by application of the 30%:70% with an increasing range of 28% to 175%. A non-reducing sugar increase was observed at an application of Ca(NO3)2:(NH4)2SO4 at a ratio of 20%:80% by 47.0%. The findings of this study suggest that using calcium nitrate with ammonium sulphate at a ratio of 30%:70%, using the fertigation approach during the growth season, could be a safe, natural, and novel method for the pomegranate cv. ‘Wonderful’ to improve fruit quality, and its amount of antioxidants—specifically, phenolics, vitamin C, anthocyanin, and fruit minerals—with health benefits at harvest.

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.

Jujube fruit is quickly damaged and it has a short shelf life in ambient temperature mainly due to senescence and flesh browning. The effects of postharvest calcium salts on quality attributes and physico-chemical characteristics of fresh jujube fruit were investigated with four replications. Fresh jujube fruits at crisp mature (whitish red) stage were picked from a local commercial jujube orchard during early in August in Birjand. Uniform fruits were then selected and immersed in solutions of different calcium sources (calcium chloride, calcium nitrate and calcium sulfate) at two concentrations (0.5 and 1%) or distilled water as control for 5 minutes, air-dried and then stored in cold storage for 50 days. The physico-chemical and sensory quality attributes of fresh fruit were evaluated at the end of storage time. The results showed that weight loss and pH was not influenced by the calcium salt solutions, whereas immersion of jujube fruits in different concentrations of calcium salts had a significant effect on the firmness of the fruit tissue. Calcium salts treatment significantly reduced fruit decay and shrinkage. In addition, postharvest dipping in calcium chloride and calcium nitrate solutions preserved nutritional value (ascorbic acid and total phenolic content) and maintained the sensory quality of fresh jujube fruit. Postharvest calcium salts application preserved the bioactive compounds, quality and improve the overall acceptability of jujube fruit, especially at a concentration of 1% of both salts. However, to determine the proper concentration of calcium salts and the time of dipping treatment for practical applications further studies are required. [Fundam Appl Agric 2019; 4(3.000): 890-897]

The research consists in the design of the new cementitious materials capable of mitigating microfisurative damage through autonomous healing. This lies in the characterization of the materials to employees, study of the expanding agents (sodium silicate and calcium nitrate) and analysis of its mechanical properties and durability. The results revealed that under laboratory conditions, the applied repair agents proved to be powerful in producing an increase in the content of ettringite, favoring the sealing of the fissure. When they heal themselves, they lead to an improvement in durability and mechanical performance.

Emissions of nitrous oxide (N2O), a potent greenhouse gas, are a challenge associated with application of nitrogen (N) fertilizers to soil. However, N source selection can play a role in reducing these emissions. Nitrous oxide emissions were measured from ammonium (ammonium sulfate) and nitrate (calcium nitrate) fertilizers over one year in temperate grassland using the closed static chamber method. Nitrogen was applied at a system representative rate of 220 kg ha−1 y−1 in six split applications. Cumulative annual N2O-N emissions were 0.29 kg ha−1 for the control, 1.07 kg ha−1 for the ammonium fertilizer and significantly higher at 2.54 kg ha−1 for the nitrate fertilizer. The annual emission factor (EF) for the ammonium fertilizer was 0.35% vs 1.02% for the nitrate fertilizer, a 66% reduction in the EF for ammonium vs nitrate and a 2.9 times higher EF for nitrate compared with ammonium. No difference in grass yield or N uptake was detected between fertilizers. This study shows that an ammonium fertilizer produces the same yield and N efficiency as a nitrate fertilizer with lower N2O emissions. The results also demonstrate that the nitrate portion of fertilizers is a key factor in N2O emissions in temperate grassland. This work is the first of its kind detailing the annual EF of both a solely ammonium-N and a solely nitrate-N fertilizer we could find.

Introduction: Date bunch fading disorder has been one of the most important problems, which caused economic damage to date plantation area of Iran. It has been first reported on Mozafti cultivar in Kahnuj area, Kerman province. It has often been observed on soft and mid ripening cultivars such as Mozafti, Mordaseng and Kalote. Furthermore, it usually appears on Mozafti cultivar when fruits change from Khalal to Rutab stage. The most important symptoms of this disorder are sudden wilting of fruits and necrotic strips on the upper surface of the main bunch stalk. Incidence and development of these symptoms increase by high temperature, low relative humidity, and hot and dry wind. Several research studies have been carried out on this disorder so far, but the only research about the effect of nutrition on disorder was performed by Rosta (2003). The aim of the present study was to investigate the effect of calcium and potassium spray on date bunch fading and some traits of date fruit in Rigan region, Kerman province. Materials and Methods: The experiment was conducted based on randomized complete block designs with three replicates in Rigan located in east south of Kerman province, Iran, in 2012. Treatments were: T1: control, T2: spray of calcium nitrate at the concentration of 5 ppm, T3: spray of potassium sulfate at the concentration of 5 ppm, and T4: combined spray of calcium nitrate and potassium sulfate at the concentration of 5 ppm. Treatments were applied at Kimri, Hobabok and Khalal stages. Sampling was performed from 3 date palms (3 bunches from each date palm were selected randomly) at the second date harvest. Totally, the traits of 200 fruits were measured in each date palm. The traits measured in the present study were: fruit length, fruit diameter, fruit weight, stone weight, stone diameter, and bunch fading percentage. Results and Discussions: According to the data of variance analysis, treatments had a significant effect on wet fruit weight, fruit length, fruit diameter, stone weight, stone diameter, and bunch fading percentage at 1℅ level. The highest wet fruit weight, fruit length, fruit diameter, stone weight, and stone diameter were attained in the treatment containing combined application of calcium nitrate and potassium sulfate. Furthermore, the lowest amounts of these traits were obtained in control. The lowest and highest percentage of date bunch fading belonged to the combined treatment of calcium nitrate and potassium sulfate, and control, respectively. In general, application of calcium nitrate and potassium sulfate with each other improved fruit traits and reduced bunch fading percentage. Calcium mobility in the plant takes place mainly in the xylem, together with water. Therefore, calcium uptake is directly related to plant transpiration rate. Conditions of high humidity, cold and low transpiration rates may result in calcium deficiency. Salinity might also cause calcium deficiency because it decreases water uptake by the plant. Since calcium mobility in plants is limited, calcium deficiency appears in younger leaves and in fruits, because they have a very low transpiration rate. Therefore, it is necessary to have a constant supply of calcium for continued growth. Calcium deficiency is usually caused by low calcium availability or water stress which results in low transpiration rates. Calcium is an essential plant nutrient with many roles including participation in metabolic processes of other nutrients uptake, promotion of proper plant cell elongation, and improvement of cell wall structure – calcium is an essential part of plant cell wall. It forms calcium pectate compounds which give stability to cell walls and bind cells together. It also helps protecting the plant against heat stress - calcium improves stomata function and participates in induction of heat shock proteins. In addition, it helps protecting the plant against diseases - numerous fungi and bacteria secret enzymes which impair plant cell wall. Stronger cell walls, induced by calcium, can avoid the invasion of diseases. Considering the important roles of calcium, calcium spray increased thetraits of date fruit and decreased bunch fading percentage. As an important element in photosynthesis, , potassium regulates the opening and closing of stomata, and therefore regulates CO2 uptake. Potassium plays a major role in the regulation of water in plants (osmo-regulation). Both uptake of water through plant roots and its loss through the stomata are affected by potassium. Moreover, protein and starch synthesis in plants requires potassium, so that the enzymes responsible for starch synthesis are activated by potassium. Potassium has also an important role in the activation of many growth related enzymes in plants. Results of the analysis of the studied soil showed that available potassium content in soil was less than plant requirement. So spraying of potassium sulfate could result in the improvement of date fruit traits and reduction of bunch fading disorder. Finally, combined spray of calcium and potassium caused a significant reduction in date bunch fading percentage. Conclusion: The results of the present study indicated that spray of calcium and potassium solely improved fruit traits and bunch fading disorder, but maximum values of fruit yield components and minimum bunch fading percentage obtained from foliar spray of calcium and potassium together.

One of the basis water-soluble fertilizers that are used in greenhouse enterprises is a Calcium nitrate, where its production and demand raise. At present time, calcium nitrate is produced in a granulated and crystaline form consisted of tetrahydrate, dihydrate and concentrated variants. These forms are significantly distinguished by their chemical composition. Besides the basic form of nitrogen – nitrate – there is ammoniacal nitrogen in the composition of Calcium nitrate that is found to be undesirable element, particularly with drip irrigation system in the greenhouse. The new product, calcium nitrate has been worked out with minimal content of ammoniacal nitrogen at URALCHIM. The study showed the advantages of the product for such characteristics as solubility and time of dissolving. It dissolves 3.4-7 time faster than those of tetrahydrate and dihydrate analogues. At present time, the concentrated calcium nitrate is used in many greenhouse industrial complexes and enterprises, and has shown its efficiency in practice.

Seed priming provides a variety of benefits, including seed invigoration and reduced dormancy. Urochloa brizantha seeds are typically primed with difficult-to-acquire potassium nitrate (KNO3). In this sense, calcium salts stand out as an alternative, but it is important to determine whether they provide the same benefits as potassium nitrate. This study aimed to evaluate the physiological quality of U. brizantha seeds after priming with calcium salts, and compare the results to those obtained with potassium nitrate. Seeds were submitted to priming with calcium nitrate [Ca(NO3)2] and calcium sulphate (CaSO4) at -0.55 MPa and -1.10 MPa, for 12 h and 24 h, and potassium nitrate (KNO3) at -1.10 MPa for 12 h, as well as to no priming (control). A completely randomized design, with ten treatments and four repetitions, was used. Priming promoted a higher germination percentage and lower seed dormancy, with a greater seedling emergence in a shorter time period. CaSO4 did not differ from KNO3 in shoot dry weight of seedlings, but reduced the electrical conductivity of seeds. Calcium nitrate and calcium sulfate show a promising potential for use in the osmotic priming of Urochloa brizantha (BRS Piatã cultivar) seeds, since they are as efficient as potassium nitrate, as well as less costly and easier to purchase. Calcium sulfate priming at -0.55 MPa for 12 h, at 25 ºC, is recommended to replace the potassium nitrate solution.

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

Recently, there has been increased use of calcium-nitrite and calcium-nitrate as the main components of chloride- and alkali-free anti-freezing agents to promote concrete hydration in cold weather concreting. As the amount of nitrite/nitrate-based accelerators increases, the hydration of tricalcium aluminate (C3A phase) and tricalcium silicate (C3S phase) in cement is accelerated, thereby improving the early strength of cement and effectively preventing initial frost damage. Nitrite/nitrate-based accelerators are used in larger amounts than usual in low temperature areas below −10 °C. However, the correlation between the hydration process and strength development in concrete containing considerable nitrite/nitrate-based accelerators remains to be clearly identified. In this study, the hydrate composition (via X-ray diffraction and nuclear magnetic resonance), pore structures (via mercury intrusion porosimetry), and crystal form (via scanning electron microscopy) were determined, and investigations were performed to elucidate the effect of nitrite/nitrate-based accelerators on the initial strength development and hydrate formation of cement. Nitrite/nitrate-AFm (aluminate-ferret-monosulfate; AFm) was produced in addition to ettringite at the initial stage of hydration of cement by adding a nitrite/nitrate-based accelerator. The amount of the hydrates was attributed to an increase in the absolute amounts of NO2− and NO3− ions reacting with Al2O3 in the tricalcium aluminate (C3A phase). Further, by effectively filling the pores, it greatly contributed to the enhancement of the strength of the hardened cement product, and the degree of the contribution tended to increase with the amount of addition. On the other hand, in addition to the occurrence of cracks due to the release of a large amount of heat of hydration, the amount of expansion and contraction may increase, and it is considered necessary to adjust the amount used for each concrete work.

Mineral fertilizers are one of the important factors of agriculture intensification and increasing of food products quantity. The volume of fertilizers production and its domestic consumption in Ukraine indicate that nitrogen fertilizer using only comes nearer to the required number of science-based. One of the most widespread artificial fertilizers is the calcium nitrate. Aim: The aim is to study and theoretically substantiate the processes occurring in the preparation of suspensions of calcium hydroxide Са(ОН)2 in solution of calcium nitrate Ca(NО3)2. Materials and Methods: The technical calcium oxide (quicklime) DSTU BV.2.7-90-99, solutions of calcium nitrate of 15, 20, 25, 30, 35 and 40% Ca(NО3)2 concentrations were used in the work. The content of lime in the preparation of a suspension in the solution changed (in terms of calcium oxide CaO) from 150 g/dm3 to the maximum possible. Each of these solutions saturated at 40°С in lime to maximum concentration. Suitable for use in these experiments and in the technology of calcium nitrate obtaining are considered the solutions (suspensions) that within 12 hours did not lose their mobility (transportability). Results: The experimental results show that increasing of the concentration of calcium nitrate in solution within the range 15...40%, the amount of lime that you can put into the solution without loss of transportability decreases. Further increasing of lime quantity in solutions concentrations causes to its solidifying, loss of mobility (transportability). Calculations showed that in the presence of calcium nitrate the solubility of Са(ОН)2 is reduced nearly by order that can lead to the formation of calcium oxide CaO the solid phase Са(ОН)2 on the surface, which also can form hydrogen bonds with the components of the solution. As the probability of formation of hydrogen bonds in solutions is high, there is a possibility of formation of clusters.

Recently, calcium nitrite (Ca(NO2)2) and calcium nitrate (Ca(NO3)2) have been increasingly used as the main components of salt- and alkali-free anti-freezing agents, for promoting concrete hydration in cold-weather concreting. With an increase in the amount of nitrite-based accelerator, the hydration of C3A, C3S, and βC2S in the cement is accelerated, thereby improving its early strength and effectively preventing the initial frost damage. Meanwhile, with an increase in the amount of nitrite-based accelerator, the expansion and shrinkage of the concrete—and, therefore, the crack occurrence—are expected to increase. In this study, various experiments were conducted on shrinkage, crack initiation, and the development of mortar containing a considerable amount of a nitrite-based accelerator. The result confirmed that, as the amount of nitrite-based accelerator was increased, the shrinkage was increased, and cracking in early age was more likely to occur, compared to the cases without the addition of this accelerator.

To investigate the influence of salinity and calcium (Ca) on some properties of Plantago ovata, a pot factorialexperiment based on randomized complete block design with three replicates was conducted in Jiroft, south of KermanProvince, Iran. Three salinity levels of 0, 100 and 200 mM NaCl and Ca levels of 0, 5 and 10 mM Calcium nitrate wereapplied as the first and second factors, respectively. Results showed that salt levels significantly affected plant height, dryweight, number of spikes per plant, spike length, number of seeds per spike, mucilage and 1000 seed weights. Maximumvalues for the measured variables were obtained in control and the minimum values in 100 mmol sodium chloride. Theeffect of Ca on these traits was significant as well; it diminished the adverse effects of salinity. In addition, the interactiveeffects of salt and Ca on all the above traits were remarkable except for mucilage and spike length on which no significanteffect was observed.

The influence of the ammonium nitrate-based oxidizer composition on the technological and detonation parameters of the emulsion energy condensed systems for mining industry has been considered. It is shown that the use of sodium nitrate as a part of oxidizer is limited by its solubility and decreasing of detonation characteristics of energy condensed systems. It is found that for obtaining of highly efficient packaged systems an aqueous solution of ammonium or calcium nitrate with water content 7…10 % by weight should be used as oxidizer. It is shown that with decreasing of water content in the system by 1 % by weight the detonation velocity of energy condensed systems increases by 100…150 m/s.

Tomato is a typical plant that has distinct response to different nitrogen forms in hydroponic culture. In addition, it is a well known susceptible plant to ammonium nutrition in hydroponic culture. However, its response to foliar application of nitrogen sources and N-forms has not been well investigated. In the present study, the growth, productivity and fruit quality of tomato was investigated under foliar application of nitrogen from different sources. Ammonium sulfate, urea and calcium nitrate with constant concentration of 100 mM N were weekly sprayed during four months under hydroponic culture system. A water spray treatment was considered as control. The results showed that vegetative growth parameters were significantly affected by N sources in different patterns. The factors such as plant height, leaf area, number of lateral shoots and shoot fresh and dry weight, as well as leaf nitrate reductase activity was significantly reduced by foliar application of ammonium sulfate and to less extent by urea, while there was improvement of these traits by foliar application of calcium nitrate compared to control. However, ammonium sulfate treated plants had the highest leaf SPAD value and leaf N concentrations. Plant fruiting pattern was also influenced by treatments, as ammonium sulfate spray reduced the fruit yield, and fruit vitamin C content, while it increased fruit TSS and titratable acidity. The highest value of yield and vitamin C was recorded in calcium nitrate sprayed plants.

An investigation was carried out to study the effect of foliar spray of micronutrients, viz, calcium and boron and sorbitol on fruit-set, yield and fruit quality in mango (Mangifera indica L). cv. Himsagar, at Bidhan Chandra Krishi Viswavidyalaya, Regional Research Station, Gayeshpur. The experiment was laid out in Randomized Block Design (RBD), with three replications. Results revealed that boric acid (0.02%) + sorbitol (2.0%) were the most effective for enhancing fruit-set (1.58%), yield (48.51 kg tree-1), fruit weight (165.6 g), TSS (18.59°Brix), total sugars (14.92%) and ascorbic acid content (20.32 mg 100 g-1), while, calcium nitrate (Ca-0.06%) + boric acid (B-0.02%) proved to be the most effective for increasing shelf life in mango cv. Himsagar, at ambient room temperature.

The effect of chemical, physical, biologycal and cultural strategies individually or combinated were evaluated in the epidemiology of the basal rot (Sclerotium rolfsii), charcoal rot (Macrophomina phaseolina) and the Phaseolus vulgaris cv Tacarigua yield at Barinas state from Venezuela. In the experiment, Tebuconazole (Teb) was applicated at seed (1 L/Ton) and at soil, a los 30 y 60 days after of the sow (1 L/ha); Trichoderma harzianum (Tri) was applicated at seed (15 g for each 1.5 k) and to 15, 30, 45 y 60 days after of the sow (30 g/10 L of water). On the other hand, soil was solarizated (Sol) during 15 days and calcium nitrate (Ca) (60 g/10 L of water) was applicated each 15 days until 60 days of growth of cultivated plants. Basal rot was registered as far as 42 days after of the sow, showing less of 5.3% in Teb y the combination SolTeb. The hightest incidence of this disease was observed in the treatment Tri with 28.5%, being highter that control (14.5%). Last to 42 days predominated the charcoal rot in the rest of the plants for a total of 100% of incidente in everything the treatments. Nevertheless, Teb showed the hightest yield with 555 k/ha, being different estatistically at treatment TriCa, which showed the lowest yield with 31 k/ha, however, the roots not formed nodules nitrogen uptake in these replications with the fungicide and Ca. It is concluded that S. rolfsii was sensible at action of some of the treatments; but not M. phaseolina; nevertheless, the plants were capables to produce seeds health apparently in treatments in which observed less severity of charcoal rot.

An investigation was conducted on uniform, healthy, eight year old trees of Nagpur mandarin (citrus reticulata Blanco) at Fruit Research Farm, Department of Fruit Science at College of Horticulture and Forestry, Jhalawar during 16 September, 2014 to 1 March, 2015. Various doses of calcium nitrate (1.0%, 2.0% and 3.0 %), boric acid (0.2 %, 0.4 % and 0.6 %) and zinc sulphate (0.2 %, 0.4 % and 0.6 %) were sprayed before harvesting and compared with untreated ones. The results obtained indicated that the trees sprayed with T27 i.e. (calcium nitrate 3.0 % + boric acid 0.6 % + zinc sulphate 0.6 %) showed maximum increase diameter of fruit, fruit weight, fruit volume, number of fruits per plant, fruit yield per plant, estimated yield per hectare, reducing sugar, non reducing sugar, total sugar, juice per cent, sensory score and reduced peel thickness over control. Further, T24 treatment combination (calcium nitrate 3.0 % + boric acid 0.4 % + zinc sulphate 0.6 %) has also significantly increased number of segments per fruit, TSS, TSS: Acid ratio, ascorbic acid content, and reduced number of seeds per fruit and acidity percent of fruits.

The rheological properties of the cement pastes have been determined using a rotational viscometer under a special testing routine by increasing and retaining a steady rotation speed of the viscometer cylinder up to certain values and for a certain time. These tests, using rotational viscometer, have been conducted by making the assessment of ce­ment paste flow curves, using Bingham rheological model. Rheological properties of cement pastes were tested at dif­ferent times after pastes mixing: 0 min, 30 min, 60 min, 90 min, 120 min and 180 min. Cement pastes with same W/C ratio equal to 0.35 were tested. The content of admixture was used 0%, 0.5%, 1%, 2%, 3% and 5%. The admixture of Ca(NO3)2 can be used in cement pastes and concretes without a reduction in consistency during 120 min in the dosage of up to 2%. Dosages of Ca(NO3)2 from 3% are not recommended for cement pastes and concrete, they significantly increase the viscosity of mixtures immediately after mixing The admixture of calcium nitrate changes thixotropy of ce­ment pastes. In this case, a bigger dosage of calcium nitrate increases the thixotropy of pastes.

Bell pepper (Capsicum annuum L.) high-quality and yield implies the management of N nutrition. Field and pot experiments with bell pepper and Italian ryegrass were carried out during 2009 and 2010. The experimental design included three N delaying fertilizers (Sulfammo Meta 46-5-0, controlled-release fertilizer; Nitrophoska Gold 15-9-15, slow-release fertilizer; Entec 26 26-0-0, stabilized fertilizer), two conventional N fertilizers, urea and calcium nitrate and one N-unfertilized control. The fertilizer's rate was 150 kg N/ha. A pot experiment with bell pepper followed by ryegrass with the same fertilizers treatments was carried out in 2009. Dry matter (DM) yield, plant N concentration, plant N recovery and fruit mineral concentration were measured. Calcium nitrate and urea produced statistically higher DM in both field and pots. Sulfammo Meta produced always lower yields. In the field plants recovered a minimum of 18% and a maximum of 82% of the N applied, respectively, in Sulfammo Meta and calcium nitrate. In the pot experiment, bell pepper + ryegrass recovered only 32.5% of N applied with Sulfammo Meta and nearly 100% of N applied in the other fertilized pots. None of the slow-release N materials provided clear advantages over conventional fertilizers to be used in this crop.

Having assessed in various aspects the study materials (salts), used for road maintenance in a cold period of the year, and taking a special consideration of the impact of these materials (salts) on the environment as well as their price, it could be stated that the most acceptable alternative for Lithuania is the already used sodium and calcium chloride salts. A large disadvantage of two materials (sodium chloride and calcium chloride) is that chloride ions strongly increase the speed of corrosion reactions of metals. Larger concentrations of chlorides aggravate vegetation processes and, thus, cause damage to roadside plants. Having assessed all the materials (salts) according to their chemical and physical properties and also according to their price and availability from technological point of view in the production, at present the following compounds could be distinguished: carbamide and calcium magnesium nitrates. When using calcium nitrate fewer chlorides get into the environment and the environment is less corrosive in regard to metals, however, here another problem occurs. If too large concentrations get into the environment, nitrates can cause pollution of ground water and soil. In future, having expanded the production of calcium and magnesium nitrates, it will be possible to start producing certain mixtures, e.g. carbamide with those nitrates or the mixture of carbamide, calcium, magnesium nitrates and calcium chloride, and, thus, to reduce a direct use of chlorides.

The aim of this study was to evaluate the response of maize to two sources of nitrogen, and the influenceof time of nitrogen fertilization on yield of corn grown in a reduced row spacing under no-tillage system. The experimentwas conducted in the 2005/06 growing season, in Coimbra, MG, Brazil. The soil was classified as an Acrisol dystrophicphase terrace. A randomized blocks experimental design was used, in a factorial scheme (3 x 7) with four replications,being the factors: three hibrids (AG 9010, P 3041, DKB 333), seven treatments: 1 - pre-planting with urea, 2 - preplantingwith calcium nitrate, 3 - planting with urea, 4 - planting with calcium nitrate, 5 - application of urea duringthe vegetative stage 4 th leaf fully expanded, 6 - application of calcium nitrate at the vegetative stage of 4th fullyexpanded leaf and 7 - 30.4 kg ha-1 nitrogen at planting. The cultivar P 3041 showed better performance in the evaluatedcharacteristics, except for nitrogen content.The timing of N application did not affect rates of productivity of maize.

Visando a dar suporte a trabalhos de melhoramento genético para porta-enxertos de pera e ajuste de protocolo de germinação de pólen para fins de polinização intra e interespécies, objetivou-se ajustar os componentes básicos do meio de cultura e as condições ambientais para a realização de testes de germinação in vitro e viabilidade de grãos de pólen dos porta-enxertos para pereiras 'Taiwan Nashi-C' (Pyrus calleryana) e 'Taiwan Mamenashi' (P. betulaefolia). O pólen utilizado foi obtido de anteras provenientes de flores em estádio de balão. Em seguida, com auxílio de um pincel n°2, os grãos de pólen foram espalhados sobre a superfície de placas de Petri, contendo 20ml de meio de cultura de acordo com os seguintes experimentos: 1) concentrações de sacarose (0, 30, 60 e 90g L-1) e agar (4, 6, 8 e 10g L-1); 2) concentrações de nitrato de cálcio (0, 200, 400 e 800mg L-1) e ácido bórico (0, 400, 800 e 1200mg L-1); 3) valores de pH (4,0; 4,5; 5,0; 5,5; 6,0 e 6,5); 4) temperaturas (20; 25; 30 e 35); e 5) tempo de emissão do tubo polínico (1, 2, 3, 4, 5, 6 e 12 horas após a inoculação), os quais foram montados de forma sequencial. A utilização de 10g L-1 de agar e 90g L-1 de sacarose para o porta-enxerto 'Taiwan Mamenashi' e 47,78g L-1 para 'Taiwan Nashi-C', com 795 a 838mg L-1 de ácido bórico, na ausência de nitrato de cálcio, pH entre 5,2 e 5,8 e temperatura de 28°C, proporcionou as melhores condições de germinação de grãos de grãos. A porcentagem máxima de polens germinados é obtida com oito horas após a inoculação para 'Taiwan Nashi-C' e com 12 horas para 'Taiwan Mamenashi'.In order to support the works with genetic improvement for pear rootstocks and adjust the pollen germination protocol for intra and inter species polinization, this study aimed to adjust the culture medium basic compounds and environmental conditions for the realization of in vitro pears pollen grains germination and viability tests of 'Taiwan Nashi-C' (Pyrus calleryana) e 'Taiwan Mamenashi' (P. betulaefolia) pear rootstock. Thus, five experiments were performed: 1) Sucrose concentrations (0, 30, 60 and 90g L-1) and agar (4, 6, 8 and 10g L-1); 2) calcium nitrate (0, 200, 400 and 800mg L-1) and boric acid (0, 400, 800 and 1200mg L-1); 3) pH (4.0; 4.5; 5.0; 5.5; 6.0 and 6.5); 4) temperatures (20; 25; 30 and 35 ) and 5) emission time of the pollen tube (1, 2, 3, 4, 5, 6 and 12 hours after inoculation), which were assembled sequentially. The use of 10g L-1 of agar combined with 90g L-1 sucrose for the rootstock 'Taiwan Mamenashi' and 47.78g L-1 for the 'Taiwan Nashi-C', with 795 to 838mg L-1 of boric acid, under absence of calcium nitrate and pH between 5.2 and 5.8 and temperature of 28 °C, provided the best conditions to the germination of the pollen grains. The maximum percentage of germinated pollen is obtained with eight hours after inoculation for 'Taiwan Nashi-C' and twelve hours for 'Taiwan Mamenashi'.

Background: Borage (Borago officinalis L.) is a valuable medicinal plant of Boraginaceae family, which is used in treatment of different human diseases. Therefore, it is necessary to determine optimum levels of agronomical factors affecting plant growth and production. Objective: To determine the effects of foliar application of calcium nitrate on quantitative yield and some quality components of borage. Methods: This study was done in Research farm of ACECR, Institute of Medicinal Plants Research in a randomized complete block design with three replications and four treatments along 2008 - 2009. The treatments were four concentrations of Ca(NO3)2 foliar application (0, 5, 10 and 15 mM Calcium Nitrate). Results: The results showed that foliar application of calcium nitrate had significant effects (p

Objetivou-se avaliar diferentes concentrações de nitrato de cálcio e nitrato de amônio no crescimento in vitro de orquídea. Plântulas de Cattleya loddigesii oriundas de sementes germinadas in vitro, com 1,0 cm de comprimento, foram inoculadas em frascos contendo 60 mL de meio de cultura WPM modificado em suas concentrações de nitrato decálcio (0, 278, 556, 834 e 1112 mg L-1) e nitrato de amônio (0, 200, 400, 600 e 800 mg L-1). O meio foi acrescido de 20 g L-1 de sacarose, 150 g L-1 de polpa de banana ‘nanica’ madura e 2 g L-1 de carvão ativado, pH ajustado para 5,7 ± 0,1 e solidificado com 6 g L-1 de ágar, antes da autoclavagem a 121ºC e 1,5 atm, por 20 min. Após a inoculação, os frascos foram transferidos para sala de crescimento a 25 ± 2ºC, fotoperíodo de 16h e 35 μmol m-2 s-1 de intensidade luminosa. Decorridos 90 dias, observaram-se melhores resultados para número de folhas e de brotos com 400 e 450 mg L-1 de nitrato de amônio, respectivamente, enquanto que o maior número de raízes foi obtido com 600 mg L-1 de nitrato de amônio e 278 mg L-1 de nitrato de cálcio. Recomenda-se a utilização do meio WPM em sua composição original, sem nitrato de cálcio na micropropagação desta espécie.This work aimed to evaluate the effect of different concentrationsof calcium and ammonium nitrate on the in vitro development of orchids. Cattleya loddigesii orchid plantlets, 1.0 cm in size produced by self pollinization and also by in vitro germinatedseeds, were inoculated in flasks containing 60 mL of WPM culture medium, modified with different concentrations of calcium nitrate (0, 278, 556, 834 and 1112 mg L-1) and ammonium nitrate (0, 200, 400, 600 and 800 mg L-1). The culture medium was supplemented with 20 gL-1 of sucrose, 150 g L-1 of ‘nanica’ banana pulp, activated charcoal 2 g L-1, solidified with agar 6 g L-1, and pH adjusted to 5.7 ± 0.1 before being autoclaved at 121ºC, 1.5 atm pressure during 20 minutes. After inoculations, the flasks were transferred to a growth room with controlled temperature around 25 ± 2ºC, 16h photoperiod regime, with a light intensity of 35 μmol m-2 s-1. After 90 days, it was observed that the best results in terms of number of leaves was achieved with 400 mg L-1 of ammonium nitrate, and the highest number of sprouts was obtained with 450 mg L-1 of ammonium nitrate, but the majornumber of roots was verified in the treatment with 600 mg L-1 of ammonium nitrate and 278 mg L-1 of calcium nitrate. In resume, it is recommended to use the WPM medium in its original composition, without calcium nitrate to micropropagate C. loddigesii orchidplantlets.

A percolação do N adicionado ao solo na forma amoniacal ou em formas que resultem em NH4+ depende parcialmente da nitrificação porque o NH4+ é adsorvido pelas cargas negativas do solo, enquanto o NO3- permanece na solução do solo. Como a diminuição do pH na zona de aplicação dos fertilizantes pode prejudicar a nitrificação, o presente trabalho objetivou avaliar o efeito da adição de fosfato acidificante junto com adubos nitrogenados na diminuição da percolação de N num solo ácido. O experimento foi realizado em colunas de lixiviação, em 2003, usando-se amostra de um Nitossolo Vermelho com 760 g kg-1 de argila, 40 g kg-1 de matéria orgânica e pH-H2O 4,8. Uréia, sulfato de amônio e nitrato de Ca (150 mg kg-1 N), além de um tratamento sem N, foram combinados fatorialmente com 0 e 751 mg kg-1 P na forma de superfosfato triplo (SFT). Efetuaram-se 19 percolações semanais com 300 mL de água destilada cada, totalizando o equivalente a 720 mm de chuva. A adição de SFT antecipou a percolação de NH4+ devido ao seu deslocamento das cargas negativas pelo Ca. A percolação de NO3- ocorreu nas primeiras adições de água onde foi aplicado N nítrico, independentemente do SFT. Para os demais fertilizantes, a mobilidade de NO3- só foi intensificada a partir da sétima percolação, porém foi antecipada pela adição de SFT, provavelmente devido à antecipação da nitrificação causada pelo deslocamento do NH4+ para a solução do solo. A adição de SFT dobrou a percolação de NO3- onde foi aplicada uréia, porém diminuiu em aproximadamente 20 % nos tratamentos com sulfato de amônio ou nitrato de Ca. Na ausência de SFT, 70 % do N aplicado pela uréia permaneceu no solo após as percolações, mas, na presença do fosfato, nada dele ficou no solo. A adição do SFT juntamente com os fertilizantes amoniacais ou amídicos aumenta e, ao invés de retardar, antecipa a percolação de N, possivelmente em conseqüência da adição de Ca.Leaching of N added to soils as ammonium or as other forms that transform into it depends partially on nitrification because ammonium is retained by the soil negative charges, while nitrate remains completely in the soil solution. Since the decrease of the soil pH at fertilized sites can negatively affect nitrification, our study aimed to evaluate the effect of adding an acidifying phosphate together with nitrogen fertilizers on nitrogen leaching in an acid soil. The experiment was carried out in 2003, in an Alfisol with clay and organic matter contents of 760 and 40 g kg-1, respectively and pH (H2O) of 4.8. Treatments consisted of three nitrogen sources (urea, ammonium sulfate and calcium nitrate) at rates of 150 mg kg-1 of N plus one control treatment without N in factorial combination with triple superphosphate (TSP) at a rate of 751 mg kg-1. Treated experimental soil units were packed into PVC leaching columns and percolated with 300 mL of distilled water every seven days, during 19 weeks, totalizing an amount equivalent to 720 mm of rain. TSP addition anticipated ammonium leaching due to displacement of ammonium from the soil negative charges by added calcium. Nitrate leaching from the soil treated with calcium nitrate occurred in the first percolations regardless of TSP addition. In soils treated with the other two N fertilizers, nitrate leaching was intensified only after the seventh percolation, but it was anticipated to the fifth percolation by TSP addition due to earlier nitrification caused by displacement of exchangeable ammonium to the soil solution. TSP addition doubled nitrate leaching in the urea treated soil, while leaching decreased by about 20 % when TSP was mixed with ammonium sulfate or calcium nitrate. In the absence of TSP, 70 % of the N added via urea remained in the soil after the end of the percolations, but in the presence of TSP all applied N was lost. Overall, TSP combined with ammonium or amide-containing nitrogen fertilizers anticipates, rather than delay N leaching, possibly as a result of calcium addition.

Vários fatores influenciam na produtividade do maracujazeiro, dentre os quais o clima, o solo e as práticas de adubação e de irrigação. A nutrição mineral é essencial para elevar a produtividade e melhorar a qualidade dos frutos, e o nitrogênio é o nutriente mais absorvido pelo maracujazeiro. O trabalho objetivou avaliar doses e fontes de nitrogênio, aplicadas em fertirrigação, em 17 meses de produção do maracujá-amarelo (Passiflora edulis Sims f. flavicarpa Deg.), na produção e qualidade dos frutos, em Latossolo Amarelo de Tabuleiro Costeiro do Estado da Bahia. Estudaram-se, em blocos casualizados com parcelas subdivididas, duas fontes de N (uréia e nitrato de cálcio), nas parcelas, e cinco doses de N (0; 100; 200; 400 e 800 kg ha-1), nas subparcelas, com três repetições. O maracujá-amarelo foi plantado no espaçamento de 3,00 x 1,25 m, contendo a subparcela oito plantas úteis, com bordadura simples, e avaliado no período de janeiro de 2000 a janeiro de 2002. Os resultados mostraram que a produtividade máxima de frutos, 34,3 t ha-1, foi obtida com aplicação de 457 kg de N ha-1, na forma de uréia. Contudo, a adubação nitrogenada e as fontes utilizadas não influenciaram nas características do fruto e na qualidade do suco.Passion fruit yield is influenced by several production factors, among them the climate, the soil and the manuring and irrigation practices. Nitrogen (N) is the most absorbed nutrient by the passion-fruit plant and has structural functions in the plant, and it can be supplied by nitric, ammoniacal and starchy sources. The experiment objective was to evaluate nitrogen sources and doses applied in fertirrigation of passion-fruit (Passiflora edulis Sims f. flavicarpa Deg.) production and fruit quality in 17 months of production in a Coastal Tableland Yellow Latosol in Bahia State, Brazil. It was studied, in randomized blocks with split-plots, two sources of N (urea and calcium nitrate), on the plots, and five N doses (0, 100, 200, 400 and 800 kg ha-1), on the split-plots with three replicas. The yellow passion-fruit was planted in a spacing of 3.00 x 1.25 m, in a total area of 1,237.50 m², and evaluated from january 2000 to january 2002. The results showed maximum yield of 34 ton ha-1, applying 457 kg of N ha-1, in urea form. Nitrogen fertilizer and sources did not interfer in the fruit characteristics and juice quality.

Thí nghiệm được thực hiện nhằm đánh giá hiệu quả của việc bổ sung calcium và phân dơi vào môi trường dinh dưỡng thủy canh cà chua Savior. Thí nghiệm được bố trí theo thể thức hoàn toàn ngẫu nhiên 10 lần lặp lại. Thành phần công thức dinh dưỡng thủy canh theoBenton(1999). Sự bổ sung calcium dưới dạng calcium nitrate ở mức thêm 50% của công thức chuẩn ở giai đoạn ra hoa và tạo trái. Phân dơi được cho vào bao giá thể 5 kg với lượng 20 g/bao trước khi trồng cây. Giá thể trồng cây là mụn xơ dừa được cho vào bao plastic, mỗi bao 5 kg và trồng 2 cây. Kết quả thí nghiệm cho thấy rằng, sự bổ sung calcium ở giai đoạn ra hoa tạo trái không có hiệu quả rõ rệt so với dinh dưỡng nguyên thủy. Sự bổ sung thêm phân dơi vào thành phần dinh dưỡng của thủy canh giúp cải thiện thành phần năng suất và năng suất cà chua giống Savior.

The rain induced fruit cracking is a big, serious problem especially for sour cherry growers but in some year sour cherry growers had also problem with fruit cracking caused by too much rainfall in the harvesting season. The cracked sour cherry fruits can be easily infected by different diseases like Monillinia sp. Cracked and infected fruits can not be transported for long distance and using for preservation because they lost their market value by the pour fruit quality. There are two possibilities to protect fruits against the rain induced fruit cracking. The most effective protection technique is the plastic rain cover over the tree rows. The installation of these equipments is too expensive for the growers. That is the reason why researchers tried to find other less expensive and sufficiently effective ways like sprayings different mineral salts, hormone and other type chemicals against the rain induced fruit cracking. Several calcium formulas calcium chloride (CaC12), calcium hydroxide (Ca (OH),) and calcium nitrate (Ca(NO3)2) can be sprayed in appropriate solution concentration. The aim of our trial is to determinate the fruit cracking susceptibility of wide grown Hungarian sour cherry varieties and find the most effective calcium formula and its concentration for spraying in orchards to prevent the fruit cracking. In the first trial year (2006) cracking index of tested sour cherry varieties were determined under field and laboratory conditions. Under field conditions were not found differences between cracking tendency of tested cultivars. After results of immersing fruits in distillated water for 24 hours tested sour cherry varieties were divided to three groups by the susceptibility to rain induced fruit cracking: very susceptible (`Maliga emléke', 'Piramis', 'Érdi jubileum', 'Erdi nagygyümölcsű’ and 'Meteor korai'); susceptible ‘Érdi bőtermő, Tandy 279' and Cigány 59.; moderately susceptible/tolerant ("T" and "R" clones). In the second trial year (2007) calcium chloride (CaCl2) and calcium nitrate (Ca(NO3)2) were sprayed in 0,35m/m%; 0,5m/m% and 1,0m/m% solution concentration. One more commercial product "Damisol-Kalcium" was also applied in the advised 1,0m/m% concentration. Like in the trial year before (2006) under field conditions we did not kept differences between the cracking susceptibility of varieties and calcium treatments. As the result of laboratory testing (immersing calcium treated fruits in distillated water) we kept that calcium chloride (CaCl2) seems the most effective against the fruit cracking in 0,5m/in% solution concentration. The other calcium formulas also decreased the cracking ratio but in less scale.

This study evaluated the acute toxicity of sediment in a eutrophic reservoir after remediation with a calcium nitrate solution to retain phosphorus. The study involved microcosms of surface sediments and water from the sediment-water interface in the Ibirité reservoir. This reservoir, located in the vicinity of metropolitan Belo Horizonte (Minas Gerais, SE Brazil), is a water body that receives treated effluents from an oil refinery (REGAP-Petrobras), as well as high loads of untreated urban effluents from the city of Ibirité and surrounding areas and industrial effluents from a major industrial park. Incubation times of the treatment experiments were: t = 0, t = 5, t = 10, t = 25, t = 50, t = 85 and t = 135 days. One control microcosm and three treated microcosms were analysed in each time interval. Acute toxicity of water samples was assessed with Ceriodaphnia silvestrii Daday, 1902 and that of bulk sediment samples with Chironomus xanthus Rempel, 1939. Toxicity tests were carried out concomitantly with chemical analyses of dissolved inorganic nitrogen species (ammonia, nitrate and nitrite), sulfate and metals in the water samples of the microcosms. Acid volatile sulfides (AVS), simultaneously extracted metal (SEM) and potentially bioavailable metal were analyzed in bulk sediment samples. Neither of the tested organisms showed toxicity in the control microcosm samples. The water column of the treated microcosm showed toxicity to C. silvestrii, starting at t = 10 days, while the sediment pore water toxicity started at t = 0 day. However, toxicity was found to decline from t = 85 days to t = 135 days. Sediments showed toxicity to C. xanthus during the entire experiment, except at the longest incubation time (t = 135 days). The overall results indicate that nitrate, which reached concentrations exceeding 1,200 mg N-NO3- L-1 in the sediment pore water of the treated microcosms, was most probably responsible for the toxicity of the samples. Although the calcium nitrate technology proved effective in retaining phosphorus, promoting sediment oxidation via denitrification, from the ecotoxicological standpoint and under the experimental conditions of this study, the application of nitrate for remediation of the sediments in the Ibirité reservoir did not prove effective up to a period of 135 days of incubation. However, we presume that after longer periods of incubation, treated sediments may recover their ability to sustain a benthic community. More advanced experiments are planned involving longer incubation times, thus extending the denitrification process, which may lead to a higher phosphorus retention capacity and to more complete abatement of sediment toxicity.