Calcium Fertilization Research Articles

Molecular and ionomic responses of Solanum lycopersicum L. (cv. Micro-Tom) plants treated with a novel calcium-based plant biostimulant

In this study, we investigated the leaf treatment effects of a novel trace elements calcium-based fluid mixture with a supposed biostimulant action on Solanum lycopersicum L. cv. Micro-Tom. Seedlings were grown on standard peat substrate and treated with two different products: a calcium-based fluid mixture and a common calcium fertilizer, CaCl2. Both treatments were compared to an untreated control. We first investigated the effects of treatments on fruit yield and dry matter production in greenhouse-grown tomato. These effects were then assessed in leaves by gene expression profiling of 60 genes involved in different biological pathways and functional categories, and by ionomic analysis. Leaf treatment on tomato with the calcium-based fluid mixture allowed the highest fruit yield per plant (6.17 fruits plant−1) and above-ground dry matter (13.99 g plant−1) to be obtained. Also, 4 genes related to the nutrient transporter category, NCX, NRAMP3, SI BOR2, and CHLM, were upregulated in plants treated with the novel product. CRK, a gene related to the calcium-dependent protein kinases (CDPK), was upregulated in plants treated with the novel product whereas SODCC.1, a gene related to the superoxide dismutase family, was downregulated in the same plants. A substantial reduction of elemental contents was observed for CaCl2-treated plants, while the novel Ca-based mixture increased the leaf mineral content of Zn (+61%) and Mn (+65%). These results highlighted the biostimulant activity of the novel product resulting in changes in fruit yield and dry matter production, gene expression, and ionome profiles of tomato leaves.

Transcriptomics-based Analysis of the Response of Sugar Content in Litchi Pulp to Foliar Calcium Fertilizer Treatment

Ten 16-year-old trees were used as test materials to investigate the effect of foliar calcium fertilizer on the sugar content of ‘Feizixiao’ litchi (Litchi chinensis Sonn.) pulp. The experiment began 35 days after anthesis (DAA) in 2020 and 2021, and the treatment was a foliar spray application of 0.3% CaCl2 aqueous solution, whereas the control was a foliar spray application of water. The sugar content, sucrose-metabolizing enzymes, and ATP-dependent phosphofructokinase (PFK) activities in pulp were measured in 2020 and 2021. Transcriptome sequencing (RNA-seq) was performed on RNA samples from treatment and control fruit pulps at 35, 63, and 69 DAA (full mature stage) in 2020, and 10 genes were chosen for confirmation by real-time polymerase chain reaction (PCR) in 2020 and 2021. At full maturity, the soluble sugar content in the calcium-treated group was extremely significantly or significantly higher than that in the control group. After 63 DAA, the net sucrose-metabolizing enzyme activity in the calcium-treated group was significantly higher than that in the control group. Furthermore, at full maturity, the calcium-treated group had significantly higher sucrose synthase cleavage activity and significantly lower PFK activity than the control group. Fifty-four highly expressed genes in the glycolytic pathway (EMP) were screened from transcriptome data, including hexokinase, PFK, and pyruvate kinase genes; 87% of these genes were downregulated in the treatment group compared with the control group at 69 DAA in 2020. The linear regression between RNA-seq and real-time PCR results was significant in 2020 (r = 0.9292) and 2021 (r = 0.8889). When the fruit is fully ripe, calcium treatment increases net sucrose-metabolizing enzyme activity by increasing sucrose synthase cleavage activity, promoting the accumulation of reducing sugars, and it downregulates phosphofructokinase gene expression in EMP, promoting sugar accumulation.

RESPONSE OF TOMATO (LYCOPERSICON ESCULENTUM) TO NP ORGANIC FERTILIZER (RICH IN PHOSPHORUS) AND CALCIUM

This current research proceeded during the growing season of 2021 at the Al-Nakhil Station, Al-Najaf Governorate, Iraq, to evaluate the response of hybrid tomato (Lycopersicon esculentum) ‘OULA F1’ to foliar application of organic fertilizers NP and calcium. The first factor included spraying phosphorous and nitrogen with three concentrations (0, 1, and 2 ml.L-1), while the second consisted of calcium spray with three different concentrations (0, 1.25, and 2.5 ml.L-1). The experiment was setup according to the randomized complete block design (RCBD) with three replications in a factorial arrangement. The results showed that the organic fertilizer rich in phosphorus at a concentration of 2 ml.L-1 significantly improved the traits, i.e., plant height (49.98 cm), leaf number (34.80 leaves.plant1), leaf area (3775.90 cm2.plant-1), shoot dry weight (156.70 g.plant-1), and leaf content of total chlorophyll (183.19 mg.l00g-1 FW) in comparison with the control treatment. Also, the same concentration of phosphorus revealed superiority in the percentage of N, P, K, and Ca in tomato leaves and fruit yield per plant (1.79%, 0.71%, 2.23%, 1.69%, and 2.89% kg.plant-1, respectively), compared with the control treatment. Moreover, the results further revealed that the organic calcium fertilizer at a concentration of 2.5 ml L-1 realized the highest averages for plant height, leaf number, leaf area, shoot dry weight, leaf N percent, leaf P percent, leaf K percent, and fruit yield per plant by 52.39 cm, 35.27 leaves.plant-1, 3850.20 cm2.plant-1, 175.73 g.plant-1, 1.74%, 0.70%, 2.17%, and 3.12 kg.plant-1, respectively. The foliar application of calcium at a concentration of 1.25 ml.L-1 provided the maximum total chlorophyll (175.03 mg.l00g-1 FW) and Ca (1.74%) in the leaves.

Radioactive Concentrations in Chemical Fertilizers

Background: The aim of the present study was to determine radioactive concentrations in fertilizers known to contain essential nutrients. Results of this study could be used as basic data to monitor the impact of chemical fertilizers on the environment and public health. Nitrogen fertilizers, calcium fertilizers, sulfur fertilizers, phosphate acid fertilizers, and potassium chloride fertilizers were used in this study.Materials and Methods: Five chemical fertilizers were pulverized, placed in polyethylene containers, and weighed. The time to measure each specimen was set to be 3,600 seconds for a scintillator-based gamma-ray spectroscopy system. Concentration of gamma radionuclide was analyzed based on obtained spectra. At the end of the measurement, the spectrum file was stored and used to calculate radioactive concentrations using a gamma-ray spectrometer software.Results and Discussion: In the nitrogen fertilizer, 3.49 ± 5.71 Bq/kg of <sup>137</sup>Cs, 34.43 ± 7.61 Bq/kg of <sup>134</sup>Cs, and 569.16 ± 91.15 of <sup>40</sup>K were detected whereas <sup>131</sup>I was not detected. In the calcium fertilizer, 5.74 ± 4.40 Bq/kg of <sup>137</sup>Cs (the highest concentration among all fertilizers), 22.37 ± 5.39 Bq/kg of <sup>134</sup>Cs, and 433.67 ± 64.24 Bq/kg of <sup>40</sup>K were detected whereas <sup>131</sup>I was not detected. In the sulfur fertilizer, 347.31 ± 55.73 Bq/kg of <sup>40</sup>K, 19.42 ± 4.53 Bq/kg of <sup>134</sup>Cs, 2.21 ± 3.49 of <sup>137</sup>Cs, and 0.04 ± 0.22 Bq/Kg of <sup>131</sup>I were detected. In the phosphoric acid fertilizer, 70,007.34 ± 844.18 Bq/kg of <sup>40</sup>K (the highest concentration among all fertilizers) and 46.07 ± 70.40 Bq/kg of <sup>134</sup>Cs were detected whereas neither <sup>137</sup>Cs nor <sup>131</sup>I was detected. In the potassium chloride fertilizer, 12,827.92 ± 1542.19 Bq/kg of <sup>40</sup>K was and 94.76 ± 128.79 Bq/kg of <sup>134</sup>Cs were detected whereas neither <sup>137</sup>Cs nor <sup>131</sup>I was detected. The present study examined inorganic fertilizers produced by a single manufacturer. There might be different results according to the country and area from which fertilizers are imported. Further studies about inorganic fertilizers in more detail are needed to create measures to reduce <sup>40</sup>K.Conclusion: Measures are needed to reduce radiation exposure to <sup>40</sup>K contained in fertilizers including phosphoric acid and potassium chloride fertilizers.

The effects of calcium fertilization on morphological and physio-biochemical characteristics in peanut seedlings under waterlogging stress

Peanut is vulnerable under waterlogging stress, and it is important to explore efficient agronomic practices to reduce adverse effects induced by waterlogging stress. In this study, the effects of waterlogging stress on plant morphology, physiological and biochemical characters in peanut seedlings were studied. It was founded waterlogging stress posted adverse effects on plant growth and development and triggered the activities of antioxidant enzymes and osmotic adjustment substances to improve the plant tolerance under stress. It was also found that exogenous calcium fertilization could significantly improved root growth and development under stress. Moreover, higher dose of calcium fertilizer (1600 mg/kg) showed better performance on improving waterlogging tolerance than lower dose one (800 mg/kg) in peanut seedlings. This study explored positive effects of exogenous calcium on recovering damages especially in roots caused by waterlogging stress, providing a theoretical guidance in agronomic practice to improve waterlogging tolerance, and laying a foundation for agronomic practice when further discovering molecular mechanisms in response to waterlogging stress.

Evolution trend of soil fertility in tobacco-planting area of Chenzhou, Hunan Province, China.

In this study, the data of fertility indicators of soil samples (0-20 cm) in 1980s, 2000 and 2015 in Chenzhou city were used, and the soil integrated fertility index (IFI) was calculated. The results showed that the soil pH was decreased, total nitrogen (TN), organic matter (OM), available phosphorus (AP) and potassium (AK), exchangeable calcium (Ca2+), magnesium (Mg2+) and available copper (Cu) contents were increased, total phosphorus (TP), available sulfur (S) and water-soluble chlorine (Cl-) contents were decreased, total potassium (TK), available boron (B), iron (Fe), manganese (Mn) and zinc (Zn) were decreased first and then increased. In 2015, most of the fields were higher in pH, OM, TN, AN, AK, Ca2+, Mg2+, S, Fe, Mn, Cu and Zn, suitable in B, but lower in TP, AP, TK, available molybdenum (Mo) and Cl-. Most of the fields were in the middle grade of IFI in 2000 and 2015, and the mean IFI increased from 0.492 to 0.556 from 2000 to 2015. Thus, for soil improvement, more attention should be paid to adjust soil pH, reduce the application of organic, nitrogen and calcium fertilizers, while increase the fertilizer application of other nutrients.

Spraying sorbitol-chelated calcium affected foliar calcium absorption and promoted the yield of peanut (Arachis hypogaea L.).

The prevalent use of foliar calcium fertilizers in peanut production is inorganic, but calcium absorbed from the foliar has poor availability. Sorbitol-chelated calcium is a novel organic foliar calcium fertilizer that has rarely been studied for application in peanut production. To explore whether calcium absorption and peanut yields can be affected by foliar application of sorbitol-chelated calcium, this study conducted two field experiments using Virginia peanut (Huayu-22) in 2020 and 2021. The five spray treatments included: deionized water (CK), sorbitol (Sor), calcium nitrate (CaN), a mixture of sorbitol and calcium nitrate (SN), and sorbitol-chelated calcium (SC). The yield of peanuts treated with sorbitol-chelated calcium was increased by 12.31-16.63%, 10.22-11.83%, 6.31-9.69%, and 4.18-6.99% compared to the CK, Sor, CaN, and SN treatments, respectively. Sorbitol-chelated calcium had the lowest contact angle due to the wetting effect of sorbitol, which promoted calcium absorption by leaves. Sorbitol-chelated calcium improved the leaf calcium concentration by 13.12-19.32% and kernel calcium concentration by 6.49-8.15% compared to the CK treatment. Foliar fertilization increased the calcium concentration of each subcellular fraction of leaves and changed the distribution of calcium in mesophyll cells. This change was directly observed by transmission electron microscopy. Additionally, spraying sorbitol alone obtained similar effects to spraying calcium nitrate alone, indicating that the benefits of sorbitol itself were not negligible. The results of the principal component and correlation analysis showed that the increase in calcium concentrations and the change in calcium distribution improved the pod traits of the peanut, thus affecting the peanut yield. The above results showed that from the perspective of calcium absorption and distribution, sorbitol-chelated calcium is a more effective foliar calcium fortifier for peanuts and effectively improves peanut yields.

Holistic Assessment of Calcium Fertilization in Potato: Diagnostic, Productivity, and Tuber Quality

Holistic Assessment of Calcium Fertilization in Potato: Diagnostic, Productivity, and Tuber Quality

Structure, Function, and Applications of Soybean Calcium Transporters.

Glycine max is a calcium-loving crop. The external application of calcium fertilizer is beneficial to the increase of soybean yield. Indeed, calcium is a vital nutrient in plant growth and development. As a core metal ion in signaling transduction, calcium content is maintained in dynamic balance under normal circumstances. Now, eight transporters were found to control the uptake and efflux of calcium. Though these calcium transporters have been identified through genome-wide analysis, only a few of them were functionally verified. Therefore, in this study, we summarized the current knowledge of soybean calcium transporters in structural features, expression characteristics, roles in stress response, and prospects. The above results will be helpful in understanding the function of cellular calcium transport and provide a theoretical basis for elevating soybean yield.

Soil quality assessment of cropland in China and its relationships with climate and topography

AbstractAssessing soil quality (SQ) of cropland is fundamental for food security and sustainable land management. However, there is limited information regarding SQ assessment on a national scale, which is vital to answer important SQ‐related questions in quantitative terms on that scale. Here, the SQ of cropland in China was assessed by constructing a minimum data set (MDS) from 23 soil physicochemical properties based on principal component analysis. The interaction roles and relative contributions of climate and topography on SQ was evaluated by a structural equation model. The MDS comprised eight indicators: proportion of silt, bulk density, total phosphorus, total potassium, available nitrogen, exchangeable calcium, chlorite, and vermiculite. The soil quality index (SQI) varied from 0.245 to 0.705 and showed a clear pattern of decreasing quality from the north to the south of the country. Of the total cropland area in China, the largest share (27.91%) was of soils of high quality, followed by those of moderate quality (24.63%), low quality (20.37%), very high quality (14.18%), and very low quality (12.91%). The north and the south differed significantly in terms of total potassium, exchangeable calcium, chlorite, and vermiculite, which are the four most important indicators of SQ. Climate and elevation explained about 2.2%–30.1% of the variation in SQ on the national and regional scales. These findings suggest that croplands in southern China will benefit from potassium and calcium fertilizers, which will contribute to enhance food security and promote sustainable land management in China.

Effects of Spraying Calcium Fertilizer on Photosynthesis, Mineral Content, Sugar–Acid Metabolism and Fruit Quality of Fuji Apples

This study was conducted at the Taidong Base of the Shandong Institute of Pomology, Tai’an City, Shandong Province, China, from May to October 2020. The effects of spraying calcium fertilizer on the photosynthetic characteristics, mineral element content, sugar and acid metabolism, and quality of apples were assessed. Fuji Apple Tianhong.2/SH/Malus robusta (M. robusta) was treated with the calcium fertilizers Niucui (Ca ≥ 100 g/L, B: 1–10 g/L) and Naipu 9 (Ca: 90 g/L, Mg: 21 g/L, N: 110 g/L) at the young fruit stage (25 May), the expansion stage (5 July), and the coloring stage (25 September). Water was sprayed as the control application. The results revealed that spraying calcium fertilizer increased the chloroplast pigment content and photosynthetic capacity of the apple leaves. Compared with the control, the net photosynthetic rate of apple leaves sprayed with Niucui increased by 4.3–34.6%, and that of leaves sprayed with Naipu 9 increased by 15.0–57.4%. Spraying calcium fertilizer promoted the accumulation of Ca, Mg, and B mineral elements in leaves and fruits while inhibiting the accumulation of Cu. Spraying calcium fertilizer improved the quality of apple fruit. Compared to the control fruit, the single fruit weight, fruit hardness, soluble solid content, and Vitamin C content of fruit sprayed with Niucui and Naipu 9 increased by 6.5 and 12.1%, 3.6 and 16.1%, 6.3 and 12.0%, and 30.5 and 29.4%, respectively. Spraying calcium fertilizer increased the sugar content and decreased the acid content of the apples. Naipu 9 was more effective at increasing fruit sugar content, especially sucrose and sorbitol, while Niucui was more effective at reducing the acid content, especially malic acid. This was observed because Naipu 9 increased the sugar metabolism enzyme activity, while Niucui increased the acid decomposition-related enzyme activity. In conclusion, according to the nutrition quality and flavor of the fruit, Naipu 9 application was determined to be the best fertilizer for the Fuji apple.

Anatomical characteristics of cocoa plant roots as affected by the levels of calcium fertilization

Cocoa plant (Theobroma cacao L.) is one of good annual crops grown in Indonesia. The disadvantages and advantages of Ca in plants can affect morphology and anatomy in plants. This research aimed to identify the effect of Ca on the anatomical performance of the roots of cocoa plants and determine the optimal dose of Ca for the anatomical characteristics of the roots of cocoa plant. The research was conducted at the cocoa plantation owned by PT. Pagilaran at North Segayung Production Unit, Tulis Subdistrict, Batang Regency, Central Java, in October 2019 – February 2021. The observation of root anatomy was carried out by making preparations, and the plant roots were taken destructively and sliced transversely. The field experiment was arranged using a single factor randomized complete block design. The treatments consisted of without fertilizer application and calcium fertilization at a dose of 100 g/tree/year, 200 g/tree/year, 300 g/tree/year, and 400 g/tree/year. The cocoa clone used was clone RCC 71. The results showed that an increase in the dose of CaCl2 fertilizer up to 400 g/tree/year was generally followed by an increase in the size of the xylem and phloem diameters, the thickness of the cork layer, the thickness of secondary cortex, and the diameter of the stele. The quadratic effect of the dose of CaCl2 fertilizer was observed only on the thickness of the root cambium tissues. Thus, it is necessary to conduct further research to determine the optimal dose of Ca fertilizer for the anatomical characteristics of cocoa roots.

Assessment of soil fertility in Artemisia argyi planting areas in Qichun county based on minimum data set

This study aims to explore the soil fertility in the main Artemisia argyi planting areas in Qichun county.To be specific, the soil physical and chemical properties in the main planting areas of A.argyi in Qichun county were analyzed.On this basis, 12 indexes were selected for principal component analysis(PCA) which was then combined with the norm value of each index and the correlation coefficients between the indexes to establish the minimum data set(MDS).The radar map was plotted to directly demonstrate the level of each index and the comprehensive level of the sampling sites.The comprehensive index model was used to calculate the soil fertility quality index(SFQI) of the total data set(TDS) and MDS(SFQI-TDS and SFQI-MDS, respectively), and linear regression of the two was performed.The results showed that the indexes that made up the MDS for soil fertility evaluation were pH, available potas-sium, available iron, available zinc, available manganese, available copper, and available magnesium.The radar map suggested the greatest difference in soil organic matter and smallest difference in available nitrogen among the 14 sampling sites.Moreover, the overall content of available phosphorus and available iron was high, while that of available nitrogen was the lowest.The SFQI-MDS which was yielded based on the weight of each index in MDS calculated with the norm value was more sensitive and the SFQI had stronger correlation with TDS-SFQI, which can better represent TDS-SFQI.SFQI-MDS was in the range of 0.298-0.784, with the average of 0.565 and variation coefficient of 18.38%.Caohe Town had the highest average SFQI-MDS.Clustering of SFQI-MDS value suggested that the soil fertility can be classified into 4 levels: level Ⅰ(SFQI ≥ 0.677) indicated excellent soil fertility, which accounted for 11.24%(mainly in Qingshi town, Balihu, and Zhangbang town); level Ⅱ(0.571≤SFQI≤0.680) meant good fertility, which made up 43.82%(mainly in Caohe town, Hengche town, and Pengsi town); level Ⅲ(0.466≤SFQI≤0.557) indicated average fertility, which took up 32.58%(mainly in Chidong town and Zhulin town); level Ⅳ(SFQI≤0.421) suggested poor fertility, which accounted for 12.36%(mainly in Guanyao town).It is recommended that nitrogen, potassium, magnesium, and calcium fertilizers should be increased and organic ferti-lizer should be applied for the cultivation of A.argyi in Qichun county to improve soil fertility and soil physical and chemical properties.

Estimation of nitrogen use efficiency by mango seedlings under nano and convention calcium fertilization using the enriched stable isotope (N-15)

This study aimed to investigate the effect of nano-Ca fertilizer on nitrogen uptake, nitrogen use efficiency and determine the best calcium form and dose for mango. A pot experiment was conducted using two year old mango seedlings (cv. Zebda). The pots were filled with sandy soil (8 kg per pot) and one seedling was transplanted into each pot. Four treatments including nano-Ca, convention Ca, soil application and foliar application have been formulated. Calcium was applied as CaO for both the convention and nanoforms. The enriched (15NH4)2SO4 was applied at a rate of (5g per pot). Plants were harvested at the end of the fall, spring, and summer growth cycles and dried at 70 oC. The dried plant is used for making fine powder and to determine total nitrogen, calcium, and %15N atom excess. Results of the study revealed that in all growth cycles, the 15N translocation was higher under foliar nano-Ca treatment than under convention Ca at a 100% rate. The highest uptake, translocation, and nitrogen use efficiency were observed at 50% (250 mg. L-1) foliar nano-Ca treatment in all cycles. In the Fall growth cycle, the values for nitrogen fertilizer use efficiency at 50% nano-Ca rate was 81.8%, while it recorded 64.9% for 25% rate and 51.2% for 100% rate. Calcium concentration, in shoot and roots, was also higher under nano-calcium (for fall cycle = 3.0 for the shoot and 2.8 for root) than the convention calcium (for fall cycle = 2.7% for the shoot and 2.2 for root) for all cycles. The summer growth cycle recorded the highest total biomass under all treatments compared with the fall or spring growth cycles. Allocation of biomass to the shoot was also reported higher under nano-Ca foliar application than that of soil application in all cycles. The best treatment is 50% (250 mg.L-1) foliar nano-Ca as it resulted in the highest N-15 uptake, translocation, and nitrogen use efficiency. Nano calcium proves to be more efficient as fertilizer than conventional calcium.

Occurrence of Stem Topple and Growth of Cut Flowers by Calcium Fertilization Level of the Tulip ‘Dynasty’ in the Plant Facility

Occurrence of Stem Topple and Growth of Cut Flowers by Calcium Fertilization Level of the Tulip ‘Dynasty’ in the Plant Facility

Green Conversion of Coal Fly Ash into Soil Conditioner: Technological Principle and Process Development

White mud is residue discharged during the acid method in the aluminum extraction process from coal fly ash, and this material is harmful to the environment. The implementation of an environmentally friendly and valuable way to use white mud is a key factor restricting the commercial application of the acid method in the fly ash alumina extraction technology. An analysis of white mud revealed the following: (1) it was highly enriched in SiO2 (70–80%) while concentrations of acid-soluble elements, such as Na, Al, and Fe, and some hazardous heavy metals, including Pb and Cr, were significantly lower than raw fly ash; (2) approximately 80% of SiO2 had relatively high reaction activity because of the foregoing Al-extraction treatment. Through an ingenious green chemical process, the complete conversion of white mud into silicon–calcium fertilizer (SCF) was achieved under very mild reaction conditions (approximately 100 °C and atmospheric pressure). Waste liquor was totally recycled, and no secondary solid waste was generated. The SCF had an available silicon content (ASC) of 35%, significantly higher than the commercial standard (20%). Converting them into soil conditioners or ecological remediation materials with the lowest possible energy consumption and secondary pollution may be the most promising approach for the future disposal of aluminosilicate industrial solid wastes.

Production and quality of Sweet Grape tomato in response to foliar calcium fertilization

In tomato, foliar application of calcium-based nutrient solutions is used to complement soil fertilization. However, knowledge regarding the factors that influence the effectiveness of foliar fertilizer applications remains incomplete. The objective of this study was to evaluate the efficiency foliar fertilization with calcium for improving production and quality of hydroponic Sweet Grape tomatoes. An experiment was conducted in a commercial hydroponic system in a split-plit-plot scheme, with two calcium doses: 1,5 and 3 mmol L-1 of Ca. The solutions were sprayed on the leaves at intervals of 7 and 14 days, using commercial foliar fertilizers containing 0.3 g L-1 of calcium chloride or calcium acetate. The results indicate that the foliar application of calcium fertilizers, regardless of the amount of calcium provided in the nutrient solution and the frequency of applications, positively affects fruit production and quality. No difference was found between the effects of application of the two calcium sources, as well as the frequency of application.

The Effects of Calcium Fertilizer Sprays during Fruit Development Stage on Pineapple Fruit Quality under Humid Tropical Climate

Low calcium content in pineapple could decrease its quality, such as fruit translucency (electrolyte leakage), bruises (fruit firmness), and the other fruit quality standards. The purpose of the current study was to assess the effect of different sprays of calcium (Ca) fertilizer sources during the fruit development stage on the overall fruit quality. Four sources of calcium, chelated calcium, calcium nitrate (Ca(NO3)2), calcium chloride (CaCl2), each in 75 kg ha−1, and calcium boron (calcibor) of 10 L ha−1 mixed with 2000 L water, were directly sprayed onto individual fruit and crown, 75, 85, 95, and 105 days after forced flowering induction (forcing). The Smooth Cayenne “MD-2” pineapple cultivar was utilized for the experiment in a randomized complete block design with four replications and conducted at two different times. Fruit quality analyses were carried out on the harvested fruits 140 days after forcing. The application of calcium sprays did not have significant effects on fruit p H , total soluble solids, total acidity, fruit firmness, and the content of sucrose and vitamin C. There was a different response of calcium spray in the first and second trials on the content of glucose, fructose, β-carotene, Ca, and Mg, probably due to climate condition. All treatments with calcium sprays reduced the fructose and glucose contents in the first trial and β-carotene content in the second trial. Calcium chloride and calcibor increased Ca and decreased electrolyte leakage significantly than the other treatments. The scanning electron microscope analysis revealed that CaCl2 sprays generated greater turgor and more rigidity in the pineapple cell wall. The result showed that the application of CaCl2 and calcibor sprays could decrease electrolyte leakage incidence in pineapple with any potential to reduce glucose, fructose, and β-carotene without influencing other fruit qualities significantly.

Calcium Fertilizer Effect on Rhizopus Tuber Rot and Anthracnose Disease Caused by Colletotrichum Gloeosporioides in Dioscorea Rotundata Var. Efuru

The response of Dioscorea rotundata var Efuru, one of the popular white guinea yam varieties in South West Nigeria to calcium soil amendment for control of Rhizopus stolonifer.Ehrenb., tuber rot and Anthracnose disease caused by Colletotrichum gloeosporioides Penz. was investigated in this study. The field design was randomized complete block (RCBD) with three replicates.The mineral elements Calcium (Ca), Magnesium (Mg) and Potassium (K) in the soil of the experimental site were above the criticals reported for optimum yam production in South West Nigeria, but Nitrogen (N) and Phosphorus (P) were below. Soil amendment at 3MAP (months after planting) was with 0 kg ha-1 control, 3 kg ha-1 and 4 kg ha-1 Calcium from Calcium Nitrate. Anthracnose severity was not significantly different across treatments in any of the four periods of assessment. Severity score was resistant (1.00) at 4MAP, resistant (1.22) at 5MAP moderately resistant (2.00) at 6MAP, but moderately susceptible (2.89) at 7MAP.This implies that variety Efuru is susceptible late in the growth cycle. Future trials may accommodate additional (in addition to the 3MAP calcium soil amendment), calcium nitrate foliar spray at 6MAP and 7MAP with trial doses less than 100 mgl-1, as is reported for D. alata var. Alakisa, for reduction of anthracnose severity to resistant level. Shoot number per plant, mean values 2.45 and 2.71 at 4MAP and 6MAP respectively, were not significantly different across treatments. Shoot length at 4MAP (309.58cm) was significantly higher in the 4 kg ha-1 treatment than the control (277.80cm), but was similar across treatments at 6MAP. Mean tuber number per plant at 8MAP was similar across treatments and had overall mean of 2.39. Tuber yield at 8MAP, which was similar across treatments was the equivalent of 31.50 tons ha-1 (control), 30.10 tons ha-1 (3 kg ha-1) and 35.70 tons ha-1  (4 kg ha-1), which is similar to 34.20tons ha-1 reported as optimum for economic production of white guinea yam in South West Nigeria. Yield obtained in this study may be due to firstly Ca, Mg and K being above critical for optimum yam production in the soil site. And secondly even though N and P were below critical, N was supplied from the fertilizer and the requirement for P was invariably taken care of by the mycorrhizal associations of the roots. Tubers inoculated at 6MAP for 4 weeks with Rhizopus stolonifer were similar across treatments in infection (mean 1.37%) and weight loss (mean 16.88%). Infection in tubers inoculated at 8MAP for 4 weeks was high, that is 48.79% in the control, significantly higher than the 3kg ha-1treatment which was 0.57%, which was in turn higher than the 0.61 % of the 4 kg ha -1treatment. Mean infection of 0.59% in the two calcium treatments is a reduction of 98% of infection in the control. Thus3kg ha-1 and 4 kg ha -1 calciun soil amendment are appropriate for R. stolonifer rot control in Dioscorea rotundata var. Efuru. However, 3 kg ha-1 calcium soil amendment is to be preferred as it gave lower infection.Weight loss at 6MAP and 8MAP, overall means of 16.88% and 2.39% respectively were similar across treatments. Weight loss of 2% at 8MAP in the two calcium treatments is a reduction of over 88% of mean weight loss of 17.33% of the two treatments at 6MAP. Crude fibre and fat were higher in tubers of the calcium-fertilized plants than the control, but crude protein, ash and carbohydrate were higher in control tubers. Ca, Mg, K, Fe and Zn were higher in the calcium-treated plant tubers than the control but Mn and Cu were higher in the control. Calcium fertilization improved accumulation/acquisition of four of the seven mineral elements reported to be often lacking in human diets that is Ca, Mg, Fe and Zn, in Dioscorea rotundata var. Efuru tubers.

Magnesium fertilization has a greater impact on soil and leaf nutrient concentrations than nitrogen or calcium fertilization in Florida orange production

Magnesium fertilization has a greater impact on soil and leaf nutrient concentrations than nitrogen or calcium fertilization in Florida orange production