Application Of Superphosphate Research Articles

Application of Single Superphosphate with Humic Acid Improves the Growth, Yield and Phosphorus Uptake of Wheat (Triticum aestivum L.) in Calcareous Soil

In calcareous soil, the significant portion of applied phosphorus (P) fertilizers is adsorbed on the calcite surface and becomes unavailable to plants. Addition of organic amendments with chemical fertilizers can be helpful in releasing the absorbed nutrients from these surfaces. To check out this problem, a field experiment was conducted for two years to determine the effect of P fertilizers and humic acid (HA) in enhancing P availability in soil and their ultimate effect on growth, yield and P uptake of wheat in calcareous soils. The experiment was comprised of five levels of P (0, 45, 67.5, 90 and 112.5 kg P2O5 ha−1) as a single superphosphate (SSP) and 2 levels of locally produced humic acid (with and without HA) arranged in a two factorial randomized complete block design (RCBD) with three replications. Wheat plant height, spike length, number of grains per spike, 1000-grain weight, grain, straw and biological yield were significantly improved by the addition of HA with SSP. Very often, the performance of 67.5 kg P2O5 ha−1 with HA were either similar or better than 90 or even 112.5 kg P2O5 ha−1 applied without HA. Post-harvest soil organic matter, AB-DTPA extractable and water-soluble P, plant P concentration and its uptake were also significantly improved by the addition of HA with SSP compared to sole SSP application. It was evident that P efficiency could be increased with HA addition and it has the potential to improve crop yield and plants P uptake in calcareous soils.

Dynamics of phosphorus fractions in soils treated with dairy manure

The evaluation of phosphorus (P) transformations in soil after application of manure or mineral P can improve soil management and optimise P use by plants. The objectives of the present study were to assess organic and inorganic P forms in two soils treated with dairy manure and triple superphosphate and to establish relationships between soil P fraction levels and P availability. Soil organic and inorganic P fractions were quantified using a pot experiment with two soils, a typical Hapludox and an arenic Hapludult, with three types of fertiliser treatments applied (no fertiliser application, application of dairy manure, and application of triple superphosphate, by adding 100 mg P dm–3 in the form of fertiliser in the two latter treatments) and four incubation times (15, 45, 90, and 180 days). Inorganic P was fractionated into aluminium-bound, iron-bound, occluded, and calcium-bound P. Organic P was extracted sequentially using sodium bicarbonate, hydrochloric acid, microbial biomass, sodium hydroxide, and residual organic P. After incubation, maize plants were cropped to quantify dry matter yield and absorbed P. Application of dairy manure resulted in a significant increase in most of the organic P fractions, and application of triple superphosphate led to a significant increase in inorganic P fractions. Both fertilisers raised labile organic P fractions in the two soils. The major sinks of P in Hapludox were occluded and fulvic acid-associated P. In contrast, the major sink of P in Hapludult was iron-bound P. The available P levels were stable after application of dairy manure, and decreased with time when fertilised with triple superphosphate. In the Hapludox, the organic P fractions had a significant positive correlation with P uptake by plants. The results suggest that organic P mineralisation plays a more significant role in plant P uptake in the Hapludox soil and inorganic P forms are the main contributors to plant P uptake in the Hapludult soil.

Оптимизация состава удобрений на основе молотых фосфоритов

The phosphorites of many domestic deposits can be used as cheap natural phosphorus fertilizers of regional importance. The limitation of their use is due to the low solubility and, consequently, low agrochemical effectiveness. To increase the solubility of phosphorites (activation), it is proposed to use the method of granulation of phosphorite flour (PF) with an organomineral additive containing milled sulfur, glauconite and highly decomposed peat, dispersed by hydrodynamic cavitation. Phosphate activation is ensured by acids formed in the process of microbiological oxidation of sulfur in soils (convert insoluble phosphates to more soluble hydrophosphates), glauconite (promotes adsorption and ion exchange binding of cations that form insoluble phosphates, activates soil microbiota) and humic acid peat (oxides into stable complexes, stimulate the activity of soil microorganisms). In laboratory conditions, samples of the corresponding organic-mineral fertilizer were obtained. As phosphate raw materials, the PF of the Vyatka-Kama deposit (Russia) and the Khneifis deposit (Syria) were used. The study of the effect of fertilizer on the chemical composition of soils was carried out in a laboratory experiment. As a comparison object, simple superphosphate was used. Fertilizers were applied to the soil in an amount of 0.1 g per 1 kg of air-dried soil. It was revealed that already 7 days after fertilizing, the mobility of phosphorus increases by 31-45%, while the pH of the soil solution does not change. The sulfate content in soils increased by an average of 33%. In all variants of the experiment, the application of activated PF in the soil led to the same result as the application of simple superphosphate. Based on PF and an activating organomineral additive, a granular form of phosphorus fertilizer with sulfur and humic substances can be obtained that is not inferior in effectiveness to simple superphosphate. The production of appropriate fertilizer can be arranged at small enterprises and directly at phosphate mines, which will create new jobs and provide regional crop production with relatively cheap and fairly effective forms of phosphate fertilizers that comply with the principles of green chemistry. The composition and technology of fertilizer production make it possible to position it as a natural organic-mineral fertilizer for organic farming.

Application of superphosphate complexed with humic acid in an area of sugarcane

Phosphorus (P) fertilization presents low efficiency due to P adsorption on clay surface in tropical soils. Superphosphate complexed with humic acid (SSP+HA) is presented as an alternative phosphorus source to improve P use efficiency and crop yields. In this way, the aim of this study was investigated the SSP+HA performances in sugarcane production as a response to the increment of dry matter and plant P contents. The experiment was run with two P sources (simple superphosphate - SSP; SSP+HA) and five rates (0; 45; 90; 135 and 180 kg ha -1 of P 2 O 5 ). The rate of135 kg ha -1 of P 2 O 5 was used to explain the P residual effect. Samples of stalks, tops and roots were collected to determine dry matter and P contents; and phosphorus assimilation efficiency (PaE) was calculated. Results show that application of SSP increased dry matter and P contents in plants, with a superior performance compared to SSP+HA. The SSP+HA presented a better PaE, indicating that P is metabolized more efficiently, but it did not reflect in higher production. Applications of P rates are required in the planting, not requiring additional application due to residual effect. Taking in consideration these results and others from literature, the findings suggest that SSP+HA is not attractive to sugarcane in cane plant and ratoon, and further investigations are needed to better illustrate this effect on sugarcane development in both absorption and translocation.

Efficiency of Various Reagents on Ammonia Reduction in Litter Removal From Belt Conveyors for Battery Cages

With the development of technogenic civilization, various anthropogenic factors (ionizing radiation, toxic substances, etc.) affect virtually all living organisms, and often this effect is negative. The current state of affairs on many poultry farms is that they have a negative impact on the surrounding biosphere due to harmful emissions. This is due to the accumulation of litter. The purpose of the study was to investigate the microclimate parameters in the poultry house with the addition of various reagents and zeolite in the belt conveyors of cage batteries. It was proposed to add adsorbents (zeolite) and chemical reagents (phosphogypsum, superphosphate, and aluminium chloride and iron sulphate) directly onto the litter removal belt conveyors of cage batteries. It was found that application of zeolite onto the conveyor belt in an amount of 600 g/m2 reduces the content of ammonia in the premises by 1.6 times on the first day of accumulation of litter, and by 1.25 times on the seventh day, not exceeding during all seven days of maximum allowable concentrations. However, within all seven days of litter accumulation, a difference in this indicator with control was statistically significant (P=0.001). The reduction of ammonia emissions was less significant when applying a dose of zeolite of 300 g/m2 conveyor belt: by 1.6 times on the first day of accumulation of litter, and from the fifth day the difference with control was statistically significant. The application of phosphogypsum onto the conveyor belt in the amount of 600 g/m2 provided a reduction of ammonia emission by 2.1-1.1 times, 300 g/m2-by 1.8 times on the first day of accumulation of litter. Since the fifth the day, the difference in control was statistically significant. The application of superphosphate onto the litter removal conveyor belts reduced the ammonia content in the poultry house in almost the same extent as when applying phosphogypsum. The effective time of this reagent was also close in importance. Aluminium chloride and ferrous sulphate were used in smaller doses than other absorbents and reagents, but on the initial five days of litter accumulation, they provided a relatively significant reduction in the ammonia content of the air in the poultry house: ferrous sulphate at a dose of 200 g/m2 of the conveyor belt area - by 2.0-1.2 times, aluminium chloride - by 4.0-1.5 times. Anyway, the efficacy of these reagents in the last days of litter accumulation was considerably decreased. The use of aluminium chloride and ferrous sulphate in doze of 100 g/m2 for the conveyor belt provided a proper reduction of indoor ammonia content only for the initial tree-four days.

Improving growth, phytochemical, and antioxidant characteristics of peppermint by phosphate-solubilizing bacteria along with reducing phosphorus fertilizer use

Phosphorus is a vital nutrient for plant growth and development. Its deficiency in farmlands is obviated by the phosphate fertilizer application. Excessive consumption of phosphate fertilizers harms to human health and the environment. Some soil bacteria are capable to increase phosphate fertilizers efficiency. Two-year field experiment was conducted to evaluate the effect of phosphate-solubilizing bacteria inoculation with phosphorus fertilizer on growth, antioxidant status, and phytochemical features of peppermint (Mentha piperita L.). The treatments were three amounts triple superphosphate (0, 50, and 100 kg ha−1) and PSB strains (Pseudomonas putida and Pantoea agglomerans) which were arranged as factorial based on randomized complete block design. The results showed that phosphorus supplying by chemical fertilizer or PSB improved peppermint growth features included stem number, leaf length, leaf number, and dry weights of leaf, stem, and plant. The contents of photosynthetic pigments increased by chemical or biological phosphorus fertilizer application. The application of PSB with triple superphosphate reduced soluble carbohydrates and increased protein. The antioxidant enzymes activities including catalase, peroxidase, ascorbate peroxidase, and polyphenol oxidase were increased by the PSB inoculation. In contrast, activities of these enzymes were reduced by the triple superphosphate application. The highest EO yield was obtained by Pseudomonas putida and Pantoea agglomerans inoculation as phosphate-solubilizing bacteria with 50 kg ha −1 triple superphosphate. The menthol content was increased in response to the triple superphosphate and the PSB inoculation. Therefore, PSB inoculation increased phosphate fertilizer efficiency which leads to reducing phosphate fertilizer consuming and increasing the plant biomass as well as EO yield.1

Water Availabilities Associated with Natural Phosphate and Triple Superphosphate in Radish Cultivation

Aims: The objective of this study was to evaluate the development of giant Crimson radish cultivated in a oxisol under phosphate fertilizer sources (natural phosphate, triple superphosphate, natural phosphate + triple superphosphate and control) associated with water availabilities (40, 80 and 120% of the field capacity).
 Study Design: The experimental design was completely randomized, in a 4x3 factorial scheme, with 4 replications (48 units).
 Place and Duration of Study: The research was conducted in a greenhouse belonging to the Federal University of Mato Grosso, in the municipality of Rondonópolis (MT).
 Methodology: The dystrophic Oxisol was used to fill the 1.5 dm3 pots. The irrigation management was in accordance with the methodology of the maximum water retention capacity, by the gravimetric method. Phosphate fertilization was applied before sowing using 265 mg dm-3 phosphorus, varying the source used, triple superphosphate and Bayovar Natural phosphate. After the emergence of the plants, the other nutrients were applied to the soil. The parameters related to vegetative development and after the harvest of radish were evaluated at 20 and 35 days after sowing.
 Results: The parameters fresh mass of the aerial part, dry mass of the tubercle, dry mass of the aerial part, fresh mass of tubercle and length of tubercle had the highest values with the use of triple superphosphate, and for the field capacities of 80 and 120%. The highest harvest index (1.51) was found for the use of Natural phosphate in the field capacity of 120%. The water consumption by the plants was higher with the use of triple superphosphate and field capacity of 120% (6,425.25 L). The efficiency of water use was better with the application of triple Superphosphate and 40% of the field capacity (0.0547 g mL-1).
 Conclusion: There was influence of both water availabilities and phosphate fertilization on the studied parameters. Triple superphosphate associated with 80% of the field capacity allowed the best productivity averages for radish.

Mass balance assessment of phosphorus dynamics in a fertilizer trial with 57 years of superphosphate application under irrigated grazed pasture

Improving the efficiency of phosphorus (P) use is a major challenge for agricultural production and sustainability. Using a combination of new and historic data, a mass balance approach was employed to construct and discuss a comprehensive P budget under temperate irrigated grazed pasture that had received different inputs of superphosphate fertilizer for 57 years [nil (Control), 188 kg ha−1 (188PA) and 376 kg ha−1 (376PA)]. Most (97–99%) of the applied P was accounted for in soil storage, plant residues, removal in animal products, excretal transfers, losses via irrigation outwash, rainfall runoff and leaching in the soil–plant–animal system. Management of soil available P that exceed the critical level (17–22 mg L−1) for optimal pasture production can result in low P balance efficiency and excessive soil legacy P in the soil profile (0–1 m). Results of this study revealed that accumulation of P in soil and plants (68–80%), P losses by irrigation outwash (8–11%), and excretal transfers to stock camps (6–12%) were important factors that determined applied P use efficiency. These findings highlight the need to apply appropriate quantities of P fertilizer to maintain optimal soil P fertility, plant growth, and animal production, together with enhanced utilization of accumulated soil P and reduced P transfer in drainage.

EFFECT OF DIFFERENT SOURCES OF PHOSPHORUS AND BIO FERTILIZERS ON YIELD AND SEEDS QUALITY OF SOYBEAN

Phosphorus (P) is the second important key plant nutrient after nitrogen. An adequate supply of P is therefore required for proper functioning and various metabolisms of plants. Majority of P in soils is fixed and hence, plant available P is scarcely available despite the abundance of both inorganic and organic P forms in soils. A group of soil microorganisms capable of transforming insoluble P into soluble and plant accessible forms across different genera, collectively called phosphate-solubilizing bacteria (PSB), have been found as best ecofriendly option for providing inexpensive P to plants. These organisms in addition to supplying soluble P to plants also facilitate the growth of plants by several other mechanisms, for instance, improving the uptake of nutrients and stimulating the production of some phytohormones. Two field experiments were conducted at EL-Gemmiza, Agric. Res. Station,(30o 47׳ 22.5״ N, 31° 07׳ 34״ E, elev. 10 m), Agric. Res. Centre., El-Gharbia Governorate, Egypt, during the two successive summer seasons of 2017 and 2018, to study the effect of different application sources and rates of phosphorus on the growth, productivity, yield characters and quality of soybean (Glycine max L.), c.v. Giza 111. The treatments consisted of four sources of phosphorus [single super phosphate (SSP), rock phosphate (RP), single super phosphate (SSP) + phosphate solubilizing bacteria (PSB) and rock phosphate (RP) + phosphate solubilizing bacteria (PSB)] at three levels of added P.i.e (0, 15 and 22.5 kg P2O5 fed-1).Results revealed that seed and straw yield and uptake of N, P and K increased significantly with both sources of P over control. Application of single superphosphate proved superior increases compared to rock phosphate in respect of yield and uptake of nutrients. There was a significant increase in yield and uptake of nutrients with increase in P application rate from 15 kg P2O5 fed-1 to 22.5 kg P2O5 fed-1 applied either as SSP or RP. Protein content in soybean seed increased significantly with both the sources of P.The application of SSP +PSB (T9) recorded higher yield (grain and straw) and uptake of nutrients than phosphorus alone. The maximum seed (1572 kg/fed) and straw (4473.33 kg/fed) yields were recorded with 22.5 kg P2O5 fed-1 as SSP+PSB. Significant differences among the treatments were noticed with respect to number of pods per plant, seed yield per plant, test weight and seed yield. Application of 22.5 kg P2O5 fed-1 with PSB (T9) produced maximum number of pods/plant (150.67), seed yield (74.23 g/plant) and hundred seed weight (18.77 g/plant) as SSP and the lowest was in the control. Regarding evaluation of phosphorus use efficiency had more pronounced effects on combined application of SSP+PSBfollowed by RP+ PSB. Quality parameters viz., oil content, oil yield and crude protein content differ markedly among different treatments with the application of levels of phosphorus and bio-fertilizer.

Source Identification of Trace Elements in Peri-urban Soils in Eastern China

The source identification of trace elements in peri-urban soils has not been fully explored, especially for the areas in eastern China. Here, 80 soil samples, including 40 from cropland, 11 from orchards and 29 from forests, were collected in a typical peri-urban catchment, Ningbo, eastern China. The concentrations of arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb) and zinc (Zn), Pb isotopes and basic soil properties were measured for each soil sample. Multivariate analysis of correlation, regression, principal component analysis and isotopic tracers were used. The results showed that the concentrations of trace elements significantly differed based on land uses, especially for Cd, Cu and Zn. For the seven trace elements, the Cd, Cu and Zn in crop soils are contaminant elements. In the peri-urban soils, Cr and Ni are dominated by parent material and paedogenic processes. Difference in As and Pb concentrations between land uses maybe attributed to atmospheric deposition induced by fossil fuel combustion. Applications of fertilisers, calcium phosphate and calcium superphosphate, livestock manure and compost, are the dominant sources of pollutants in peri-urban soils, especially for Cd, Cu and Zn, indicating the key point for pollution control for this area. Calcium and P are effective indicators of Cd, Cu and Zn contamination for the peri-urban catchment.

Influence of phosphate amendment and zinc foliar application on heavy metal accumulation in wheat and on soil extractability impacted by a lead smelter near Jiyuan, China

Higher concentrations of Pb and Cd in wheat grains harvested in several lead-smelting-polluted areas in northern China have been reported. This field experiment was conducted to investigate the effect of phosphate amendment and Zn foliar application on the accumulation of Pb and Cd in wheat grains grown in a lead-smelting impacted area in Jiyuan in northern China. The soil (total Pb and Cd are 261 and 2.65mgkg-1, respectively) was amended with superphosphate at P:Pb ratios (mol:mol) of 1.90 or 2.57 either during wheat (Triticum aestivum L.) planting or a split of 60% of the phosphate applied at planting, with remaining 40% applied at the jointing stage. Zn was sprayed on the canopy of the wheat plants at the jointing stage. The phosphate amendment resulted in lower DTPA (diethylene triamine pentaacetic acid)-extractable Pb (1.39-10.7% lower than the control) and Cd (0.040-7.12%) in the soil. No significant effect of split application of phosphate was found on Pb and Cd availability in soil; however, higher rates of P resulted in lower Pb and Cd availabilities in the soil. Grain Pb (5.41-21.5% lower than the control), Cd (3.62-6.76%), and Zn (4.29-9.02%) concentrations were negatively affected by the phosphate application, with higher rates of phosphate resulting in lower grain heavy metal concentrations. Foliar application had no statistically significant influence on Pb and Cd concentrations in the grain (p > 0.05). Although Pb and Cd concentrations in wheat grains were reduced by the phosphate application, their concentrations were still much higher than the maximum permissible concentrations for wheat in the national standards of China. The results suggest that it is feasible to reduce wheat grain concentrations of Pb and Cd in Pb-smelting-polluted areas in northern China by soil application of superphosphate; however, the split application of the phosphate and the foliar application of Zn compounds do not have substantial impact on reducing accumulation of Pb and Cd in the wheat grains.

Response of three soils in the derived savanna zone of southwestern Nigeria to combined application of organic and inorganic fertilizer as affecting phosphorus fractions

Phosphorus inputs to the soil are primarily from the application of fertilizer P and organic resources. A ten week incubation study was carried out to determine the effects of organic and inorganic P sources on phosphorus fractions in three derived savanna soils. Poultry manure was applied at 0, 0.75g, 1.5g, 2.25g and 3g per 300g weight of soil while single superphosphate was applied at 0.0023g, 0.0046g, 0.0069g and 0.0092g per 300g of soil. Sampling was done at two weeks interval. At 0 week of the incubation study, Ekiti series had the largest amount of P fractions i.e. Fe-P, Al-P, residual P, reductant soluble P, occluded P, organic P and occluded P while Ca-P was high in Apomu series. However, increases in Fe-P, Al-P, Ca-P and organic P were observed in the three soil series evaluated and poultry manure was notably effective in reducing P occlusion. In conclusion, it was observed that irrespective of the soil series at different stages of the incubation studies, poultry manure and the combined application of poultry manure and Single superphosphate was highly effective in increasing P fractions.

Effect of Timing of Nitrogen and Potassium Application in Combination with Local Application of Calcium Superphosphate on the Growth and Yield of Direct-seeded Onions (<i>Allium cepa</i> L.)

Effect of Timing of Nitrogen and Potassium Application in Combination with Local Application of Calcium Superphosphate on the Growth and Yield of Direct-seeded Onions (<i>Allium cepa</i> L.)

Sorghum (Sorghum bicolor) physiology and phytomass in saline-sodic soil treated with amendments and single superphosphate

This study aimed to evaluate the physiology and phytomass accumulation of sorghum plants, in saline-sodic soil treated with amendments and doses of single superphosphate. The experiment was conducted in the period from January to June 2013, in a greenhouse in the municipality of Pombal, Paraiba, Brazil, using samples of a saline-sodic soil. The experimental design was randomized blocks, in a 2 x 5 factorial scheme, relative to two types of amendments of sodic soil and 5 levels of single superphosphate, with 3 replicates, totaling 30 experimental units. Each plot was represented by two pots with capacity for 2 dm3 with one plant each. At 30 days after sowing, sorghum plants were evaluated for gas exchanges, chlorophyll a fluorescence and phytomass accumulation. Single superphosphate application positively stimulated the gas exchanges of sorghum plants at the doses of 97.9 mg dm-3, for the soil treated with gypsum, and 88.1 mg dm-3, for the soil treated with elemental sulfur. Soil treatment with agricultural gypsum promoted the highest levels of chlorophyll a fluorescence, in comparison to elemental sulfur treatment. Phytomass accumulation was favored by the single superphosphate, with highest accumulation when the dose of 75 mg dm-3 was applied.

Effects of anabolic and catabolic nutrients on woody plant encroachment after long-term experimental fertilization in a South African savanna.

The causes of the worldwide problem of encroachment of woody plants into grassy vegetation are elusive. The effects of soil nutrients on competition between herbaceous and woody plants in various landscapes are particularly poorly understood. A long-term experiment of 60 plots in a South African savanna, comprising annual applications of ammonium sulphate (146–1166 kg ha-1 yr-1) and superphosphate (233–466 kg ha-1 yr-1) over three decades, and subsequent passive protection over another three decades, during which indigenous trees encroached on different plots to extremely variable degrees, provided an opportunity to investigate relationships between soil properties and woody encroachment. All topsoils were analysed for pH, acidity, EC, water-dispersible clay, Na, Mg, K, Ca, P, S, C, N, NH4, NO3, B, Mn, Cu and Zn. Applications of ammonium sulphate (AS), but not superphosphate (SP), greatly constrained tree abundance relative to control plots. Differences between control plots and plots that had received maximal AS application were particularly marked (16.3 ± 5.7 versus 1.2 ± 0.8 trees per plot). Soil properties most affected by AS applications included pH (H2O) (control to maximal AS application: 6.4 ± 0.1 to 5.1 ± 0.2), pH (KCl) (5.5 ± 0.2 to 4.0 ± 0.1), acidity (0.7 ± 0.1 to 2.6 ± 0.3 cmol kg-1), acid saturation (8 ± 2 to 40 ± 5%), Mg (386 ± 25 to 143 ± 15 mg kg-1), Ca (1022 ± 180 to 322 ± 14 mg kg-1), Mn (314 ± 11 to 118 ± 9 mg kg-1), Cu (3.6 ± 0.3 to 2.3 ± 0.2 mg kg-1) and Zn (6.6 ± 0.4 to 3.7 ± 0.4 mg kg-1). Magnesium, B, Mn and Cu were identified using principal component analysis, boundary line analysis and Kruskal-Wallis rank sum tests as the nutrients most likely to be affecting tree abundance. The ratio Mn/Cu was most related to tree abundance across the experiment, supporting the hypothesis that competition between herbaceous and woody plants depends on the availability of anabolic relative to catabolic nutrients. These findings, based on more than six decades of experimentation, may have global significance for the theoretical understanding of changes in vegetation structure and thus the practical control of invasive woody plants.

Fertilization of Phaseolus vulgaris with the Tunisian rock phosphate affects richness and structure of rhizosphere bacterial communities

Tunisian rock phosphate (TRP) extracted from the region of Gafsa is one of the most promising rock phosphates for soil fertilization. Its appropriate use as a source of phosphate nutrition can substitute chemical fertilizers for sustainable agriculture. The main objective of this study is to investigate the impact of P fertilizers on soil bacterial communities in the rhizosphere of bean (Phaseolus vulgaris). Application of chemical triple superphosphate (TSP) or TRP at similar P rates induced a significant increase in alkaline phosphatase and fluorescein diacetate hydrolysis activities. T-RFLP analysis of 16S rDNA revealed that P fertilization affected soil bacterial richness. Application of TRP at the same P rate as TSP was characterized by the stimulation of Actinobacteria both in the rhizosphere and in the uncultivated soil. Some of these Actinobacteria are known by their ability to produce organic acids thus promoting the dissolution of calcium and phosphore. Another important feature was the stimulation of ‘mycorrhiza helper bacteria’ like Comamonadaceae, Bradyrhizobacteriaceae and Oxalobacteraceae and other plant growth promoting bacteria such as Enterobacteriaceae and Pseudomonodaceae. These bacteria may contribute to the solubilization of phosphate through the production of organic acids (i.e., citric acid) and phytohormones (i.e., indol acetic acid) that stimulate plant root development and help P uptake by increasing the absorptive surface area. However, many putative plant growth promoting bacteria (mainly Sphingomonadaceae and Rhizobiaceae) were found to be inhibited by the chemical TSP fertilizer.

EFFECT OF ROCK PHOSPHATE AND SUPERPHOSPHATE APPLICATION ON MOBILITY OF ELEMENTS (Cd, Zn, Pb, As, Fe, Mn) IN CONTAMINATED SOILS

Weakly acidic Litavka and alkaline Mal n soils are some of the most contaminated soils by multiple risk elements in the Czech Republic. The aim of this paper was to determine the effect of P sources (rock phosphate, superphosphate), each applied at three rates on the mobility of risk elements (Cd, Zn, Pb, As) and micronutrients (Fe, Mn) in soils and to compare their effectiveness with lime and dolomite tested in our previous study. In 7, 14, 28, and 42 days, we determined CaCl2-extractable and acid-extractable concentrations of elements by ICP-OES. In alkaline soil, there was an increase in Cd, Zn, As, and Mn CaCl2-and acid-extractable concentrations after superphosphate application but no effect on concentrations of these elements after rock phosphate application. In acidic soil, there was a decrease in CaCl2-extractable concentrations of Cd and Zn and no effect on CaCl2-extractable Pb, As, Fe, and Mn after rock phosphate application. With the exception of a decrease in Pb and Mn, the same trends were recorded for acid-extractable concentrations. Superphosphate was less effective than rock phosphate for immobilisation of CaCl2-extractable Zn, As, and Mn. Phosphate additives were ineffective for immobilisation of all tested elements in alkaline soils. In acidic soils, phosphate additives were ineffective in immobilising As and Fe compared to lime application and were substantially less effective in Cd and Zn immobilisation than lime. Superphosphate application was a suitable measure to decrease acid-extractable Pb concentrations only in acidic soils at higher rates and was comparable with lime application at lower rates.

Assessment of Penicillium bilaii inoculation in wheat (Triticum aestivum L.) for improving growth, yield and phosphorus availability in Mollisols of India

A field experiment was carried out with an aim to study the influence of two strains of Penicillium bilaii (PB -201 and PB-208) inoculation along with superphosphate application on growth, yield and P uptake of wheat (cv. PBW-343) and, also to examine the inoculation effect on P availability, forms of P and soil properties in Mollisols of Uttarakhand, India. The results showed that both strains of P. bilaii effectively solubilized tri-calcium phosphate in Pikovskaya agar medium, which was much higher over native fungal isolates. Wheat seed inoculation with P. bilaii strains along with superphosphate levels significantly influenced shoot height, shoot dry weight, number of total and effective tillers, yield attributes, yield components, tissue content and uptake of P. The treatment T7 (P. bilaii, strain PB-208 + 50% P) has resulted into the highest amount of shoot height (87.9 cm at 90 DAS), shoot dry weight (1.5 and 3.8 g at 60 and 90 DAS, respectively), grain (66.8 q ha-1) and straw yield (42.7 q ha-1) and P uptake (26.5 kg ha-1). The Olsen-P, organic carbon, dehydrogenase activity and fungal populations also increased in soil inoculated with P. bilaii strains combined with superphosphate application compared to the control soil. The conjoint use of the fungal strains with or, without P fertilization has developed an antagonistic interaction that has caused decline in yield, tissue content and uptake of P and its availability in soil. In conclusion, it is possible to reduce the rate of soluble P-fertilizer added by 50% without reducing yield, if wheat is inoculated with P-solubilizing fungi like P. bilaii.

The content of available mineral phosphorus compounds in chestnut soils of Northern Mongolia upon application of different forms of phosphorite

The effect of different forms of phosphorite (activated and crude ground) of the Burenkhansk deposit on the phosphate status of chestnut soils and the productivity of spring wheat was studied in Northern Mongolia. It was found that the transformation of mineral soil phosphates upon the application of activated phosphorite (together with NK) is similar to that upon superphosphate application, and the available phosphorus concentration is even a gradation higher. The application of crude ground phosphorite helped to preserve the content of mineral phosphates in the soil at the initial level. Optimum concentrations of available phosphorus and the sum of loosely bound and calcium phosphates in the plow horizon were estimated 33–35 mg/kg) and 16–18 mg/100 g, respectively. Under these concentrations, high and sustainable yields of spring wheat were obtained upon application of activated phosphorite.

Aluminium uptake and translocation in Al hyperaccumulator Rumex obtusifolius is affected by low-molecular-weight organic acids content and soil pH.

Background and AimsHigh Al resistance of Rumex obtusifolius together with its ability to accumulate Al has never been studied in weakly acidic conditions (pH > 5.8) and is not sufficiently described in real soil conditions. The potential elucidation of the role of organic acids in plant can explain the Al tolerance mechanism.MethodsWe established a pot experiment with R. obtusifolius planted in slightly acidic and alkaline soils. For the manipulation of Al availability, both soils were untreated and treated by lime and superphosphate. We determined mobile Al concentrations in soils and concentrations of Al and organic acids in organs.ResultsAl availability correlated positively to the extraction of organic acids (citric acid < oxalic acid) in soils. Monovalent Al cations were the most abundant mobile Al forms with positive charge in soils. Liming and superphosphate application were ambiguous measures for changing Al mobility in soils. Elevated transport of total Al from belowground organs into leaves was recorded in both lime-treated soils and in superphosphate-treated alkaline soil as a result of sufficient amount of Ca available from soil solution as well as from superphosphate that can probably modify distribution of total Al in R. obtusifolius as a representative of “oxalate plants.” The highest concentrations of Al and organic acids were recorded in the leaves, followed by the stem and belowground organ infusions.ConclusionsIn alkaline soil, R. obtusifolius is an Al-hyperaccumulator with the highest concentrations of oxalate in leaves, of malate in stems, and of citrate in belowground organs. These organic acids form strong complexes with Al that can play a key role in internal Al tolerance but the used methods did not allow us to distinguish the proportion of total Al-organic complexes to the free organic acids.