Phosphate-dissolving Bacteria Research Articles

Influence of the use of remediated soil and agricultural drainage water on the safety of tomato fruits

The objective of this study is to assess the effectiveness of different techniques employed in remediating contaminated soil and wastewater ecosystems to ensure the safety of tomato fruits (Solanum lycopersicum L. var. cerasiforme) cultivated in these environments. Three biochemical techniques T1–T3, besides two controls CCU and CCT, were used to remediate contaminated soil ecosystems using rock phosphate, elemental sulfur, bentonite, phosphate-dissolving bacteria, and Thiobacillus sp. The contaminated agricultural drainage water was remediated by a down-flow hanging sponge (DHS) system. Two experiments were conducted: a pot experiment took place in the greenhouse at the National Research Center of Cairo (Egypt) and a field experiment was carried out at the basin site in the village of El-Rahawy, applying the optimal treatment(s) identified from the greenhouse experiment. The health risk assessment for potentially toxic elements (PTEs) in the harvested tomato fruits was conducted by calculating estimated daily intake (EDI) and target risk quotient (THQ) values. Results from the greenhouse experiment indicated the high effectiveness of the DHS technique in remediating El-Rahawy agricultural drainage water. The content of PTEs after remediation was significantly reduced by 100%, 93.3%, 97.8, and 77.8% for cadmium, copper, manganese, and zinc, respectively. The application of treated drainage water in employed reclaimed soil ecosystems led to a remarkable decrease in PTE levels, especially under T3 treatment; the reduction reached 89.4%, 89.5%, and 78.4% for nickel, copper, and zinc, respectively. The bioremediation technique also reduced the content of PTEs in tomato fruits harvested from both greenhouse and field experiments; the cadmium content, for example, was below detection limits in all treatments. The T3 treatment applied in the greenhouse experiment caused the highest percentage decrease among the employed PTEs in tomato fruits grown in the greenhouse. The same trend was also reached in the field experiment. Microbiological analyses of tomato fruits revealed that E. coli, Salmonella, or S. aureus bacteria were identified on tomato fruits harvested from either greenhouses or field experiments, showing that the counted total bacteria were higher under the field experiment compared to the greenhouse experiment. The health risk assessment parameter THQ was below 1.0 for all tested metals under all treatments. This means that no potential health risk is expected from consuming tomato products produced under the different employed remediation treatments. In conclusion, the employed bioremediation techniques successfully reduced the PTE content and microbial load in both soil and drainage water ecosystems and in harvested tomato fruits. Henceforth, no health risks are expected from the consumption of this product.

The Effect of Local Bio Fertilizer and Their Enzymatic Activity on Growth of Maize Plant and some Biological Therites in the Soil

The pots experiment was carried out in green house which belong to the Department of horti culture and Engineering,College of Agriculture, University of Anbar, to study the effect of locally prepared biofertilizers and their enzymatic activity on the growth of maize (Al Maha gender) and the activity of phosphatase, protease, glucosidase, urease, respiratory efficiency, and survival of nitrogen-fixing and phosphate-dissolving bacteria in the soil and some Morphological and physiological characteristics of corn plant, during the spring agricultural season of 2022. The experiment included testing 5 isolates with doubled combinations of isolates: Azotobacter chroococcum, Bacillus megaterium, Azosprillum lipoferum, Pseudomonas putida, Actinomycetes.There were 16 treatments with control treatment (without addition). The treatment A. chroococcum + Az. lipoferum has the highest content of total nitrogen in the soil and in the presence of maize after 60 days reach to 185 mg N kg−1 followed by Az lipoferum treatment at a rate of 177 mg N kg−1, while the lowest nitrogen content in the control treatment was 65 mg N kg−1, and the B. megaterium + P. putida treatment excelled with the highest phosphorus content of 13.65 mg P kg−1, it was found that the bacterial number in the soil reach the highest level in the treatment of B.megaterium + P. putida with the highest level of cfu g−1 soil reach to 3.3*10 7 of cfu g−1 soi.

Fixating lead in coal gangue with phosphate using phosphate-dissolving bacteria: Phosphorus dissolving characteristics of bacteria and adsorption mechanism of extracellular polymer

Controlling and preventing lead pollution is currently the focus of environmental remediation. Coal gangue contains large quantities of lead, and its environmental impact cannot be ignored. This study investigated the tolerance of Stenotrophomonas maltophilia (YZ-1 train) to lead ion and its fixation effect on lead in coal gangue. The fixation mechanism of lead ions by using the YZ-1 train was studied with CaHPO4 and Ca3(PO4)2. The tolerance mechanism and fixation characteristics of the three bacterial extracellular polymers and cell components to lead were analyzed. The results show that the YZ-1 train had a strong resistance to lead ions. The amount of lead released from coal gangue can be reduced by up to 91.1% upon treatment with the YZ-1 train, which can dissolve phosphate minerals to form stable hydroxyapatite (Pb5(PO4)3(OH)) and pyromorphite (Pb5(PO4)3Cl) with lead ions. Tryptophan and tyrosine from cellular components and extracellular polymers with loosely and tightly bound proteins are the main participants in the fixation of lead ions. The by-products of soluble microbes affect the fixation of lead ions in soluble extracellular polymers. The carboxylic acids and carboxylates secreted by bacteria are involved in the adsorption and fixation of lead ions.

The effect of fermentation of organic solid waste with C:N ratios with phosphate rock reinforcement on its biorecycling

A solid waste of organic materials was collected from the residential neighborhoods of Ramadi during 2017. To convert these wastes into valuable organic fertilizers resources that reduces their negative impacts. The study included two mixtures of collected solid waste of organic materials. The first mixture, involved preparing sample has Carbone over nitrogen ration of 40:1 prepared from the collected organic materials. While the second mixture had C/N of 30:1 by supporting the mixture with urea. The prepared mixtures were inoculated as percentage of its weight w/w with 5%( (organic waste: soil) using agricultural soil taken from 60 cm depth and the fermentation was completed aerobically for 40 days. The second stage of fermentation included application of 0,10 and 20 % of phosphate rock to the products of the first stage of fermentation. The results show reducing the concentration of carbon and increasing the concentration of nitrogen in the components of the mixtures. Regarding the interaction treatment of 30:1(C/N) with 20% RP recorded the lowest carbon concentration and the highest amount of fulvic acid 342 and 13.3 g. kg-1 respectively, the same mixture with no phosphate application gave the highest rate of N and humic acid reached 29.9 and 24.2 g. kg-1, respectively. The interaction treatment of 30:1 with 20% gave the highest average density of phosphate-dissolving bacteria reached 6.25 Logcfu.g-1, while 40: 1 with 10% RP gave the highest number of BFN bacteria reached 6.75 Logcfu.g-1. However, 40: 1 with no phosphate application gave the highest rate of formation of phenolic acids reached 8.8 g.kg-1, while the highest average amount of dissolved phosphorous was 9.69 g. kg-1 obtained from the treatment of 30:1 treated with 20% RP.

ASSESSING THE REMEDIATION OF A CONTAMINATED SOIL ECOSYSTEM WITH SOME RECENT CHEMO BIOLOGICAL TECHNOLOGIES THROGH BIOREMEDIATION INDEX

In a soil ecosystem irrigated with low-quality water out at El-Rahway village, Giza Governorate, Egypt, a completely randomized field trial was carried out to assess the suitability of some soil biochemical remediation technologies on minimizing the inorganic contaminants hazards, their bioavailability as well as the relationship between potential toxic elements (PTEs) distribution in remediated soil ecosystem, the bioavailability index (BI) and pollutants uptake by cultivated hyperaccumulated plants. Turnip Brassica rapa and radish Raphanus sativus were separately cultivated in the contaminated after being enriched with elemental sulfur (T1), elemental sulfur fortified with a mixture of Thiobacillus Thiooxidans and Thiobacillus ferrooxidans (T2), rock phosphate impregnated with phosphate dissolving bacteria (PDB) (T3), bentonite inoculated with Pseudomonas fluorescence (T4), kaolinite associated with Pseudomonas fluorescence (T5), sulfur mixed with rock phosphate and inoculated with a mixture of Thiobacillus thiooxidans, Thiobacillus ferrooxidans and phosphate dissolving bacteria (PDB) (T6), a mixture of bentonite and kaolinite inoculated with Pseudomonas fluorescence (T7) and a combined mixture of bentonite, kaolinite and rock phosphate inoculated with Pseudomonas fluorescence and phosphate dissolving bacteria (PDB) (T8), as well as control treatments represented by cultivated untreated soil ecosystem.Results implied that the concentration of most contaminants was found in F6 (Residual form) in control cultivated, decreased, T1, T2, and increased in the treatments supplied with modified clay minerals. Results also emphasized that T8 is the best management practice in the remediation of targeted inorganic contaminants grown in a contaminated soil ecosystem cultivated with radish or turnip plants that showed the lowest values compared to other trailed treatments. The combination of phytoremediation and chemo-biological techniques was very effective in minimizing the hazards of PTEs bioavailability and the distribution of the inorganic contaminants, and BI was verified to be promising tools in evaluating soil remediation.

Assessing the remediation of a contaminated soil ecosystem with some recent chemo biological technologies throgh bioremediation index

In a soil ecosystem irrigated with low-quality water out at El-Rahway village, Giza Governorate, Egypt, a completely randomized field trial was carried out to assess the suitability of some soil biochemical remediation technologies on minimizing the inorganic contaminants hazards, their bioavailability as well as the relationship between potential toxic elements (PTEs) distribution in remediated soil ecosystem, the bioavailability index (BI) and pollutants uptake by cultivated hyperaccumulated plants. Turnip Brassica rapa and radish Raphanus sativus were separately cultivated in the contaminated after being enriched with elemental sulfur (T1), elemental sulfur fortified with a mixture of Thiobacillus Thiooxidans and Thiobacillus ferrooxidans (T2), rock phosphate impregnated with phosphate dissolving bacteria (PDB) (T3), bentonite inoculated with Pseudomonas fluorescence (T4), kaolinite associated with Pseudomonas fluorescence (T5), sulfur mixed with rock phosphate and inoculated with a mixture of Thiobacillus thiooxidans, Thiobacillus ferrooxidans and phosphate dissolving bacteria (PDB) (T6), a mixture of bentonite and kaolinite inoculated with Pseudomonas fluorescence (T7) and a combined mixture of bentonite, kaolinite and rock phosphate inoculated with Pseudomonas fluorescence and phosphate dissolving bacteria (PDB) (T8), as well as control treatments represented by cultivated untreated soil ecosystem.

An integrated chemo- bio- mineral technology for agricultural drainage water remediation

ABSTRACT During the last decades, technologies for agricultural drainage water remediation had been widely explored to oppose the arising intimidation of their pollutants on health, biotas and farming sustainability. The present study targeted to augment the remediation competence of inorganic pollutants and faecal coliforms from agricultural drainage water using different types of clay minerals. Kaolinite, Bentonite, Ball clay and Aswan clay were used either solely or in amalgamation with some biological premeditative amendments (cultures of Phosphate dissolving Bacteria (PDB) and/or Acidithiobacillus sp.] for drainage water remediation of samples delivered from Belbies and Rahawy agricultural drains. Nineteen trails and four groups were implemented for each drain together with a control sample. Water samples were analysed before and after clay minerals’ trails application for detection of Cd(II), Cu(II), Ni(II), Zn(II) and As(V) by Atomic Spectroscopy. Total faecal bacteria presence was also quantified through direct culturing on MacConkey agar plates. The obtained results confirmed a significant decrease in the concentrations of Cd, Cu, Ni, Zn and As pollutants as well as a decrease in the faecal coliform intensities under all trailed treatments compared to control samples. Worthy to mention that 4th group and especially T18 (Bentonite + Acidithiobacillus+ phosphate dissolving bacteria) was the most efficient in minimising the hazards of PTEs and the existence of faecal microbes.

Effect of Humic Acid, Biofertilizers and Mineral Phosphate on Soil Microbial Activity and Productivity of Pea Plants under Toshka Conditions

Two field experiments were conducted during the winter season of 2015/2016 & 2016/2017, at Toshka Research Station - Desert Research Center. The aim of the study was to investigate the effect of humic acid (HA) at rates of 0, 4 and 8 kg / fed. combined with phosphate dissolving bacteria(PDB) and mineral phosphate fertilizer at rates of 100, 90, 80 and 70% P2O5 of the recommended dose in commercial production on pea plants. Treatment with humic acid at 8 kg / fed. combined with inoculation of PDB and 100% of mineral phosphate fertilizer significantly increased the total microbial count, Bacillus megaterium count, CO2 evolution , organic carbon and phosphatase and dehydrogenase enzymes activities. The bio-fertilizer treatments (PDB) showed a clear superiority when added in combination with the phosphate fertilizer and humic acid compared to the results of using a mixture of humic acid and superphosphate only. Adding of humic acid and superphosphate with the presence of phosphate dissolving bacteria improved most of the vegetative growth characteristics of plants. Yield components had the highest positive response to humic acid combined with mineral fertilizer percentage with phosphate-dissolving bacteria. The highest concentration of N, P, and K were with the use of humic acid at (8 kg), phosphate-dissolving bacteria and 100% phosphate fertilization P2O5. The study revealed that using 8 kg HA/fed in combination with PDB and high level of P2O5 as a fertilizer application to improve soil properties, vegetative growth, mineral content and yield of pea plants in new soils was recommended.

Absorption, translocation, and effects of Bt Cry1Ac peptides from transgenic cotton to the intercrops and soil functional bacteria

Insecticidal proteins encoded by the truncated genes from Bacillus thuringiensis (Bt) in transgenic crops are released into soil mainly through root exudate and crop residues. In the present study, Bt Cry1Ac protein was hydrolyzed by pronase that was secreted by the soil bacterium Streptomyces griseus. Six peptides were identified as the products of enzymatic hydrolysis by nano liquid chromatography tandem mass spectrometry (LC–MS/MS). One of the six peptides was labeled with radioactive isotope iodine-125 and then purified. The 125I-peptide solution was irrigated to the rhizosphere soil of watermelon seedlings (Citrullus lanatus L.) and wheat seedlings (Triticum aestivum L.), which the two crops usually intercrop with cotton in China. Detection of radioactivity in both plant tissues within one hour proved adsorption, uptake and translocation of the peptide into watermelon and wheat seedlings. Three of the identified peptides were sprayed onto the seedling leaves of watermelon, wheat and maize (Zea mays L.) in the field or the growth chamber. No significant effects on plant growth were observed. These peptides also did not affect growth of organic phosphate-dissolving, nitrogen-fixing, and potassium-dissolving bacteria in the culture. This study provides a new view of GMO risk assessment methodology.

Chemotaxis of Bacillus cereus YL6 and its colonization of Chinese cabbage seedlings

Phosphorus-solubilizing bacteria can colonize the surface of plant roots under natural conditions and may enter plant tissues to form endophytic symbiosis. They can convert unavailable phosphorus in the soil into available phosphorus, which can be utilized by plants. The aims of this study were to investigate the chemotaxis of Bacillus cereus YL6 and its migration and colonization sites in Chinese cabbage and to provide some technical support for the subsequent investigation of the physiological regulation mechanism of phosphate-dissolving bacteria in plants. This study demonstrated that the green fluorescent protein marker did not affect the physiological and biochemical properties of YL6. Through the chemotaxis test and pot experiment, the colonization and growth promoting mechanism of YL6 in Chinese cabbage was explored. YL6 showed a strong positive chemotactic response to cabbage roots. The addition of organic acids to the soil promotes the colonization of YL6 in Chinese cabbage roots. Colonization of YL6 in Chinese cabbage is a dynamic process that moves from the root surface to root tissues and then up to stems and leaves. Fluorescence microscopy showed that YL6 mainly colonized cortical cells and vascular bundles of various plant tissues and was also observed in mesophyll cells. The proliferative effect of YL6 resulted from the interaction of effective phosphorus, and exuded auxin and gibberellin in the rhizosheath. This study enhanced our understanding of the interaction mechanisms between phosphate-dissolving bacteria YL6 and Chinese cabbage. YL6 has the potential for future development into bio-fertilizer for agricultural production.

Agronomic Advancement in Nutrients Management for Sustaining Growth and Crop Contribution in Wheat ( Triticum aestivum L.)

Challenges of the coming few years lies in the debate that agriculture can provide the world population with food needs, which are annually exceed and shortage increased. Unprecedented pressure placing on agriculture researchers invited them to concentrate their efforts to achieve food security. Field experiments in Randomized complete block design (RCBD) with four replications were conducted to evaluate fertilizers management in winter wheat production. Treatments included nine combinations of prepared decaying compost using three types of manure as activators and NPK fertilizers, the treatments were dual replicated two times, one with seed inoculation with mixture of nitrogen fixer bacteria (Azotobacter) and Phosphate Dissolving Bacteria (PDB) (Pseudomonas sp.) and the others without seed inoculation. Based on the results obtained, poultry litter manure followed by camel and sheep exceeded cow manure in most of the studied characters. Moreover, mixing the three types of composts (5 and10-ton ha -1) with the half dose of chemical fertilizers could compensate the reduce dose of inorganic fertilizers, even the reduction equals the half dose, and recorded supervision effect in growth contribution, photosynthetic productivity, accumulation, grain yield, yield component parameters and protein percentage. However, insignificant differences were detected due to further increase the doses of the three types of manures. Seed inoculation with biofertilizers enhanced plants to better growth and yield performances. Lastly, it could be concluded that, recycling of agriculture wastes to compost and using it in combination with NPK fertilizers is acceptable option and an effective practice could produce greater yield production with better quality.

EFFECT OF MINERAL, ORGANIC AND BIO FERTILIZATION ON WHEAT PRODUCTION IN TWO DIFFERENT SOILS

Biological experiment was conducted in the clay and sandy soils to study the effect of inorganic, organic and bio fertilization on growth and yield components as well as N, P and K- uptake by wheat plants. Ammonium sulphate (N) was added at the rates of 25 [50% the recommended dose (RD)] and 50 (100% RD) mg N kg-1 soil, while ordinary superphosphate (P1) and rock phosphate (P2) were applied at the rates of 9.72 (50% RD) and 19.44 (100% RD mg P kg-1 soil. Potassium sulphate (K1) and feldspar (K2) were added at the rates of 20.8 (50% RD) and 41.5 (100% RD) mg K kg-1 soil. The organic materials i.e. clover straw (CS), sunflower seed teflon (ST) and banana peel (BP) were added at a rate of (0.5%). Some wheat grains were inoculated by biofertilizers i.e. nitrobein (nit), phosphate dissolving bacteria (PDB) and potassiumage (Pot). The results showed that the treatments of [50% RD (NP1K1) + CS + ST + BP + Nit + PDB + Pot] gave the greatest values of the straw and grains dry weight, biological yield and harvest index, N-uptake by grains and P- and K- uptake by straw and grains if compared to the other treatments in both soils under study. Wherease the highest 1000 grains weight was observed with the treatment of [50% RD (NP2K2) + CS + ST + BP + Nit + PDB + Pot] in the clayey soil and [50% RD (NP1K1) + CS + ST + BP] in the sandy soil compared to the other treatments. The greatest values of N- uptake by straw were recorded with treatments of [50% RD (NP1K1) + CS + ST + BP] in the clayey soil and [50% RD (NP1K1) + CS + ST + BP + Nit + PDB + Pot] in the sandy soil compared to the other treatments. Finally, it could be concluded that the use of 50% of the recommend dose of the most mineral fertilizers (NP1K1) mixed with organic materials (CS + ST + BP) and biofertilizers (Nit + PDB + Pot) may reduce the mineral fertilization (NP1K1) dose, production cost and environmental contamination.

Maximizing Efficiency of Rock Phosphate as a Source of P-Fertilization for Faba Bean (Vicia faba L.) Plant

A field experiment was conducted at the experimental farm of faculty of agricultural, Mansoura University, Dakahlia Governorate, Egypt during 2014 /2015 winter season to evaluate the efficiency of phosphate dissolving bacteria (PDB), sulphur (S), as well as foliar application of iron, zinc and Fe + Zn to enhance the availability of phosphorus from rock phosphate and their effects on vegetative growth parameters, chemical composition, yield and yield components of faba bean seeds cv. Giza 461. Twenty treatments were arranged according to complete randomized block design (CRBD) with three replicates; which were the sample possible combination between five treatments as soil addition (super phosphate (SP) , rock phosphate (RP), RP + phosphate dissolving bacteria (PDB) , RP + sulphur (S) and RP + PDB + S) and four spraying treatments; (1) spraying with tap water , (2) spraying with iron at the rate of Fe 300 mg/L, (3) spraying with zinc at the rate of Zn 100 mg/L, (4) spraying with solution containing 300 and 100 mg/L of Fe and Zn thus, the total number of the experimental plots were 60 plots. The results indicated that the highest values of vegetative growth (plant height , fresh and dry weight , chlorophyll a , chlorophyll b , chlorophyll a + b), yield and yield components (number of flowers. plant-1, number of pods. plant-1, fruit setting % , weight of pods. plant-1, 100-seeds weight and seed yield) of faba bean plant as well as nitrogen , phosphorus , potassium and protein contents in faba bean seeds were significantly increased for the plants treated with rock phosphate + PDB + S + (Fe + Zn) as compared to those obtained from the treatment of rock phosphate in single form except Fe content in faba bean seeds, the highest values were recorded when faba bean plants were treated with rock phosphate + PDB + S + Fe, but had no significant effect on K content. Faba bean seeds decreased significantly in their content of Zn as a result of the applied treatments. So, the lowest Zn content in faba bean seeds were recorded from (RP + PDB + S + Fe + Zn) compared with (RP + Zn) because of the dilution caused by growth response of P values which is known as P induced Zn deficiency. Generally, under the conditions of the present study, it can be concluded that adding RP mixed with PDB + S under sprayed of Fe 300 mg/L + Zn 100 mg/L may be the recommended treatment for enhancing the productivity of faba bean crop.

Characterization of Pantoea Sp. Strain MK1D, and Erwinia Sp. Strain MK2Y as Tricalcium Phosphate Dissolving Bacteria Isolated from Calcareous Soil

This study aimed to isolate and characterize bacterial strains capable of solubilizing tricalcium phosphate (TCP) as the most commonly and insoluble phosphate in soils. Normal and molecular approaches were used to isolate and characterize phosphate dissolving bacteria (PDB) adapted to arid and semi-arid climate conditions. In this study, two strains were successfully isolated and taxonomically classified as Pantoea sp. strain MK1D, and Erwinia sp. strain MK2Y based on sequences of their 16S rRNA gene and were given GenBank accession numbers KU358676 and KU358677, respectively. This was confirmed by the formation of large halo zones on both Pikovskaya (PVK) and National Botanical Research Institute's Phosphate (NBRIP) culture media. The significant bacterial growth on liquid media was associated with the reduction of pH from 7.0 to 2.0 which lead to 83% solubilization of added TCP of 0.75 g/L. This study confirmed that both PVK and NBRIP media were reliable and comparable for the isolation of PDB and measuring their efficiency. Further studies are needed to confirm the effectiveness of these strains under pot and field conditions and their potential for commercial biofertilizers production.

Heavy Metal and Phosphorus Contents of Jew's Mallow (Corchorus olitorius L.) Plants Grown on Soil Amended with Phosphate, Bio and Organic Fertilizers

This study was conducted to assess the impact of different chemical, organic and bio fertilizers on growth, phosphorus and heavy metal (Zn, Cd, Co, Cu and Ni) contents of Jew's mallow (Corchorus olitorius L.) plants. Pot and field experiments were carried out in the screen house and experimental farm, Faculty of Agriculture, South Valley University, Egypt in the summer season of 2013 and 2014, respectively. The experimental treatments included rock phosphate, superphosphate and triple superphosphate fertilizers singly or in combination with phosphate dissolving bacteria (PDB) and/or filter mud cake (FMC) as biological and organic amendment to the soil. They had a completely randomized design and complete block randomized design with three replications for pot and field experiment, respectively. The results of both experiments showed that, although the second and third cuts gave greater plant growth than that of the first cut, only the first cut of the plants received rock phosphate fertilizer either alone or in a combination with PDB and FMC or their mixture contained the lowest level of heavy metals. The results indicated that, only in the first cut with plants receiving rock phosphate fertilizer either alone or combined with PDB, FMC and PDB+FMC recorded the lowest Zn content values of 45.0, 56.0, 64.0 and 94.0 mg / kg, respectively which were below permissible limit, while the second and third cut Zn concentration in plants with different combination treatments was higher than the permissible levels. Also, rock phosphate treatment alone or with PDB in the first cut showed lowest plant Ni content (10 mg/kg) which on the border of the permissible level. The cobalt level in C. olitorius plants that received all phosphate fertilizer types (ranged from 7.0 to 16 mg/Kg) were below the permissible limit. The Cu level in investigated plants received all phosphate fertilizer types with different combination treatments with the three cuts were within the acceptable range. Also the results showed that plants grown on the soil amended with natural rock phosphate alone or in combination with phosphate dissolving bacteria recorded lowest Cd values. It is recommended to use the natural rock phosphate in combination with phosphate dissolving bacteria for growing Jew’s mallow plants instead of chemical phosphate fertilizers and the plants should be harvested by pulling the whole plant including roots from the soil after 40 days from planting to avoid high heavy metal uptake by the plants of the second and third cuts which had a possible health impacts.

IMPROVING THE EFFICIENCY OF INORGANIC PHOSPHORUS AS AFFECTED BY PHOSPHATE DISSOLVING BACTERIA UNDER CALCAREOUS SOILS

A filed experiment in split-split plot design was conducted on acalcareous soil at Nubaria Agriculture Research Station, El-BeheraGovernorate, Egypt, during the growing seasons of 2012/2013 and2013/2014 to study the effectiveness of seed inoculation by Bacillusmegaterium (as a phosphate dissolving bacteria (PDB)) on enhancementthe P availability and improvement use efficiency of many inorganicphosphorus forms and rates in soil to improve the production of fababean (Vicia faba L.) cultivar sakha 4 . Three fertilizer P forms namelyP1; single super phosphate 15.5% P2O5 (SSP), P2; triple super phosphate46% P2O5(TSP) and P3; phosphoric acid (H3PO4) 72.4% P2O5 (PA), at75% and 100% of recommended doses (45 kg P2O5 fed-1 RD).The results revealed that PDB inoculation increased theirpopulation in soil and significantly increased the availability of P incalcareous soil whether applied alone or combined with added P formscompared without it, where the treatments of TSP at 75 and 100% RDcombined with PDB gave the highest percentage (125.8, 136.4%) at the50 days age and the lowest percentage (50.9, 53.3%) at harvest,respectively. The results indicated to increase macronutrients uptake byfaba bean plants, which positively reflected on quantities and qualities ofyields. It can be concluded that adding TSP at 75% RD combined withPDB inoculation is the recommended for improving the productivity offaba bean crop, while the means values of seed yield relatively increasedabout with 41.4% over the same treatment without PDB and about 34.2,36.9% for PDB inoculation and TSP forms as individual effectrespectively. It was noticed that the PDB-inoculated seeds increasedphosphorus use efficiency (PUE), phosphorus agronomic efficiency(PAE) and phosphorus recovery efficiency (PRE) by about 33.04, 101.1and 138.1%, respectively over the uninoculated. Triple superphosphate(TSP) has the greater efficiency whether it was alone or combined withPDB inoculation at 75% RD addition compared to other forms.

Bio-chemical properties of sandy calcareous soil treated with rice straw-based hydrogels

Completely randomized drip irrigated field experiments, with three replications for each treatment, were conducted at El-Saff-Giza Governorate, Egypt to evaluate the beneficial effects of applying the rice straw (RS)-based hydrogels as soil conditioners for sandy calcareous soil. In this respect three successive growing seasons (summer season 2010 using tomatoes vs. custle rock, winter season 2010–2011 using wheat vs. Seds 1 intercropped with onion vs. Giza 20, and summer season 2011 using caw pea vs. Bafb as indicator crops) were carried out. Two rice straw-based hydrogels (with two rates; 2 and 4gkg−1 soil) were examined. After the third growing season some biochemical properties of the soil were determined.The results obtained show that, application of the investigated hydrogels positively affects bio-chemical properties of the soil. These effects are assembled in the following: (a) slightly decreasing soil pH, (b) increasing cation exchange capacity (CEC) of the soil indicating improvement in activating chemical reactions in the soil, (c) increasing organic matter (OM), organic carbon, total nitrogen percent in the soil. Because the increase in organic nitrogen surpassed that in organic carbon, a narrower CN ratio of treated soils was obtained. This indicated the mineralization of nitrogen compounds and hence the possibility to save and provide available forms of N to growing plants, (d) increasing available N, P and K in treated soil, and (e) improving biological activity of the soil expressed as total count of bacteria and counts of Azotobacter sp., phosphate dissolving bacteria (PDB), fungi and actinomycetes/g soil as well as the activity of both dehydrogenase and phosphatase.

Response of Prosopis chilensis to biofertilization under calcareous soil of RasSudr 1-Vegetative growth

A field experiment was carried out during two successive seasons, 2006 and 2007 on Prosopis chilensis at six month old transplants. Experiment was conducted in RasSudr Research Station, Desert Research Center, at South Sinai Governorate, Egypt. Aiming to study the effect of adding biofertilizers Bradyrhizobium spp., Azotobacter chroococcum, Bacillus megaterium and vesicular arbuscular mycorrhizae (VAM) as well as their interaction, viz. control (without microbial inoculation) on soil microbials counts, plant growth parameters, total chlorophyll and some chemical contents of leaves and branches. Results revealed that different biofertilizer treatments increased the microbial counts (total microbial counts, azotobacter, azospirilla, phosphate dissolving bacteria (PDB) and VAM), the growth parameters (plant height, stem diameter, initiative branching point, number of branches, fresh weight and dry weight) and some chemical constituents such as total chlorophyll, crude protein, crude fiber and ash% compared to untreated plants. Concerning to inoculate plants with biofertilizers interaction treatments, a mixture of bradyrhizobium, azotobacter, PDB and VAM was the most effective in raising the productivity of prosopis plants followed by triple inoculated treatments, then double inoculation treatments and finally single inoculation treatments compared to control treatment.

ENHANCING YIELD AND NUTRIENTS UTILIZATION VIA PHOSPHORIN SOIL INOCULATION AND MG FOLIAR APPLICATION TO PUMPKIN (Cucurbita moschata Duchesne) PLANTS GROWN IN SANDY CALCAREOUS SOIL

Inoculation with phosphorien-containing phosphate-dissolving bacteria (PDB) and/or foliar application of magnesium (Mg) at the rates of 0, 0.5 and 1 mM on the growth, some chemical constituents and fruit yield and yield quality of pumpkin (Cucurbita moschata Duchesne) grown on a sandy calcareous soil were investigated. Two field experiments (2012 and 2013) were performed in a completely randomized blocks design with six treatments, each with four replicates. The results indicated that PDB and/or Mg significantly increased stem length, canopy dry weight plant–1, number of leaves plant–1, total leaf area plant–1, leaf area leaf–1, leaf contents of pigments, free proline, nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca) and the ratio of Ca/Na, while leaf Na content was reduced. The application of PDB and/or Mg also increased fruit yield and yield quality (fruit length and diameter, flesh thickness, average fruit weight and fruit yield fed–1). It could be concluded that that PDB and Mg have pronounced positive effects on the growth, fruit yield and yield quality of pumpkin plants grown on sandy calcareous soil. PDB and Mg, therefore, have the potential to be used as a soil inoculation and foliar application, respectively for various crops to overcome the adverse effects of the newly-reclaimed sandy calcareous soils.

Significance of Some Soil Amendments and Phosphate Dissolving Bacteria to Enhance the Availability of Phosphate in Calcareous Soil

A field experiment was carried-out on a private farm at the Salah El-Din village, El-Bostan district, Nobaria, El-Behera Governorate, Egypt. The aim of this study was to evaluate the best combination of rock phosphate (RP), sulphur (S), organic manure, and phosphate dissolving bacteria (PDB) inoculation to enhance the availability of phosphorous from rock phosphate and their effects on yield of broad bean plants (cv. Luz doe Otono L.). It was found that either sulphur application or PDB inoculation with RP had a significant effect on broad bean yield and its quality. Application of RP and different soil amendments individually or together increased N, P, and K contents in straw and seeds of broad bean plant. The highest contents of the studied nutrients were found when the plants were fertilized by a mixture of RP and different soil amendments. Results also showed the important role of organic matter, sulphur, and PDB for releasing phosphorus from rock phosphate. The combination of soil amendments with RP as a natural P-source, has the possibility of saving significant quantities of industrialized inorganic phosphate fertilizers.