Effect Of Phosphate Solubilizing Bacteria Research Articles

Phosphate solubilizing bacteria, Pseudomonas aeruginosa, improve the growth and yield of groundnut (Arachis hypogaea L.).

For agricultural safety and sustainability, instead of synthetic fertilizers the eco-friendly and inexpensive biological applications include members of plant-growth-promoting rhizobacteria (PGPR) genera, Pseudomonas spp. will be an excellent alternative option to bioinoculants as they do not threaten the soil biota. The effect of phosphate solubilizing bacteria (PSB) Pseudomonas aeruginosa (MK 764942.1) on groundnuts' growth and yield parameters was studied under field conditions. The strain was combined with a single super phosphate and tested in different combinations for yield improvement. Integration of bacterial strain with P fertilizer gave significantly higher pod yield ranging from 7.36 to 13.18% compared to plots where sole inorganic fertilizers were applied. Similarly, the combined application of PSB and inorganic P fertilizer significantly influenced plant height and number of branches compared to sole. However, a higher influence of phosphorous application (both PSB and P fertilizer) observed both nodule dry weight and number of nodules. Combined with single super phosphate (100% P) topped in providing better yield attributing characters (pod yield, haulm yield, biomass yield, 1000 kernel weight, and shelling percentage) in groundnut. Higher oil content was also recorded with plants treated with Pseudomonas aeruginosa combined with single super phosphate (SSP) (100% P). Nutrients like nitrogen (N), phosphorous (P), and potassium (K) concentrations were positively influenced in shoot and kernel by combined application. In contrast, Ca, Mg, and S were found to be least influenced by variations of Phosphorous. Plants treated with Pseudomonas aeruginosa and lower doses of SSP (75% P) recorded higher shoot and kernel P. We found that co-inoculation with PSB and SSP could be an auspicious substitute for utilizing P fertilizer in enhancing yield and protecting nutrient concentrations in groundnut cultivation. Therefore, PSB can be a good substitute for bio-fertilizers to promote agricultural sustainability.

Effect of phosphate-solubilizing bacteria on growth and yield of Arachis hypogaea L. in varied soil types

Peanut (Arachis hypogaea L.) is widely cultivated both in monoculture and polyculture (usually with corn) on dry land in Madura. Generally, the soil types of Madura are grumusol, regosol, and mediterranean. These three types of soil each have different physical and chemical properties. The effect of the addition of phosphate-solubilizing bacteria on the three soil types is unknown. The study aimed to determine the response of peanut plant growth due to the addition of phosphate solubilizing bacteria, Pseudomonas fluorescens, in three different soil types. The research was conducted in the experimental garden of Agroecotechnology, Faculty of Agriculture, Universitas Trunojoyo Madura. The research design used a non-factorial completely randomized design (CRD) with six treatments and four replications. The treatment consisted of three types of soil, namely regosol, grumosol, and mediteran as well as with and without the addition of P. fluorescens. The results showed that the treatment had a significant effect on the parameters of plant height, number of leaves, number of pods, pod dry weight, seed weight, above-ground biomass, root dry weight, and plant P content. The treatment did not show a significant effect on the root-canopy ratio and P. fluorescens population parameters.

Effects of phosphate-solubilizing bacteria on phosphorus components, humus and bacterial community metabolism during spent mushroom substrate composting

To address the low conversion of effective phosphorus during previous studies on spent mushroom substrate (SMS) composting, phosphorus-solubilizing bacteria (PSB) were utilized to increase the effective phosphorus content in this study. The results demonstrated that PSB treatments exhibited higher temperature levels up to 66 °C. The TN, NH4+-N, and NO3−-N contents were higher than those of the control treatment (CK) by 9.01%, 50.01%, and 4.61%, respectively. Inoculation with PSB increased effective phosphorus, total phosphorus, and humus content in the SMS compost by 6.84%, 11.05%, and 9.10%. In addition, based on PICRUSt analysis, inoculation with PSB significantly promoted metabolic pathways associated with phosphorus conversion or the production of substances that can facilitate phosphorus conversion or phosphorus leaching, thus improving phosphorus utilization in compost. In conclusion, the addition of PSB can improve the bioavailability of P and the humus content in SMS compost to realize the green and sustainable development of the edible mushroom industry.

The Effect of Phosphate-Solubilizing Bacteria and IAA Producers from Cactus Rhizosphere on the Germination of Vigna sinensis L.

This study aims to examine the effect of phosphate-solubilizing bacteria and IAA producers on the germination of Vigna sinensis L. The bacteria were isolated from the cactus rhizosphere in Senteluk Village, Batulayar Subdistrict, West Lombok. The soluble phosphate was measured qualitatively and quantitatively. Qualitative measurement was based on the solubility of P in the growth medium (solid Pikovskaya) with a clear zone indicator around the bacterial colonies. The solubility of P (liquid Pikovskaya) and IAA production were measured using a spectrophotometer at wavelengths of 430 nm and 530 nm, respectively. In vitro testing of the effects of phosphate-solubilizing bacteria and IAA-producing bacteria on the germination of long beans (Vigna sinensis L.), specifically the Parade tavi variety, was conducted by soaking the long bean seeds in the bacterial suspension and then planting them on Murphy agar medium. The plant height, root length, fresh weight, and dry weight were measured and analyzed using One-Way ANOVA. The bacterial characterization included colony morphology, cell shape, and biochemical tests. The research results obtained 8 isolates that could solubilize phosphate in the low category while producing IAA and 2 other isolates that only produced IAA. Quantitative phosphate solubilization showed the highest soluble phosphate on days 4 and 6 of incubation. The highest IAA production (14.25 ppm) was achieved by the rhizosphere bacterial isolate with the code RK7. The results showed that there was an indication of the influence of phosphate solubilizing and IAA-producing bacteria isolated from the rhizosphere of cactus on Vigna sinensis L. germination, although not significantly different. This shows that local bacterial isolates are quite potential as a source of biofertilizer development in the future.

Effect of phosphate solubilizing bacteria and blue green algae on phosphorus uptake and its apparent recovery in hybrid rice

A pot experiment was conducted during kharif season of 2020 on sandy loam soil in texture to investigate the impact of phosphate solubilizing bacteria (PSB) and blue green algae (BGA) on P uptake and its apparent recovery in hybrid rice cultivation. Thirteen treatments laid in completely randomized design with two different doses of chemical fertilizers (100% and 75%), two isolates of PSB (Enterobacter cloacae strain BAU3 and Bacillus aryabhattai strain BAUMS8) and blue green algae had been used in the study. The P uptake and its apparent recovery increased significantly when supplied with 100% recommended dose of inorganic fertilizers (RDF) + PSB @ 750 ml ha-1 + BGA @ 10 kg ha-1 as compared to 100% RDF. The P uptake augmented from control treatment (T1) 23.09 kg ha-1 to 30.33 kg ha-1 in the treatment (T8) (100% RDF + PSB1 @ 750 ml ha-1 + BGA @ 10 kg ha-1) due to increase in the grain and straw yield and P concentration. The apparent recovery percentage was maximum in treatment T8 (100% RDF + PSB1 @ 750 ml ha-1 + BGA @ 10 kg ha-1) i.e. 13.63 per cent. Finally, it can be concluded that application of 100% RDF along with PSB @ 750 ml ha-1 + BGA @ 10 kg ha-1 significantly increased the P uptake and its apparent recovery in hybrid rice.

Effect of phosphate solubilizing bacteria and blue green algae on yield and NPK content in hybrid rice

A pot experiment was conducted during kharif season of 2020 on sandy loam soil in texture and classified as mixed hyperthermic typic haplustepts to investigate the impact of phosphate solubilizing bacteria (PSB) and blue green algae (BGA) on crop yield and NPK nutrient uptake in hybrid rice cultivation. Thirteen treatments laid in completely randomized design with two different doses of chemical fertilizers (100% and 75%), two isolates of PSB (Enterobacter cloacae strain BAU3 and Bacillus aryabhattai strain BAUMS8) and blue green algae had been used in the study. The grain and straw yield of hybrid rice and nutrient uptake in both grain and straw increased significantly when supplied with 100% recommended dose of inorganic fertilizers (RDF) + PSB @ 750 ml ha-1 + BGA @ 10 kg ha-1 as compared to 100% RDF. It had been observed that combined application of PSB and BGA along with 100% RDF, enhanced grain and straw yield upto 11.17 and 6.53 percent, respectively in comparison to 100% RDF. Increase in the concentration of grain and straw N in treatment T8 was 8.65% and 11.42%, respectively, when compared with treatment T2 (100% RDF). The concentration of grain P in treatment T8 were 5.80% when compared with treatment T2 (100% RDF) while the magnitude of increase in rice straw was 7.28 percent. A similar trend of result was obtained in the case of K content in grain and straw of hybrid rice but the K concentration was higher in straw. Finally, application of 100% RDF along with PSB @ 750 ml ha-1 + BGA @ 10 kg ha-1 significantly augmented the yield and nutrient content in hybrid rice.

Hyphosphere interactions between Rhizophagus irregularis and Rahnella aquatilis promote carbon-phosphorus exchange at the peri-arbuscular space in Medicago truncatula.

Arbuscular mycorrhizal (AM) fungi form a continuum between roots and soil. One end of this continuum is comprised of the highly intimate plant-fungus interface with intracellular organelles for nutrient exchange, while on the other end the fungus interacts with bacteria to compensate for the AM fungus' inability to take up organic nutrients from soil. How both interfaces communicate in this highly complex tripartite mutualism is widely unknown. Here, the effects of phosphate-solubilizing bacteria (PSB) Rahnella aquatilis dwelling at the surface of the extraradical hyphae of Rhizophagus irregularis was analysed based on the expression of genes involved in C-P exchange at the peri-arbuscular space (PAS) in Medicago truncatula. The interaction between AM fungus and PSB resulted in an increase in uptake and transport of Pi along the extraradical hyphae and its transfer from AM fungus to plant. In return, this was remunerated by a transfer of C from plant to AM fungus, improving the C-P exchange at the PAS. These results demonstrated that a microorganism (i.e., a PSB) developing at the hyphosphere interface can affect the C-P exchange at the PAS between plant and AM fungus, suggesting a fine-tuned communication operated between three organisms via two distantly connected interfaces.

Effects of Phosphate-solubilizing Bacteria on Soil Phosphorus Fractions and Supply to Maize Seedlings Grown in Lateritic Red Earths and Cinnamon Soils.

Phosphorus (P) is often the limiting factor for plant growth because of its low mobility and availability in soils. Phosphate-solubilizing bacteria (PSB) have been shown to increase the availability of soil P fractions, thereby promoting plant growth. We herein investigated the effects of PSB on P availability in two important Chinese soil types: Lateritic red earths (La) and Cinnamon soils (Ci). We initially isolated 5 PSB strains and assessed their effects on soil P fractions. PSB mainly increased moderately labile P in La and labile P in Ci. We then selected the most promising PSB isolate (99% similarity with Enterobacter chuandaensis) and examined its effects on P accumulation in maize seedlings. The results obtained showed that plant P accumulation increased in response to a PSB inoculation in both soil types and the combination of the PSB inoculation and tricalcium phosphate fertilization in La significantly enhanced P accumulation in plant shoots. The present study demonstrated that the PSB isolates tested differed in their ability to mobilize P from distinct P fertilizers and that PSB isolates have potential as a valuable means of sustainably enhancing seedling growth in Chinese agricultural soils.

Silicon improves the effect of phosphate-solubilizing bacterium and arbuscular mycorrhizal fungus on phosphorus concentration of salinity-stressed alfalfa (Medicago sativa L.)

Under salinity stress, the availability of soil nutrients to plants is reduced, leading to disruption of nutrition and the balance of plant nutrients, including phosphorus (P). The use of phosphate-solubilizing microorganisms (PSM) and silicon (Si) in alleviating salinity stress and improving the uptake of P by plants has become a global solution. However, there is limited information on the effect of phosphate-solubilizing bacteria and arbuscular mycorrhizal fungi in the combination with Si on improving the absorption of P by plants including legumes under salinity stress. In this study, the plant growth-promoting potential of an effective phosphate-solubilizing bacterial strain (R115), Microbacterium shaanxiense, and an arbuscular mycorrhizal fungus, Claroideoglomus etunicatum, alone or in the combination with Si to alleviate salinity stress in alfalfa inoculated with its rhizobial symbiosis, Ensifer meliloti N44, and improve the absorption of P by this plant was investigated by a pot-experiment in a completely randomized design with factorial arrangement in three repetitions. Experimental treatments included: Si factor at two levels of 0 and 4 mM Si from potassium silicate source, bacterial strain R115 factor at two levels of B0 (control), and strain R115 (B1), mycorrhizal fungus factor at two levels of F0 (control) and mycorrhizal fungus (F1), and salinity (saline water) factor at three levels of 0, 5, and 15 dS m−1. Salinity stress reduced plant biomass, the content of chlorophyll, the concentration of N, P and K of plant and increased the concentration of Na in shoot tissue and the activity of antioxidant enzymes (catalase and superoxide dismutase) in alfalfa plant. However, the use of PSM (M. shaanxiense R115 and C. etunicatum) and Si improved the morphological and physiological characteristics of the plant, reduced the plant Na concentration, and increased the concentration of N, P, and K of alfalfa plants. The highest improvement in plant growth indices (shoot P concentration) was recorded in plants inoculated with PSM in the presence of Si. The results of this study showed that Si fertilization can be suggested as a sustainable strategy for improving the plant growth promoting effects of PSM on the growth of alfalfa (e.g., increased shoot P concentration) and encouraging ecological adaptability of this plant under saline water irrigation.

Phosphate-solubilizing bacteria abate cadmium absorption and restore the rhizospheric bacterial community composition of grafted watermelon plants

The grafting of watermelon plants to rootstocks is common due to the strong capacity of rootstocks to adapt to abiotic and biotic stresses. However, the effect of phosphate-solubilizing bacteria (PSB) on grafted watermelon plant growth and bacterial structures in root soil is unclear. In this study, the growth and hormone levels of grafted plants were measured, and the bacterial communities under cadmium (Cd) stress and inoculation with PSB were sequenced in three treatments (S1, control; S2, 50 μmol Cd [CdCl2]; and S3, 50 μmol Cd plus inoculation with the Cd-resistant PSB strain ‘N3′). The results showed that inoculation with PSB significantly (P < 0.05) improved the total dry weight of the grafted plants. Typically, inoculation with PSB significantly (P < 0.05) reduced Cd content in scions and roots. The level of the phytohormone jasmonic acid increased in treatment S2, but decreased in treatment S3 under inoculation with PSB. The functional annotation of prokaryotic taxa showed that Cd decreased the abundance of nitrogen respiration and chloroplast functional groups. Nevertheless, inoculation with PSB helped restore bacterial community structures. These findings provide a new understanding of the effect of PSB on the promotion of seedling growth and bacterial communities in grafted watermelon plants under Cd stress.

Performance of Phosphate Solubilizing Bacteria in Tea (Camellia sinensis L.) Rhizosphere

A pot experiment was conducted to assess the effect of phosphate solubilizing bacteria (PSB) on the availability of applied P in acid soil using tea (Camellia sinensis L. var. CP-1) as test crop. Six strains of PSB (Bacillus firmus strain TPB-1, Burkholderia sp. strain TPB-33, Bacillus firmus strain TPB-38, Burkholderia sp. strain TPB-40, Burkholderia cepacia strain TPB-52 and Burkholderia sp. strain TPB-57) were used for inoculation using liquid and charcoal-based delivery system. To assess the effect of PSBs on P solubilization, bacterial inocula were used with and without rock phosphate (RP) application. Results indicated that maximum P-uptake (15.6 mg/pot) in tea shoot was recorded in case of inoculation with Burkholderia sp. strain TPB-57 using charcoal-based delivery system (T12-TPB 57C). As far as the crop response is concerned, the highest biomass yield of test crop (10.5 g/pot) was also recorded with T12-TPB 57C in the presence of RP. The study indicates that as far as P solubilization by PSB in tea rhizosphere is concerned, Burkholderia sp. strain TPB-57 is an efficient microbial genus.

Effect of phosphate-solubilizing bacteria on the gene expression and inhibition of bacterial fruit blotch in melon

Pathogenic bacteria Acidovorax avenae subsp. citrulli can cause bacterial fruit blotch (BFB) in melon (Cucumis melo L.). However, the process in which melon plant inoculated with biocontrol bacteria cope with A. citrulli invasion remains unclear. This study aimed to analyze the expression of genes involved in the BFB with a biocontrol strain through RNA sequencing. Results showed that the disease incidence of BFB was reduced by 57.1 % when melon was inoculated with antagonistic phosphate-solubilizing bacteria (PSB) Burkholderia sp. ‘N3’ strain. The plant height, dry weight, leaf area, and uptake of nutrients of melon seedlings increased after it was inoculated with two strains (‘N3’ and ‘M01’). The P content in TN (inoculated with ‘N3’) significantly increased by 17.48 % compared with the control (TR1). Fe3+ significantly increased in melon plant inoculated with ‘N3’ and ‘Pslb24’ and might play an important role in the suppression of BFB in melon. A total of 129 upregulated genes and 33 downregulated genes were involved in the resistance of melon to A. citrulli infection (TP2 versus TP1). Gene ontology analysis revealed that most differentially expressed genes were located in biological regulation, cell component organization, binding, and catalytic activity functions. Kyoto Encyclopedia of Genes and Genomes analysis illustrated that pathways related to cell cycle, ribosome biogenesis, plant hormone signal transduction, starch and sucrose, and signal transmission mechanisms were involved. These findings will be helpful to elaborate and uncover the expression of resistance genes involved in controlling BFB in melon inoculated with beneficial PSB.

Pengaruh Jenis Bakteri Pelarut terhadap Pertumbuhan dan Hasil Benih G3 Kentang (Solanum tuberosum L.) Varietas Medians.

This article aims to examine the effect of phosphate solubilizing bacteria (PSB) on the growth and yield of G3 seeds of potato (solanum tuberosum L.) varieties of medians. The experiment was conducted in the experimental garden of The Faculty of Agriculture of Winaya Mukti University Tanjungsari, Sumedang with a height of 850 meters above sea level with the order of land Andisol. Time trials are conducted from May to August 2019. The design used is a simple RandomIzed Group Design consisting of five types of phosphate Solubilizing bacteria, namely without PSB, Pseudacidovorax intermedius, Agrobacterium fabrum, Agrobacterium tumefaciens, Serratia nematodiphila and repeated five times each. The results of the experiment showed that the administration of this type of PSB was able to increase the height of the plant and the number of leaves at the age of 28 DAP and 42 DAP and give the result of the number of potatoes and the weight of the perpetak tubers on the potato crop of the medians varieties better.

Effects of phosphate-solubilizing bacteria on phosphorous release and sorption on montmorillonite

Most of P is fixed in pedosphere and lithosphere, i.e., not directly available to ecosystem. Interactions between phosphate-solubilizing bacteria and clay minerals contribute heavily to P biogeochemistry. In this study, hydroxylapatite (HAp), montmorillonite (Mt.) and Enterobacter sp. were applied to investigate their influences on P release, sorption, and transformation. Enterobacter sp. promoted the dissolution of HAp via secreting formic acid (pH declined from neutral to ~5.0). However, respiration of the bacteria with addition of Mt. was decreased by ~15.0% after their logarithm growth. SEM analysis also indicated that the number of Enterobacter sp. cells was significantly reduced on Mt. surface. Mt. was hence able to inhibit the activity of the adsorbed bacteria on its surface. Meanwhile, the mobile bacteria helped to transform HAp mineral to nanoparticles via partial dissolution. Despite the low sorption of mobile P anions (< 0.2 mg L−1), Mt. was able to adsorb plenty of HAp nanoparticles. The subsequently enhanced adsorption of P nanoparticles by Mt. protects the environment from P losses. Therefore, interaction of mobile bacteria and clay minerals have a positive feedback in regulating P transportation in long-term. This study elucidated the different roles of mobile and fixed bacterial cells in P biogeochemistry influenced by Mt.

Combining phosphorus (P) with phosphate solubilizing bacteria (PSB) improved wheat yield and P uptake in alkaline soil

Phosphate solubilizing bacteria can reduce dependence on chemical phosphorus (P) fertilizers by mineralizing and solubilizing indigenous soil P. What’s why, we assessed the interactive effect of phosphate solubilizing bacteria (with and without PSB) and phosphorus levels (60, 90 and 120 kg P2O5 ha-1) on P uptake and yield of wheat crop under field conditions. Two factorial randomized complete block design (RCBD) with three replications was used. The PSB inoculation significantly enhanced plant height (3%), 1000 grains weight (12%), grain (6%), biological (13%) and straw yield (18.5%) of wheat over control. Inoculation with PSB also significantly improved plant P concentration and uptake (26% each) over un-inoculated control. Similarly, with increasing application rates of P from 60 to 120 kg P2O5 ha-1 the tested parameter were significantly improved except straw yield. The interactive effect of PSB and P exhibited significant effect on 1000 grains weight while the rest of parameter didn’t respond significantly. However, generally PSB inoculation with P enhanced yield attributes and improved P use efficiency over sole application of P. Thus it may be concluded that PSB should be applied with P to enhance wheat yield and P use efficiency. Keywords: Alkaline soils; PSB inoculation; Phosphorus uptake; Wheat http://dx.doi.org/10.19045/bspab.2019.80124

The effect of phosphate solubilizing bacteria and organic fertilizer on phosphatase, available P, P uptake and growth sweet corn in andisols

This experiment conducted at the greenhouse of Agriculture Faculty, Universitas Padjadjaran, Jatinangor, West Java, Indonesia elevated at ± 782 m above sea levels. The aim of this experiment is to determine the effect of phosphate solubilizing bacteria and organic fertilizer on the phosphatase, P available, P uptake, and growth of sweet corn which planted on Andisols from Lembang, West Java, Indonesia. The Randomized Block Design (RBD) was used in this experiment with twelve treatments and three replications. The treatments were three isolates (Bacillus mycoides, Bacillus maceransand Pseudomonas pseudoalcaligenes) combined with organic fertilizers: cow manure and green manure. The result shows that phosphate solubilizing bacteria and organic fertilizer significantly increased the soil phosphatase and P-available. The treatments did not have a significant effect on the growth of sweet corn on Andisols. The isolate of P. pseudoalcaligenes combined with green manure gave the highest to soil available P.

Effect of Phosphate-Solubilizing Bacteria on the Mobility of Insoluble Cadmium and Metabolic Analysis.

Phosphate-solubilizing bacteria (PSB) can promote plant growth by dissolving insoluble phosphate. Therefore, PSB may have the potential to improve the mobility of heavy metals in soils and enhance phytoextraction. This study isolated a few PSB strains that could dissolve CdCO3 and solid Cd in soil. Two typical PSB, namely, high- and low-Cd-mobilizing PSB (Pseudomonas fluorescens gim-3 and Bacillus cereus qh-35, respectively), were selected to analyze the metabolic profiles, metabolic pathways, and mechanisms of mobilization of insoluble Cd. A total of 34 metabolites secreted by the two PSB strains were identified. Gluconic acid was the main contributor to Cd dissolution (42.4%) in high-Cd-mobilizing PSB. By contrast, gluconic acid was not secreted in low-Cd-mobilizing PSB. Metabolic pathway analysis showed that gluconic acid was produced by the peripheral direct oxidation pathway. Hence, PSB with peripheral direct oxidation pathway were likely to have high-Cd-mobilizing capacity.

Comparison of Response of Canola (Brassica napus L. cv Hyola 401) to Biofertilizer Inoculation in Optimal and Delayed Cropping Dates

In order to compare the effects of phosphate solubilizing bacteria as biofertilizer and mineral phosphorous application in optimal date of sowing with delayed cropping date on canola (Brassica napus L.) growth and productivity, a split-plot experiment using randomized complete block design with three replications was conducted at Dasht-e-Naz Agronomy Research Station in 2014. Four levels of bacterial inoculation (Pseudomonas putida, Pseudomonas fluorescens, singly or in combination) were applied as main plots and five levels of mineral phosphorous application (0, 25, 50, 75, and 100 kg/ha of mineral phosphorous) were applied as sub plots. Canola plant were sown at two dates of sowing, one at optimal date of sowing (Sept. 30, 2014) and the other one month later as delayed cropping (Oct. 30, 2014). The results obtained showed that effects of bacterial inoculation on number of seeds per pod, number of pods on plant, and seed yield were significant at one percent probability level at both sowing dates. Moreover, rates of phosphate application had significant effects on all traits at one percent level. Comparing the means showed that application of mineral P resulted in substantial increase in seed yield. At optimal date of sowing, it was shown that while minimum seed yield obtained at control treatment (1600 kg/ha), the maximum (2980 kg/ha) obtained with interaction effects of application of both bacterial strains along with 75 kg/ha mineral P, having no statistically difference with that of P. fluorescence along with 75 kg/ha mineral P (2940 kg/ha). It was shown that delayed cropping resulted in decreasing canola growth which is reflected in seed yield and yield components. Minimum seed yield at control plot at first date of sowing (1600 kg/ha) decreased to 740 kg/ha in second date of sowing, showing 54% decrease. The maximum seed yield also decreased in delayed cropping, from 2980 kg/ha at Sept. 30, 2014 as compared to 1074 kg/ha at Oct. 30, 2014, showing a 64% decrease. The results obtained showed that an increase in P level, eventually enhanced the seed yield. This increasing trend continued until a threshold level (75 kg/ha of P), after which seed yield showed a declining fashion.

Effect of phosphate-solubilizing bacteria on phosphorus dynamics and the bacterial community during composting of sugarcane industry waste

Sugarcane processing generates a large quantity of residues, such as filter cake and ashes, which are sometimes composted prior to their amendment in soil. However, important issues still have to be addressed on this subject, such as the description of bacterial succession that occurs throughout the composting process and the possibilities of using phosphate-solubilizing bacteria (PSB) during the process to improve phosphorus (P) availability in the compost end product. Consequently, this study evaluated the bacterial diversity and P dynamics during the composting process when inoculated with Pseudomonas aeruginosa PSBR12 and Bacillus sp. BACBR01. To characterize the bacterial community structure during composting, and to compare PSB-inoculated compost with non-inoculated compost, partial sequencing of the bacterial 16S rRNA gene and sequential P fractionation were used. The data indicated that members of the order Lactobacillales prevailed in the early stages of composting for up to 30 days, mostly due to initial changes in pH and the C/N ratio. This dominant bacterial group was then slowly replaced by Bacillales during a composting process of up to 60 days. In addition, inoculation of PSB reduced the levels of Ca-bound P by 21% and increased the labile organic P fraction. In PSB-inoculated compost, Ca–P compound solubilization occurred concomitantly with an increase of the genus Bacillus. The bacterial succession and the final community is described in compost from sugarcane residues and the possible use of these inoculants to improve P availability in the final compost is validated.

Effects of phosphate-solubilizing bacteria application on soil phosphorus availability in coal mining subsidence area in Shanxi

ABSTRACTThe effect of phosphate-solubilizing bacteria (PSB) application on phosphorus (P) availability in reclaimed soil in coal mining subsidence region was investigated. Seven treatments were carried out including control, chicken manure (CM), PSB, PSB + tricalcium phosphate (TCP), CM + TCP, PSB + ground phosphate rock (GPR) and CM + GPR. The results showed soil Olsen-P concentration and phosphatase level as well as the yield of pakchoi (Brassica chinensis L.) were significantly higher in PSB application treatments compared to the corresponding CM application treatments. Soil phosphatase, invertase and urease contents were increased most significantly in PSB treatment, 1.18-, 1.31- and 2.32-fold higher than those in the control, respectively. Soil Ca2-P, Ca8-P, Fe-P and Al-P concentrations exhibited the greatest increases in PSB + TCP treatment, while occluded-P showed minor changes in different treatments. Application of PSB fertilizer reduced the transformation of Olsen-P to Ca10-P, thus increasing P availability in reclaimed soil of coal mining subsidence area.