Increased Plant Yield Research Articles

PLL-based Enhanced Control of Boost PFC Converter for Smart Farming Lighting Application

Controlled environment farming has become an attractive solution to increase the food production with limited use of resources. LED lights are often used in this type of farming to increase plant yield. LED lights are dc load, whereas the grid provides ac power. This necessitates the use of power factor correction (PFC) converter as an interface between the grid and the lights. This paper proposes an innovative control method for the boost PFC converter, where an advanced phase-locked loop scheme is developed that can eliminate measurement dc offset and provide harmonic robust estimation of the grid voltage fundamental component. The applied nonlinear control uses the existing two-loop control architecture. Based on a baseline PI controller, a nonlinear function is added to make the controller react faster when it is far from the reference and vice-versa. Comprehensive simulation studies are conducted to assess the performance of the proposed method under various challenging test scenarios. Compared to the baseline method, the proposed technique achieved 42%∼65% reduction in total harmonic distortion depending on the test cases, which makes the technique a suitable candidate for improving the operational efficiency and, consequently, the running cost of a smart farming lighting system on an industrial scale. Results show the effectiveness of the proposed method over the conventional counterpart.

Continuous Cropping Inhibits Photosynthesis of Polygonatum odoratum.

Polygonatum odoratum (Mill.) Druce possesses widespread medicinal properties; however, the continuous cropping (CC) often leads to a severe consecutive monoculture problem (CMP), ultimately causing a decline in yield and quality. Photosynthesis is the fundamental process for plant growth development. Improving photosynthesis is one of the most promising approaches to increase plant yields. To better understand how P. odoratum leaves undergo photosynthesis in response to CC, this study analyzed the physiochemical indexes and RNA-seq. The physiochemical indexes, such as the content of chlorophyll (chlorophyll a, b, and total chlorophyll), light response curves (LRCs), and photosynthetic parameters (Fv/Fm, Fv/F0, Fm/F0, Piabs, ABS/RC, TRo/RC, ETo/RC, and DIo/RC) were all changed in P. odoratum under the CC system. Furthermore, 13,798 genes that exhibited differential expression genes (DEGs) were identified in the P. odoratum leaves of CC and first cropping (FC) plants. Among them, 7932 unigenes were upregulated, while 5860 unigenes were downregulated. Here, the DEGs encoding proteins associated with photosynthesis and carbon assimilation showed a significant decrease in expression under the CC system, such as the PSII protein complex, PSI protein complex, Cytochorome b6/f complex, the photosynthetic electron transport chain, light-harvesting chlorophyll protein complex, and Calvin cycle, etc., -related gene. This study demonstrates that CC can suppress photosynthesis and carbon mechanism in P. odoratum, pinpointing potential ways to enhance photosynthetic efficiency in the CC of plants.

Rhizosphere Microorganisms with Different Strategies and Mechanisms to Enhance Plant Growth in the Occurrence of Different Environmental Stress Factors

Every minute, the world’s population grows, and in order to feed them, crop output and agricultural productivity must be improved by adding crucial microorganisms that boost plant yields in various ways through nitrogen fixation, the secretion of both plant growth regulators and 1-aminocyclopropane 1-carboxylate deaminase, as well as some antimicrobial agents. Numerous endophytic bacteria have recently been used to increase plant yields, and agricultural production in addition to reducing salt stresses. Many scientists have made an effort to clarify and comprehend the processes by which bacteria promote plant growth and production. A vital substance known as 1-aminocyclopropane-1-carboxylate (ACC) deaminase is produced by several bacteria, plants, and fungi to decrease ethylene levels in a plant grown under different environmental stress. The gaseous hormone ethylene (C2H4) is synthesized in plant tissues from the precursor ACC, and it has numerous biochemical roles in plants, such as cells differentiation and tissue development, seedling, root hair, leaf, and flower growth and development in addition to fruit ripening and formation of anthocyanin and volatile compounds. Thus, this critical enzyme had influential roles in plants during their positive interaction with bacteria which increase plant growth due to auxin production and protect plants against different environmental stress like drought, high salts, wilting, high level of heavy metals, contaminants with pesticides, and microbial pathogen infections. Different bacterial genera are highly ACC deaminase-producer, and these bacteria support plant growth and agricultural process. In conclusion, bacteria can replace chemicals in a variety of environmentally benign methods to boost soil fertility and plant productivity. However, much research is required to determine the efficacy of these bacteria before suggesting their use on a broad scale in the field.

Inoculation with Azospirillum brasilense Strains AbV5 and AbV6 Increases Nutrition, Chlorophyll, and Leaf Yield of Hydroponic Lettuce.

Inoculation with Azospirillum brasilense has promisingly increased plant yield and nutrient acquisition. The study aimed to estimate the dose of A. brasilense that increases yield, gas exchange, nutrition, and foliar nitrate reduction. The research was carried out in a greenhouse at Ilha Solteira, in a hydroponic system in randomized blocks with four replicates. The treatments consisted of doses of inoculation with A. brasilense strains AbV5 and AbV6 via nutrient solution (0, 8, 16, 32, and 64 mL 100 L-1). Inoculation with A. brasilense at calculated doses between 20 and 44 mL provided the highest fresh and dry mass of shoots and roots, number of leaves, and leaf yield. In addition, the calculated doses of inoculation with A. brasilense increased the accumulation of N, P, K, Ca, Mg, S, B, Fe, Mn, and Zn in shoots and roots, except the accumulation of Ca in roots. It also increased cell membrane integrity index (15%), relative water content (13%), net photosynthesis rate (85%), intracellular CO2 concentration (15%), total chlorophyll (46%), stomatal conductance (56%), transpiration (15%), and water use efficiency (59%). Hence, inoculation with A. brasilense at doses between 20 and 44 mL 100 L-1 is considered the best approach for increasing the growth, yield, accumulation of nutrients, and gas exchange of hydroponically grown iceberg lettuce.

Zinc Oxide Nanoparticles mitigate toxic effects of Cadmium heavy metal in Chilli (Capsicum annuum L.)

Heavy metals contaminated soils and water sources are one of the major global causes of inhibition of plant growth and productivity. Different strategies are being employed to overcome the challenging issue to increase plant yield requirements to fulfil the needs of future generations. The objective of the present study was to observe the effects of spray (foliar) of green synthesized ZnO nanoparticles (100 ppm), alone and its interaction in conjugation with Cd (Cd+ZnO-NPs) 100 ppm of both on the growth and biochemical activities of the target plant, i.e., two chilli varieties. After two weeks of transplant, treatments viz., Control (T1), ZnO nanoparticles 100 ppm (T2), Cd 100 ppm (T3), and ZnO nanoparticles 100 ppm + Cd 100 ppm (T4) were given for six weeks and different parameters of growth and biochemical analysis were made. Results have shown that 100 ppm foliar spray of ZnO-NPs has significantly increasing effects on root and shoot growth of chilli plants in alone (ZnO nanoparticles) and Combined (ZnO nanoparticles +Cd heavy metal) treatments mitigating toxic effects of Cd stress. A similar increase in values of total carbohydrates, soluble proteins, free amino acids, and photosynthetic pigments were observed mostly in a combination of Cd+ZnO-NPs treatment showing remediation properties of ZnO nanoparticles against Cd stress in chilli plant. In conclusion, it may be suggested that 100 ppm ZnO-NPs foliar spray can have an increasing effect on the growth parameters of the plants under stressful conditions of Cd heavy metal.

Evaluation of short-term anaerobic fermentation using bioflocs waste and performance assessment

Excessive bioflocs are becoming a novel challenge to the development of biofloc technology (BFT). The present study assessed the viability of utilizing short-term anaerobic fermentation as a potential technique for the reclamation of bioflocs waste (BW). According to the different composition of fermentation substrates, the experiment was divided into: a group fermented with BW only (BG), a group fermented with the mixture of BW and straw (BSG), and a group fermented with the mixture of BW, effective-microorganism products (EM), and straw (BESG). Our results indicated that the contents of total potassium (TK) and organic matter (OM) were improved through 30 days fermentation, and the highest TK (1.3 g·100 g−1) and OM (53.4%) were both found in BESG. However, the fermentation process altered the microbial structure of the original bioflocs and reduced microbial diversity. The highest abundance of representative microorganisms of fermentation such as Clostridium_sensu_stricto_1 sp., and Ureibacillus sp. were detected in the BG group, and the obvious ammonification process was also detected in the BG. The final germination index (GI) values ranged between 98.8%-113.7% and all fermented products met the criteria for fertilizer maturity since day 20th. The application of fermented products was tested through the pot experiment with Brassica rapa L. chinensis, and the highest fresh weight (14.1 g) and yield (312.6 g·m−2) were found in the group with BG fermented products. However, a prominent improvement in Brassica rapa L. chinensis' quality had not been found. Overall, the anaerobic fermentation improves the quality of the original bioflocs, and the addition of fermented products based solely on the BW can significantly increase plant yield.

Integrated approaches for increasing plant yield under salt stress.

Salt stress affects large cultivated areas worldwide, thus causing remarkable reductions in plant growth and yield. To reduce the negative effects of salt stress on plant growth and yield, plant hormones, nutrient absorption, and utilization, as well as developing salt-tolerant varieties and enhancing their morpho-physiological activities, are some integrative approaches to coping with the increasing incidence of salt stress. Numerous studies have been conducted to investigate the critical impacts of these integrative approaches on plant growth and yield. However, a comprehensive review of these integrative approaches, that regulate plant growth and yield under salt stress, is still in its early stages. The review focused on the major issues of nutrient absorption and utilization by plants, as well as the development of salt tolerance varieties under salt stress. In addition, we explained the effects of these integrative approaches on the crop's growth and yield, illustrated the roles that phytohormones play in improving morpho-physiological activities, and identified some relevant genes involve in these integrative approaches when the plant is subjected to salt stress. The current review demonstrated that HA with K enhance plant morpho-physiological activities and soil properties. In addition, NRT and NPF genes family enhance nutrients uptake, NHX1, SOS1, TaNHX, AtNHX1, KDML, RD6, and SKC1, maintain ion homeostasis and membrane integrity to cope with the adverse effects of salt stress, and sd1/Rht1, AtNHX1, BnaMAX1s, ipal-1D, and sft improve the plant growth and yield in different plants. The primary purpose of this investigation is to provide a comprehensive review of the performance of various strategies under salt stress, which might assist in further interpreting the mechanisms that plants use to regulate plant growth and yield under salt stress.

Effects of melatonin and Trichoderma harzianum on pak choi yield, chlorophyll contents and antioxidant defense system under clubroot disease

Clubroot disease causes significant damage to cruciferous crops worldwide, resulting in severe decrease in plant yield. Plants tolerate biotic stresses through various mechanisms, including pathogen-associated molecular patterns (PAMPs) that activate immunity and plant resistance proteins. However, humans often resort to non-ecofriendly methods such as chemical applications to control biotic stresses. Melatonin (N-acetyl-5-methoxytryptamine) and Trichoderma are environmentally friendly and cost-effective alternative strategies to protect plants from pathogen attacks. Additionally, they have favorable effects on horticultural crop growth, fruit ripening, flowering, and provide stress resistance to abiotic and biotic diseases. In the present study, we aimed to control clubroot disease in Pak choi through single and combined exogenous application of melatonin and Trichoderma. We analyzed their effects on plant biomass, chlorophyll contents and observed alterations in their antioxidant system. Our results demonstrated that the combined application of 50 µM melatonin and 100 g Trichoderma efficiently control clubroot disease up to 74.85% compared to plants only supplemented with Plasmodiophora brassicae, as indicated by the disease index. Furthermore, we observed increased plant growth and antioxidant enzyme activities, including Ascorbic acid peroxidase (APX), superoxide dismutase (SOD); catalase (CAT), glutathione reductase (GR), and peroxidase (POD). Additionally, malondialdehyde (MDA) and hydrogen peroxide (H2O2) levels were reduced. Moreover, increased levels of chlorophyll, carotenoids and plant biomass have been observed in plants co-inoculated with melatonin and Trichoderma application. These findings provide valuable insights that can be utilized to enhance crop stress tolerance in challenging environments and increase plant yield. The use of environmentally friendly and cost-effective alternatives to chemical control can help mitigate the damage caused by clubroot disease to cruciferous crops.

Compost Formulation from Different Wastes to Enhance the Soil and Plant Productivity A Review

Different types and sources of compost are used to increase agricultural productivity. This review reveals different compost formulation methods and the incorporation of those methods into agriculture to reduce waste production, providing a better way to maintain soil fertility for better plant yield. This review furnishes an in-depth update on the impact of prepared compost from different ingredients like municipal waste, kitchen-based food waste, livestock waste, agricultural waste, algae, and industrial waste to find the effects on soil health, plant growth parameters (height, stem diameter, leaf number, chlorophyll content, etc.), and plant yield. Several studies have shown that compost significantly affects the soil’s health and improves different plants’ morphological (height, width, stem diameter, leaf shape, leaf size, leaf arrangement, root system), physiological (photosynthesis rate, transpiration rate, respiration rate, stomatal conductance, chlorophyll content, carbon dioxide assimilation, nutrient uptake, water use efficiency, flowering time, germination rate), and chemical properties (pH, macronutrient content, micronutrient content, carbohydrate content, protein content, lipid content, phytochemical content, essential oil content, pigment content). Produced compost from different ingredients has significant results for enhancing soil health, nutrient supply to plants, reducing heavy metal accumulation in plants, increasing plant yield, and reducing the environmental pollution. Overall, the results of this study demonstrate the potential of compost formulations made from different waste materials to enhance soil fertility and plant productivity. These findings have important implications for sustainable agriculture and waste management practices. Using compost as a soil amendment can help reduce waste and improve soil health, increasing plant yields and reducing the need for chemical fertilisers. However, the dose of compost prepared from various wastes in different climatic conditions should be optimized at the farm level, with particular emphasis on economic sustainability.

New seed coating containing Trichoderma viride with anti-pathogenic properties.

To ensure food security in the face of climate change and the growing world population, multi-pronged measures should be taken. One promising approach uses plant growth-promoting fungi (PGPF), such as Trichoderma, to reduce the usage of agrochemicals and increase plant yield, stress tolerance, and nutritional value. However, large-scale applications of PGPF have been hampered by several constraints, and, consequently, usage on a large scale is still limited. Seed coating, a process that consists of covering seeds with low quantities of exogenous materials, is gaining attention as an efficient and feasible delivery system for PGPF. We have designed a new seed coating composed of chitin, methylcellulose, and Trichoderma viride spores and assessed its effect on canola (Brassica napus L.) growth and development. For this purpose, we analyzed the antifungal activity of T. viride against common canola pathogenic fungi (Botrytis cinerea, Fusarium culmorum, and Colletotrichum sp.). Moreover, the effect of seed coating on germination ratio and seedling growth was evaluated. To verify the effect of seed coating on plant metabolism, we determined superoxide dismutase (SOD) activity and expression of the stress-related RSH (RelA/SpoT homologs). Our results showed that the T. viride strains used for seed coating significantly restricted the growth of all three pathogens, especially F. culmorum, for which the growth was inhibited by over 40%. Additionally, the new seed coating did not negatively affect the ability of the seeds to complete germination, increased seedling growth, and did not induce the plant stress response. To summarize, we have successfully developed a cost-effective and environmentally responsible seed coating, which will also be easy to exploit on an industrial scale.

Immobilization of Cr3+, Cd2+, and Pb2+ added to calcareous soil amended with composted agro-industrial residues

The bioavailability of trace metals in soils poses a major threat to the environment, especially with massive mineral fertilizers added to increase plant yield. A plot experiment was conducted for the effectiveness evaluation of compost and vermicompost, recycled from agro-industrial wastes, in immobilizing chromium, cadmium, and lead added to calcareous soil (artificially contaminated). Moreover, immobilization efficiency was compared to the natural occurrence of these metals in the soil without metal addition (uncontaminated soil). In both soils, amendments and mineral fertilizers were applied at three different levels alone and combined to each other. The experimental design was arranged in factorial complete randomized blocks using contamination, organic and mineral fertilizer levels, and their combination as categorical factors. The distribution of metal fractions and their bioavailability in soils and bioaccumulation in wheat grains were evaluated. Soil alkalinity, the contents of soil organic carbon and nitrogen, available phosphorus, and soil micronutrients were significantly improved under vermicompost and compost compared to mineral fertilizer and control. Vermicompost was more effective than compost in reducing metals bioavailability in contaminated soils by increasing the immobilized organic fractions, but it regressed when combined with mineral fertilizers. The bioavailability of the naturally occurring metal levels in uncontaminated soil did not change significantly compared to contaminated soil. Likewise, wheat yield, plant biomass, and nutrient enrichment in wheat grains improved due to enhanced soil nutrient availability. These composted agro-industrial residues, by-products from food industries, can be classified as environmentally-friendly soil amendments for their great potential to enrich soil nutrients, reduce mineral fertilizer addition, enhance plant growth, and stabilize Cr, Cd, and Pb in contaminated calcareous soils under wheat plants.

Assessment of Manure Compost Used as Soil Amendment—A Review

Organic waste management is an important concern for both industries and communities. Proper management is crucial for various reasons, such as reducing greenhouse gas emissions, promoting sustainability, and improving public health. Composted manure is a valuable source of nutrients and organic matter that can be used as a soil amendment in agriculture. Some important benefits of using composted manure in agriculture include: improves soil fertility, enhances soil structure, reduces soil erosion, suppresses plant diseases, and reduces reliance on synthetic fertilizers. Composted manure represents one of the most effective methods of organic waste valorization. Its macronutrients and micronutrients content can increase plant yield, without any reported negative or toxic effects on the soil and plants at various application rates. However, improper use of farmyard manure can have negative effects on the environment, such as air pollution from greenhouse gas emissions, soil acidification, and contamination of surface water and groundwater by nitrates and phosphates. The properties of the soil, including aeration, density, porosity, pH, water retention capacity, etc., can be improved by the structure and composition of manure. The slow-release source of nutrients provided by the nutrient content of compost can determine proper plants growth. However, it is crucial to use compost in moderation and regularly test soil to prevent excessive nutrient application, which can have adverse effects on plants and the environment.

Efficiency of Using Superabsorbent Polymers in Reducing Mineral Fertilizer Rates Applied in Autumn Royal Vineyards

Superabsorbent polymers (SAPs) addition to soil enhances the properties of soil and increase plant yields. Investigation of the efficacy of SAPs to reduce the rate of mineral fertilizers and produce high-quality grapes was the study’s main goal. This investigation was carried out for three seasons (2019, 2020, and 2021) in a private vineyard located in El-Menofia Governorate, Egypt. Autumn Royal grapevines were grafted on Freedom. The vines were seven years old and grown in newly reclaimed sandy soil irrigated by drip irrigation. Several concentrations of polyacrylamide polymer (50, 75, and 100 g/vine/three years) were applied to the examined soil with nitrogen and potassium fertilization rates of 100%, 75%, and 50% of the recommended rate of fertilizer. The data revealed that increasing the amount of applied polymer significantly improved bud burst and fruitful buds percentages; growth parameters; total leaf chlorophyll content; N, P, and K percentages in leaves; and yield. Thus, the most effective method for increasing fruit production was to apply 45 units of N and 75 units of K per feddan, along with 70 kg per feddan of soil conditioner, which is safe for humans and improves the physical and chemical properties of the soil. This treatment considers the impact of SAPs on the preservation of nutrients.

Effects of Drip Irrigation and Top Dressing Nitrogen Fertigation on Maize Grain Yield in Central Poland

Maize is a plant of a global cultivation range and great economic importance, which is mainly due to its high yield potential and versatile use as food, fodder, and energy source. To evaluate the effects of drip irrigation and nitrogen fertigation on maize growth in light soil in the climate conditions of Central Poland, a field experiment was carried out in 2015–2017, as a dependent split-plot design with four replications. Two factors were used: I. drip irrigation (W0—no irrigation, W1—optimal irrigation, ensuring 100% coverage of the water needs of maize during the period of increased water needs), II—method of top dressing application of two doses of nitrogen 2 × 40 kg·ha−1 (T—traditional application as broadcasted urea, F—fertigation with the use of a 6% aqueous solution of urea). The results presented in the paper concerning the absolute, relative and unitary average increases in corn grain yields under the influence of drip irrigation indicated the potential for increasing significantly the productivity of corn under the condition of optimizing the water factor. The average yield increase was 2.35 t·ha−1, varying depending on rainfall pattern: in the dry season it was 4.79, and in the wet season 1.03–1.22 t·ha−1. The application of top-dressing nitrogen fertigation resulted in a significant increase in the yield of maize grain in relation to the traditional method of nitrogen fertilization. Drip irrigation and fertigation are treatments that, ensuring the stability of maize yield over the years, contribute to an increase in plant yield by approximately 25% on average, and over 80% in the dry seasons.

Development and testing of zinc sulfate and zinc oxide nanoparticle-coated urea fertilizer to improve N and Zn use efficiency.

Nitrogen (N) losses from conventional fertilizers in agricultural systems are very high, which can lead to serious environmental pollution with economic loss. In this study, innovative slow-release fertilizers were prepared using zinc (Zn) [nanoparticles (NPs) or in bulk], using molasses as an environmentally friendly coating. Several treatments were prepared using Zn in different concentrations (i.e., 0.25%, 0.5%, and 4% elemental Zn). The zinc oxide nanoparticles (ZnO-NPs) were prepared from zinc sulfate heptahydrate (ZnSO4·7H2O), and were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Furthermore, the Zn-loaded urea samples were tested for urea N release rate, leaching of water from soil, and crushing strength to assess the impact of coating on the final finished product. Pot experiments were conducted simultaneously to check the agronomic effects of Zn-coated slow-release urea on the growth and development of wheat (Triticum aestivum L.). The laboratory and pot results confirmed that the ZnO-NP treatments boost wheat growth and yield as a result of reduced N and Zn release. UZnNPs2 (urea coated with 0.5% ZnO-NPs and 5% molasses) demonstrated the best results among all the treatments in terms of slow nutrient release, N and Zn uptake, and grain yield. The UZnNPs2 treatment increased plant yield by 34% (i.e., 4,515 vs. 3,345 kg ha-1) relative to the uncoated prill-treated crop because of the slower release of Zn and N.

Spectrophotometric indicators of “Zamin-M” biopreparation immobilized with gypan flocculinate

From the turn of the 20th century, biopreparations that quicken plant growth and development have been frequently employed. The accumulated knowledge of the mechanisms governing interactions between microorganisms and plants necessitates the use of minimal resources and energy in the targeted design of phytomicrobial systems and the optimization of their adaptability in order to increase soil fertility and plant productivity, increase plant yield, and increase plant resistance to diseases and unfavorable environmental conditions and stress factors. In the article today, enough experience has been collected on the scientific management of soil microorganism processes in the optimization of agricultural production and maintaining soil fertility, and it envisages the creation and use of microbiological preparations as the main link of intensive technologies in plant science. It is known that concentration of biomass of microorganisms using flocculants in the technological processes of production of bacterial preparations, after the stage of growth in enzymes, the stage of concentration of biomass of microorganisms from culture liquid is carried out.

Drought tolerance induction in wheat by inoculation of seeds with a novel growth-promoting bacteria

The use of Plant Growth Promoting Rhizobacteria (= PGPR) to increase crop tolerance to biotic and abiotic stresses such as drought is considered a novel method to increase plant yield. For this purpose, several rhizobacteria isolates from the wheat rhizosphere were screened in Northwest Iran. After sieving the bacteria in the media with PEG6000 5 g/100 ml (PEG= Polyethylene Glycol), a total of 22 bacterial isolates were selected for further experiment. The study was performed as a factorial experiment with three replications. The effect of selected bacterial isolates in three different concentrations of PEG (−0.5, −0.9, −1.2-1.2 MPa) on wheat seeds was evaluated under standard laboratory conditions for two weeks, and major growth factors were measured. After analyzing the data, to confidently conclude the selection of better bacteria, PCA (=Principal Component Analysis) was used for the importance of traits. The first and second components were 49.15% and 15.4% of the changes, respectively which justified all traits. In the first main component, germination percentage (PG), germination rate (GV) and seed vigor index (SV) traits had high coefficients which indicated the greater importance of these traits in justifying the general changes in traits. Finally, three bacterial strains were selected as the desired bacteria on the base of these traits for greenhouse work. The results indicated that all the three bacteria strains increased the mean value of the studied traits compared to that of the control. Among the three selected strains, the 16srDNA region of the bacterium with the best performance was sequenced. The sequencing results showed that this bacterium belonged to Bacillus wiedmannii with 98.8% Likelihood.

Effect of biofertilizers on leaf yield, nitrate amount, mineral content and antioxidants of basil (Ocimum basilicum L.) in a floating culture

Hydroponics is one of the systems in agriculture which reinforce productivity by controlling environmental and growing conditions. In this study, we evaluated the effect of three bio-fertilizers, namely bacteria, micro-algae, and mycorrhiza, on basil leaf yield and quality (Ocimum basilicum L.) in a floating culture system. Soil has rich amounts of beneficial microorganisms, supporting plant nutrition, producing phytohormones, controlling phytopathogens, and improving soil structure. However, soilless culture usually contains no beneficial microorganisms if we do not include them in the system. This study aims to evaluate the response of three bio-fertilizers where mineral fertilizers are reduced by 50%. Considering the total harvest data, bacteria, mycorrhiza, and micro-algae treatments increased basil yield compared to 50% control by about 18.94%, 13.94%, and 5.72%, respectively. The maximum total yield and leaf area were recorded using bacteria with 2744 g m−2 and 1528 cm2 plant−1. Plants with mycorrhiza achieved the highest number of leaves and branches, with 94.3 leaves plant−1 and 24.50 branches plant−1, respectively. It was observed that this bio-fertilizer increased the formation of lateral branches in the basil plant without thickening its stems. In addition, bacteria and mycorrhiza induced the highest percentage of dry matter and total soluble solids. The effect of bio-fertilizers on basil leaf EC and pH was insignificant for all the treatments at different harvest periods (p < 0.05). Using bio-fertilizers enhanced the intake of nutrients N (nitrogen), P (phosphorus), K (potassium), Ca (calcium), Mg (magnesium), Fe (iron), Mn (manganese), Zn (zinc), and Cu (copper). Using bio-fertilizers represents a promising and environmentally friendly approach to increasing crop yields and ameliorating quality and antioxidant compounds with fewer resources. An application of bio-fertilizers in hydroponic cultivation of basil cv. ‘Dino’ reduced the need for mineral fertilizers. At the same time, bio-fertilizers affected an increased plant yield and improved product quality. Furthermore, the bacteria had a pronounced enhancing effect on the increase of phenol and flavonoids in the leaves of basil plants.

Bio-Organic Fertilizer Promotes Pear Yield by Shaping the Rhizosphere Microbiome Composition and Functions.

Bio-organic fertilizers (BOF) containing both organic amendments and beneficial microorganisms have been consistently shown to improve soils fertility and yield. However, the exact mechanisms which link amendments and yields remain disputed, and the complexity of bio-organic fertilizers may work in parallel in several ways. BOF may directly improve yield by replenishing soil nutrients or introducing beneficial microbial genes or indirectly by altering the soil microbiome to enrich native beneficial microorganisms. In this work, we aim to disentangle the relative contributions of direct and indirect effects on pear yield. We treated pear trees with either chemical fertilizer or organic fertilizer with/without the plant-beneficial bacterium Bacillus velezensis SQR9. We then assessed, in detail, soil physicochemical and biological properties (metagenome sequencing) as well as pear yield. We then evaluated the relative importance of direct and indirect effects of soil amendments on pear yield. Both organic treatments increased plant yield by up to 20%, with the addition of bacteria tripling the increase driven by organic fertilizer alone. This increase could be linked to alterations in soil physicochemical properties, bacterial community function, and metabolism. Supplementation of organic fertilizer SQR9 increased rhizosphere microbiome richness and functional diversity. Fertilizer-sensitive microbes and functions responded as whole guilds. Pear yield was most positively associated with the Mitsuaria- and Actinoplanes-dominated ecological clusters and with gene clusters involved in ion transport and secondary metabolite biosynthesis. Together, these results suggested that bio-organic fertilizers mainly act indirectly on plant yield by creating soil chemical properties which promote a plant-beneficial microbiome. IMPORTANCE Bio-organic fertilization is a widely used, eco-friendly, sustainable approach to increasing plant productivity in the agriculture and fruit industries. However, it remains unclear whether the promotion of fruit productivity is related to specific changes in microbial inoculants, the resident microbiome, and/or the physicochemical properties of rhizosphere soils. We found that bio-organic fertilizers alter soil chemical properties, thus manipulating specific microbial taxa and functions within the rhizosphere microbiome of pear plants to promote yield. Our work unveils the ecological mechanisms which underlie the beneficial impacts of bio-organic fertilizers on yield promotion in fruit orchards, which may help in the design of more efficient biofertilizers to promote sustainable fruit production.

Phytoremediation of crude oil-contaminated sediment using Suaeda heteroptera enhanced by Nereis succinea and oil-degrading bacteria

A 150-day experiment was performed to investigate the stimulatory effect of a promising phytoremediation strategy consisting of Suaeda heteroptera (S. heteroptera), Nereis succinea (N. succinea), and oil-degrading bacteria for cleaning up total petroleum hydrocarbons (TPHs) in spiked sediment. Inoculation with oil-degrading bacteria and/or N. succinea increased plant yield and TPH accumulation in S. heteroptera plants. The highest TPH dissipation (40.5%) was obtained in the combination treatment, i.e., S. heteroptera + oil-degrading bacteria + N. succinea, in which the sediment TPH concentration decreased from an initial value of 3955 to 2355 mg/kg in 150 days. BAF, BCF, and TF confirmed the role of N. succinea and oil-degrading bacteria in the amelioration and translocation of TPHs. In addition, TPH toxicity of S. heteroptera was alleviated by N. succinea and oil-degrading bacteria addition through the reduction of oxidative stress. Therefore, S. heteroptera could be used for cleaning up oil-contaminated sediment, particularly in the presence of oil-degrading bacteria + N. succinea. Field studies on oil-degrading bacteria + N. succinea may provide new insights on the rehabilitation and restoration of sediments contaminated by TPHs.