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Arsenic (As) poisoning in groundwater and rice paddy soil has increased globally, impacting human health and food security. There is an urgent need to deal with As-contaminated groundwater and soil. Biochar can be a useful remedy for toxic contaminants. This study explains the synthesis of pinecone-magnetic biochar (PC-MBC) by engineering the pinecone-pristine biochar with iron salts (FeCl3.6H2O and FeSO4.7H2O) to investigate its effects on As(V) adsorption and immobilization in water and soil, respectively. The results indicated that PC-MBC can remediate As(V)-contaminated water, with an adsorption capacity of 12.14 mg g-1 in water. Isotherm and kinetic modeling showed that the adsorption mechanism involved multilayer, monolayer, and diffusional processes, with chemisorption operating as the primary interface between As(V) and biochar. Post-adsorption analysis of PC-MBC, using FTIR and XRD, further revealed chemical fixing and outer-sphere complexation between As(V) and Fe, O, NH, and OH as the main reasons for As(V) adsorption onto PC-MBC. Recycling of PC-MBC also had excellent adsorption even after several regeneration cycles. Similarly, PC-MBC successfully immobilized As in paddy soil. Single and sequential extraction results showed the transformation of mobile forms of As to a more stable form, confirmed by non-destructive analysis using SEM, EDX, and elemental dot mapping. Thus, Fe-modified pine-cone biochar could be a suitable and cheap adsorbent for As-contaminated water and soil.
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Arsénico , Carbón Orgánico , Agua Subterránea , Contaminantes del Suelo , Contaminantes Químicos del Agua , Humanos , Arsénico/análisis , Adsorción , Contaminantes del Suelo/análisis , Agua , Contaminación del Agua/análisis , Suelo , Fenómenos Magnéticos , Contaminantes Químicos del Agua/análisisRESUMEN
The world's human population is increasing exponentially, increasing the demand for high-quality food sources. As a result, there is a major global concern over hunger and malnutrition in developing countries with limited food resources. To address this issue, researchers worldwide must focus on developing improved crop varieties with greater productivity to overcome hunger. However, conventional crop breeding methods require extensive periods to develop new varieties with desirable traits. To tackle this challenge, an innovative approach termed plant nanobionics introduces nanomaterials (NMs) into cell organelles to enhance or modify plant function and thus crop productivity and yield. A comprehensive review of nanomaterials affect crop yield is needed to guide nanotechnology research. This article critically reviews nanotechnology applications for engineering plant productivity, seed germination, crop growth, enhancing photosynthesis, and improving crop yield and quality, and discusses nanobionic approaches such as smart drug delivery systems and plant nanobiosensors. Moreover, the review describes NM classification and synthesis and human health-related and plant toxicity hazards. Our findings suggest that nanotechnology application in agricultural production could significantly increase crop yields to alleviate global hunger pressures. However, the environmental risks associated with NMs should be investigated thoroughly before their widespread adoption in agriculture.
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Productos Agrícolas , Fitomejoramiento , Humanos , Agricultura , Nanotecnología , Seguridad AlimentariaRESUMEN
BACKGROUND: Pasture farming in south-western Australia is challenged by nutrient-poor soils. We assessed the impact of microbial consortium inoculant (MI) and rock mineral fertiliser (MF) on growth, nutrient uptake, root morphology, rhizosphere carboxylate exudation and mycorrhizal colonisation in three pasture grasses - tall fescue (Festuca arundinacea L.), veldt grass (Ehrharta calycina Sm.) and tall wheatgrass (Thinopyrum ponticum L.) grown in low-phosphorus (P) sandy soil in a glasshouse for 30 and 60 days after sowing (DAS). RESULTS: Veldt grass produced the highest specific root length and smallest average root diameter in both growth periods, and had similar shoot weight, root surface area and fine root length (except at 30 DAS) to tall fescue. Compared with the control, MI alone or combined with MF significantly increased shoot and root biomass (except root biomass at 30 DAS), likely due to the significant increases in root surface area and fine root length. Plants supplied with MI + MF had higher shoot N and P contents than those in the MI and the control treatments at 60 DAS. Malate, citrate and trans-aconitate were the major rhizosphere carboxylates exuded at both 30 and 60 DAS. Malate exudation varied among species and treatments in both growth periods, but citrate exudation was consistently higher in the low-P treatments (control and MI) than the MF and MI + MF treatments. CONCLUSION: Microbial consortium inoculant can positively influence pasture production in low-P soil by increasing root surface area and fine root length, whereas exudation of nutrient-mobilising carboxylates (citrate) is dependent more on soil P supply than microbial consortium inoculant. © 2021 Society of Chemical Industry.
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Inoculantes Agrícolas/crecimiento & desarrollo , Micorrizas/crecimiento & desarrollo , Fósforo/análisis , Exudados de Plantas/metabolismo , Raíces de Plantas/crecimiento & desarrollo , Poaceae/microbiología , Ácidos Carboxílicos/análisis , Ácidos Carboxílicos/metabolismo , Fertilizantes/análisis , Consorcios Microbianos , Fósforo/metabolismo , Exudados de Plantas/análisis , Raíces de Plantas/química , Raíces de Plantas/metabolismo , Raíces de Plantas/microbiología , Poaceae/química , Poaceae/crecimiento & desarrollo , Poaceae/metabolismo , Rizosfera , Suelo/químicaRESUMEN
BACKGROUND AND AIMS: Arbuscular mycorrhizal (AM) symbiosis begins with molecular signal communication (MSC) between AM fungi and the roots of the host plant. We aimed to test the hypothesis that the transcriptional profiles of wheat roots can be changed significantly by AM symbiotic signals, without direct contact. METHODS: Non-mycorrhizal (NM) and MSC treatments involved burying filter membrane bags containing sterilized and un-sterilized inoculum of the AM fungus Rhizophagus irregularis, respectively. The bags physically separated roots and AM structures but allowed molecular signals to pass through. Extracted RNA from wheat roots was sequenced by high-throughput sequencing. RESULTS: Shoot total nitrogen and phosphorus content of wheat plants was decreased by the MSC treatment. A total of 2360 differentially expressed genes (DEGs), including 1888 up-regulated DEGs and 472 down-regulated DEGs, were found dominantly distributed on chromosomes 2A, 2B, 2D, 3B, 5B and 5D. The expression of 59 and 121 genes was greatly up- and down-regulated, respectively. Only a portion of DEGs could be enriched into known terms during gene ontology analysis, and were mostly annotated to 'catalytic activity', 'protein metabolic process' and 'membrane' in the molecular function, biological process and cellular component ontology categories, respectively. More than 120 genes that may be involved in key processes during AM symbiosis development were regulated at the pre-physical contact stages. CONCLUSIONS: The transcriptional profiles of wheat roots can be changed dramatically by MSC. Much of the information provided by our study is of great importance for understanding the mechanisms underlying the development of AM symbiosis.
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Micorrizas , Triticum , Regulación de la Expresión Génica de las Plantas , Raíces de Plantas , SimbiosisRESUMEN
The application of 33P or 32P isotopes to directly trace phosphorus (P) uptake during arbuscular mycorrhizal (AM) symbiosis is limited by the radioactivity of the two P isotopes, especially under field conditions. A potential alternative method for tracing P uptake in plant-soil systems relies on the analysis of the stable oxygen (O) isotopes of ortho-phosphate (Pi); however, little is known about the fate of the P-O bond during Pi uptake in AM symbioses. This study investigated whether the abundance of 18O in Pi extracted from the shoots of maize increased after 18O-labeled Pi added to soil was taken up by either roots of maize or AM extraradical hyphae. A two-compartment culture system, consisting of a root and AM hyphal compartment (RHC, including both roots and AM hyphae) and an AM hyphal compartment (HC, including only hyphae) was designed, and the AM fungus Funneliformis mosseae was used to inoculate the roots of maize. Our results indicated that the abundance of 18O in Pi extracted from the maize shoots increased significantly 3 months after the addition of 18O-labeled Pi to the soil in the pots which only contained roots. The abundance of 18O was much lower than expected, however, which suggests a great majority of 18O in labeled Pi was lost in the soil or during Pi metabolism in the shoots of maize. The abundance of 18O in Pi extracted from the maize shoots did not increase 3 months after 18O-labeled Pi was added to the HC, and therefore, loss of 18O in labeled Pi may also occur during Pi metabolism in AM hyphae. Use of 18O-labeled Pi as a qualitative tracer of P uptake during AM symbiosis appears unfeasible for such a long-term (3 months) experiment, although it should be investigated in a short-term labeling experiment.
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Micorrizas/fisiología , Isótopos de Oxígeno/análisis , Fosfatos/metabolismo , Raíces de Plantas/metabolismo , Brotes de la Planta/metabolismo , Zea mays/metabolismo , Transporte Biológico , Glomeromycota/fisiología , Raíces de Plantas/microbiología , Zea mays/microbiologíaRESUMEN
Biochar may alleviate plant water stress in association with arbuscular mycorrhizal (AM) fungi but research has not been conclusive. Therefore, a glasshouse experiment was conducted to understand how interactions between AM fungi and plants respond to biochar application under water-stressed conditions. A twin chamber pot system was used to determine whether a woody biochar increased root colonisation by a natural AM fungal population in a pasture soil ('field' chamber) and whether this was associated with increased growth of extraradical AM fungal hyphae detected by plants growing in an adjacent ('bait') chamber containing irradiated soil. The two chambers were separated by a mesh that excluded roots. Subterranean clover was grown with and without water stress and harvested after 35, 49 and 63 days from each chamber. When biochar was applied to the field chamber under water-stressed conditions, shoot mass increased in parallel with mycorrhizal colonisation, extraradical hyphal length and shoot phosphorus concentration. AM fungal colonisation of roots in the bait chamber indicated an increase in extraradical mycorrhizal hyphae in the field chamber. Biochar had little effect on AM fungi or plant growth under well-watered conditions. The biochar-induced increase in mycorrhizal colonisation was associated with increased growth of extraradical AM fungal hyphae in the pasture soil under water-stressed conditions.
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Carbón Orgánico/farmacología , Micorrizas/efectos de los fármacos , Micorrizas/fisiología , Microbiología del Suelo , Suelo/química , Agricultura , Fósforo/fisiología , Trifolium/microbiología , Trifolium/fisiología , Agua/químicaRESUMEN
Plants rapidly release photoassimilated carbon (C) to the soil via direct root exudation and associated mycorrhizal fungi, with both pathways promoting plant nutrient availability. This study aimed to explore these pathways from the root's vascular bundle to soil microbial communities. Using nanoscale secondary ion mass spectrometry (NanoSIMS) imaging and (13) C-phospho- and neutral lipid fatty acids, we traced in-situ flows of recently photoassimilated C of (13) CO2 -exposed wheat (Triticum aestivum) through arbuscular mycorrhiza (AM) into root- and hyphae-associated soil microbial communities. Intraradical hyphae of AM fungi were significantly (13) C-enriched compared to other root-cortex areas after 8 h of labelling. Immature fine root areas close to the root tip, where AM features were absent, showed signs of passive C loss and co-location of photoassimilates with nitrogen taken up from the soil solution. A significant and exclusively fresh proportion of (13) C-photosynthates was delivered through the AM pathway and was utilised by different microbial groups compared to C directly released by roots. Our results indicate that a major release of recent photosynthates into soil leave plant roots via AM intraradical hyphae already upstream of passive root exudations. AM fungi may act as a rapid hub for translocating fresh plant C to soil microbes.
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Micorrizas/fisiología , Fotosíntesis , Exudados de Plantas/metabolismo , Microbiología del Suelo , Biomarcadores/metabolismo , Carbono/metabolismo , Isótopos de Carbono , Recuento de Colonia Microbiana , Ácidos Grasos/análisis , Hifa/fisiología , Hifa/efectos de la radiación , Luz , Micorrizas/crecimiento & desarrollo , Micorrizas/efectos de la radiación , Nanotecnología , Nitrógeno/metabolismo , Isótopos de Nitrógeno , Fosfolípidos/análisis , Fotosíntesis/efectos de la radiación , Raíces de Plantas/citología , Raíces de Plantas/microbiología , Espectrometría de Masa de Ion Secundario , Fracciones Subcelulares/metabolismo , Factores de Tiempo , Triticum/microbiologíaRESUMEN
Mining operations degrade natural ecosystems by generating a large quantity of mine tailings. Mine tailings remain in dams/open ponds without further treatment after valuable metals such as iron ore have been extracted. Therefore, rehabilitation of tailings to mitigate the negative environmental impacts is of the utmost necessity. This review compares existing physical, chemical and amendment-assisted phytoremediation methods in the rehabilitation of mine tailings from the perspective of cost, reliability and durability. After review and discussion, it is concluded that amendment-assisted phytoremediation has received comparatively great attention; however, the selection of an appropriate phytoremediator is the critical step in the process. Moreover, the efficiency of phytoremediation is solely dependent on the amendment type and rate. Further, the application of advanced plant improvement technologies, such as genetically engineered plants produced for this purpose, would be an alternative solution. Further research is needed to determine the suitability of this method for the particular environment.
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Phosphorus (P) is a vital macronutrient required for soybean growth and development but is a finite resource in agriculture worldwide. Low inorganic P availability in soil is often a significant constraint for soybean production. However, little is known about the response of P supply on agronomic, root morphology, and physiological mechanisms of contrasting soybean genotypes at various growth stages and the possible effects of different P on soybean yield and yield components. Therefore, we conducted two concurrent experiments using the soil-filled pots with six genotypes (deep-root system: PI 647960, PI 398595, PI 561271, PI 654356; and shallow-root system: PI 595362, PI 597387) and two P levels [0 (P0) and 60 (P60) mg P kg-1 dry soil] and deep PVC columns with two genotypes (PI 561271 and PI 595362) and three P levels [0 (P0), 60 (P60), and 120 (P120) mg P kg-1 dry soil] in a temperature-controlled glasshouse. The genotype × P level interaction showed that increased higher P supply increased leaf area, shoot and root dry weights, total root length, shoot, root, and seed P concentrations and contents, P use efficiency (PUE), root exudation, and seed yield at different growth stages in both experiments. At the vegetative stage (Experiment 1), shallow-rooted genotypes with shorter life cycles had more root dry weight (39%) and total root length (38%) than deep-rooted genotypes with longer life cycles under different P levels. Genotype PI 654356 produced significantly higher (22% more) total carboxylates than PI 647960 and PI 597387 under P60 but not at P0. Total carboxylates positively correlated with root dry weight, total root length, shoot and root P contents, and physiological PUE. The deep-rooted genotypes (PI 398595, PI 647960, PI 654356, and PI 561271) had the highest PUE and root P contents. In Experiment 2, at the flowering stage, genotype PI 561271 had the greatest leaf area (202%), shoot dry weight (113%), root dry weight (143%), and root length (83%) relative to the short-duration, shallow-rooted genotype PI 595362 with external P applied (P60 and P120), with similar trends at maturity. PI 595362 had a greater proportion of carboxylates as malonate (248%), malate (58%), and total carboxylates (82%) than PI 561271 under P60 and P120 but no differences at P0. At maturity, the deep-rooted genotype PI 561271 had greater shoot, root, and seed P contents and PUE than the shallow-rooted genotype PI 595362 under increased P rates but no differences at P0. Further, the genotype PI 561271 had higher shoot (53%), root (165%), and seed yield (47%) than PI 595362 with P60 and P120 than P0. Therefore, inorganic P application enhances plant resistance to the soil P pool and maintains high soybean biomass production and seed yield.
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Intensive fertilizer use can constrain contributions from soil biological processes in pastures, including those associated with arbuscular mycorrhizal (AM) fungi. We evaluated the effect of fertilizers of different P solubility on the colonization of the roots of two common pasture plants by a community of AM fungi in a pasture soil. The treatments were a rock mineral fertilizer, a chemical fertilizer and a microbial inoculant. Subterranean clover and annual ryegrass were grown in pots for 10 weeks. Both fertilizers reduced the proportion and length of roots colonized by naturally occurring AM fungi. However, by 10 weeks, there was a much greater length of mycorrhizal root for annual ryegrass than for subterranean clover. The relative abundance of mycorrhizal fungi in the families Glomeraceae and Acaulosporaceae in roots was not affected by the form of fertilizer, but diversity indices of AM fungi in roots were altered. The chemical fertilizer had a greater negative effect on AM fungal diversity indices in the annual ryegrass roots compared with the subterranean clover roots. The reduction in OTU richness of AM fungi with fertilizer application corresponded with reduced soil pH. Differential effects of P fertilizers on naturally occurring AM fungi in this agricultural soil have the potential to influence the efficacy of P fertilizer use and dominance of plant species in grasslands.
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Antimony (Sb-V), a carcinogenic metalloid, is becoming prevalent in water and soil due to anthropogenic activities. Biochar could be an effective remedy for Sb(V)-contaminated water and soil. In this study, we used pristine and engineered pinecone-derived biochar as an innovative approach for treating Sb(V)-contaminated water and shooting range soil. Biochar was produced from pine-cone waste (pristine biochar) and enriched with Fe and Al salts via saturation (engineered biochar). Adsorption tests in water revealed that iron-modified biochar showed higher adsorption capacity (8.68 mg g-1) than that of the pristine biochar (2.49 mg g-1) and aluminum-modified biochar (3.40 mg g-1). Isotherm and kinetic modeling of the adsorption data suggested that the adsorption process varied from monolayer to multilayer, with chemisorption as the dominant interaction mechanism between Sb(V) and the biochars. The post-adsorption study of iron-modified biochar by Fourier Transform Infrared (FTIR) and X-ray diffraction (XRD) further supported the chemical bonding and outer-sphere complexation of Sb(V) with Fe, N-H, O-H, C-O and CC components. The pristine and iron-modified biochars also successfully immobilized Sb(V) in a shooting range soil, more so in the latter. Subsequent sequential extractions and post-analysis by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and elemental dot mapping revealed that Sb in the treated soil transformed to a more stable form. It was concluded that iron-modified biochar could act as an efficient material for the adsorption and immobilization of Sb(V) in water and soil, respectively.
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Personal Militar , Contaminantes Químicos del Agua , Humanos , Antimonio/análisis , Suelo , Adsorción , Carbón Orgánico , Hierro/análisis , Agua/análisis , Cinética , Contaminantes Químicos del Agua/análisisRESUMEN
Soil acidification in managed ecosystems such as agricultural lands principally results from the increased releasing of protons (H+) from the transformation reactions of carbon (C), nitrogen (N) and sulphur (S) containing compounds. The incorporation of liming materials can neutralize the protons released, hence reducing soil acidity and its adverse impacts to the soil environment, food security, and human health. Biochar derived from organic residues is becoming a source of carbon input to soil and provides multifunctional values. Biochar can be alkaline in nature, with the level of alkalinity dependent upon the feedstock and processing conditions. This review covers the fundamental aspects of soil acidification and of the use of biochar to address constraints related to acidic soil. Biochar is increasingly considered as an effective soil amendment for reducing soil acidity owing to its liming potential, thereby enhancing soil fertility and productivity in acid soils. The ameliorant effect on acid soils is mainly because of the dissolution of carbonates, (hydro)-oxides of the ash fraction of biochar and potential use by microorganisms.
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Ecosistema , Suelo , Humanos , Suelo/química , Protones , Carbón Orgánico/química , Carbono/química , Óxidos , Ácidos , Concentración de Iones de HidrógenoRESUMEN
Improper disposal of heavy metal-contaminated iron ore tailings poses a significant risk to the surrounding environments. Adding compost and growing ryegrass could be a cost-effective long-term solution for remediation of iron ore tailings. We conducted a glasshouse study to investigate the impact of compost amendment (0, 50, 75 and 100% w/w) on growth and accumulation of heavy metals (Cu, Fe, Mn, Pb, Ni and Zn) and As in shoots of perennial ryegrass (Lolium perenne L.) grown in two iron ore tailings (Site A and Site B mines, Pilbara, Western Australia). Ryegrass was harvested 45 and 60 days after sowing. Site A iron ore tailings had total concentrations (mg kg-1) of Fe (449,000), Mn (6900), Zn (109), Co (16) and As (7.3). Site B mine tailings had total concentrations (mg kg-1) of Fe (457,000), Ni (21), Zn (109) and As (45). Both tailings had low cation exchange capacity, organic matter, air porosity and near-neutral pH, but varied in particle size distribution (Site A-clay loam and Site B-sandy loam). Ryegrass germination was higher in the extract of Site B than Site A tailings. Increasing compost-to-tailings ratio increased dry shoot biomass at 45 days. The heavy metal/metalloid concentrations in shoots significantly decreased with increasing compost-to-tailings ratio, except for Cu and Zn. The bioconcentration factor (BCF) of heavy metals (metal concentration in shoot/total metal concentration in substrate) significantly decreased with an increasing proportion of compost in growth substrate. The BCF was >1 for Zn and Cu, and <1 for other heavy metals. A high concentration of organic matter in compost treatments likely contributed to the enhanced mobilisation of Cu and Zn for plant uptake. In contrast, compost stabilised other metals/metalloids in the tailings to decrease their uptake by ryegrass and maintain plant growth despite relatively high Mn, Fe, As and Pb concentrations in iron ore tailings.
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Compostaje , Lolium , Metales Pesados , Hierro , Australia OccidentalRESUMEN
While plant growth promotion with increased nutrient uptake had been well addressed for biochar soil amendment in agriculture, there was limited knowledge on the variation of such effects with crop genotypes. In a rice field experiment without and with biochar soil amendment at 20 t ha-1, 19 mutants of a rice cultivar Wuyunjing 7 (Oryza sativa L.) were tested for plant growth in split plots respectively. At harvest, the biomass of grain, stem and leaves were measured and soil and plant samples were collected for measuring N, P and K nutrients. Across the 19 mutants, relative change with biochar soil amendment varied in a range of -41.6% to +35.6% for biomass production and agronomic traits, and -87.0% to +117% for nutrient accumulation. For the nutrients content, the relative change for N was seen in a narrow range of -29.4% to +16.6%, being similar among grain, leaf and shoot samples while that for P in a wide range of -109% to +105%. With factor analysis, variation of biomass and nutrient uptake was least explained with biochar effect (up to 7.0%) but largely by genotype effect (mostly by 40-70%). However, the genotype × biochar interaction effect could also explain 10-40% of the total variations though the interaction explained 40-70% of leaf P variation. Therefore, mutant and mutant × biochar interactions dominated the agronomic variation of rice production of the Wuyunjing 7 cultivar. Furthermore, across the traits analyzed, genotype effects were shown very significantly but negatively correlated to biochar effects. In other words, biochar soil amendment provided little growth or nutrient enhancement for those mutants bred for high efficiency. Hence, genotype selection should be considered in optimizing prioritizing biochar application in crop production. Of course, variation of biochar effect with crop genotypes deserved further plant physio-ecological studies.
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Oryza , Suelo , Carbón Orgánico , Genotipo , Oryza/genética , FitomejoramientoRESUMEN
Integrated Plant Nutrient System (IPNS) is practiced worldwide to maintain soil quality. Two field experiments were conducted in 2019 and 2020 in acidic and charland soils to assess the impact of different manures, viz., poultry manure (PM), vermicompost (VC), compost (OF), rice husk biochar (RHB), poultry manure biochar (PMB)-based IPNS, and dolomite over control on productivity and nitrogen use efficiency (NUE) of the Mustard-Boro-Transplanted Aman and Maize-Jute-Transplanted Aman cropping patterns, and on soil properties. The experiments were laid out in a randomized complete block design with four replications. The results showed that IPNS treatments significantly improved soil aggregate properties and total nitrogen in acidic soil, and bulk density in charland soil. In both years, IPNS treatments increased system productivity from 55.4 to 82.8% in acidic soil and from 43.3 to 115.4% in charland soil over that of control. IPNS and dolomite treatments increased nitrogen uptake from 35.5 to 105.7% over that of control and NUE in both soils in 2019 and 2020. PMB- and OF-based INPS treatments exhibited superior performances in both soils, and the impact was more prominent in 2020. Therefore, PMB- and OF-based IPNS can be recommended for maximizing system productivity and NUE with concurrent improvement of physicochemical properties of acidic and charland soils.
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Co-application of biochar and biosolids to soil has potential to mitigate N leaching due to physical and chemical properties of biochar. Changes in N cycling pathways in soil induced by co-application of biological amendments could further mitigate N loss, but this is largely unexplored. The aim of this study was to determine whether co-application of a biochar and a modified biosolids product to three pasture soils differing in texture could alter the relative abundance of N cycling genes in soil sown with subterranean clover. The biosolids product contained lime and clay and increased subterranean clover shoot biomass in parallel with increases in soil pH and soil nitrate. Its co-application with biochar similarly increased plant growth and soil pH with a marked reduction in nitrate in two coarse textured soils but not in a clayey soil. While application of the biosolids product altered in silico predicted N cycling functional genes, there was no additional change when applied to soil in combination with biochar. This supports the conclusion that co-application of the biochar and biosolids product used here has potential to mitigate loss of N in coarse textured soils due to N adsoption by the biochar and independently of microbial N pathways.
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Biosólidos/microbiología , Carbón Orgánico/metabolismo , Genes Microbianos/genética , Nitratos/metabolismo , Biomasa , Concentración de Iones de Hidrógeno , Plantas/genética , Plantas/metabolismo , Transducción de Señal/genética , SueloRESUMEN
While biochar use in agriculture is widely advocated, how the effect of biochar on plant growth varies with biochar forms and crop genotypes is poorly addressed. The role of dissolvable organic matter (DOM) in plant growth has been increasingly addressed for crop production with biochar. In this study, a hydroponic culture of rice seedling growth of two cultivars was treated with bulk mass (DOM-containing), water extract (DOM only), and extracted residue (DOM-free) of maize residue biochar, at a volumetric dosage of 0.01, 0.05, and 0.1%, respectively. On seedling root growth of the two cultivars, bulk biochar exerted a generally negative effect, while the biochar extract had a consistently positive effect across the application dosages. Differently, the extracted biochar showed a contrasting effect between genotypes. In another hydroponic culture with Wuyunjing 7 treated with biochar extract at sequential dosages, seedling growth was promoted by 95% at 0.01% dosage but by 26% at 0.1% dosage, explained with the great promotion of secondary roots rather than of primary roots. Such effects were likely explained by low molecular weight organic acids and nanoparticles contained in the biochar DOM. This study highlights the importance of biochar DOM and crop genotype when evaluating the effect of biochar on plants. The use of low dosage of biochar DOM could help farmers to adopt biochar technology as a solution for agricultural sustainability.
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Biostimulants are gaining momentum as potential soil amendments to increase plant health and productivity. Plant growth responses to some biostimulants and poorly soluble fertilizers could increase soil microbial diversity and provide greater plant access to less soluble nutrients. We assessed an agricultural soil amended with a multispecies microbial biostimulant in comparison with two fertilizers that differed in elemental solubilities to identify effects on soil bacterial communities associated with two annual pasture species (subterranean clover and Wimmera ryegrass). The treatments applied were: a multispecies microbial biostimulant, a poorly soluble rock mineral fertilizer at a rate of 5.6 kg P ha-1, a chemical fertilizer at a rate of 5.6 kg P ha-1, and a negative control with no fertilizer or microbial biostimulant. The two annual pasture species were grown separately for 10 weeks in a glasshouse with soil maintained at 70% of field capacity. Soil bacteria were studied using 16S rRNA with 27F and 519R bacterial primers on the Mi-seq platform. The microbial biostimulant had no effect on growth of either of the pasture species. However, it did influence soil biodiversity in a way that was dependent on the plant species. While application of the fertilizers increased plant growth, they were both associated with the lowest diversity of the soil bacterial community based on Fisher and Inverse Simpson indices. Additionally, these responses were plant-dependent; soil bacterial richness was highly correlated with soil pH for subterranean clover but not for Wimmera ryegrass. Soil bacterial richness was lowest following application of each fertilizer when subterranean clover was grown. In contrast, for Wimmera ryegrass, soil bacterial richness was lowest for the control and rock mineral fertilizer. Beta diversity at the bacterial OTU level of resolution by permanova demonstrated a significant impact of soil amendments, plant species and an interaction between plant type and soil amendments. This experiment highlights the complexity of how soil amendments, including microbial biostimulants, may influence soil bacterial communities associated with different plant species, and shows that caution is required when linking soil biodiversity to plant growth. In this case, the microbial biostimulant influenced soil biodiversity without influencing plant growth.
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The use of biochar in avocado orchard soils has not yet been investigated in rigorous scientific experiments. We determine the effect of wood biochar on avocado growth, fruit production and economic benefit. Biochar was applied at 0%, 5%, 10% and 20% volume by volume basis. Biochar significantly improved the growth of avocado seedlings and increased fruit yield in the first three years after planting. There was an overall increase in soil carbon, fruit yield, tree diameter and height in all biochar treatments relative to the control over the seasons. Trees planted with biochar had 18-26% greater growth rates (in terms of height and stem diameter) than the control. Tree diameter was significantly greater with biochar (145.4 ± 3.3 mm) relative to the control treatment (125.0 ± 2.7 mm). Tree height was also significantly greater with biochar (3.7 ± 0.1 m) relative to the control treatment (3.4 ± 0.1 m). The fruit count from the biochar row was significantly greater (97%) in 2018. Heavy bearing trees typically have a lower yield in the subsequent year but despite this, the 2019 fruit counts were higher in aggregate for the biochar amended trees (20%) relative to the control. A cost-benefit analysis indicated that if yield surplus of fruit trees continued for three years, and assuming avocado prices remain at similar levels, then the discounted net benefit over a hectare would amount to US$8581, or US$105 per metric tonne of biochar applied.
Asunto(s)
Persea , Suelo , Carbono , Carbón OrgánicoRESUMEN
Renewing carbon and re-establishing it again in the soil is one of the valuable means to cope with climate change. There are many technologies for carbon apprehension and storage, but the most important one gaining attention is biochar technology. So, to carbonize and return different biological materials back to the farmland, a comprehensive study was proposed to characterize and evaluate the carbon (C) mineralization of biochars produced from different animal manures and crop straws. Six types of biochars were prepared from animal manures (poultry litter, swine and cattle manures) and crop straws (rice, soybean, and corn straws). The biochars were analyzed for chemical characteristics (elemental variables, thermal decomposition, cation exchange capacity, pH, electrical conductivity, specific surface area, and surface functional groups) and an incubation experiment was conducted to evaluate C mineralization from soil biochar mixture. Biochars produced from crop straws resulted to have more C as compared to the biochars produced from animal manures. Concentration of nitrogen was low, while P, K, Ca, and Mg were found reasonably higher in all biochars except swine manure biochar. The plant-derived biochars presented lower CO2 emissions when incorporated to soil at 1 and 2% of C. Varying but all the biochars prepared represented an alkaline pH. Biochars prepared from the crop straws resulted to have more C, alkaline in nature, high CEC, low CO2 emissions, can sequester C and more suitable to enhance the soil fertility in comparison to biochars produced from other sources.