Ontario Corn and Soybean Micronutrients Knowledge Hub

In the present study (i) the impact of plant Boron (B) status on foliar B absorption and (ii) the effect of B complexation with polyols (sorbitol or mannitol) on B absorption and translocation was investigated. Soybean ( Glycine max (L.) Meer.) plants grown in nutrient solution containing 0 µM, 10 µM, 30 µM or 100 µM B labelled boric acid (BA) were treated with 50 m MB labelled BA applied to the basal parts of two leaflets of one leaf, either pure or in combination with 500 m M sorbitol or mannitol. After one week, B concentrations in different plant parts were determined. In B deficient leaves (0 µM B), B absorption was significantly lower than in all other treatments (9.7% of the applied dose vs. 26%-32%). The application of BA in combination with polyols increased absorption by 18-25% as compared to pure BA. The absolute amount of applied B moving out of the application zone was lowest in plants with 0 µM B supply (1.1% of the applied dose) and highest in those grown in 100 µM B (2.8%). The presence of sorbitol significantly decreased the share of mobile B in relation to the amount absorbed. The results suggest that B deficiency reduces the permeability of the leaf surface for BA. The addition of polyols may increase B absorption, but did not improve B distribution within the plant, which was even hindered when applied a sorbitol complex.

Insufficient iron (Fe) availability, which frequently occurs in soils with high pH levels, can lead to leaf chlorosis, a reduced Fe content in harvest products, and yield reduction in maize. The objectives of this study were ( i) to describe patterns of sequence variation of 14 candidate genes for mobilization, uptake, and transport of Fe in maize, as well as regulatory function on these processes; ( ii) to examine whether Fe-efficiency is an adaptive trait by determining if these genes were targets of selection during domestication; and ( iii) to test if the allele distribution at these candidate genes is different for the different subpopulations of maize. The nucleotide diversity of Mtk was reduced by 78% in maize compared with teosinte. The results of our study revealed for the genes Naat1, Nas1, Nramp3, Mtk, and Ys1 a selective sweep, which suggests that these genes might be important for the fast adaptation of maize to new environments with different Fe availabilities.

Although NH4+ fertilization is known to acidify rhizosphere and enhance nutrient uptake, the effects on a nutrient-sufficient acidic soil amended with lime are not demonstrated. Thus, the influence of NH4+ fertilization of an unlimed and limed (3 g calcium carbonate per kg soil) acidic soil on the nutrient uptake and growth of maize was studied in comparison to NH4NO3 fertilization. The pH of limed rhizosphere soil was about two units higher than that of the unlimed soil. The maize plants were grown in pots under greenhouse conditions for about two months. The results showed that the pH of the NH4+-fertilized unlimed and limed soil was 0.54 and 0.15 units lower than the NH4NO3-fertilized soil. Liming negatively affected shoot and root dry matter production, whereas the NH4+-fertilized plants produced higher dry matter than the NH4NO3-fertilized plants, with significant difference of 28% in the limed soil only. Liming decreased Fe concentration in rhizosphere soil from 99 to 69 mg kg(-1) and decreased plant-available Mn the most (71%), whereas the NH4+-fertilized unlimed and limed soil had 48% and 21% higher Mn concentration than the respective NH4NO3-fertilized soils. Similarly limed rhizosphere soil had 50% lower plant-available Zn concentration than the unlimed soil, and the NH4+-fertilized soil had an 8% higher Zn concentration than the NH4NO3-fertilized unlimed soil. The liming negatively affected P, K, Mn, and Zn concentrations and contents in maize shoot to a lower degree in the NH4+-fertilized soil, whereas the positive effect of NH4+ on the nutrient concentration and contents was vigorous in the unlimed soil than the limed soil. It is concluded that NH4+ fertilization could be beneficial in enhancing nutrient uptake and growth of maize in both acidic and alkaline soils, despite the higher inherent plant-available concentrations of the nutrient in soil.

Although the nanoparticle (NP) utilization in agronomy is currently orientated to intensify crop yield, the potential negative effects on soil and plant reproductive organs, including effects on pollen are largely absent in the literature. For this reason, our study was set to evaluate the impact of ZnO nanoparticles (ZnO-NPs) on the selective properties of Fluvisol, on the direct microbial activity and zinc (Zn) phytoavailability, and crop yield after their foliar application on soybean [Glycine max (L.) Merril] under field conditions. Additionally, the potential hazardous impact to plant reproductive structures was evaluated, focusing on the agronomically and environmentally sensitive biomarker - pollen viability. The soil biological activity was evaluated through microbial respiration while Zn phytoavailability was determined using reaction agents with nutrients analysis conducted through flame atomic absorption spectroscopy (F-AAS). Pollen viability was evaluated using the iodine potassium iodide (IPI) test. The experiments were carried out at an experimental site of the Faculty of Agrobiology and Food Resources (FAFR) at the Slovak University of Agriculture (SUA) in Nitra, located in Central Europe, during the 2023 vegetation season. Depending on increasing concentrations of ZnO-NPs through order of 1.4, 14, and 140 mg·L-1, revealed no harmful effect on soil microbial activity or hazardous Zn accumulation in the context of its Fluvisol-phytoavailable distribution compared to NPs-free control. A positive impact on soybean pollen viability was observed at all applied ZnO-NP concentrations compared to the NP-free control. The highest pollen viability, reaching up to 97.04%, was achieved at a concentration of 1.4 mg·L-1, and, subsequently, it slightly decreased with increasing concentrations of ZnO-NPs. Moreover, the application of ZnO-NPs had a positive impact on soybean weight of thousand seeds and seed yield, where it's the highest concentration was the most effective. Thus, our results directly demonstrate the positive efficiency on selective properties of soil and reproductive structure - pollen, where ZnO-NP spray application acted positively and stimulatingly. Additionally, ZnO-NPs had positive impact on weight of thousand seeds (TSW) and seed yield. Therefore, the use of nanoparticles in foliar applications could be considered as kind of novelty in precision and sustainable agriculture.

The increasing application of nanotechnology and beneficial microbiomes in agriculture highlights the need to understand the role of arbuscular mycorrhiza fungi (AMF) in the uptake and distribution of nanoparticles (NPs) in host plants. In this study, we investigated the effects of different ZnO particle sizes (NPs and bulk) and concentrations (0, 200, 400, and 800 mg/kg) on zinc uptake by maize (Zea mays) grown with or without AMfungus Funneliformis mossae. Our results showed that neither ZnO particle form nor AMF presence significantly affected maize shoot biomass. However, 200 mg/kg ZnO concentration in both bulk and NPs, enhanced root biomass, indicating a concentration-dependent effect of Zn on plant growth. 800 mg/kg ZnO, regardless of particle size, reduced AMF colonization by 16.6 % (bulk) and 22.1 % (NPs) compared to the control, demonstrating a negative impact of elevated Zn on the plant-AMF symbiosis. Interestingly, despite reduced colonization, AMF external hyphal length increased in the 400 and 800 mg/kg ZnO NP treatments, suggesting that the utilization of AMF hyphae represents a potential strategy to reduce Zn toxicity. Analysis of Zn concentrations revealed that, in the absence of AMF, shoot Zn concentrations were 28 % higher in plants treated with bulk ZnO as compared to ZnO NPs, whereas this difference between ZnO forms disappeared in the presence of AMF. Moreover, AMF inoculation decreased Zn concentrations in roots for both bulk and NPs treatments, while in shoots, AMF reduced Zn concentration by 52 % in the bulk treatment across all concentrations, highlighting the protective role of AMF against heavy metal toxicity. These findings demonstrate that Zn uptake and distribution in maize depend on ZnO particle size and are strongly influenced by AMF. The observed changes in external hyphal length further suggest that this parameter should be considered in future studies on plant-AMF-NPs interactions.

The use of biochar in agriculture is a promising management tool to mitigate soil degradation and anthropogenic climate change. However, biochar effects on soil nutrient bioavailability are complex and several concurrent processes affecting nutrient bioavailability can occur in biochar-amended soils. In a short-term pot experiment, the concentration of N, P, K, S, Ca, Mg, Cu, Zn, Mn, B, Fe, and Na in the shoots of maize grown in three different soil types [sandy soil (S1), sandy loam (S2), and sandy clay loam (S3)] was investigated. The soils were either unamended or amended with two different biochars [wheat straw biochar (SBC) or pine wood biochar (WBC)] at two P fertilizer regimes (?/+ P). We used three-way ANOVA and Principal Component Analyses (PCA) of transformed ionomic data to identify the effects of biochar, soil, and P fertilizer on the shoot nutrient concentrations. Three distinct effects of biochar on the shoot ionome were detected: (1) both biochars added excess K to all three soils causing an antagonistic effect on the uptake of Ca and Mg in maize shoots. (2) Mn uptake was affected by biochar with varying effects depending on the combined effect of biochar and soil properties. (3) WBC increased maize uptake of B, despite the fact that WBC increased soil pH and added additional calcite to the soil, which would be expected to reduce B bioavailability. The results of this study highlight the fact that the bioavailability of several macro and micronutrients is affected by biochar application to soil and that these effects depend on the combined effect of biochar and soils with different properties.

Effect of the application of blackcurrant seed post-extraction residues (BS) enriched via biosorption with Zn(II), Mn(II) and Cu(II) was examined in field tests on maize. As a nominal dose (100%), 2.5 kg of zinc, 1 kg of manganese and 0.5 kg of copper per hectare, were applied. The preparation was applied, also, in higher doses (150%, 200%). Crop yield and quality were assessed and multielemental analysis of grains was conducted. Grain yield obtained for maize treated with different doses of micronutrients (7.3 and 7.2 Mg ha(-1) for BS 100% and BS 200%, respectively) was higher than in control group (6.2 Mg ha(-1)) and similar to a commercial reference product (7.1 Mg ha(-1)). Bioavailability of micronutrients from BS was shown to be higher than from reference commercial fertilizer. The highest content of micronutrients delivered to plants was observed for groups fertilized with BS in nominal dose of micronutrients (1.79, 7.08 and 28.55 mg kg(-1) for Cu, Mn and Zn, respectively). The content of each micronutrient was 5.6% (Cu) 12.1% (Mn) and 12.6% (Zn) higher than in untreated group and 8.9% (Cu) 9.7% (Mn) and 8.7% (Zn) higher than commercial reference micronutrient fertilizer. New biocomponents are cheap and biodegradable carriers of nutrients which can be released in controlled way.

Background Aims Methods Results Conclusions Boron (B) is an essential micronutrient for plants. Dicot plants respond to insufficient B supply by altering root architecture and root hair growth. How root systems of rather low-B demanding monocot species such as maize (Zea mays L.) respond to B deficiency in terra has not been experimentally resolved, yet.The study aims to investigate root responses and their physiological consequences under B deficiency during the vegetative growth of maize.B73 wild-type (WT) maize and its root hairless rth3 mutant were grown under varying B supply conditions in soil columns and in an automated root phenotyping facility. Biomass data, root system architecture traits, the mineral elemental composition and molecular B-deficiency responses were quantified.Though having very low leaf B concentrations, no major growth deficit, apart from chlorotic stripes on leaves, was recorded on maize root and shoot development, with or without root hairs, on B-deficient conditions. Although leaf B concentration of the rth3 mutant is significantly lower under B-deficient and under B-surplus conditions compared to the WT, the rth3 mutant neither developed a larger total root length, more fine roots nor displayed a higher expression of B uptake transporters as compensatory adaptations.Strikingly, maize plants did neither react with an inhibited root growth nor by a compensatory root foraging behaviour to severe B-deficient in terra growth conditions. This is rather atypical for plants. The performance and altered leaf B concentrations of rth3 mutants may be biased by secondary effects, such as an overall reduced root growth.

Experiments to assess the rate of absorption and translocation of foliar-applied, isotopically labeled boric acid (BA) were carried out with lychee (Litchi chinensis Sonn.) and soybean (Glycine max [L.] Merr.) plants. Boron (B) absorption and translocation within the plant, one week after treatment, was investigated after adding to the boric acid (BA solutions 0.5 mM CaCl2 and/or 50 or 500 mM sorbitol). The contribution of stomata to the absorption process was assessed by applying the solutions either to the adaxial or to the abaxial leaf side. Both plant species differed greatly in total absorption rates. The adaxial leaf surface (lacking stomata) of lychee leaves was nearly impermeable, while the stomatous abaxial surface was permeable to BA solutions. In this species, no translocation of 10B to other leaf parts and no effect of adjuvants in increasing 10B absorption were recorded. In contrast, 10B was absorbed both by adaxial and abaxial leaf surfaces of soybean leaves. Boron concentrations measured in treated soybean leaves were sixfold higher after application to the abaxial as compared to the adaxial leaf surface. The addition of adjuvants significantly enhanced the rate of 10B absorption, but not its translocation within the plant. Treatments containing 500 mM sorbitol led to increased 10B absorption and enhanced acropetal 10B movement, whereas adding only 50 mM sorbitol had no significant effect. Application of 0.5 mM CaCl2 in combination with 500 mM sorbitol decreased the rate of 10B absorption, compared to the performance of 500 mM sorbitol alone. Basipetal 10B translocation was very limited. A distinct effect of B-sorbitol complexes on B translocation apart from the pure adjuvant effect could not be discerned in this investigation.

This paper evaluates boron management for crops in Minnesota, detailing specific findings for corn and soybean production. Boron is immobile in both corn and soybean, meaning deficiency symptoms appear first on the youngest leaves. In corn, boron deficiency causes short and bent cobs, barren stalks, poor kernel development, elongated watery stripes that turn white on new leaves, and dead growing points. Boron sufficiency range for corn whole tops less than 12? tall and base of ear at initial silk all is 5-25 ppm. In soybean, deficiency symptoms involve yellowing leaves, curling leaf tips, interveinal chlorosis, tip dieback, stunted roots, and stopped flowering. Both crops are classified as having a small response potential to boron. Boron sufficiency range for corn whole tops less than 12? tall and base of ear at initial silk all is 5-25 ppm. For soybean (trifoliate leaves) at early flowering, boron sufficiency range is 20-60 ppm. Field experiments across Minnesota demonstrated that boron fertilizer applications produced no grain yield increases in corn, showing that standard soil boron tests are unreliable predictors for corn. Similarly, multi-location trials on soybeans found that although boron application elevated tissue concentrations above sufficiency thresholds, grain yields did not increase at any site and actually decreased at two locations. Furthermore, soybeans exhibit high sensitivity to boron toxicity, which manifests as leaf yellowing and marginal scorching. Consequently, B fertilizer should not be applied to soybean, regardless of soil test recommendations. to prevent toxicity risks.