Crop Uptake Research Articles

Optimizing multi-surface modelling of available cadmium as measured in soil pore water and salt extracts of soils amended with compost and lime: The role of organic matter and reactive metal

The effectiveness of strategies to reduce cadmium (Cd) availability for crop uptake can be assessed using various measures of Cd availability, such as Cd concentration in pore water and Cd extracted with salt solutions. This study evaluated the performance of multi-surface modelling (MSM) to predict dissolved Cd in two Irish tillage soils treated with lime, zinc (Zn) and spent mushroom compost (SMC). Predictions were assessed against Cd measured in three solution media, i.e., 1 mM Ca(NO3)2 and 0.1 M CaCl2 extractions, as well as in soil pore water. Results indicate that reactive soil organic matter (SOM) may be underestimated using a single 0.1 M NaOH extraction in the investigated soils, leading to substantial overestimation of dissolved Cd by MSM, particularly at higher pH. Repeating the 0.1 M NaOH extraction three times substantially improved model predictions. Additionally, using reactive Cd determined by isotopic dilution instead of 0.43 M HNO3 improved model predictions for one of the soils that was rich in manganese (Mn) oxides, revealing a possible role of Mn oxides in determining the reactive Cd fraction. After optimizing reactive SOM and reactive Cd, residuals between predicted and measured Cd showed an increasing trend along with increasing solution pH and decreasing dissolved Cd. This is likely related to Cd binding to high affinity sites due to uncertainties in the binding parameters for these sites and/or to slow desorption kinetics for Cd bound to these sites. Despite significant variations in solution properties, including higher dissolved Ca and reactive dissolved organic matter (DOM), 1 mM Ca(NO3)2 extracts exhibited similar extractable Cd levels, model performance, and Cd speciation compared to soil pore water especially at higher pH. Thus, 1 mM Ca(NO3)2 can be a reliable proxy for soil pore water in assessing Cd availability for crop uptake in soils with circumneutral to alkaline pH.

Effects of Fresh and Composted Azolla on Soil Chemical Properties

The rise in chemical fertilizer use in Malaysia raises concerns about soil degradation and potential long-term yield reductions, highlighting the importance of using organic matter for soil restoration. Azolla has been extensively studied as an alternative soil amendment due to its high nitrogen and nutrient content, as well as its rapid growth. However, the effects of fresh and composted Azolla amendments on soil chemical properties are not yet fully understood. A soil incubation study was thus conducted to determine the effects of fresh and composted Azolla on soil chemical properties over a 3-month incubation period. The soil treatments consisted of non-amended soil (control); fresh Azolla at 3, 6, and 9% w/w; and composted Azolla at 1, 2, and 3% w/w, with soil water holding capacity maintained at 55% throughout the incubation period. The collected soil samples were analyzed for soil pH and electrical conductivity (EC), total carbon (C) and nitrogen (N), available phosphorus, exchangeable bases—potassium (K), calcium, and magnesium, using inductively coupled plasma optical emission spectrometry, and cation exchange capacity (CEC). All data were subjected to variance analysis for statistical analysis. The study revealed significant effects of interaction between soil treatments and incubation periods for all soil parameters. At the end of the incubation period, the soil treated with 3% composted Azolla exhibited higher soil EC, total C and N, exchangeable K, and CEC compared to other soil treatments. The 3% fresh Azolla treatments were also observed to improve the soil’s exchangeable calcium by the end of the incubation period. In conclusion, 3% composted Azolla is best to help restore soil nutrient levels for crop uptake.

Cut-off walls alter nitrogen loads and fluxes in small islands

The measure of constructing cut-off walls in coastal islands has been tested effective to upgrade the freshwater lenses (FWL). Meanwhile, cut-off walls can also affect the FWL quality by changing the loads and fluxes of nitrogen (N). Previous research has been focused on the effects of cut-off walls on the N fluxes in groundwater (like, e.g., nearshore denitrification), assuming a constant N source while changes of the N loads and fluxes associated to the N source in shallow soils have only rarely been considered. In this study, we numerically simulated seawater intrusion and transport of land-sourced nitrate on a 2D, vertically oriented island equipped with a cut-off wall. A simplified framework was used to simulate the N fate in the shallow soil. We selected different aquifer permeability and the depth of cut-off wall. The cut-off wall effect on the N loads and fluxes in soil and groundwater, and on the nitrate concentration within the FWL, was quantitatively assessed. The results show that cut-off walls can considerably reduce the soil N load in high permeability islands (> 10−11.5 m2), because of the increased potential crop uptake due to the increased groundwater level and higher soil moisture. The opposite effect was observed in low permeability islands (< 10−11.5 m2) due to the smaller N leaching fluxes from soil to groundwater under the reduced groundwater flow rate. For the high and low permeability islands the leaching flux can generally be reduced by up to 63 %; for the intermediate permeability islands (10-11.5 m2 ≤ k ≤ 10-11 m2), however, the leaching is increased by up to 38 %. Highly depending on how the leaching changes, cut-off walls can reduce the groundwater N load and the nitrate concentration of FWLs, and thus improve the FWL quality in many cases except for the intermediate permeability islands. Therefore, special caution and investigation are required for constructing cut-off walls on islands with intermediate permeability. As a first attempt to assess the influence of cut-off walls on N loads and fluxes considering the N source dynamics, our study is important for the management of FWL quality and coastal environments.

Nitrogen and Carbon Mineralization from Organic Amendments and Fertilizers Using Incubations with Sandy Soils

Synthetic fertilizers are the main nitrogen (N) input used in specialty crop systems established on sandy soils of Florida, although organic amendments and fertilizers can be used as a substitute. Organic N contained in these products must be mineralized before crop uptake, which is affected by amendment properties, soil properties, and temperature. A better method for predicting N release can help maximize the nutrient cycling benefits of organic amendments and fertilizers while avoiding negative environmental impacts. The main objective of this study was to measure N release and CO2 emissions from two poultry manure-based amendments (PMA) and two processed organic fertilizers (OF) made from livestock byproducts (e.g., feather meal). We conducted an 8-week incubation using two sandy Florida soils belonging to two soil orders (Entisol and Spodosol) and with a greater than two-fold difference in soil organic C. We incubated these soils at 10 °C, 17 °C, 24 °C, and 30 °C, measured plant-available N at 0, 1, 4, and 8 weeks, and measured CO2 emissions weekly. In both soils, OF released more inorganic N and at a faster rate compared with PMA, but CO2 emissions were greater from PMA than OF. Nitrogen mineralization and CO2 emissions increased with temperature, but temperature effects were less important than expected. These results on the mineralization of PMA and OF in sandy soils are key to optimize their use and management in Florida and other areas dominated by sandy soils.

Soil metagenomics reveals reduced tillage improves soil functional profiles of carbon, nitrogen, and phosphorus cycling in bulk and rhizosphere soils

Conservation tillage practices (CAT) are known to benefit soil health and soil ecosystem functions relative to conventional tillage (CVT); however, much uncertainty remains concerning microbial functional traits and their subsequent effects on soil nutrients under different tillage practices. We analyzed the functional profiles of the C, N, and P cycles in response to CAT of no-tillage (NT), reduced tillage (RT), and CVT of moldboard plowing (MP) in bulk and rhizosphere soils using shotgun sequencing. CAT induced distinct microbial functional patterns relative to CVT, and these differences were generally more evident in rhizosphere soils than in bulk soils. CAT promotes multiple metabolic pathways such as C and N decomposition, fermentation, CO oxidation, N fixation, nitrate reduction and inorganic-P and organic-P transformations in bulk and/or rhizosphere soils. Variations in these metabolic pathways were mainly driven by Bradyrhizobium, Mesorhizobium, Nitrososphaera, Phenylobacterium, Rhizobium which are affiliated with Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidota and Thaumarchaeota. Furthermore, 24 high-quality metagenome-assembled genomes (MAGs) were reconstructed, of which three novel MAGs (TL100, TL46, and TL57) harbored functional genes regulating all metabolic pathways. In particular, NT-enriched MAGs (such as Sphingomonas) promote fermentation, resulting in the reduction of soil total carbon (TC) relative to MP in bulk soils. RT retained the contents of soil TC and total nitrogen (TN) well and up-regulated the phoR gene carried by Streptomyces, which promoted the regulation of P-starvation concomitantly with the increase in the contents of total phosphorous (TP) and available phosphorous (AP) in bulk soil. Additionally, assimilatory nitrate reduction coupled with organic-P mineralization was facilitated by CAT in rhizosphere soil, leading to the mitigation of N loss and the activation of soil organic-P for crop uptake. Overall, our results revealed that CAT significantly accelerated multiple metabolic potentials, and RT could sustain soil nutrient contents better than NT.

Decreased Sulfamethoxazole Uptake in Lettuce (Lactuca sativa L.) due to Transpiration Inhibition by Polypropylene Microplastics

Microplastics and antibiotics are emerging contaminants in agricultural soil that can have negative effects on crops. However, limited research has been conducted on the effects of the polypropylene (PP) microplastic and sulfamethoxazole (SMX) co-exposure on crops, specifically regarding the impact of PP microplastics on SMX uptake and transport in crops. In this study, hydroponic experiments were carried out using lettuce (Lactuca sativa L.), PP microplastics (1.0 g L−1), and SMX (0.5 mg L−1 or 2.5 mg L−1) to investigate the individual and co-exposure effects of PP microplastics and SMX on Lettuce growth, explore the uptake and translocation of SMX in lettuce and elucidate the underlying mechanism of PP microplastic impact on SMX uptake. Results demonstrated that co-exposure to 1.0 g L−1 of PP microplastics and 0.5 mg L−1 of SMX resulted in an enhanced toxic effect. However, no intensified toxic effect on the lettuce was observed when 1.0 g L−1 PP microplastics were added in the presence of 2.5 mg L−1 SMX, indicating that the SMX dominated the toxic effect on lettuce at high concentrations. Additionally, the study found that the water absorption process controlled by the aquaporin and transpiration contributed to the uptake and translocation of SMX in lettuce. When exposed to PP microplastics, no impact was observed on the aquaporin contents of the lettuce while the transpiration rate was significantly decreased by 31.6 % - 44.2 % resulting from microplastics adhered to the root surface. Therefore, in the presence of 2.5 mg L−1 SMX, the SMX uptake in the lettuce root was inhibited by 35.9 % (P < 0.05) when exposed to 1.0 g L−1 PP microplastic. This work deepens our understanding of the behaviour of microplastics and antibiotics in the terrestrial environment.

Faba bean-wheat intercropping controls the occurrence of faba bean Fusarium wilt by improving the microecological environment of rhizosphere soil

BackgroundFusarium wilt is a severe soil-borne disease that affects faba bean production. Faba bean-wheat intercropping is often used to control the occurrence of Fusarium wilt in faba bean. AimsTo evaluate the effects of faba bean-wheat intercropping on the occurrence of faba bean Fusarium wilt and soil microecology. MethodsWe established two planting patterns, faba bean monocropping (M) and faba bean-wheat intercropping (I), to investigate Fusarium wilt occurrence and plant dry weight and assess changes in soil enzyme activities, microbial diversity, and community composition during different stages of disease onset. ResultsIntercropping effectively controlled faba bean Fusarium wilt at the three disease stages and increased the dry weight of faba bean plants. Intercropping promoted the activities of catalase (CAT), urease, sucrase, and acid phosphatase in the rhizosphere soil of faba bean at three disease stages. Bacterial and fungal diversity decreased with disease progression, and intercropping mitigated this trend. Compared with monocropping, intercropping increased the abundance of beneficial bacteria such as Proteobacteria, Actinobacteriota, Gemmatimonadota, Gemmatimonas, Conexibacter, and Sphingomonas, while reducing the abundance of pathogenic fungi such as Alternaria, Cladosporium, and Fusarium. Intercropping also increased the abundance of arbuscular mycorrhiza, soil saprophytes, and undefined saprophytes while decreasing the abundance of plant pathogens. ConclusionFaba bean-wheat intercropping enhanced soil enzyme activities, effective nutrient content, and alpha diversity indices of bacteria and fungi in the rhizosphere soil of faba bean, while promoting the abundance of beneficial bacteria, arbuscular mycorrhizal fungi, as well as both soil and undefined humus. Simultaneously, intercropping reduced the abundance of plant pathogens, facilitated nutrient cycling in the soil, provided sufficient nutrients for crop uptake, and mitigated the toxic effects of hydrogen peroxide on cells. Ultimately, this resulted in a reduced occurrence of Fusarium wilt.

Poplar based agroforestry system: Symmetry to maximize productivity and optimized nutrient acquisition in fodder sorghum–wheat rotation in semiarid region of Haryana

A field experiment was conducted during the kharif and rabi season of 2 years (2022–24) at the farm of agroforestry of Chaudhary Charan Singh Haryana Agricultural University, Hisar to evaluate the impact of different geometry of poplar on the yield and nutrient uptake of sorghum and wheat under poplar-based agroforestry sys- tems. The experiment was laid out in a randomized block design with 3 replications. The sorghum and wheat were sown as per the treatment comprising different spacing of poplar i.e. 3 m × 3 m, 4 m × 3 m, 5 m × 3 m, 6 m × 3 m, 7 m × 3 m, 8 m × 3 m and control (sole crops without trees). The results showed that sorghum (14.02 and 14.48 t/ ha) dry fodder yield and wheat grain yield (5.14 and 5.30 t/ha) and straw yield (7.17 and 7.28 t/ha) were maximum under control in 2022–23 and 2023–24, respectively. The yield of sorghum (13.62 and 15.54%), wheat grain (44.55 and 45.66%) and wheat straw (39.05 and 39.15%) were lower at 3 m × 3 m spacing compared to control in 2022–23 and 2023–24, respectively. The increase in spacing of poplar increase the yield of sorghum and wheat during both the years of study i.e. least yields at 3 m × 3 m popular spacing and highest under 8 m × 3 m spacing. However, popular based system yields of sorghum (8.01 and 8.42%), wheat grain (50.18 and 50.00%) and wheat straw (42.56 and 42.44%) were higher under 8 m × 3 m than 3 m × 3 m spacing in 2022–23 and 2023–24, respec- tively. Similar significant results were obtained in case of nutrient uptake N, P and K as yield of sorghum (143.9, 147.2, 18.3, 19.9 and 31.4, 29.2 kg/ha) and wheat in grain (81.8, 83.4, 13.7, 14.3 and 13.3 14.4 kg/ha) and straw (26.8, 28.4, 7.5, 8.7 and 64.2, 66.3 kg/ha) under 8 m × 3 m during 2022–23 and 2023–24, respectively. Hence, control has significant effect on the yield and nutrient uptake of crops than under agroforestry systems. While, among all the treatments of poplar-based alley crop systems, spacing of 8 × 3 m the significantly higher green for- age, and grain yields and nutrient uptake.

Effect of integrated nutrient management practices on nutrient content &amp; nutrient uptake and productivity of wheat crop

Effect of integrated nutrient management practices on nutrient content &amp; nutrient uptake and productivity of wheat crop

Stabilization of Arsenic and Heavy Metal Contaminated Soil Using Fishery By-Products and Evaluation of Heavy Metal Uptake in Crops

Objectives : Heavy metals eluted from mine waste pollute surrounding soil and water systems, which can spread to crops and have a harmful effect on the human body. The purpose of this study was to evaluate the feasibility of recycling discarded mussel shells(MS) and manila clam shells (MC) as stabilizers for the immobilization of arsenic(As) and heavy metals(Pb, Zn) in soil.Methods : MS and MC were processed with -#10 mesh natural material, -#20 mesh natural material, and -#10 mesh calcined material and treated at 0-10 wt%. After 1 week or 4 weeks of wet curing, it was eluted with 0.1 N HCl and the concentrations of As, Pb, and Zn in the soil were analyzed through inductively coupled plasma optical emission spectroscopy(ICP-OES) analysis. In addition, red lettuce was cultivated in the stabilized soil and the concentration of heavy metals that were transferred to crops was evaluated. The stabilization mechanism was investigated by scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDX) analysis.Results and Discussion : The stabilization efficiency for arsenic and heavy metals was in the order of natural -#10 mesh &lt; natural -#20 mesh &lt; calcined -#10 mesh. The calcined stabilizer showed a high stabilization efficiency of 98% at a 2 wt% treatment level. Pb was not detected in the red lettuce grown in the stabiliz ed soil, and the standard for leafy vegetables (Pb-0.3 mg/kg or less) was satisfied according to the Ministry of Food and Drug Safety. The SEM-EDX analysis revealed that As was stabilized through Ca-As precipitation and heavy metals(Pb, Zn) were stabilized through pozzolanic reactions.Conclusion : Stabilizers developed from MS and MC can be effectively applied to the stabilization of As and heavy metal-contaminated soil, and are expected to be used as economical and environmentally friendly stabilizers.

Nanoparticles Mediated Modulation of Nitrogen Fixation in Legumes: A Biochemical Perspective

This review article explores the emerging role of nanoparticles in enhancing nitrogen fixation in leguminous crops, a critical process for sustainable agriculture. Focusing on metal-based nanoparticles like iron oxide (Fe₂O₃) and zinc oxide (ZnO), as well as carbon-based nanoparticles such as carbon nanotubes (CNTs), the review discusses their effects on nitrogenase enzyme activity, root nodule formation, and nutrient uptake. Empirical studies demonstrate significant improvements in nitrogenase efficiency, nodule count, and nitrogen uptake in crops like soybean, chickpea, and peanut when treated with these nanoparticles. However, the potential risks of nanoparticle bioaccumulation, toxicity at higher concentrations, and environmental impacts are also highlighted, emphasizing the need for biodegradable nanoparticle development and regulatory guidelines. The review concludes that while nanoparticle-mediated nitrogen fixation holds promise for improving crop yields and reducing reliance on synthetic fertilizers, careful management and future research are crucial to ensuring the safe and effective integration of nanotechnology into agriculture.

The transcription factor OsNAC5 regulates cadmium accumulation in rice

Cadmium (Cd) is a hazardous heavy metal that threatens human health through the consumption of contaminated rice. To mitigate Cd accumulation in rice grains, it is crucial to reduce Cd uptake. Nevertheless, the transcriptional mechanisms governing Cd uptake in rice remain largely unknown. This research identifies the transcription factor OsNAC5 in Oryza sativa as a positive regulator of the Cd transporter gene OsNRAMP1, thereby influencing Cd uptake. OsNAC5 is predominantly expressed in the roots, resides in the nucleus, and is upregulated by Cd-induced hydrogen peroxide (H2O2). Knocking out OsNAC5 results in lower Cd concentrations in both shoots and roots and heightens sensitivity to Cd. The expression of OsNRAMP1, enhanced by Cd stress, is dependent on OsNAC5. OsNAC5 binds to "CATGTG" motifs in the OsNRAMP1 promoter, activating its expression. The loss of OsNAC5 function leads to reduced Cd accumulation in rice grains. Our findings provide insights into the transcriptional regulation of Cd stress response in rice and propose biotechnological strategies to lower Cd uptake in crops.

Pharmaceutical and personal care products in recycled water for edible crop irrigation: Understanding the occurrence, crop uptake, and water quantity effects

Global water scarcity poses a great challenge to agriculture productivity. Recycled water offers a promising alternative for agricultural irrigation, yet residual pharmaceutical and personal care products (PPCPs) in recycled water can transfer to edible crops during irrigation, and adversely affect food safety. Furthermore, irrigation water quantity can influence the accumulation of PPCPs in edible crops. This study comprehensively investigates the use of recycled water for agricultural irrigation by critically reviewing three key components: PPCPs occurrence in recycled water, their accumulation in edible crops, and the impact of water quantity on PPCPs accumulation. Literature analysis showed that PPCPs were present from 130 to 1400 ng/L in secondary effluent and 25–400 ng/L in tertiary effluent, with sulfamethoxazole being the most prevalent in both effluents. PPCPs uptake and accumulation varied between leafy and fruity vegetables, with diclofenac accumulating highest in leafy vegetables and fluoxetine in fruity vegetables. Furthermore, the water requirement of leafy and fruity crops vary throughout the growing season. In leafy vegetables, PPCPs accumulation in leaves is influenced by transpiration rate, with reduced accumulation occurring under limited water availability due to slower transpiration. In fruity vegetables, osmotic adjustment drives the water transport in fruits, leading to increased PPCPs accumulation under limited water conditions. This study contributes insights into PPCPs occurrence, accumulation, and irrigation water quantity, aiding in the development of effective strategies for recycled water use in agriculture.

Effect of fertility levels and stress mitigating chemicals on nutrient content, uptake, intercropping advantage and competition effect in cowpea-baby corn intercropping

The primary goal of this study was to analyze how various row ratios of intercrops, in conjunction with different fertilizer levels with spray of two stress mitigating chemical, affect nutrient content, land productivity, and economic viability during Summer season. Furthermore, we aimed to explore the competitive dynamics within legume/cereal intercropping systems. Hence, A field experiment at Agriculture University, Kota, during the summers of 2019 and 2020, investigated different cowpea + baby corn intercropping system's intercropping indices, nutrient dynamics, uptake, and post-harvest soil nutrient balance under varying recommended fertilizer levels and foliar spray of stress mitigating chemicals. Using a split-split plot design replicated four times, the experiment involved thirty treatment combinations, including five intercropping techniques viz. Sole cowpea, sole baby corn, cowpea + baby corn 2:1, cowpea + baby corn 3:1, cowpea + baby corn 4:1 in the main plot, three fertility levels viz. 100 %, 125 % and 150 % recommended dose of fertilizer (RDF) in subplots, and two stress mitigation chemicals; CaCl2 0.5 % and KNO3 1% in sub-subplots. The findings revealed notable trends, including nitrogen (N) and (P) content in cowpea seeds and straw, baby corn cobs and fodder, as well as enhanced land-equivalent ratio (LER) and monetary advantage index (MAI) within the cowpea + baby corn 2:1 row ratio. However, despite these advantages, total N and P uptake were markedly higher in sole crops. Notably, sole cowpea demonstrated the highest actual N and P balance and lowest was under sole baby corn. Among the fertility levels, the 150 % RDF level exhibited the most favorable outcomes across various parameters, including LER, MAI, NP content, and uptake in both crops. Additionally, higher fertility levels correlated with increased apparent and actual soil nutrient balances. While, among stress mitigation chemicals, CaCl2 0.5 % resulted in significantly heightened N and P uptake. Hence, to optimize intercropping dynamics and maintain soil nutrient balance, it is advisable to intensify cowpea cultivation along with baby corn in a 2:1 row ratio, utilizing 150 % RDF is beneficial. Additionally, alleviating higher temperature stress during the summer season can be achieved by applying a 0.5 % solution CaCl2 through spraying at the flowering and pod development stages of cowpea.

Developmental responses of roots to limited phosphate availability: research progress and application in cereals.

Phosphorus (P), an essential macronutrient, is crucial for plant growth and development. However, available inorganic phosphate (Pi) is often scarce in soil, and its limited mobility exacerbates P deficiency in plants. Plants have developed complex mechanisms to adapt to Pi-limited soils. The root, the primary interface of the plant with soil, plays an essential role in plant adaptation to Pi-limited soil environments. Root system architecture significantly influences Pi acquisition via the dynamic modulation of primary root and/or crown root length, lateral root proliferation and length, root hair development, and root growth angle in response to Pi availability. This review focuses on the physiological, anatomical, and molecular mechanisms underpinning changes in root development in response to Pi starvation in cereals, mainly focusing on the model monocot plant rice (Oryza sativa). We also review recent efforts to modify root architecture to enhance P uptake efficiency in crops and propose future research directions aimed at the genetic improvement of Pi uptake and use efficiency in crops based on root system architecture.

Effect of Ni and Fe Co-Application on the Soybean Crop Grown in Nickel and Iron Deficient Soils of Mirzapur District

ABSTRACT Considering the importance of nickel and iron nutrition for the soybean crop, their deficiency inhibits the yield drastically specially in the area where soybean crop is dominant. To encounter this problem, a pot experiment was conducted in glass house on low nickel and iron soil in Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, during 2019–20 and 2021–22. The study was carried out to investigate the effect of Ni (nickel) and Fe (iron) on the post-harvest soil parameters, growth, yield, nutrient uptake and nutrient content of soybean crop. There were 10 treatments with two levels of Ni (5 and 10 mg kg −1) and Fe (10 and 20 mg kg−1) with recommended dosage of fertilizers nitrogen, phosphorus, potassium (8.93, 35.71, and 17.86 mg kg−1) applied to all treatments except control. The result of the experiment revealed that the co-application of nickel and iron@10 mg kg−1 and 20 mg kg−1 (RDF + Ni10Fe20), resulted in the increase in plant height, greeness index, no of seed per pod, no of pod per plant, seed yield, and stover yield. Similar, findings for the post- harvest soil parameter indicated that there was increase in pH, electrical conductivity, and organic carbon content of soil. DTPA (Diethylenetriaminepentaacetic acid) extractable Ni, Fe, Zn, and Cu, also found highest in treatment where nickel and iron@10 mg kg−1 and 20 mg kg−1 (RDF + Ni10Fe20) were applied in soil, but in case of DTPA extractable Mn, the highest amount was found in treatment where nickel and iron@10 mg kg−1 and 10 mg kg−1 (RDF + Ni10Fe10) was applied in soil. The soil microbial biomass carbon and urease activity was also found highest in the treatment where nickel and iron@10 and 20 mg kg−1 was applied in soil. The minimum plant height, greeness index, no of seed per pod, no of pod per plant, seed, and stover yield was recorded in treatment where only RDF(T1) was applied. Similar, result recorded for the post-harvest soil parameters. So, overall findings of the pot experiment revealed that the conjoint application of nickel and iron has resulted in better yield of soybean crop.

Adding mineral-enriched biochar to the rhizosphere reduces heavy metal toxicity on plants and soil microbes

In this study, a mineral-enriched (Ca and P) bagasse biochar was synthesized and characterized. The formulation of Ca and P-enriched bagasse biochar (CPB) was examined for immobilizing arsenic (As), cadmium (Cd), and lead (Pb) in rhizospheric soil. The potential of CPB to alleviate heavy metal stress on plants and soil microbial communities was also investigated. The Ca and P-enriched bagasse biochar demonstrated loading of 88 % Ca and 86 % P with improved pore volume, cation exchange capacity, and water-holding capacity. The FTIR and morphology studies demonstrated an increase in surface functionalities on biochar surface and porous morphology. CPB had 1089±21 µm particle size, 1.1 µm pore size, 0.35±0.01 mv PDI, and 20.8±0.2 mv zeta potential, and displayed no phytotoxicity. The application of the CPB in the soil significantly reduced the availability of As, Cd, and Pb in the soil and their uptake in A. paniculata. CPB application altered the subcellular distribution of As, Cd, and Pb in plant tissues. The CPB spray significantly enhanced the biomass (16–27 %), protein (8–44 %), and chlorophyll (15–61 %) contents of A. paniculata. The application of CPB in metal-contaminated soil resulted in an increased relative abundance of the phylum Proteobacteria and the genera Bacillus, Gemmata, and Sphingobium in the microbial community structure of the rhizospheric soil. The study suggested that CPB formulation can be used as a potential solution to alleviate different metal uptake and toxicity of crops planted in contaminated soil, improve rhizospheric soil quality, and reconstruct the microbial community structure.

Field-based assessment of the effect of conventional and biodegradable plastic mulch film on nitrogen partitioning, soil microbial diversity, and maize biomass

In an agricultural context, the use of conventional low-density polyethylene (LDPE) and biodegradable plastic mulch film has been actively promoted, however, the effects on physical and biochemical soil properties, crop growth dynamics, yield, and nutrient cycling of conventional and biodegradable mulch film use in a temperate climate remain largely undetermined. Here, we conducted a field experiment, exploring the effects of no mulch (control), conventional (LDPE), and biodegradable (PLA/PBAT) plastic mulch film on soil and crop (Zea mays L.) nitrogen (N) partitioning after application of 15N-labelled ammonium-nitrate fertiliser. Further, we also investigated the treatment effects on soil physical and biochemical properties (e.g., microbial diversity, compound-specific microbial 15N incorporation, N dynamics), plant development, as well as monitoring the biotic and abiotic degradation of the plastic mulch films. We found that conventional mulch film increased crop yield by 25 % and 15N uptake by 34 % compared to the control, simultaneously reducing 15N retention by 40 % in the topsoil (0–10 cm), but not affecting microbial N use efficiency and N transformation and incorporation into the protein pool. Biodegradable film application resulted in similar biomass (306 ± 14 g plant−1) to both control (275 ± 14 g plant−1) and conventional mulch (344 ± 20 g plant−1) treatments, but significantly reduced 15N crop uptake by 63 % compared to the conventional mulch film. We ascribe this to the accelerated mechanical breakdown and faster degradation of the biodegradable mulch film during the growing season. These findings suggest that current biodegradable plastic mulch film polymer blends may not be a suitable alternative to conventional mulch film in terms of short-term productivity and N use efficiency in a temperate climate for maize production.

The Crop Phosphorus Uptake, Use Efficiency, and Budget under Long-Term Manure and Fertilizer Application in a Rice–Wheat Planting System

Little is known about the effect of the long-term application of organic and inorganic fertilizers on P-use efficiency, P budget, and the residual effect of P fertilizer. To clarify the effect of different fertilization on soil P balance in a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) rotation system is helpful to promote the sustainable development of agriculture. Thus, a thirty-five-year fertilizer experiment was conducted with eight treatments, including an unfertilized control (CK); chemical nitrogen (N), phosphorus (P), and potassium (K) fertilizers; and organic manure (M) either alone or in combination treatments (N, NP, NPK, M, MN, MNP, and MNPK). The results indicated that crop yields and P uptake were higher in the combined application of manure and chemical fertilizer treatments than in the manure or chemical fertilizer alone treatments. Soil P budget indicated a 23.4–55.4 kg P ha−1 yr−1 surplus in the organic combined with or without mineral fertilizer treatments, but the soil P budget indicated a 20.0 and 21.9 kg P ha−1 yr−1 deficit in the control and N treatments. The proportion of residual fertilizer P converted to soil available P in NP, NPK, M, MN, MNP, and MNPK treatments was 4.5%, 4.8%, 19.1%, 19.0%, 11.5%, and 13.3%, respectively, over a 35-year period. Furthermore, according to the higher P content and crop uptake in organic manure treatment compared with chemical P fertilizer alone, an organic addition could effectively reduce the use of chemical fertilizer and become an effective way of sustainable development in practice. Therefore, the combined application of organic and inorganic fertilizer will be a practical method to increase crop yields and soil P status in a rice–wheat planting system.

Cultivating resilience: Harnessing pyoverdine-producing Pseudomonas to contrast iron deficiency in cucumber plants

Iron (Fe) deficiency in crops significantly reduces yield, impacting agricultural productivity worldwide. Synthetic Fe chelates are commonly applied as fertilizers to address this issue, but their synthetic nature and prolonged use poses environmental risks. Thus, inoculation of plant growth-promoting bacteria rises as an alternative to enhance Fe uptake in crops while minimizing reliance on synthetic chelates. This study aimed to examine the influence of Pseudomonas RMC4 inoculation and pyoverdine application on cucumber plants cultivated hydroponically under Fe deficiency conditions. Evaluations included the SPAD index, plant biomass, root morphology, Fe-chelate reductase activity, gene expression, and ionomic analysis. Following Fe deficiency, Pseudomonas RMC4 inoculation improved the SPAD index, increased dry weight, enhanced root development, and facilitated Fe acquisition mechanisms, thus, fostering the endogenous resilience of the plant to the limited Fe availability. This improvement was observed with bacterial inoculation or pyoverdine application alongside an insoluble Fe source (ferrihydrite). Overall, the results suggest the beneficial impact of Pseudomonas RMC4 inoculation in alleviating symptoms of Fe deficiency. Future studies will investigate bacterial application under field conditions to assess its potential in replacing synthetic Fe-chelates fertilizers in crop production in favor of more sustainable agriculture.