Soil Nutrient Research Articles

Microbiome-Mediated Mechanisms Regulating Adaptability to Iron Deficiency in the Intercropping System of Soybean and Maize

Iron (Fe) deficiency is a pervasive agricultural concern on a global scale. Intercropping plays a pivotal role in activating soil nutrient cycling and crop nutrient uptake and utilization. This study integrates plant physiology, soil physicochemical determination, high-throughput sequencing, and metabolomics techniques to conduct pot experiments using field-collected soils with soybean and maize plants. This study aims to investigate the mechanisms through which microorganisms in a soybean–maize intercropping system regulate Fe deficiency adaptation. The results revealed that intercropping enhances the resilience of soybean and maize in Fe-deficient environments, facilitates nutrient absorption by plants, and enriches soil nutrient content. Moreover, intercropping fostered more intricate microbial interactions in comparison to monocropping. The dominant microorganisms in the rhizosphere of intercropped soybean and maize included genera Microbacterium, Sphingomonas, Shinella, and Rhizobium. Microbacterium, Sphingomonas, Shinella, and Rhizobium have the potential to produce Fe chelators or enhance plant Fe absorption. Additionally, intercropping notably modified the composition of root exudates derived from soybean and maize. The soybean and maize rhizosphere exhibited significant enrichment with oleamide, coumestrol, glycitein, and daidzein. Coumestrol may have an effect of promoting Fe absorption, and it is significantly positively correlated with the genus Nakamurella in the maize rhizosphere and the genus Pirellula in the soybean rhizosphere. Consequently, these findings suggested that the rhizosphere of intercropped soybean and maize significantly enriches specific microbial communities and root exudates, thereby enhancing microecosystem stability and improving plant tolerance to Fe deficiency.

Organic Farming Is an Important Way to Achieve Low Accumulation of Heavy Metals in Soil

In this study, the accumulation characteristics of As, Hg, Cd, Cr, and Pb in 63 soil samples from 28 organic farms in Beijing, China, were analyzed to investigate the risk of heavy metal pollution in organic agriculture, and the key related factors were evaluated. The results revealed that the As, Hg, Cd, Cr, and Pb concentrations in the soil samples were below the risk screening values and substantially lower than those in the soil under conventional agriculture. However, the coefficients of variation for Hg and Cd were 112.45% and 38.34%, respectively, indicating a notable anthropogenic impact. Notably, 35.92% of the sampling sites had medium to high potential ecological risk values for Cd, and the Cd concentration increased considerably as the number of planting years increased. Different crop types impacted the soil heavy metal concentrations. The concentrations of Cd and As in the soil of Brassica crops were 0.265 and 12.915 mg/kg, respectively, which were substantially higher than those in the soil of other crop types. The Random Forest model indicated that soil nutrients had the most significant impact on soil heavy metal accumulation, particularly phosphorus. In conclusion, compared with conventional agriculture, organic agricultural soils have lower heavy metal concentrations and exhibit lower ecological risks, with no significant heavy metal pollution detected. However, there is a risk of Cd accumulation, and preventive measures should be implemented, especially for soils under prolonged cultivation and with potential sources of heavy Cd inputs.

Integrating rainwater harvesting and organic soil amendment to enhance crop yield and soil nutrients in agroforestry

Abstract More than 90% of rainfed croplands in Sub-Saharan Africa (SSA) are severely affected by highly intermittent rainfall and frequent drought limiting crop productivity in the region. Besides, 27.1% of the population in SSA are currently food insecure and this is likely to increase with the current rapid population growth in the region. Soil erosion and water scarcity remain to be the core problem affecting agricultural productivity of smallholder farming. In the current study, we analysed rainwater harvesting assisted small-scale agroforestry system in order to mitigate both soil erosion and water scarcity issues simultaneously. The system included in-situ rainwater harvesting, soil organic amendment (raw poultry litter, poultry litter biochar, wood ash) and an agroforestry system (AFS) containing maize, barley- Eucalyptus globulus all intercropped in a holistic approach. The effect was evaluated on selected soil parameters and crop yield in a field experiment on a completely randomized design. The treatments were poultry litter (PWAFS), poultry litter biochar (BWAFS) wood ash (AWAFS) with supplementary irrigation (WAFS) and agroforestry system AFS (control). The first three treatments contained poultry litter, poultry litter biochar and wood ash along with rainwater harvesting respectively while the fourth treatment contained only rainwater harvesting. Besides, a control plot-AFS was assigned with neither rainwater harvesting nor soil organic resources. The result indicated that BWAFS increased the pH by 19.4% followed by AWAFS and PWAFS (9%). Maximum and minimum SOM (2.26%, 1.21%) were observed under BWAFS and the control (AFS) respectively. BWAFS significantly increased Av.P by 78.1% while WAFS increased by 40% compared to the control. Similarly, BWAFS and PWAFS had significant effect on maize yield with increase by 74% and 36% respectively. The study concluded that integrating rainwater harvesting and soil amendment with agroforestry systems can enhance crop yield and soil nutrient levels. Therefore, such agricultural practices should be adopted by smallholder farmers in areas with limited water and nutrients levels.

Effect of Different Sources and Levels of Zinc on the Nutrient Content, Uptake and Fertility Status of Wheat

Indian farmers face challenges in wheat production due to poor soil nutrients and imbalanced fertilizer use, making zinc-supplemented fertilizers vital for boosting productivity. Wheat (Triticum aestivum L.) is a vital global food crop, rich in carbohydrates, protein, and essential nutrients, with India being a major producer, although many regions face significant zinc deficiency in their soils. A field study was conducted during Rabi 2021-2022 at Wheat Research Unit, Dr. Panjabrao Deshmukh Krishi Vidyapeeth, Akola. The experimental soil collected from the wheat research unit field was slightly alkaline in reaction, medium in organic carbon, moderately calcareous, low in available N, medium in available P, remarkably high in available K, marginal in available S, and sufficient in micronutrients but deficient in Zn. The nine treatments T1 to T9 are applied in the plots in Randomized Block Design with three replications. The higher nutrient content and N, P, K, S, Zn, Fe, Cu, and Mn uptake was recorded with the soil application of RDF + soil application of ZnSO4 @ 30 kg ha-1. It is concluded that the soil application of ZnSO4 @ 30 kg ha-1 along with a recommended dose of fertilizer (RDF) at the time of sowing recorded the highest nutrient content, nutrient uptake and improvement in soil fertility.

Saprotrophic fungal community responses to nitrogen additions in a Korean pine plantation: insights from using the mycoindicator

Human activities contribute to elevated nitrogen input in terrestrial ecosystems, influencing the composition of soil nutrients and microbial diversity in forest ecosystems. In this study, we built four addition treatments (0, 20, 40, and 80 kg ha−1 a−1 N for 6 a) at a Korean pine plantation of different soil horizons (organic (O) horizon, ranging from 0 to 10 cm, and organomineral (A) horizon, extending from 10 to 20 cm) to evaluate responses of the structure of saprophytic fungal communities. Here, 80 kg ha−1 a−1 N treatment significantly decreased the community richness in soil A horizon with the Chao1 index decreasing by 12.68%. Nitrogen addition induced changes in the composition of saprophytic fungi community between the different soil horizons. The co-occurrence network and its associated topological structure were utilized to identify mycoindicators for specific fungi to both soil horizons and nitrogen addition levels. In soil O horizon, the mycoindicators included Penicillium, Trichoderma, Aspergillus, and Pseudeurotium across control, low, medium, and high nitrogen treatments. In soil A horizon, Geomyces, Cladophialophora, Penicillium, and Pseudeurotium were identified as mycoindicators. Structural equation modeling determined NH4+-N as the key factor driving changes in saprotrophic fungal communities. Our study aimed to screen mycoindicators that can respond to the increasing global nitrogen deposition and to assess the roles of these mycoindicators in the saprophytic fungal community structure within Korean pine plantations in northeast China.

Broad-spectrum applications of plant growth-promoting rhizobacteria (PGPR) across diverse crops and intricate planting systems.

Multifunctional plant growth-promoting rhizobacteria (PGPR) have garnered significant attention in agricultural applications; however, a few have applied them in crop rotation or intercropping fields. To identify PGPR with strong colonization ability and broad spectrum benefit, we screened strains from the local tobacco rhizosphere and evaluated their growth-promoting effects across various crops and farming systems. In this study, strain L8, identified as Bacillus thuringiensis, was selected as a multifunctional PGPR capable of producing indole-3-acetic acid (IAA), solubilizing potassium, and mobilizing both organic and inorganic phosphorus. Compared with the control group, the soil treated with strain L8 in tobacco pot experiments showed significantly higher levels of IAA, available potassium, and available phosphorus. Furthermore, tobacco plants inoculated with L8 exhibited significantly improved growth parameters compared with the uninoculated control. The results indicated that compared with the control, strain L8 increased tobacco fresh weight (by 83.18%), plant height (by 29.32%), relative chlorophyll content (by 14.33%), as well as plant phosphorus (by 23.78%) and potassium (by 30.81%). Interestingly, L8 not only enhanced tobacco growth but also improved tobacco root morphology, significantly increasing root length (1.55-fold), root surface area (1.78-fold), and root volume (2.05-fold) compared with the control. These findings provide valuable insights into utilizing plant growth-promoting bacteria for tobacco production. Moreover, the inoculation strain L8 enriched soil organic matter and nutrient content in both wheat (Triticum aestivum)-maize (Zea mays) rotation and peanut (Arachis hypogaea)-maize intercropping systems. Furthermore, within the intricate tillage systems of wheat-corn rotation and peanut-corn intercropping, multifunctional PGPR strain L8 can play a crucial role in crop growth promotion, yield increase, and higher soil nutrient availability.IMPORTANCEThese findings aim to study the application of plant growth-promoting rhizobacteria (PGPR) in diverse crops and complex planting systems, showing their adaptability and effectiveness in various agricultural contexts. The study suggests that this strain improves nutrient utilization in the soil, enhances soil health, and plays a significant role in plant growth through the secretion of substances like auxin (IAA). In parallel, we observed that applying this strain improved the production efficiency of wheat, corn, and peanuts within complex farming systems, indicating that this method holds the potential for enhancing both the yield and quality of various crops.

Spatiotemporal Dynamics of Fine Root Biomass in Chinese Fir (Cunninghamia lanceolata) Stumps and Their Impacts on Soil Chemical Properties

Stumps are residuals from artificial forest harvesting, persist in forest ecosystems, and have garnered attention for their ecological roles in soil and water conservation, carbon sequestration, and forest regeneration. However, the spatiotemporal dynamics of stump fine root biomass and their impact on soil nutrient cycling remain unclear. This study focuses on the fine roots of Chinese Fir (Cunninghamia lanceolata) stumps generated during the construction of national reserve forests at Xishan State Forest Farm, Linwu County, Hunan Province, from 2014 to 2022. Employing a space-for-time substitution approach, we investigated the spatiotemporal dynamics of fine root biomass (FRB) and its effects on soil chemical properties. The results indicated that the Chinese Fir stump FRB significantly differed with increasing residual time across various soil layers and distances, with an average annual loss rate of 8.40%–9.96%. The living fine root biomass (LFRB) was predominantly concentrated in the 0–20 cm soil layer and decreased with increasing soil depth. Initially, the LFRB was closer to the stumps; however, this proximity effect diminished over time. There were no significant differences in the fine root loss coefficients between layers, within the vertical soil profile with 95% root loss over a time span of 15.1–15.9 years. However, there were horizontal differences, with a 95% root loss over a time span of 13.7–17.0 years. The changes in soil organic matter (SOM) and total nitrogen (STN) content over the study period exhibited a trade-off relationship with the loss of LFRB, with SOM and STN peaking 1 year after the peak of dead fine root biomass (DFRB), suggesting a combined effect of living root exudates and dead root decomposition on SOM and STN enhancement. The trend of LFRB loss was generally inverse to the changes in the soil’s total phosphorus (STP) content, which gradually increased with extended stump retention, indicating that stumps provide a long-term source of phosphorus for the soil. The study also revealed that living fine roots of Chinese Fir stumps can persist in forest soils for a relatively long time and that their biomass dynamics positively affect soil nutrients and carbon storage. These findings provide theoretical support for forest management and suggest that retaining stumps in post-harvest forest management can maintain soil fertility and ecological functions.

Green Ammonia, Nitric Acid, Advanced Fertilizer and Electricity Production with In Situ CO2 Capture and Utilization by Integrated Intensified Nonthermal Plasma Catalytic Processes: A Technology Transfer Review for Distributed Biorefineries

An Integrated Process Intensification (IPI) technology-based roadmap is proposed for the utilization of renewables (water, air and biomass/unavoidable waste) in the small-scale distributed production of the following primary products: electricity, H2, NH3, HNO3 and symbiotic advanced (SX) fertilizers with CO2 mineralization capacity to achieve negative CO2 emission. Such a production platform is an integrated intensified biorefinery (IIBR), used as an alternative to large-scale centralized production which relies on green electricity and CCUS. Hence, the capacity and availability of the renewable biomass and unavoidable waste were examined. The critical elements of the IIBR include gasification/syngas production; syngas cleaning; electricity generation; and the conversion of clean syngas (which contains H2, CO, CH4, CO2 and N2) to the primary products using nonthermal plasma catalytic reactors with in situ NH3 sequestration for SA fertilizers. The status of these critical elements is critically reviewed with regard to their techno-economics and suitability for industrial applications. Using novel gasifiers powered by a combination of CO2, H2O and O2-enhanced air as the oxidant, it is possible to obtain syngas with high H2 concentration suitable for NH3 synthesis. Gasifier performances for syngas generation and cleaning, electricity production and emissions are evaluated and compared with gasifiers at 50 kWe and 1–2 MWe scales. The catalyst and plasma catalytic reactor systems for NH3 production with or without in situ reactive sequestration are considered in detail. The performance of the catalysts in different plasma reactions is widely different. The high intensity power (HIP) processing of perovskite (barium titanate) and unary/binary spinel oxide catalysts (or their combination) performs best in several syntheses, including NH3 production, NOx from air and fertigation fertilizers from plasma-activated water. These catalysts can be represented as BaTi1−vO3−x{#}yNz (black, piezoelectric barium titanate, bp-{BTO}) and M(1)3−jM(2)kO4−m{#}nNr/SiO2 (unary (k = 0) or a binary (k > 0) silane-coated SiO2-supported spinel oxide catalyst, denoted as M/Si = X) where {#} infers oxygen vacancy. HIP processing in air causes oxygen vacancies, nitrogen substitution, the acquisition of piezoelectric state and porosity and chemical/morphological heterogeneity, all of which make the catalysts highly active. Their morphological evaluation indicates the generation of dust particles (leading to porogenesis), 2D-nano/micro plates and structured ribbons, leading to quantum effects under plasma catalytic synthesis, including the acquisition of high-energy particles from the plasma space to prevent product dissociation as a result of electron impact. M/Si = X (X > 1/2) and bp-{BTO} catalysts generate plasma under microwave irradiation (including pulsed microwave) and hence can be used in a packed bed mode in microwave plasma reactors with plasma on and within the pores of the catalyst. Such reactors are suitable for electric-powered small-scale industrial operations. When combined with the in situ reactive separation of NH3 in the so-called Multi-Reaction Zone Reactor using NH3 sequestration agents to create SA fertilizers, the techno-economics of the plasma catalytic synthesis of fertilizers become favorable due to the elimination of product separation costs and the quality of the SA fertilizers which act as an artificial root system. The SA fertilizers provide soil fertility, biodiversity, high yield, efficient water and nutrient use and carbon sequestration through mineralization. They can prevent environmental damage and help plants and crops to adapt to the emerging harsh environmental and climate conditions through the formation of artificial rhizosphere and rhizosheath. The functions of the SA fertilizers should be taken into account when comparing the techno-economics of SA fertilizers with current fertilizers.

ι-Carrageenan Manganese Oxide Bionanocomposites as a Promising Solution to Agricultural Challenges

Agriculture faces numerous challenges: infectious diseases through phytopathogens and soil nutrient deficiencies hinder plant growth, reducing crop yields. Biopolymer nanocomposites offer promising solutions to these challenges. In this work, we synthesize and characterize novel bionanocomposites (ι-CG-Mn) of manganese (hydr)oxide nanoparticles (approx. 3 to 11 nm) embedded in the matrix of the natural polysaccharide ι-carrageenan (ι-CG). Using spectroscopic methods we verify the presence of the nanoparticles in the polymer matrix while leaving the polysaccharide structural characteristics unaffected. Elemental analysis determines the mass content of metal ions in the ι-CG-Mn to be approx. 1 wt%. Electron microscopy techniques show the supramolecular organization of the ι-CG-Mn and the homogeneous nanoparticle distribution in the polymer matrix, while thermal analysis reveals that the bionanocomposite maintains high thermal stability. Moreover, the co-incubation of the phytopathogen Clavibacter sepedonicus with ι-CG-Mn inhibits the pathogen growth by 67% compared to the control. Our bionanocomposites demonstrate (1) strong bactericidal activity and (2) potential as microfertilizers that stimulate agricultural plant growth through the dosage of metal ions. These properties arise from the bioactivity of the widely available, naturally sulfated polysaccharide biopolymer matrix, combined with the antimicrobial effects of manganese (hydr)oxide nanoparticles, which together enhance the efficacy of the biocomposite. The non-toxic, biocompatible, and biodegradable nature of this biopolymer satisfies the high environmental demands for future biotechnological and agricultural technologies.

Plant Adaptability to Improved Dredged Sediment

Traditional dredged sludge disposal methods are characterized by low resource utilization and high carbon emissions, leading to serious environmental pollution. This study used dredged sludge, composted pig manure, and sawdust as raw materials, and supplemented them with composite biological agents to prepare improved soil. Plant adaptability to the improved soil was comprehensively evaluated using factors such as seed germination index (GI). The alkaline nitrogen content in the improved soil increased by 78.61% compared to the dredged sludge, and the content of other nutrients such as available potassium also increased to varying degrees. Ryegrass seed GI increased by 51.06% in improved soil (IS1) compared to dredged sludge. The main dominant fungi in the improved soil (IS1) were Tausonia, Trichoderma, and Cystoflobasidium, which promote soil nutrient activation and antagonize pathogenic bacteria, making the environment more conducive to plant growth. Dredged sludge was successfully converted into planting soil. Fully utilizing the nitrogen, phosphorus, and other substances enriched in dredged sludge to provide nutrients for plant growth is an efficient method to achieve dredged sludge resource utilization.

Effects of Film-Bottomed Treatment on Absorbability and Translocation of Nitrogen in Spring Wheat in Arid Area

Plastic film-bottomed treatment (FBT) is a critical agricultural practice in arid regions, aimed at enhancing crop productivity by improving soil moisture retention and nutrient availability. However, the effects of different depths of film-bottomed treatment (DFBT) on nitrogen (N) absorption and translocation in spring wheat remain inadequately understood. We conducted a field experiment on sandy soil to investigate the effects of different DFBT depths (60, 70, 80, 90, and 100 cm) and on total N absorption amount (TNAA), total N translocation amount (TNTA) in all nutritive organs, grain nitrogen content (GN), and grain yield (GY). Morphological measurements included GY, GN, TNAA, and TNTA in the stem, sheath, leaf, spike axis, kernel husk (SAKH), and culm. The results showed that FBT significantly reduced soil moisture loss, with the 100 cm depth reducing soil leakage by 59.6% (p < 0.001). At the flowering stage, nitrogen derived from fertilizer (NDF) and soil nitrogen (NDS) were significantly higher at the 80 cm depth (p < 0.001). At maturity, the total nitrogen absorption amount (TNAA) and translocation amount (TNTA) in the main stem and across nutrient organs were significantly higher under the 80 cm DFBT (p < 0.001), leading to improved nitrogen use efficiency. The correlation between TNTA and GN was strongest at 80 cm (p < 0.001). Grain yield (GY) and GN were optimized at intermediate depths, particularly at 80 cm, suggesting this depth provides an optimal balance between water retention and drainage efficiency. These findings underscore the importance of optimizing DFBT depth, particularly at 80 cm, to achieve enhanced water retention, efficient nitrogen utilization, and improved crop productivity in arid agricultural systems. This research provides critical insights into sustainable agricultural practices under water-limited conditions, offering practical guidance for improving food security in arid regions.

Soil fertility differences due to tillage methods modulate maize yield formation at different planting densities

To address the problems of planting density and low soil nutrient content in maize cultivation and production in western Inner Mongolia. This study aims to elucidate the regulatory mechanism by which soil fertility augmentation affects maize yield formation under a variety of planting densities. In this study, nine soil fertility conditions were established by deep tillage, no-tillage and in situ straw return. Utilizing Xianyu 696 as the experimental subject, this study documents variations in the parameters of maize grain filling rate and yield components under differing planting densities. Enhancement of soil fertility can modify diverse parameters of maize grain filling characteristics, effectively undermining the adverse impact of a lower average filling rate on grain weight post-densification. The enhancement in soil fertility predominantly augments the grain weight by prolonging the active grain-filling period. This results in a reduced decline in final grain growth during densification under conditions of high soil fertility. The improvement of soil fertility significantly enhances the harvested number of panicles, the number of grains per panicle, and the 100-grain weight of maize, consequently increasing the maize yield. High soil fertility (0.73–0.82) is particularly advantageous for densification and yield increase, resulting in yield increments ranging from 0.99 to 2.16 t ha− 1. Appropriate tillage methods can significantly improve soil fertility, and the effects of straw incorporation with subsoiling (SSR) and straw incorporation with deep tillage (DPR) are the best. Enhancing soil fertility through tillage and straw return measures can markedly augment grain weight by changing maize grain filling characteristics, ultimately achieving the cultivation goal of increased density and yield.

Aboveground-belowground linkages across vegetation degradation gradients differ among native eucalypt communities.

Native vegetation degradation impacts soil communities and their functions. However, these impacts are often studied by comparing soil biotic attributes across qualitatively defined, discrete degradation levels within a single plant community at a specific location. Direct quantification of the relationships between vegetation and soil attributes across continuous degradation gradients and at larger scales is rare but holds greater potential to reveal robust patterns in aboveground-belowground linkages that may apply across different plant communities. We investigated how native vegetation attributes relate to soil communities and their functions across a degradation gradient within three native temperate eucalypt woodland and forest communities that differed in soil nutrient availabilities. Across remnant patches of native vegetation in the Sydney Basin bioregion, we established plots representing different levels of decline in their vegetation quality (i.e., increased exotics and canopy changes) compared to relevant reference communities. In those plots, we assessed soil community groups (microbes and fauna), carbon (C) and nutrient cycling (litter decomposition, enzyme activity, and phosphate and nitrate accumulation rates), soil pH, texture and vegetation attributes (composition, structure, and function). Our unique study design revealed that the relationships between vegetation degradation and soil biota across the food web (i.e., AM fungi, Fungi:bacteria ratio, Gram-positive bacteria, total nematodes) were highly dependent on the plant community. However, the degradation impacts on soil functions (i.e., total enzyme activity, and phosphate availability) were mostly consistent, suggesting their potential as belowground indicators of ecosystem degradation, with a notable positive association observed in phosphate availability rates. Additionally, the effects of vegetation degradation on soil biota and their functions appeared stronger in the nutrient-poor plant communities, suggesting greater vulnerability of their belowground components. Our findings call for caution when generalizing belowground responses to degradation and for further research on how nutrient availability mediates the impacts of degradation on aboveground-belowground linkages.

The Effect of Biochar Application Rates on Soil Fertility and Phyto-Availability of Heavy Metals is Dependent on Soil Type and pH

ABSTRACT The effect of biochar application rate on soil nutrient and heavy metal phyto-availability may differ depending on soil properties. To investigate this hypothesis, a pot experiment was conducted with three soil types (yellow soil (YS), yellow-brown soil (YBS) (slightly alkaline), and calcareous soil (CS) (neutral soil)), using five biochar application rates: 0, 0.1%. 1.0%, 2.5%, and 5.0%. The results showed that the total organic carbon increased progressively in all three soil types, while the labile organic carbon only increased progressively in yellow soil with an increasing rate of biochar from 0% to 5%. The ammonia and Olsen-phosphorus concentrations increased with higher biochar rates for the slightly alkaline soils, but decreased significantly at higher rate for the neutral soil. Additionally, the application of biochar at 2.5% and 5.0% significantly reduced soil nitrate concentrations in slightly alkaline YS soil (by 31.10% and 37.83%) and YBS soil (by 65.96% and 76.70%) compared to the control, but did not change significantly in the neutral soil. Biochar application increased soil exchangeable potassium (K) concentration more significantly in high K soils compared to low K soil. The exchangeable calcium (Ca) concentration increased with increasing biochar rate if the exchangeable Ca was < 10.6 cmol kg−1. The effect of biochar application rate on phyto-availability of cadmium, copper, and nickel concentrations varied with the background soil value and soil pH. For all three types of soil, the phyto-availability of lead, chromium, and arsenic decreased significantly with increasing biochar rates. In conclusion, it is important to carefully consider soil type and pH when utilizing biochar as a soil amendment to maximize its efficiency.

Mitigating soil compaction and enhancing corn (Zea mays L.) growth through biological and non-biological amendments

Soil compaction is a pressing issue in agriculture that significantly hinders plant growth and soil health, necessitating effective strategies for mitigation. This study examined the effects of sugarcane bagasse, both in its raw form and as biochar, along with biological activators (Bacillus simplex UTT1 and Phanerochaete chrysosporium) on soil characteristics and corn (Zea mays L.) plant biomass in a compacted soil. Using a completely randomized factorial design, we assessed their impact on soil bulk density, porosity, nutrient concentrations, and plant growth parameters. Results indicated that combining organic amendments with microbial inoculation (B. simplex UTT1 + P. chrysosporium) significantly reduced soil bulk density (7–14%) (p < 0.05) and enhanced soil aggregate stability (38%), soil permeability coefficient (52%), and total porosity (40%) (p < 0.01) compared to controls. Notably, the application of biochar and microbial inoculants improved soil moisture retention (p < 0.05) and soil nutrient availability, particularly potassium and phosphorus, which increased by 18% and 23%, respectively. Plant biomass responses (10–35%) varied, with combined microbial treatments (B. simplex UTT1 + P. chrysosporium) yielding optimal outcomes (p < 0.01) compared to individual applications. The study emphasizes that integrating organic amendments with biological processes not only mitigates soil compaction but also fosters soil health and productivity. These findings support the need for sustainable agricultural practices, highlighting the role of effective resource management in enhancing soil structure and crop yields. Future research should focus on understanding the underlying mechanisms of these interactions and their long-term implications for soil health and agricultural sustainability.Clinical trial number Not applicable.

Microbial Composition Change and Heavy Metal Accumulation in Response to Organic Fertilization Reduction in Greenhouse Soil.

Increased application of organic fertilizer is an effective measure to improve greenhouse soil quality. However, prolonged and intensive application of organic manure has caused nutrient and certain heavy metal accumulation in greenhouse soil. Therefore, the optimal quantity of organic manure required to sustain soil fertility while mitigating the accumulation of heavy metals and other nutrients resulting from continuous application remains unclear. This study evaluated the impacts of sustained and reduced organic manure application on soil physicochemical properties, heavy metal contents, and microbial community through a 9-year greenhouse field experiment. Treatments included a control without any fertilizer (CK), conventional manure (M), and three reduced manure treatments (-25%M, -37.5%MNPK, and -50%MNPK). Compared to CK, either M treatment or manure reduction treatments either maintained or significantly elevated soil pH and soil organic matter, total nitrogen, total phosphorus, and available phosphorus. Notably, -37.5%MNPK exhibited further increases in the available nitrogen and potassium. The M treatment significantly increased in the total concentrations of cadmium, copper, lead, zinc, and the availability of chromium and zinc. However, reduced manure treatments showed no change or a significantly reduced in heavy metal availability. The -25%M and -37.5%MNPK treatments significantly improved bacterial diversity. Reducing organic manure altered microbial taxa abundance. The soil pH emerged as the primary driving factor for variation in the bacterial community structure, whereas available nitrogen, potassium, and lead were the key factors influencing fungal community structural changes. These results indicate that reducing excessive organic manure input is an effective strategy to control heavy metal accumulation, enhance soil fertility, and optimize microbial community structure.

An Assessment of Nutritional Deficiency Symptoms in the Tea Plant (Camellia sinensis L.) Through Field Survey

The most important factor in both plant development and productivity, which mostly depends on nutrient availability in the soil and environment, is the constituents of soil nutrients. Soil is always losing its nutrients by leaching, surface runoff as well as through harvesting and cultural operations like: pruning. For maintaining the balance of agricultural ecosystem fertilizer application is necessary to improve soil condition and gain better yield. In case of tea industry for maintaining better and uniform production applying fertilizer is a widespread management technique in worldwide. Tea requires a lot of macro and micronutrients for growth because it cannot be grown without the usage of fertilizer and other nutrient supplies. The purpose of this field survey was to ascertain the nutritional condition of tea leaves as well as the signs of nutrient deficiencies in tea plants. In this study, deficiency symptoms of the essential nutrients were found out at different tea estates of Moulvibazar and Sylhet districts as well as photographs were taken. Photographs of the nutrient deficient tea plants were correlated with the established symptoms. The range of total nitrogen, phosphorus, potassium, calcium, magnesium and zinc content in the collected tea leaf samples were 2.95- 5.18%, 0.28- 0.49%, 0.56-1.88%, 0.12-0.49%, 0.07-0.08% and 0.002- 0.004%, respectively.

From Young to Over-Mature: Long-Term Cultivation Effects on the Soil Nutrient Cycling Dynamics and Microbial Community Characteristics Across Age Chronosequence of Schima superba Plantations

Optimizing forest management requires a comprehensive understanding of how soil properties and microbial communities evolve across different plantation ages. This study examines variations in soil nutrient dynamics, enzyme activities, and bacterial communities in Schima superba Gardn. &amp; Champ plantations of 10, 15, 27, 55, and 64 years. By analyzing soil from depths of 0–20 cm, 20–40 cm, and 40–60 cm, we identified significant age-related trends in soil characteristics. Notably, nutrient contents, including total organic carbon (TOC), total phosphorus (TP), total carbon (TC), total nitrogen (TN), and nitrate nitrogen (NO3−-N), as well as soil water content (SWC), peaked in 55-year-old mature plantations and decreased in 64-year-old over-mature plantations. Enzyme activities, such as urease, sucrase, and acid phosphatase, decreased with soil depth and exhibited notable differences across stand ages. Microbial community analysis indicated the predominance of Acidobacteria, Chloroflexi, Proteobacteria, Actinobacteria, and Verrucomicrobiota in nutrient cycling, with their relative abundances varying significantly with age and depth. Mature and over-mature plantations exhibited higher absolute abundances of functional genes related to methane metabolism, nitrogen, phosphorus, and sulfur cycling. Reduced calcium ion levels were also linked to lower gene abundance in carbon degradation, carbon fixation, nitrogen, and phosphorus cycling, while increased TOC, NH4+-N, NO3−-N, and AP correlated with higher gene abundance in methane metabolism and phosphorus cycling. Our findings suggest that long-term cultivation of Schima superba enhances soil nutrient cycling. Calcium ion was identified as a significant factor in assessing soil properties and microbial dynamics across different stand ages, suggesting that extended plantation rotations can improve soil health and nutrient cycling.

Intermittent deep tillage increases soil quality and ecosystem multifunctionality in a Fluvo-aquic soil on the North China Plain.

Intensive tillage operations often disrupt soil structure and accelerate the decomposition of organic matter, resulting in negative long-term impacts on soil health. Thus, identifying sustainable tillage practices is key for enhancing soil nutrient cycling and improving soil biochemical and biological properties. This study evaluated the effects of five tillage modes on soil quality and ecosystem multifunctionality (EMF) over three years in the North China Plain, where rotary tillage (RT) has degraded soil structure and hindered wheat yield increases. The treatments combined deep tillage (DT), RT, and shallow rotary tillage (SRT): (1) RT-RT-RT; (2) DT-RT-RT; (3) DT-RT-SRT; (4) DT-SRT-SRT; (5) DT-SRT-RT. Measurements included soil nutrients, microbial biomass carbon and nitrogen (Cmic and Nmic), enzyme activities, soil quality index (SQI), EMF, across 0-50cm soil layers, as well as crop yields. We found that DT significantly improved various soil properties compared to continuous RT, thereby improving crop yield. In the first year of the cycle, DT increased available nitrogen (AN), available phosphorus (AP), potassium (K), Cmic, Nmic, enzyme activities, SQI, and EMF in the 20-40cm soil layer. These improvements persisted in the following two years. Compared to RT-RT-RT, the largest increases in SQI (13.0%-22.2%) and EMF (11.2%-126.9%) were found in the 0-30cm layer under DT-SRT-RT. Random forest analysis identified Cmic, AN, AP, Corg, and Ntotal as key EMF drivers. Meanwhile, wheat yield under DT-SRT-RT was 14.6% higher than under RT-RT-RT. These findings demonstrate that incorporating occasional DT enhances soil properties and crop yields, offering a sustainable strategy for cropping system management.

Climate factors dominate the spatial variation of forest soil nutrients: a meta analysis

Climate factors dominate the spatial variation of forest soil nutrients: a meta analysis