Soil Phosphorus Research Articles

Responses of the soil phosphorus fraction distribution to a chronosequence and soil depth in deserts undergoing revegetation

AbstractElucidating the changes in phosphorus (P) fractions (available P [A‐P], dicalcium phosphate [Ca2‐P], aluminium‐bond phosphate [Al‐P], iron‐bond phosphate [Fe‐P], octacalcium phosphate [Ca8‐P], deca‐calcium phosphate [Ca10‐P], occluded‐P [O‐P] and organic P [Po]) in revegetated deserts is essential for understanding how P responds to environmental changes in arid regions. To investigate this, we selected a chronosequence of desert revegetation sites (12, 32, 41, 58 and 66 years old) and compared them to a moving dune without plant cover and a naturally vegetated desert. We used non‐metric multidimensional scaling to analyse the similarity among the three types of sites and redundancy analysis to explore the contribution of environmental factors on P fractions. The results showed that revegetation for >41 years significantly improved the total P, A‐P, Ca2‐P, Ca10‐P and Po concentrations in contrast to the moving dune (p < .05). Specifically, Ca8‐P and Po concentrations reached their maximum at 66 years, whereas Al‐P and Fe‐P concentrations reached their maximum at 32 years of revegetation. The Po concentration steadily increased as the number of revegetation years increased. Across a profile of 0–200 cm, two patterns of P fractions in revegetated deserts were found (from 0 to 10 cm: Ca10‐P > Ca8‐P > O‐P > Ca2‐P > Po > A‐P; from 10 to 200 cm: Ca10‐P > O‐P > Po > A‐P), with Ca10‐P accounting for 65%–85% of the total P concentration which suggested that the low bioavailable P fractions throughout the soil profile may have constrained the progress of revegetation efforts in deserts. Soil total nitrogen, soil organic matter and soil organic carbon were important in explaining the variation in P fractions, with a relatively high explanation (>20%, p < .01). This study highlights the positive impact of revegetation on P fractions and their distribution patterns in contrast to moving dunes, and also explores the responses of P to environmental variations.

Distribution and abundance of a soil centipede, Tygarrup nepalensis Shinohara, 1965 (Mecistocephalidae: Geophilomorpha: Chilopoda) in a moist temperate forest in Northwest Himalaya

Abstract This study investigates the distribution of the soil centipede, Tygarrup nepalensis (Order Geophilomorpha), in the moist temperate forest of the Northwest Himalayas, located in Himri, District Shimla, Himachal Pradesh, India. Centipedes were collected using a standardized 25 × 25 cm quadrat sampling method. We examined the influence of various environmental and edaphic parameters on its populations across different forest areas (north, northeast, southwest facing aspects). The north aspect exhibited higher density due to more favourable soil conditions, including higher phosphorus and organic carbon, which supported larger populations of detritivore earthworms, likely prey for T. nepalensis. These findings underscore the role of microhabitat characteristics in shaping centipede distribution and highlight implications for forest management strategies aimed at conserving soil biodiversity and enhancing forest productivity. Our results indicate that average soil moisture levels (25.8% to 30.5%) are conducive to the habitat requirements of T. nepalensis, which thrives in moist environments. Notably, population densities varied significantly, with lower density in the northeastern aspect, correlated with reduced soil phosphorus concentrations and increased acidity.

The Effect of Cysteine on the Removal of Cadmium in Paddy Soil by Combination with Bioremediation and the Response of the Soil Microbial Community.

Bioremediation is widely recognized as a promising and efficient approach for the elimination of Cd from contaminated paddy soils. However, the Cd removal efficacy achieved through this method remains unsatisfactory and is accompanied by a marginally higher cost. Cysteine has the potential to improve the bioleaching efficiency of Cd from soils and decrease the use cost since it is green, acidic and has a high Cd affinity. In this study, different combination modes of cysteine and microbial inoculant were designed to analyze their effects on Cd removal and the soil microbial community through the sequence extraction of Cd fraction and high-throughput sequencing. The results demonstrate that the mixture of cysteine and the microbial inoculant was the best mode for increasing the Cd removal efficiency. And a ratio of cysteine to microbial inoculant of 5 mg:2 mL in a 300 mL volume was the most economically efficient matching. The Cd removal rate increased by 7.7-15.1% in comparison with the microbial inoculant treatment. This could be ascribed to the enhanced removal rate of the exchangeable and carbonate-bound Cd, which achieved 94.6% and 96.1%, respectively. After the treatment, the contents of ammonium nitrogen (NH3-N), total phosphorus (TP), available potassium (AK), and available phosphorus (AP) in the paddy soils were increased. The treatment of combinations of cysteine and microbial inoculant had an impact on the soil microbial diversity. The relative abundances of Alicyclobacillus, Metallibacterium, and Bacillus were increased in the paddy soils. The microbial metabolic functions, such as replication and repair and amino acid metabolism, were also increased after treatment, which benefitted the microbial survival and adaptation to the environment. The removal of Cd was attributed to the solubilizing, complexing, and ion-exchanging effects of the cysteine, the intra- and extracellular adsorption, and the production of organic acids of functional microorganisms. Moreover, cysteine, as a carbon, nitrogen, and sulfur source, promoted the growth and metabolism of microorganisms to achieve the effect of the synergistic promotion of microbial Cd removal. Therefore, this study underscored the potential of cysteine to enhance the bioremediation performance in Cd-contaminated paddy soils, offering valuable theoretical and technical insights for this field.

Application and residual effects of poultry litter biochar on cropping system yields

AbstractAnimal manures such as poultry litter supply plant‐available phosphorus (P), but P loss can occur following manure application to crops, particularly in sandy soils. The transformation of poultry litter biochar (PLB) reduces P losses upon application to crops while providing essential plant nutrients. Our objectives were to evaluate: (1) the effects of PLB on crop yields when applied at the same total P rate as inorganic P fertilizer and (2) the residual effect of previous‐year PLB and inorganic P fertilization on crop yield at two locations with different soil types (Entisols and Spodosols). Inorganic P, PLB, and no‐P treatments were allocated to six replicates of a randomized complete block design at each location. The cropping system was sequential plantings of rye, corn, and sorghum each year for 2 years. The residual effect of P application was quantified in Year 2 when first‐year PLB and inorganic P plots were subdivided, with half receiving no additional P and half receiving the same P application as the previous year. After each crop was harvested, crop yield, nitrogen (N) and P levels in plant tissue, and the soil phosphorus storage capacity were determined. PLB supported either similar or significantly greater cumulative biomass yields compared with inorganic P fertilization at the two locations. The effect of residual PLB on yield varied with the location and crop, highlighting the importance of soil type and management practices in optimizing the benefits of this amendment.

Rhizobacteria and silicon modulate defense, oxidative stress, and suppress blast disease in upland rice plants in low phosphorus soils under field conditions.

Rhizobacteria and silicon fertilization synergism suppress leaf and panicle Blast, and mitigates biotic stress in rice plants. Association of bioagents and silicon is synergistic for mitigating leaf and panicle blast and low phosphorus (P) levels in upland rice, under greenhouse conditions. This study aimed to evaluate the potential of the bioagents and silicon interaction on blast disease severity suppression in upland rice plants, under field low P conditions. The experiment was conducted during two growing seasons (E1 and E2), in randomized block design with four replications, and consisted of five treatments, combining a mix of three rhizobacteria, BRM 32114 and BRM62523 (Serratia marcescens), and BRM32110 (Bacillus toyonensis), and three application methods (seed treatment, drenching, spraying). Calcium and magnesium silicate (2t/ha) was applied over a low soil P, 30days before sowing. Leaf blast (LBS) and panicle blast (PBS), area under the disease progress curve (AUDPC), activity of enzymes related to oxidative stress, pathogenesis-related (PR), biochemical indicators such as hydrogen peroxide, chlorophyll a and b, carotenoids, and grain yield (GY), were assessed. Bioagents and silicon suppressed LBS by 77.93 and PBS by 62.37%, reduced AUDPC by 77.3 (LBS) and 60.6% (PBS). Theyield in E1 was 25% higher than in E2. The treatments statistically differ only in E2, the yield with bioagents and silicon (2435.72kgha-1) was 71.95% higher compared to the absolute control. All enzymatic activities related to oxidative stress and PR proteins were modulated by bioagents and silicon association. The association of rhizobacteria and silicon exhibited a synergistic effect, and represents a bioprotective combination to reduce the effects of different stresses and indirectly reduces the use of chemical inputs.

Effects of Artificial Soil Fertility Gradient Strategy on the Soil Fertility, Nutrient Uptake and Growth Attributes of Chakravarthi Keerai (Chenopodium album)

The effect of artificial soil fertility gradient techniques on crop growth attributes, nutrient uptake, soil fertility and soil biological properties were studied in a field trial conducted in 2023 at Horticulture Research Station, Ooty, Nilgiris, Tamil Nadu. It was done using an inductive methodology. The field was split into three equal strips, with three graded levels of fertilizers viz., N (Urea), P2O5 (Single Super phosphate) and K2O (Muriate of Potash) applied to strip I (N0P0K0), II (N1P1K1) and III (N2P2K2). The N1 level has been determined on the basis of the blanket recommendation to Chakravarthi keerai, while the P1 and the K1 levels have been determined based on the fixing capacity of the soil phosphorus (250 kg ha-1) and the potassium (100 kg ha-1). Gradient crop, Chakravarthi keerai variety Ooty 1 was cultivated and green yield of Chakravarthi keerai was observed at the time of harvesting. At the time of harvesting, plant samples were taken and examined for N, P & K content and the uptake of N, P & K was calculated. The results showed that graded levels of fertilizer N, P2O5, K2O had a significant impact on soil fertility status and NPK uptake, as well as plant growth parameter. The article clearly shows a significant influence of the organic carbon, chlorophyll content, soil enzymes activity, microbial population, and Microbial biomass carbon.

Optimization of yield and rooting behaviour of pearl millet (Pennisetum glaucum) in desert region through land configuration, Mycorrhiza and zinc fertilization

Arbuscular Mycorrhizal (AM) symbiosis holds promise for enhancing soil phosphorus (P) efficiencycy and valuable in improving zinc uptake in pearl millet (Pennisetum glaucum L.), especially in Zn-deficient soils. The proper land configuration important for enhancing the rainfed crop performance by changing the rooting and soil moisture conservation patterns. Thus, a study was conducted in 2020 and 2021 at Swami Keshwanand Rajasthan Agriculture University, Bikaner, we explored the combined effects of land configuration, zinc ffertilization and Mycorrhiza on yield attributes and roots characteristics of pearl millet. We evaluated 24 treatment combinations, including flat bed (S1), ridge & furrow (S2) and pit (S3) planting techniques, Mycorrhiza control (M0) and 8 kg/ha as basal (M1), and zinc fertilization control (Z0), 0.5% ZnSO4 in two foliar sprays (Z1), ZnSO4 @10 kg/ha basal + 0.5% foliar spray (Z2), and ZnSO4 @ 20 kg/ha basal (Z3) in a split-split plot design. Our findings revealed that, the pit planting technique, combined with Mycorrhiza and zinc sulphate fertilization, significantly increased plant stand (141.2 thousand/ha), root characteristics (root volume, 42.93 cm3), and yield attributes (effective tillers: 4.75, grain yield: 30.75 q/ha, and stover yield: 71.43 q/ha) by 12.72%, 29.11%, 137.53%, 95.74% and 39.95% compared to flat bed sowing, respectively. These results underscore the immense potential of pit planting techniques for enhancing pearl millet productivity and quality by promoting robust root system development.

Optimization of yield and rooting behaviour of pearl millet (Pennisetum glaucum) in desert region through land configuration, Mycorrhiza and zinc fertilization

Arbuscular Mycorrhizal (AM) symbiosis holds promise for enhancing soil phosphorus (P) efficiencycy and valuable in improving zinc uptake in pearl millet (Pennisetum glaucum L.), especially in Zn-deficient soils. The proper land configuration important for enhancing the rainfed crop performance by changing the rooting and soil moisture conservation patterns. Thus, a study was conducted in 2020 and 2021 at Swami Keshwanand Rajasthan Agriculture University, Bikaner, we explored the combined effects of land configuration, zinc ffertilization and Mycorrhiza on yield attributes and roots characteristics of pearl millet. We evaluated 24 treatment combinations, including flat bed (S1), ridge & furrow (S2) and pit (S3) planting techniques, Mycorrhiza control (M0) and 8 kg/ha as basal (M1), and zinc fertilization control (Z0), 0.5% ZnSO4 in two foliar sprays (Z1), ZnSO4 @10 kg/ha basal + 0.5% foliar spray (Z2), and ZnSO4 @ 20 kg/ha basal (Z3) in a split-split plot design. Our findings revealed that, the pit planting technique, combined with Mycorrhiza and zinc sulphate fertilization, significantly increased plant stand (141.2 thousand/ha), root characteristics (root volume, 42.93 cm3), and yield attributes (effective tillers: 4.75, grain yield: 30.75 q/ha, and stover yield: 71.43 q/ha) by 12.72%, 29.11%, 137.53%, 95.74% and 39.95% compared to flat bed sowing, respectively. These results underscore the immense potential of pit planting techniques for enhancing pearl millet productivity and quality by promoting robust root system development.

Geostatistical assessment and mapping of soil spatial variability in Sirumugai, Western Ghats

This study examines the spatial variability of soil properties and classifies the soil in the Sirumugai Reserved Forest range, located in the Western Ghats, India. A systematic soil survey and profile studies were conducted, using landforms as the basis for investigation within the study area. Horizon-wise soil samples were analysed for key soil parameters, including pH, electrical conductivity (EC), soil organic carbon, phosphorus, and potassium. The results revealed significant variations in soil properties across different locations, primarily influenced by elevation. The coefficient of variation for phosphorus was 0.87, while for potassium, it was 0.48. The analysis also encompassed assessments of skewness and kurtosis. pH (0.15) and phosphorus (0.75) exhibited kurtosis values close to 1, indicating relatively normal and flatter distributions. Conversely, sodium (27.10), elevation (3.91), and calcium demonstrated high kurtosis. Most soil properties were found to be right-skewed, while bulk density (0.09) was left-skewed. Geostatistical analysis in the Sirumugai Reserved Forest revealed considerable spatial variability in soil properties, particularly in EC and organic carbon. Elevation emerged as a strong influencing factor for soil properties, coupled with soil depth and nutrient leaching, which were prominent at higher altitudes. Ordinary kriging provided accurate spatial predictions, offering valuable insights for land management and conservation strategies tailored to the region.

Divergent Effects of Monoculture and Mixed Plantation on the Trade-Off Between Soil Carbon and Phosphorus Contents in a Degraded Hilly Land

Carbon (C) and phosphorus (P) in soil are closely related to plantation types in afforestation practices. However, the trade-off between soil C and P in response to different restoration models on degraded hilly land is still not clear. In this study, four restoration patterns, including natural recovered shrubland (NS), Castanopsis hystrix plantation (CH), 10-species mixed plantation (10MX), and 30-species mixed plantation (30MX) were selected, and the physicochemical properties and readily oxidized carbon (ROC) in different layers of 1 m depth soil were measured to understand the effects of natural restoration and artificial afforestation on soil P and C pool and their trade-off on degraded hilly land in southern China. The results indicate that the total P (TP) content in each soil layer was observed to follow the order of CH > 10MX > 30MX > NS, with monoculture (CH) exhibiting higher levels of TP than mixed plantation. However, the soil C storage of NS (59.61 t hm−2) and 30MX (57.71 t hm−2) was similar, while 10MX boasted the highest C storage (64.99 t hm−2) of the four restoration patterns, with CH being the lowest (42.75 t hm−2). In deep soil layers (20–100 cm), the 10MX plantation presented the highest for both the C pool index (CPI) and C pool management index (CMI). Moreover, the structural equation model (SEM) revealed that the soil CMI was directly regulated by the levels of soil available P and total N, while soil C pool activity was directly influenced by soil pH. Thus, our study suggests that compared to mixed plantations, the monoculture plantation (CH) demonstrates lower P uptake and utilization, resulting in a higher soil P content. Furthermore, 10MX plantation showed a superior C fixation capacity over those with 30MX and monoculture plantations. These suggests that the trade-off between soil C and P contents was commonly observed among different plantation restoration patterns. Therefore, afforestation with different tree composition and nutrient regulation is necessary for maintaining the balance between soil C and P and keeping the sustainability of plantation management in the degraded hilly lands.

Foliar Application of Zinc Oxide Nanoparticles Alleviates Phenanthrene and Cadmium-Induced Phytotoxicity in Lettuce: Regulation of Plant-Rhizosphere-Microbial Long Distance.

Foliar application of beneficial nanoparticles exhibits potential in mitigating combined stresses from heavy metals and polycyclic aromatic hydrocarbons (PAHs) in crops, necessitating a comprehensive understanding of plant-rhizosphere-microbial processes to promote sustainable nanotechnology in agriculture. Herein, we investigated the mitigating mechanisms of foliar application of zinc oxide nanoparticles (nZnO) on lettuce growth under phenanthrene (Phe) and cadmium (Cd) costress. Compared to Phe + Cd treatment, low (L-nZnO) and high (H-nZnO) concentration of nZnO increased fresh biomass (27.2% and 8.42%) and root length (20.4% and 39.6%) and decreased MDA (35.0% and 40.0%) and H2O2 (29.0% and 15.6%) levels. L-nZnO and H-nZnO decreased Cd in roots (26.8% and 41.8%) and enhanced Zn in roots (19.9% and 107%), stems (221% and 2510%), and leaves (233% and 1500%), suggesting the long-distance migration of Zn from leaves to roots and subsequently regulating the metabolic pathways and microbial communities. Metabolomics revealed that nZnO modulated leaf glycerophospholipid metabolism and amino acid pathways and promoted rhizosphere soil carbon and phosphorus metabolism. Additionally, nZnO enriched the plant-growth-promoting, extreme, and stress-resistant bacteria in roots and leaves and heavy-metal-resistant and PAH-degrading bacteria in rhizosphere soil. These findings underscore the promising nanostrategy of nZnO to benefit plant growth in soil cocontaminated with heavy metals and PAHs.

Interaction of zinc oxide nanoparticles with soil colloidal suspensions.

The properties of soil colloids determine the interaction with nanoparticles, their behavior, and destiny in the soil environment including soil solutions. This study examines how several properties of soil colloids, including pH, phosphorus content, clay minerals, and iron oxyhydroxides, influence the interaction with zinc oxide nanoparticles (ZnO-nps). For the experimental setup, four different soils were selected from the temperate climate of central Europe, in Slovakia, exhibiting pH values ranging from 4.6 to 8.0. Two concentrations of ZnO-nps suspended in water, 20 and 200 mg Zn∙L-1 were applied to the colloidal suspensions extracted from the soils and shaken for 24 hours. Then the soil colloids were separated into three fractions, 100 to 1000 nm in size, 1 to 100 nm in size, and dissolved. Concentrations of Al, Si, Fe, Mn, P, and Zn were measured in these fractions, providing a comprehensive understanding of ZnO-NP distribution and interaction with soil colloids. The study reveals that soil pH significantly affects the distribution of Zn from ZnO-nps across different size fractions. However, the concentration of Fe, Al, and Si had an even greater impact on the concentration of dissolved Zn. Additionally, behavior of Zn following ZnO-NP application is associated with soil P content, where P may stabilize the ZnO-nps. These findings enhance the knowledge of nanoparticle behavior in various soil matrices and contribute to developing more stable, efficient, and easily usable nanoparticle-based applications in environmental science and agriculture.

Changes in the Composition and Properties of Cultured Bacterial Strains of Ginseng Rhizosphere According to Soil Characteristics in the Forest and Plots

The cultivation of Panax ginseng C.A. Meyer, a valuable medicinal plant, presents a number of challenges due to its physiology and life cycle. The composition of the soil and the microbiome living in it are important for plant growth and root quality. Modern analytical methods were used to identify differences in the rhizosphere soils of plants in the forest and in the plots. Microbiological and molecular genetic methods were used to isolate and identify bacterial isolates from these soils, allowing for the establishment of a working collection of potentially useful bacterial strains. Increases in soil pH in the plots and changes in the amount of macronutrients partially explained the changes in the activity of the forest and plot isolates and the composition of the cultivated strains. The cultivated strains belonged to the rhizosphere-dominant phyla Pseudomonadota, Bacillota, and Actinomycetota of the main functional groups of soil potassium, phosphorus, and nitrogen transformations. The ratio of bacteria functional groups was comparable in the forest and in the plots. The most common phylum of cultured microorganisms was Bacillota, while the main differences were observed in the functional group of potassium-solubilizing bacteria belonging to the phyla Pseudomonadota.

Exploring Genetic Variability in Rice for Yield Improvement under Low Phosphorus Soil Conditions

Phosphorus (P) is an essential macronutrient for all living organisms. P deficiency in soils is a major limiting factor for crop growth in rice and reduces yield. Understanding genetic variability for low P tolerance is crucial for improvement of rice genotypes for this stress. This study was conducted under low soil P and normal conditions to evaluate genetic variability in yield and its associated traits among rice genotypes. The experimental material consists of 91 F2:3 mapping population along with two checks, planted in a low P and normal plot at ICAR-IIRR, Hyderabad. Traits assessed included days to 50% flowering, plant height, total number of tillers, number of productive tillers per plant, flag leaf length, flag leaf width, panicle length, total number of grains per panicle, spikelet fertility, single plant yield, shoot length, root length, root volume, dry root weight, dry shoot weight and root to shoot ratio. ANOVA analysis suggested, mean sum of squares due to test genotypes were significant (p<0.01) for most of the traits under study. Plant height, number of tillers per plant, number of productive tillers per plant, flag leaf length, number of grains per panicle, spikelet fertility, single plant yield, shoot length, root volume, shoot dry weight, root dry weight and root to shoot ratio possessed high GCV and PCV values under low P condition. Genetic advance as per cent of mean for all traits possessed high genetic advance as per cent mean except for days to 50% flowering which showed medium GAM under low P condition. The genotypes showed varied response to genetic variability, heritability and genetic advance as per cent mean for days to 50% flowering (low), plant height (high), number of productive tillers per plant (high), panicle length (medium to high), flag leaf length (high), flag leaf width (medium to high), number of grains per panicle (high), spikelet fertility (high), single plant yield (high), root volume (high), shoot dry weight (high), root dry weight (high) and root to shoot ratio (high) under low P condition. This study identified these traits with high genetic variability and heritability, which are useful for developing P efficient rice cultivars and selection based on these traits would improve the rice for low soil P tolerance.

Field Application of Mycorrhizal Inoculant Influences Growth, Nutrition, and Physiological Parameters of Corn Plants and Affects Soil Microbiological Attributes

Mycorrhizal inoculants can contribute to the development of corn crops by improving crop productivity. In this sense, the objective of this study was to evaluate the effects of a mycorrhizal inoculant on the dynamics of root system growth, gas exchange, corn crop productivity, and microbial activity in the rhizospheric soil in a no-till area with different levels of available soil phosphorus. The experiment was conducted during the 2019/2020 and 2020/2021 growing seasons. At 75 days after plant emergence, root morphological parameters (total root length (cm), average root diameter (mm), root surface area (cm2), and root volume), shoot biomass production, P content in the plant shoots, gas exchange, and microbiological attributes of the rhizospheric soil of corn were evaluated. At the end of the cycle, corn grain yield was determined. A beneficial effect of AMF inoculation was observed on the root and shoot parameters regardless of soil P level. Under conditions of evenly distributed rainfall during the experiment (2019/2020 season), AMF inoculation contributed to a 90% increase in acid phosphatase activity and a 76% increase in microbial biomass carbon (C-BIO), independent of soil P level. In contrast, under water deficit conditions (2020/2021 season), AMF inoculation provided a 29% increase in grain yield. We concluded that introducing a commercial mycorrhizal inoculant in corn benefits root system morphological parameters and physiological traits, and favors the activity of enzymes related to increased P availability, contributing to increased crop productivity in a no-till system.

Why are some invasive plant species so successful in nutrient‐impoverished habitats in south‐western Australia: A perspective based on their phosphorus‐acquisition strategies

Abstract Invasive plants are a major cause of the global biodiversity crisis; it is therefore crucial to understand mechanisms that contribute to their success. South‐western Australia is a global biodiversity hotspot with extremely low soil phosphorus (P) concentrations. In this region, a large proportion of native plant species release carboxylates that mobilise soil P. Many widespread invasive plant species in south‐western Australia are arbuscular mycorrhizal (AM). We hypothesised that some of these invasive AM plant species exhibit similar P‐acquisition strategies as native carboxylate‐releasing P‐mobilising species which allows them to thrive in P‐impoverished soils. To test this hypothesis, we collected 23 common invasive species in the field and assessed their leaf manganese concentration [Mn], relative to that of native reference species at different locations, as a proxy for carboxylate release. In addition, we cultivated seven of the invasive species in hydroponics at different P supply to measure their root carboxylate exudation. Furthermore, we measured leaf P concentration and photosynthetic P‐use efficiency (PPUE) of five invasive species in the glasshouse. In the field investigation, almost all invasive species exhibited significantly higher leaf [Mn] than the negative references, which do not release carboxylates, indicating carboxylate release of the invasive plants. Leaf [Mn] of a few invasives even exceeded that of positive references, which exhibit significant carboxylate release, indicating substantial carboxylate release of these invasives. All glasshouse‐grown invasive species with high field leaf [Mn] released root carboxylates under low P supply. Most of the tested invasive plant species also exhibited greater PPUE than native plants under low P supply. Invasive AM plant species exhibited root exudation of carboxylates as a P‐acquisition strategy, which very likely allows their successful invasion of severely P‐impoverished habitats. Read the free Plain Language Summary for this article on the Journal blog.

Site‐Specific Nutrient Data Reveal the Importance of Soils in Driving the Mycorrhizal Make‐Up of Woody Vegetation Worldwide

ABSTRACTAimArbuscular mycorrhizas (AM) and ectomycorrhizas (ECM) have different impacts on nutrient cycling, carbon storage, community dynamics and enhancement of photosynthesis by rising CO2. Recent global analyses have concluded that patterns of AM/ECM dominance in forests worldwide are shaped by climate, with soil nutrients contributing negligible additional explanatory power. However, their reliance on nutrient data from GIS surfaces masks important local influences of parent material, topography and soil age on soil nutrient status. We asked if use of site‐specific nutrient data reveals a more important role for nutrients.Time PeriodPresent day.LocationGlobal dataset comprising 703 sites, encompassing forests, savanna/woodlands, shrublands and deserts on all continents except Antarctica.Taxa StudiedArborescent plants, including angiosperms, gymnosperms and tree ferns.MethodsGeneralised Additive Models for Location, Scale and Shape (GAMLSS) to determine the effects of climate variables, soil nitrogen and soil phosphorus on the proportional representation of ECM and of non‐mycorrhizal species (NM) in woody vegetation.ResultsGAMLSS showed a strong negative relationship of ECM representation with mean annual temperature (MAT), and a strong negative relationship with soil total nitrogen. NM representation was highest on dry sites and phosphorus‐poor sites. Reanalysis showed that GIS‐derived soil nutrient data had less explanatory power than site‐specific nutrient data, and resulted in poorer model fits.ConclusionsOur results support the long‐held belief that soil nutrients as well as climate influence the relative fitness of different mycorrhizal syndromes worldwide, and demonstrate the value of using site‐specific nutrient data. Soil nutrients should be considered when predicting the impact of climate change on the mycorrhizal composition of vegetation and resulting shifts in ecosystem processes.

Short-Term Impacts of Fire and Post-Fire Restoration Methods on Soil Properties and Microbial Characteristics in Southern China

Wildfires and post-fire restoration methods significantly impact soil physicochemical properties and microbial characteristics in forest ecosystems. Understanding post-fire soil recovery and the impacts of various post-fire restoration methods is essential for developing effective restoration strategies. This study aimed to investigate how fire and soil depth influence soil physicochemical properties, enzymatic activities, and the structure of microbial communities, as well as how these factors change under different post-fire management practices. We sampled 0–10 cm (topsoil) and 10–20 cm (subsoil) in unburned plots, naturally restored plots, and two afforestation plots in southern China. The results showed that fire reduced topsoil soil moisture, nutrient levels, and microbial biomass. The variations in soil physicochemical properties significantly influenced microbial processes. Soil bulk density, nitrate, ammonium, carbon-to-nitrogen ratio, and availability of nitrogen, phosphorus, and potassium availability influenced soil enzyme activities. Soil pH, ammonium nitrogen, and the availability of nitrogen, phosphorus, and potassium were key factors shaping microbial composition. Fire altered the soil microbial communities by reducing the availability of nitrogen. Soil depth alleviated the impact of fire on the soil to some degree. Although artificial interventions reduced soil organic carbon, total nitrogen, and phosphorus, planting nitrogen-fixing species, such as Acacia mangium, promoted microbial recovery.

Soil phosphorus fractionations under different fertilization practices on soybean (Glycine max)-based cropping systems in a Vertisol

Integration of organic and inorganic fertilizers is inevitable to sustain intensive agricultural production; however, assessment of combination of organic and inorganic fertilizers on soil phosphorus (P) fractions is yet to be understood. This study aims to investigate availability, distribution, and fractions of soil P as influenced by long-term fertilization under soybean-based cropping systems in Vertisol. Soil samples were collected during 2021 from a 17-year-old field experiment with six treatments viz., T1: 100% Organic, T2: 75% Organic + 25% Innovative approach, T3: 50% Organic + 50% Inorganic, T4: 75% Organic + 25% Inorganic, T5: 100% Inorganic, and T6: State recommendation under soybean-wheat, soybean-mustard, and soybean-chickpea cropping systems at two soil depths after wheat, mustard, and chickpea, and examined for 0.5 M NaHCO3-P, total P, inorganic P, and different P fractions namely, saloid-P (1 M NH4Cl), aluminium-P (0.5 M NH4F), iron-P (0.1 M NaOH), calcium-P (0.25 M H2SO4), and reductant soluble-P (0.3 M Na3C3H6O7 + 1 M NaHCO3 + Na2S2O3). Results demonstrates that continuous fertilization using organic, inorganic, and their combination influences soil P dynamics. Soybean-chickpea system was found better in sustaining P availability. Higher NaHCO3-P was observed under 50% organic + 50% inorganic plot. Inorganic fertilizer dominated soil P accumulation as observed from higher inorganic fractions, and total P. Addition of organic manure could contribute to solubilization of fixed-P fractions and renders plant available form. It can be concluded that fertilization with organic manures and inorganic fertilizer should be followed so that 25–50% costly P-fertilizers could be saved for crop production under soybean-based cropping systems in Vertisols.

Ecological Restoration Enhances the Stability and Associated Organic Carbon of Soil Aggregates in a Tibetan Alpine Meadow

ABSTRACTFencing and reseeding are two widely implemented ecological restoration strategies aimed at rehabilitating degraded grasslands globally. However, their effects on soil aggregates have been insufficiently explored. Employing the space‐for‐time substitution approach, we collected intact soils from a degraded alpine meadow, a fenced alpine meadow (natural restoration), a reseeded alpine meadow (interventional restoration), and an undegraded alpine meadow on the eastern Tibetan Plateau. Our main objective was to assess how the composition, stability, and associated organic carbon content of soil water‐stable aggregates responded to a 12‐year restoration effort in degraded alpine meadows. The results revealed that both restoration measures enhanced plant biomass, the levels of soil carbon, nitrogen, and phosphorus, as well as the concentrations of microbial phospholipid fatty acids. In contrast, these measures had a minimal effect on soil bulk density and glomalin‐related soil protein, while causing a reduction in soil pH. Post‐restoration, the mass proportion of macroaggregates increased notably by 66.45%–71.18%, whereas that of microaggregates and silt‐clay particles exhibited decreasing trends. The mean weight diameter and geometric mean diameter of the aggregates also significantly enhanced following restoration, indicating improvements in soil structural health and stability. However, the restored paddocks still showed lower aggregate stability than the undegraded paddock, suggesting that a longer restoration period may be required to fully recover the degraded soil structure. The aggregate‐associated organic carbon content significantly increased after reseeding but showed a negligible response to fencing alone. Nevertheless, both restoration measures improved the organic carbon stock within macroaggregates and its contribution to soil total organic carbon. Soil pH, total nitrogen content, and plant biomass were identified as key factors influencing the composition and associated organic carbon content of aggregates during restoration. Our findings indicate that ecological restoration enhances the stability and associated organic carbon accumulation of soil aggregates, primarily by promoting the formation of macroaggregates in degraded alpine meadows on the Tibetan Plateau.