Journal of Soil Science and Plant Nutrition最新文献

The fertilization with nitrogen plays a crucial role in today’s agriculture characteristic with a high demand for production. The utilization of coated fertilizers represents a possible option to lower the number of applications, lower the dose and limit the risk of environmental losses. The effect of conventional calcium ammonium nitrate (CAN) applied in a single application in blend (1:1 or 1:2) with oil-based polymer coated CAN in thicknesses of 4 (cCAN₄) or 6% (cCAN₆) by weight of the fertilizer on the yield and quality of winter wheat and oilseed rape was evaluate. The average yields of winter wheat were not significantly influenced by the examined fertilization in either the growing season (GS) or the experimental site. On the contrary, the qualitative parameters on average resulted in lower values in comparison with the control (split N fertilization), possibly due to the single application of nitrogen in early spring. The examined treatments significantly influenced the seed yield of oilseed rape in both GS and both experimental sites. On average, the highest yield of seed (2.8 t/ha) was observed on treatment cCAN₄ in a 1:2 ratio. This represents a significant increase by 24.8% compared to the control (2.2 t/ha). Similarly, to winter wheat, the qualitative parameter of oilseed rape (oil content) was lower after the examined blends with coated CAN. The fertilization of oilseed rape with blends of uncoated and coated CAN applied in the single application is a validate alternative to commonly used split nitrogen doses applied repeatedly during vegetation.

Globally, mangrove forests have been impacted by several environmental stressors including overloading with heavy metal pollution. The objective of the current study was to develop a predictive model for estimating heavy metal accumulation at Avicennia marina populations based on sediment characteristics. A transect (170 km) along Saudi Arabia’s southern coast of the Red Sea was selected and three major regions were sampled, and both sediment and plant organs (aerial roots, stems, and leaves) were collected. For both sediment and plant materials, the following metals (mg kg⁻¹) were analyzed: Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, and Zn. Metal Bioaccumulation Factors (BAFs) and Translocation Factors (TFs) were calculated. Moreover, model efficiency (ME) and validation parameters were calculated including coefficient of determination (R²), mean normalized average error (MNAE), and mean normalized bias (MNB). On average, A. marina sediment was moderately to heavily polluted with Pb and Zn (311.2 ± 56.34 and 141.9 ± 19.11 mg kg⁻¹, respectively). Cu, Zn, Mo, Cr, and Pb were translocated from A. marina’s aerial roots to the stems (TF > 1), while Cr, Cu, Zn, Fe, Mo, and Co were translocated from A. marina’s aerial roots to the leaves (TF > 1). The statistical analysis using t-tests showed no significant differences between the observed heavy metal contents and the model-estimated contents within the mangrove's leaves, stems (except for Cd), and aerial roots. Our predictive model to estimate heavy metals in different tissues of A. marina based on sediment characteristics was significantly valid (with exception for stem Cd content). Our results confirm the efficacy of A. marina as a bioindicator of toxic metal for monitoring pollution and application of A. marina as a natural phytoremediation tool.

Purpose

Grapevine (Vitis vinifera L.) is a relevant crop, which is associated to arbuscular mycorrhizal fungi (AMF) that are influenced by agricultural practices. The hypothesis of this study is that organic/biodynamic management stimulates grapevine mycorrhizal colonisation and increases AMF diversity in Chilean vineyards. The aim of this study was to determine the influence of agricultural management on AMF association and AMF diversity in Chilean vineyards.

Methods

Mycorrhizal colonisation of grapevine roots from organic/biodynamic and conventional vineyards in Northern (Elqui Valley), Central (Casablanca and Cachapoal Valleys), and Southern Chile (Maule and Itata Valleys), was determined under a microscope. AMF diversity was analysed by morphological, and molecular characterisation of spores through SSU-ITS-LSU rRNA region sequence analyses.

Results

AMF colonisation of grapevine roots was influenced by vineyard management independent of the season. Higher mycorrhizal colonisation was detected in organic/biodynamic grapevine soils (20 − 35%), compared with conventional soils (6 − 31%). Twelve AMF species were identified in vineyards, belonging to five Glomeromycota families. Interestingly, organic/biodynamic vineyards showed higher AMF diversity. The three predominant morphotypes were Funneliformis verruculosum (GL1), Septoglomus sp. (GL4) and Septoglomus constrictum (GL5). Molecular analyses of AMF spores highlighted the occurrence of Septoglomus, Acaulospora, Pacispora and Cetraspora genera in vineyards.

Conclusions

In this study, AMF diversity in Chilean vineyards is described for the first time. The diversity of AMF in vineyards in Chile was higher than the diversity reported in other wine-producing ecosystems. The understanding of agricultural practices on AMF activity and diversity may be crucial to improve the vineyard management.

Rocket salads (Diplotaxis spp. and Eruca spp.) are leafy vegetables appreciated for their typical taste and nutritional value. When exposed to salt stress, these plants undergo morpho-physiological and metabolic changes. The aim of the study was to investigate the efficacy of a “root-promoting biostimulant” (Radifarm^®) applied during germination (Experiment 1) and during the growth cycle (Experiment 2) on two rocket species under salt stress. Experiment 1 explored if Radifarm^® can protect seed from salt stress in early-stage development. Different salt levels (0, 150 and 200 mM NaCl) were combined with different Radifarm^® concentrations (0, 0.5, 1, 2.5, 5 mL L^− 1). Experiment 2 investigated how Radifarm^® can promote plant growth after transplantation when irrigated with saline water (0, 150, and 200 mM NaCl) until harvest. Experiment 1 showed that salt stress significantly affected the germination of rocket salads. The addition of Radifarm^® did not improve the germination of D. tenuifolia grown under any salt conditions, but it was beneficial for E. sativa when the highest level of Radifarm^® was applied. In Experiment 2, the application of Radifarm^® significantly reduced the symptoms of salt stress in both species. In E. sativa, salt stress affected all growth parameters (plant height, leaf number and area). However, under 200 mM NaCl, plants fully recovered when Radifarm^® was applied. The same recovery was observed for chlorophyll content in both species. Radifarm^® also contributed to increase protein and lipid content compared to plants under salt stress. This study showed that Radifarm^® was able to protect both species from salt stress.

Purpose: Soil aggregate stability is a crucial property affecting soil erodibility, water infiltration and carbon sequestration. This study aimed to determine ultrasonic aggregate stability (USAS) as well as solid and dissolved organic carbon (OC and DOC) associated with aggregate fractions of different aggregation strength and size in volcanic soils along an Andosol-Luvisol-Cambisol chronosequence on the Galápagos Islands. Methods: Aggregate stability was determined by ultrasonication at different energy levels, i.e. 20, 100, and 500 J mL^− 1. OC was measured in different aggregate size fractions, i.e. macroaggregates (250–2000 μm), microaggregates (63–250 μm), and the fraction < 63 μm, and released DOC was determined. Results: Aggregate breakdown increased with ultrasonic energy input. The Andosol (short-range order minerals, high OC) had the highest aggregate stability among the studied soils. The OC contents in the stable macro- and microaggregates (at 20 J mL^− 1) were highest in the Andosol (20.4 and 20.1%, respectively), followed by the Luvisol (11.6 and 10.8%, respectively) and the Cambisol (6.5 and 6.7%, respectively). The decreasing aggregate-associated OC stabilization with increasing soil age coincided with mineralogical changes from short-range order phases to high-activity clays to low-activity clays. The release of DOC during sonication was highest for the intermediate-aged soil (Luvisol) and mainly occurred at low and intermediate energy levels, while for the young soil (Andosol), released DOC steadily increased until the highest energy level. Conclusions: Our results imply that mineralogical/pedogenic changes over millennial time scales can make volcanic soils more susceptible to losses of OC by leaching and water erosion.

Purpose

Biofertilizer application in the agriculture industries is deemed sustainable in the long run given its ability to restore fertility of soil and increase crops productivity through several direct and indirect mechanisms. However, the dissolved fraction (DOM), which is made up of tiny molecules of plant and microbial origin produced by lysed cells and released metabolites as influenced directly through biofertilizer amendment is unknown.

Methods

An untargeted metabolomics profiling was conducted via an in vitro rhizospheric Bungor soil series incubation with IBG Biofertilizer from IBG Manufacturing Sdn Bhd. In this study, a comparative analysis between Ultisols samples inoculated with IBG biofertilizer and control samples was conducted under simulated humid tropic conditions.

Results

18 mass-to-charge ratio (m/z) values with VIP (Variable Importance in Projection) scores exceeding 1 in the IBG biofertilizer-inoculated Ultisol. The annotated metabolites primarily consisted of endogenous compounds, including amino acids, organic acids, nucleic acids, fatty acids, and amines. Notably, a signaling compound, homoserine lactone (m/z 270), exhibited the highest fold changes in response to IBG biofertilizer inoculation on the simulated Ultisol. Furthermore, key metabolic pathways such as Glycerophospholipid metabolism, Glycine, serine, and threonine metabolism, Cysteine and methionine metabolism, and Alanine, aspartate, and glutamate metabolism were notably affected by IBG biofertilizer inoculation on the simulated soil model.

Conclusions

These findings emphasized the metabolic responses induced by IBG biofertilizer in Ultisols under the simulated humid tropic conditions., which suggests that biofertilizers application have some significant changes on soil metabolites that overall soil productivity could be affected by these potential biomarkers. Understanding these metabolic shifts not only enhances crop productivity but also addresses broader questions of soil health and ecosystem sustainability in the face of climate change and agricultural intensification.

Ammonia-oxidizing archaea (AOA) and Ammonia-oxidizing bacteria (AOB) are key microorganisms in the soil nitrogen cycle, but how they change in the intercropping system, affected by interspecific interaction and N application levels, is not clear. A field experiment of soybean/maize intercropping with three nitrogen application levels was designed. Illumina MiSeq sequencing was used to determine AOA and AOB diversity and communities in the rhizosphere of intercropped soybean and maize. Nitrogen absorption of maize grain has increased by 21.09% to 33.54% in intercropping compared with monoculture, while that of soybean was reduced, especially in 240 kg N·ha⁻¹(N2). Our results showed that the α-diversity of AOA and AOB in the rhizosphere of maize was reduced in intercropping treatment across all N application levels. The opposite results were found in intercropped soybeans. Additionally, there was an increase in the α-diversity of AOB in the soybean rhizosphere with N2 treatments. Specifically, α-diversity of AOB in intercropped soybean in 240 kg N·ha⁻¹(N2) increased by 10.45% and 1.6% relative to the 0 kg N·ha⁻¹(N0) and 180 kg N·ha⁻¹(N1), respectively. This effect is further magnified within the monocropped maize under 240 kg N·ha⁻¹(N2), reflecting enhancements of 10.68% and 5.37%, respectively. Under intercropping conditions, the abundance of the dominant AOA genus, Nitrososphaera, significantly decreased more than sixfold under 180 kg N·ha⁻¹(N1). Conversely, the abundance of the dominant AOB genus, Nitrosospira, increases with the higher nitrogen application rates, although intercropping exerts a diminishing influence. While its trend within the rhizosphere of soybean is the opposite. Moreover, Redundancy Analysis (RDA) and Mantel tests showed a correlation between variations in ammonia-oxidizing microbial communities and soil-available nitrogen content (p = 0.001, r > 0.4). Due to species competition after intercropping, the soil available nitrogen content decreased, resulting in changes in the soil ammonia-oxidizing microbial community. The results indicated that interspecific competition in intercropping systems could change the diversity and composition of AOA and AOB in the rhizosphere of crops, consequently influencing N transformation and enhancing nitrogen uptake. These findings elucidated the mechanisms of how intercropping systems bolster nitrogen-use efficiency through the dynamics of rhizosphere microorganisms.

The application of mineral-solubilizing microbial inoculums is a biological strategy used for the restoration of vegetation at rock mining sites. These inoculums improve soil fertility, enhance plant growth, and accelerate soil weathering. However, their impacts on rhizospheric soil microbial communities are not well understood. This study aimed to elucidate how various mineral-solubilizing microbial inoculums affected the root systems of R. pseudoacacia. A pot experiment was conducted, and 32 samples were extracted from four different mineral-solubilizing microbial inoculum treatments to investigate the responses of soil bacterial and fungal communities in the rhizospheres of R. pseudoacacia. The results showed that the impacts of the inoculums on fungal community structures surpassed those of the bacterial communities. The relative abundance of Proteobacteria increased, which was strongly correlated with root nodulation. Interestingly, the inoculums significantly influenced the diversity and evenness of bacterial communities in the rhizospheric soil. Correlation analysis revealed positive correlations between Proteobacteria, Verrucomicrobia, Ascomycota, Zoopagomycota, soil enzyme activities, and plant growth. RDA analysis indicated that the relative abundance of these bacterial and fungal phyla positively influenced root nodulation. This study suggests that the application of mineral-solubilizing microbial inoculums optimizes the rhizospheric soil microbial community structure, promotes R. pseudoacacia root nodulation, and enhance the nitrogen fixation capacities of plants. Further, it provides a theoretical foundation for the application of mineral-solubilizing microbial inoculums for slope ecological restoration.

The addition of organic materials to the fertilization regime can be instrumental in reducing the amount of chemical fertilizers use, while maintain optimum nutrient status in the trees. The 2 year field experiment was conducted to evaluate the effect of different nutrient source combination in comparison to conventional recommendation on growth, fruit yield and leaf nutrient status of plum cv. ‘Black Amber’ grown in hills of Himachal Pradesh, India. Treatments included conventional fertilizers rate which are recommended to the farmer (NPK₁₀₀) compared with 10 treatment combinations with reduced rate of chemical fertilizer (NPK₈₀; NPK₇₀; NPK₆₀), organic manure (Farmyardmanure; Vermicompost) and microbial formulations (Biofertilizers; Jeevamrit). Data revealed that NPK₇₀ + 10% RDN through vermicompost + biofertilizer (T-6) and NPK₇₀ + 10% RDN through vermicompost + jeevamrit (T-7) yielded the best results in terms of shoot growth, leaf area, leaf chlorophyll content, photosynthesis rate, stomatal conductance and transpiration rate in both the years. Cumulative fruit yield peaked in T-7 by 6% over conventional rate NPK₁₀₀ (T-1); there were no difference in fruit yield between T-6 and T-7. Integrated fertilizers combination registered significant influence on the leaf nutritional status, but not consistent. The deviation from optimum (DOP) index revealed excess of leaf phosphorus and iron content with all the treatments application, while negative for other elements however, T-6 maintained a better nutrient status than other treatments. The treatment combinations T-6 and T-7 can be recommended to the farmers for maintaining nutrient balance, thereby ensuring sustaining crop production in subsequent years.

The intensive and repeated use of chemical herbicides has led to the emergence of herbicide-resistant weeds, which, in addition to their environmental impacts, also pose significant threats to human and animal health. This study aimed to explore the potential of oilseed industrial wastes, specifically soybean and flaxseed meals, as safe and environmentally friendly bioherbicides for controlling weeds associated with onion crops. Two field experiments were conducted along two successive winter of 2020/21 and 2021/22. Treatments involved foliar spray of soybean and flaxseed meals in three different concentrations (15, 30 and 45%), mulching of seed meals, oxyfluorfen herbicide, two hand hoeing and untreated weedy check. The findings demonstrated that all weed control treatments significantly reduced weed density, biomass and nutrient uptake. Two hand hoeing, oxyfluorfen herbicide and the mulching of soybean and flaxseed meals alternated in the top rank for weed control, showing minimal significant differences among them. Following these effective treatments, soybean meal extracts at 45 and 30% exhibited notable weed control compared to the weedy check. The greatest enhancement in onion growth, yield characteristics and bulb quality was observed with the application of hand hoeing, soybean and flaxseed meal mulching treatments, with no significant differences between them. High-Performance Liquid Chromatography (HPLC) fractionation of both meals identified various phenolic acids at different concentrations. Practically, these safe efficient treatments proved progress on chemical herbicide. Hence, onion farmers are advised to apply soybean and flaxseed meals mulching safe treatments as alternative to harmful chemical herbicides under all experimental conditions.