Soil Phosphorus Content Research Articles

Characteristics of nitrogen and phosphorus contents in soil and water in an agricultural catchment of the three Gorges reservoir area

To explore the impact of different land use modes on the contents of nitrogen and phosphorus in soil and water in the agricultural basin of the Three Gorges Reservoir, the differences in the nitrogen and phosphorus contents in soil and shallow groundwater under different land use modes were studied by using sample data collected in the field. The typical agricultural small watershed at the heart of the reservoir area was selected as the research object. The differences in the nitrogen and phosphorus loss concentrations during the rainfall process and in the daily surface runoff of the two subcatchments with different land use compositions and spatial layouts were compared. The results show that under the five land use modes, the average total nitrogen (TN) content of the paddy soil (1.51 g/kg) was the highest and was significantly higher than that of the other four land use modes (p < 0.05); the average nitrate nitrogen (NO3−-N) content of the terraced soil in dry land (30.05 mg/kg) was the highest, and the dispersion degree was the greatest; and the total phosphorus (TP) content of the three types of sloping farmland was higher than that of terraced farmland, among which the total phosphorus content of the dryland sloping farmland (1.37 g/kg) was the highest and was significantly greater than that of the other types (p < 0.05); moreover, the available phosphorus (AP) content in the soil of the closely planted mulberry garden was the highest, with an average of 36.85 mg/kg. Under the different land use modes, the concentrations of TN and NO3−-N in the shallow groundwater varied greatly, while there were no obvious differences in the TP concentrations. Influenced by fertilization, the concentrations of TN and NO3−-N in the shallow groundwater clearly increased after fertilization in spring and autumn. The concentration of TP increased slightly, and the concentration was the highest when the rainfall was concentrated in summer. A comparison of the two subcatchments revealed that the interplanted mulberry and paddy fields at the bottom of the basin effectively reduced TN and TP outputs of surface runoff in the subcatchment.

Effects of Microplastics on the Leaching of Nutrients and Cadmium from Soil

The environmental effects of microplastics, which are considered a type of emerging contaminants, have attracted increasing concern due to their small size, large specific surface area, strong adsorption capacity, and low degradability. Microplastics can change soil properties and affect the migration ability of nutrients and pollutants in soil, but their effects on the leaching of soil nutrients and heavy metals have not been sufficiently studied. A soil column leaching experiment was conducted to explore the effects of polystyrene (PS) and polylactic acid (PLA) microplastics at different mass fractions (0%, 0.2%, and 2%) on the leaching of nutrients and cadmium under simulated rainfall scenarios. The results showed that increasing rainfall intensity enhanced the leaching of nutrients and cadmium from soil. During downpour conditions, 2% PS significantly increased the leaching of total nitrogen and the content of available phosphorus in soil and reduced the leaching of inorganic phosphorus and the content of ammonium nitrogen in the soil, whereas it increased the content of available potassium during heavy rain. By comparison, 2% PLA reduced the leaching of nitrate nitrogen during heavy rain and intense rainfall and decreased the content of ammonium nitrogen in soil during intense rainfall and downpour conditions and the content of total nitrogen in soil during downpours. In addition, 0.2% PLA significantly increased cadmium leaching during downpours. To conclude, the effects of microplastics on the leaching of nutrients and cadmium were dependent on the type and concentration of microplastics, as well as the rainfall level. Our findings showed that the microplastics derived from both nondegradable PS and biodegradable PLA could affect the leaching of nutrients and heavy metals from soil.

Metagenomic insights into inhibition of soil microbial carbon metabolism by phosphorus limitation during vegetation succession.

There is growing awareness of the need for regenerative practices in the fight against biodiversity loss and climate change. Yet, we lack a mechanistic understanding of how microbial community composition and functioning are likely to change alongside transition from high-density tillage to large-scale vegetation restoration. Here, we investigated the functional dynamics of microbial communities following a complete vegetation successional chronosequence in a subtropical zone, Southwestern China, using shotgun metagenomics approaches. The contents of total soil phosphorus (P), available P, litter P, and microbial biomass P decreased significantly during vegetation succession, indicating that P is the most critical limiting nutrient. The abundance of genes related to P-uptake and transport, inorganic P-solubilization, organic P-mineralization, and P-starvation response regulation significantly increased with successional time, indicating an increased microbial "mining" for P under P limitation. Multi-analysis demonstrated microbial P limitation strongly inhibits carbon (C) catabolism potential, resulting in a significant decrease in carbohydrate-active enzyme family gene abundances. Nevertheless, over successional time, microorganisms increased investment in genes involved in degradation-resistant compounds (lignin and its aromatic compounds) to acquire P resources in the litter. Our study provides functional gene-level insights into how P limitation during vegetation succession in subtropical regions inhibits soil microbial C metabolic processes, thereby advancing our understanding of belowground C cycling and microbial metabolic feedback during forest restoration.

Transcriptome analysis of axillary buds in low phosphorus stress and functional analysis of TaWRKY74s in wheat

BackgroundWheat is one of the main grain crops in the world, and the tiller number is a key factor affecting the yield of wheat. Phosphorus is an essential element for tiller development in wheat. However, due to decreasing phosphorus content in soil, there has been increasing use of phosphorus fertilizer, while imposing risk of soil and water pollution. Hence, it is important to identify low phosphorus tolerance genes and utilize them for stress resistance breeding in wheat.ResultsWe subjected the wheat variety Kenong 199 (KN199) to low phosphorus stress and observed a reduced tiller number. Using transcriptome analysis, we identified 1651 upregulated genes and 827 downregulated of genes after low phosphorus stress. The differentially expressed genes were found to be enriched in the enzyme activity regulation related to phosphorus, hormone signal transduction, and ion transmembrane transport. Furthermore, the transcription factor analysis revealed that TaWRKY74s were important for low phosphorus tolerance. TaWRKY74s have three alleles: TaWRKY74-A, TaWRKY74-B, and TaWRKY74-D, and they all belong to the WRKY family with conserved WRKYGQK motifs. These proteins were found to be located in the nucleus, and they were expressed in axillary meristem, shoot apical meristem(SAM), young leaves, leaf primordium, and spikelet primordium. The evolutionary tree showed that TaWRKY74s were closely related to OsWRKY74s in rice. Moreover, TaWRKY74s-RNAi transgenic plants displayed significantly fewer tillers compared to wild-type plants under normal conditions. Additionally, the tiller numebr of the RNAi transgenic plants was also significantly lower than that of the wild-type plants under low-phosphorus stress, and increased the decrease amplitude. This suggestd that TaWRKY74s are related to phosphorus response and can affect the tiller number of wheat.ConclusionsThe results of this research showed that TaWRKY74s were key genes in wheat response to low phosphorus stress, which might regulate wheat tiller number through abscisic acid (ABA) and auxin signal transduction pathways. This research lays the foundation for further investigating the mechanism of TaWRKY74s in the low phosphorus environments and is significant for wheat stress resistance breeding.

Heterologous overexpression of heat shock protein 20 genes of different species of yellow Camellia in Arabidopsis thaliana reveals their roles in high calcium resistance

Yellow Camellia (Camellia sect. chrysantha) is a rare ornamental plant and an important germplasm resource globally. Camellia nitidissima thrives in normal acidic soils, while Camellia limonia can adapt to the calcareous soils found in karst areas. Our previous study on the karst adaptation of yellow camellias revealed that the expression levels of heat shock protein 20(HSP20) were higher in Camellia limonia than in Camellia nitidissima. However, the functions of the HSP20 gene of Camellia limonia remain unclear to data. In this study, the HSP20 genes of Camellia limonia (ClHSP20-OE lines) and Camellia. nitidissima (CnHSP20-OE lines) were cloned and overexpressed heterologously in Arabidopsis thaliana. Additionally, we overexpressed the HSP20 gene of Arabidopsis (AtHSP20-OE lines) was also overexpressed, and the T-DNA inserted mutants (athspmutant lines) were also used to determine the functions of HSP20 genes. Under high calcium stress, the chlorophyll, nitrogen, water content and humidity of leaves were increased in ClHSP20-OE lines, while those of other lines were declined. The size of the stomatal apertures, stomatal conductance, and the photosynthetic efficiency of ClHSP20-OE lines were higher than those of the other lines. However, the accumulation of H2O2 and O2− in the leaves of ClHSP20-OE lines was the lowest among all the lines. Energy spectrum scanning revealed that the percentage of calcium on the surfaces of the leaves of ClHSP20-OE lines was relatively low, while that of athspmutant lines was the highest. The ClHSP20 gene can also affected soil humidity and the contents of soil nitrogen, phosphorus, and potassium. Transcriptome analysis revealed that the expressions of FBA5 and AT5G10770 in ClHSP20-OE lines was significantly up-regulated compared to that of CnHSP20-OE lines. Compared to that of athspmutant lines, the expressions of DREB1A and AT3G30460 was significantly upregulated in AtHSP20-OE lines, and the expression of POL was down-regulated. Our findings suggest that the HSP20 gene plays a crucial role in maintained photosynthetic rate and normal metabolism by regulating the expression of key genes under high-calcium stress. This study elucidates the mechanisms underlying the karst adaptation in Camellia. limonia and provides novel insights for future research on karst plants.

Effects of salt stress on bacterial community composition and diversity in rhizosphere soil of Bletilla striata

Salinization environment affects the normal growth and development of plants, as well as the microbial community in the rhizosphere. To explore the succession dynamics of bacterial communities in the rhizosphere soil of Bletilla striata under salt stress condition, we performed 16S rRNA high-throughput sequencing to determine the bacterial community composition and diversity of B. striata in the rhizosphere under different salt stress concentrations, measured the effects of salt stress on the growth and development of B. striata and soil physicochemical pro-perties, and analyzed the correlation between community composition of rhizosphere bacteria and the soil environmental factors. The results showed that compared with the control, salt stress reduced growth rate and health degree of B. striata, and significantly decreased the content of soil organic matter, nitrogen and phosphorus. Under the salt stress treatment, species diversity and evenness of the bacterial communities in the rhizosphere of B. striata showed a trend of first decreasing and then increasing. There were significant differences in the relative abundance and variation trends of the dominant bacterial taxa in the rhizosphere soil of B. striata at the phylum and class levels between the control and the salt stress treatments. Salt stress intensity and duration were important factors affecting bacterial community composition in the rhizosphere soil of B. striata. Soil organic matter, available nitrogen, and total phosphorus content were key environmental factors affecting the structure of rhizosphere bacterial community composition. Functional genes related to cytoskeleton, cell motility, substance metabolism and signal transduction mechanisms may be involved in the adaptation and stress response of bacterial communities to salt stress. This study would provide theoretical basis and reference for the cultivation management of B. striatain saline area.

Stochastic process drives the dissimilarity in biodiversity patterns between Pinus kwangtungensis coniferous forest and evergreen deciduous broad-leaved mixed forest in karst area.

Pinus kwangtungensis is an endangered evergreen conifer tree species, and its in situ conservation has been considered one of the most critical issues. However, relative protection is limited by the lack of understanding of its community structure and underlying assembly processes. To study how the species diversity and assembly processes of Pinus kwangtungensis coniferous forest (CF) differed with regional climax community, this study established a series forest dynamic plots both in CF and evergreen deciduous broadleaved mixed forest (EDBM). By performing comparison analysis and PER-SIMPER approaches, we quantified the differences in species diversity and community assembly rules. The results showed that the species α-diversity of CF differed greatly from the EDBM both in species richness and evenness. In addition, the stochastic process acted a more important role in determining species composition, indicating the uncertainty in presence of species. The soil phosphorus and changeable calcium content were the main factors driving the differences in biodiversity, which the importance of soil nutrient factors in driving species composition. Our study highlighted that we should consider the community structure and ecological process when conducting conservation of Pinus kwangtungensis.

Exploring laboratory-based spectroscopy for estimating NPK content in the hutton soils of Syferkuil Farmlands, South Africa

This study seeks to identify the key wavelengths and spectral transformation techniques that may be used to accurately estimate soil nitrogen, phosphorus, and potassium (NPK) concentration in the Hutton soils. For this purpose, the reflectance spectra of 74 soil samples were measured in the laboratory, and the chemical properties of the soil were analysed. Pearson correlation (r), stepwise multiple linear regression (SMLR), and Partial Least Square Regression were used to model the relationships between the selected variables under study. The study findings revealed that moderate to weak correlations (r = −0.2 − 0.6) exist between wavelengths (400 − 2500 nm) and soil NPK content. Important wavelengths for accurately predicting Soil NPK content were found within visible (400 nm − 729nm), near-infrared (805 nm − 1200nm) and mid-infrared region (1375 nm to 2462 nm). The PLSR model coupled with different spectral transformations was found to be the optimal model for estimating soil NPK (RPD > 2). The introduction of the first and second derivate spectral transformation approach markedly improved all the models investigated in this study. The results retrieved from the study provide a high-accuracy prediction of soil nutrient contents, which is critical for soil fertility management and sustainable food production.

A novel deep learning model to predict the soil nutrient levels (N, P, and K) in cabbage cultivation

Cabbage (Brassica oleracea) is a green cruciferous vegetable. Major nutrients (nitrogen, phosphorus, and potassium) are frequently applied to the soil due to low fertility levels. However, optimizing required fertilizer levels are extremely important to avoid any overuse and underuse. Therefore, it is important to develop a comprehensive methodology for evaluating the major nutrients in the soil. In this research, a deep learning model was introduced to predict the nitrogen, phosphorus, and potassium content of the soil by analyzing the growing characteristics of the plants, such as plant height, the number of leaves, and the average leaf area of the plant. To achieve this, the growing characteristics of the cabbage plants were recorded weekly along with the respective soil nitrogen, phosphorus, and potassium content of the nearby soil. After the data was trained using the Levenberg–Marquardt algorithm and tested with different transfer functions such as logarithmic sigmoid, pure linear, and tangent sigmoid, better predictions were obtained through the model. According to the Pearson correlation values, pure linear and tangent sigmoid showed higher values, ranging from 0.99 for training, testing, validation, and all data points from the model, indicating a strong relationship between the actual and predicted values. According to the Mean Square Error values, the tangent sigmoid transfer function outperformed the others, giving a value of 1.0813, indicating better predictions of the soil nitrogen, phosphorus, and potassium content from the model.

Phosphate solubilization and plant growth properties are promoted by a lactic acid bacterium in calcareous soil.

On the basis of good phosphate solubilization ability of a lactic acid bacteria (LAB) strain Limosilactobacillus sp. LF-17, bacterial agent was prepared and applied to calcareous soil to solubilize phosphate and promote the growth of maize seedlings in this study. A pot experiment showed that the plant growth indicators, phosphorus content, and related enzyme activity of the maize rhizospheric soils in the LF treatment (treated with LAB) were the highest compared with those of the JP treatment (treated with phosphate solubilizing bacteria, PSB) and the blank control (CK). The types of organic acids in maize rhizospheric soil were determined through LC-MS, and 12 acids were detected in all the treatments. The abundant microbes belonged to the genera of Lysobacter, Massilia, Methylbacillus, Brevundimonas, and Limosilactobacillus, and they were beneficial to dissolving phosphate or secreting growth-promoting phytohormones, which were obviously higher in the LF and JP treatments than in CK as analyzed by high-throughput metagenomic sequencing methods. In addition, the abundance values of several enzymes, Kyoto Encyclopedia of Genes and Genomes (KEGG) orthology, and Carbohydrate-Active Enzymes (CAZys), which were related to substrate assimilation and metabolism, were the highest in the LF treatment. Therefore, aside from phosphate-solubilizing microorganisms, LAB can be used as environmentally friendly crop growth promoters in agriculture and provide another viable option for microbial fertilizers. KEY POINTS: • The inoculation of LAB strain effectively promoted the growth and chlorophyll synthesis of maize seedlings. • The inoculation of LAB strain significantly increased the TP content of maize seedlings and the AP concentration of the rhizosphere soil. • The inoculation of LAB strain increased the abundances of the dominant beneficial functional microbes in the rhizosphere soil.

Estimating Macronutrient Content of Paddy Soil Based on Near-Infrared Spectroscopy Technology Using Multiple Linear Regression

This study investigates the feasibility of employing near-infrared (NIR) spectroscopy with multiple linear regression (MLR) to estimate macronutrients in paddy soil compared with partial least squares (PLS) and principal component regression (PCR). Seventy-nine soil samples from West Java Province, Indonesia, are subject to conventional nutrient analysis and NIR spectroscopy (1000-2500 nm). The reflectance data undergoes various pretreatment techniques, and MLR models are calibrated using the forward method to achieve correlations exceeding 0.90. The best model calibrations are selected based on high correlation coefficients, determination coefficients, RPD, and low RMSE values. Meanwhile, the comparison of performance MLR is made with the PLS and PCR models. Results indicate that simple MLR models perform less than PLS for all nutrients, better than PCR for nitrogen, and below PCR for phosphorus and potassium. However, MLR reliably estimates soil nitrogen, phosphorus, and potassium content with ratio of performance to deviation (RPD) exceeding 2.0. This study demonstrates the potential of MLR for precise macronutrient estimation in paddy soil.

Investigation into the Effects of Different Restoration Techniques on the Soil Nutrient Status in Degraded Stipa grandis Grassland

The degradation and desertification of grassland ecosystems have garnered significant attention both domestically and internationally. Grassland restoration techniques are widely considered a principal measure to promote the sustainable utilization of grasslands, with soil nutrient content being a core indicator for assessing the effectiveness of restoration in degraded grasslands. This study aims to explore the differential impacts of various grassland restoration methods on soil nutrient distribution in degraded Stipa grandis grasslands. Three major restoration methods, i.e., root cutting, enclosure, and fertilization, were applied in the study area. The soil nutrient content was measured and analyzed under the different restoration methods and at varying depths. The results revealed that under all three restoration methods and at different soil depths (0–10 cm, 10–20 cm, 20–30 cm), the organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, alkali-hydrolyzable phosphorus, and available potassium contents were significantly higher than those in the control group (p < 0.05). Furthermore, as soil depth increased, the contents of organic matter and all nutrients gradually decreased. Specifically, regarding the contents of different nutrients, the order of organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, and available phosphorus was as follows: fertilization > enclosure > root cutting > control, while the contents of total potassium and available potassium followed the sequence: fertilization > enclosure > control > root cutting. Additionally, based on the canonical correlation analysis (R2 = 0.88), the total phosphorus content in soil had the greatest impact on soil nutrients, while vegetation cover and plant height contributed the most to vegetation characteristics. In grassland restoration, the increase in soil total phosphorus led to higher vegetation cover and height, mildly influenced plant diversity and density, and simultaneously promoted biomass accumulation. These research findings provide a solid theoretical foundation for the application of grassland restoration techniques, contributing to the sustainable development of grassland ecosystems.

Applications of Biofertilizers and Phosphorus Influence Nutrient Uptake and Nutrient Use Efficiency in Chickpea (Cicer Arietinum L.)

ABSTRACT The objective of the study was to investigate the effects of sole applications of biofertilizers and phosphorus as well as their integrated use in lentil. The field experiment was conducted to study the effect of phosphorus (0, 15, 20 and 25 kg P2O5 ha−1) and biofertilizer inoculation treatments [uninoculated control, Mesorhizobium, Mesorhizobium + RB-1 (Pseudomonas argentinensis) and Mesorhizobium + RB-2 (Bacillus aryabhattai)] on nutrient uptake, nutrient use efficiency and residual nutrient status of soil after the harvest of chickpea. Mesorhizobium + RB-1 recorded the highest uptake of nitrogen (73.7, 59.0 and 132.7 kg ha−1 in grain, straw and total, respectively), phosphorus (8.29, 11.34 and 19.63 kg ha−1 in grain, straw and total) and potassium (23.48, 43.36 and 66.84 kg ha−1 in grain, straw and total) as well as partial factor productivity (113.1 kg grain kg−1 P2O5). Application of 25 kg P2O5 ha−1 recorded the highest phosphorus concentration (0.39% in grain and 0.26% in straw), phosphorus uptake (8.35, 12.32 and 20.67 kg ha−1 in grain, straw and total, respectively) and phosphorus status in soil after crop harvest (18.7 and 16.7 kg P ha−1 in 0–15 and 15–30 cm soil layers, respectively). Partial factor productivity was recorded the highest with the application of 15 kg P2O5 ha−1 (132.2 kg grain kg−1 P2O5). It can be concluded that dual applications of biofertilizers [Mesorhizobium + RB-1 (Pseudomonas argentinensis)] and 25 kg P2O5 ha−1 improve nutrient uptake by the crop and build up of nutrients in the soil after the harvest of the crop.

Influence of ecological factors on the phytochemical composition and bioactivity of Berberis tinctoria Lesch. wild edible fruits

Berberis tinctoria Lesch. is an endemic wild plant with significant medicinal value in traditional ethnomedicine. Although its chemical composition has not yet been studied, tribal communities in Nilgiri-Hills (NH) and Palani-Hills (PH) use it as food and to cure various ailments. The present study aims to analyze the influence of ecological factors on the accumulation of active compounds and antioxidants in B. tinctoria fruits. The antiproliferative effect was also evaluated. Thus, two distinct geographic locations within the B. tinctoria cultivation area were selected. The contents of soil pH, organic carbon, nitrogen, phosphorus, potassium and primary and secondary active metabolites in the fruits were measured. Bioactive compounds were tentatively identified by liquid chromatography-mass spectrometry (LC-MS) analysis. Qualitative and quantitative phytochemical screening revealed that major primary and secondary metabolites were more abundant in fruits from the NH region, especially in terms of total phenols and alkaloids. The data acquired highlight that soil physicochemical properties have a highly positive correlation with secondary metabolites content and bioactivity. In particular, NH ethyl acetate (NH-EAF) extracts showed higher antioxidant and anti-inflammatory activiy, as well as antibacterial activity against Staphylococcus aureus and Enterococcus faecium. Furthermore, NH-EAF extract showed cytotoxic effects with IC50 equal to 102.85 μg/mL and 123.39 μg/mL towards Raw 264.7 and Caco-2 cell lines, respectively. The results of this study confirmed that the fruit variability of phytochemicals and biological activities is due to geographical variation and ecological factors.

MICROBIOLOGICAL TRANSFORMATION OF PHOSPHORUS IN THE ROOT ZONE OF SUNFLOWER UNDER THE ACTION OF BACILLUS SP. 2473 AND DIFFERENT DEGREES OF CROP FERTILIZATION

Objective. To study the peculiarities of the microbiological transformation of phosphorus compounds in the root zone of sunflower plants under the action of Bacillus sp. 2473 and different degrees of crop fertilization. Methods. Field experiment; microbiological (accounting for bacteria capable of dissolving insoluble phosphate complexes with Ca2+, Al3+, Fe3+ and hydrolysing organic phosphates in the rhizosphere soil of sunflower plants); biochemical (determination of soil phosphatase activity); chemical (determination of phosphorus content in soil and plants); statistical. Results. Under the conditions of the field experiment on leached chornozem, it was established that during the growing season of sunflower in the soil after the introduction of Bacillus sp. 2473 into the agrocenosis, the number of bacteria capable of dissolving insoluble complexes of phosphates with Ca2+, Al3+, Fe3+ and bacteria hydrolysing organic forms of phosphates increases compared to the indicators of the control variants. Phosphatase activity increases during the growing season of plants and reaches the highest values during the seed ripening phase. The lowest levels of phosphorus content in the rhizosphere soil of sunflower plants were registered after presowing inoculation with Bacillus sp. 2473. The content of Р2О5 decreased from 0.25 mg Р2О5/dm3 of the soil solution (in the control) to 0.21 mg Р2О5/dm3 in the phase of 7–8 leaves under the action of the inoculant; from 0.42 mg Р2О5/dm3 to 0.31 mg Р2О5/dm3 in the flowering phase; from 0.24 mg Р2О5/dm3 to 0.21 mg Р2О5/dm3 in the seed ripening phase, respectively, which indicates the strengthening of phosphorus assimilation by bacterized plants. The optimal agricultural background, taking into account the effect of fertilizers on the development of phosphate-mobilizing microorganisms, is the use of mineral fertilizers in a rate not exceeding N90P90K90. Conclusion. Under the influence of the phosphate-mobilizing bacterium Bacillus sp. 2473, the processes of phosphorus transformation are activated in the root zone of sunflower plants, which is indicated by an increase in the number of phosphate-mobilizing bacteria, phosphatase activity and the degree of phosphate mobility in the rhizosphere soil of plants. As a result, the assimilation of phosphorus by plants is enhanced, which is confirmed by the increase in its removal with crop yield from 47.3 kg/ha to 74.8 kg/ha, while the efficiency of phosphorus nutrition of plants is 53.8 % (against the background of N90P90K90).

Leaf and root traits are partially coordinated but they show contrasting multi-trait-based community trait dispersion patterns in a subtropical forest

Abstract The ecology of plant species relies on the synchronous functioning of leaves and roots, but few studies have simultaneously examined the community trait dispersion (CTD) patterns of both organs. We measured 16 analogous leaf and root traits on 44 co-occurring woody species in a subtropical forest in southern China, aiming to examine whether leaf and root traits were coordinated, organized into parallel trait axes, exhibited similar CTD, and displayed consistent responses in CTD and community-weighted means of (CWM) traits over environmental gradients. While the first axes of leaf and root trait variation similarly exhibited a fast–slow continuum, leaf traits covered a secondary “carbon economics” axis, contrasting to root traits depicting a collaboration axis reflecting species’ mycorrhizal dependency. Analogous leaf and root chemical traits were generally coordinated but less so for morphological traits. At the community level, changes in the CWM of the first axes were generally consistent among organs with more conservative traits found as increasing elevation but not for the second axis. While root traits became thinner and more conservative as soil phosphorus concentration decreased, leaf traits rarely varied. When different trait axes were combined, leaf traits were overdispersed but tended to converge with increased elevation and soil potassium and phosphorus levels, whereas root traits were clustered but tended to diverge along the same gradients. Our study highlights fine filtering of different suites of traits above- and belowground, which in turn might reduce overall niche overlap among species and promote coexistence with diverse functional designs.

Combination of Fertilizer and Growth Regulators Impact on Nutrient Balance in Wheat Crop (Triticum aestivum L.)

A field experiment was conducted during the rabi season of 2020 at All India Coordinated Research Project (AICRP) on Wheat, Jawaharlal Nehru Krishi Vishwa Vidyalaya, Jabalpur (M.P.) to evaluate nutrient balance under the optimization of fertilizer levels with plant growth regulators. The experiment was laid out in a randomized block design comprising nine treatment of different dose of fertilizer along with plant growth regulators namely chlormequat chloride and tebuconazole applied at the rates of 0.2% and 0.1%, respectively and replicated three times. The recommended dose of fertilizer, 120:60:40 kg NPK ha-1 was applied as per treatment. The result showed that using 150% recommended doses of NPK, recorded higher value of available nitrogen (297.320 kg ha-1), phosphorus (18.970 kg ha-1) and potassium (311.630 kg ha-1) content in soil after the harvest of wheat was significantly influenced by the application of different doses of fertilizer, while lowest available content of all the three major nutrients was recorded from control. Growth regulators had no significant influence on the available nitrogen, phosphorus and potassium content in soil. The highest nitrogen content in both grain and straw were observed with the application of 150% recommended doses of NPK with growth regulators (1.99%) and (0.567%), respectively. Phosphorus content and potassium content both in grain and straw were significantly influenced by fertilizer doses, highest value recorded with 150% recommended doses of NPK and the lowest phosphorus and potassium content in both grain and straw were recorded in control while all the other treatments receiving fertilizers with or without being at par with each other. Uptake of all the major nutrients viz., nitrogen, phosphorus and potassium showed the similar trend with significantly highest uptake recorded with the application of 150% recommended doses of NPK with growth regulator and optimal NPK application demonstrated a positive nutrient balance in the soil. It concluded that nutrient management with growth regulator in wheat, economically viable and ecologically sound option to extend these benefits of balanced nutrition in enhancing both crop production and soil heath.

Enhanced Phytoremediation and Physicochemical Parameters of Crude Oil Polluted Soil Using Pseudomonas fluorescens and Bacillus substilis

There have been worry over the Niger Delta's environmental contamination. Bacteria and other microorganisms have shown to be very helpful in the breakdown of hydrocarbons generated from petroleum. The goal of this research is to use elbow bufallow grass and sedge plants for phytoremediation of soil affected by crude oil. Standard microbiological techniques were applied to the contaminated soil once it was gathered. Using a hand auger, contaminated soil samples were taken twice a month for three months from two separate locations in Rivers State at two distinct depths: 0–15 cm and 15–30 cm. The following physicochemical parameters of samples were analysed using Standard Laboratory Procedures: pH, Temperature, Nitrogen, Phosphorus, Potassium available in the polluted soil and the total hydrocarbon content (THC). Two plant species common in the Ogoni region of Rivers state, i.e. Sedge plant (Schoenoplectus), Elbow buffalo grass (Panicum subalbidum) were used for phytoremediation monitoring. A combination of treatment consisting of the application of Pseudomonas fluorescens Bacillus substilis, Panicum subalbidum and Schoenoplectus senegalensis was evaluated during 28 days of remediation. Each pot contained crude oil mixture in the soil as a sole source of carbon and energy. THB counts ranged from 2.35 to 4.15 cfu/g. The statistical analysis revealed that there was no significant difference (p>0.05) in the total heterotrophic bacteria counts between the samples. HUB counts range from 0.7 to 1.45cfu/g. The total bacterial population counts obtained from soil sample during bioremediation monitoring ranged from 17+1.41 (CS+PAN) to 40+1.412cfu/g (CS+PSE+BAC+PAN) in Day 1. Results of Day 14 range from 13+1.41 (CS+PAN) to 35.5+3.542cfu/g (CS+BAC+SCH). Results of Day 28 ranged from 8.5+0.71 (CS+PAN) to 27+1.412cfu/g (CS+PSE+BAC+PAN). The presence of microbial activity was determined by the enumeration and isolation of total heterotrophic and hydrocarbon utilizing bacteria. The results of physicochemical parameters before bioremediation is as follows: pH (5.43), Temperature (27oC), Electrical conductivity (9), Moisture content (7.80%), Total organic carbon (0.93%), Soil organic matter (1.60%), Nitrogen (56.695mg/kg), Phosphorus (0.621mg/kg), Potassium (7.125mg/kg) and Total Hydrocarbon content (700mg/kg). Results revealed amount of soil hydrocarbon removed and percentage (%) Bioremediation remediated after 28 days of monitoring to be higher in set up with CS+PSE+SCH (3454mg/kg; 85.28%) and lowest in set up with US+SCH (434mg/kg: 62%) and the amount of root hydrocarbon content removed and percentage (%) Bioremediation remediated after 28 days of monitoring to be higher in set up with CS+BAC+SCH (632Mg/kg; 15.6%) and lowest in set up with US+SCH (12.2mg/kg; 1.74%).
 Three (3) most occurring hydrocarbon utilizing bacterial isolates were isolated and identified culturally and phenotypically from the soil samples these bacteria isolates were confirmed to be Peudomonas, Priestia megaterium and Bacillus spp molecularly via sequencing of the 16SrRNA gene. The most common bacteria isolated were Bacillus spp at a dilution of 104. This research revealed and recommend that Panicum subalbidum as a suitable plant species for phytoremediation of crude oil-contaminated soil.

Effects of Datura stramonium L. Invasion into Different Habitats on Native Plant Functional Traits and Soil Carbon, Nitrogen and Phosphorus Stoichiometric Characteristics.

Datura stramonium is an invasive herb of the family Solanaceae from Mexico and has been invading seriously in China. The effects of invasive plants on the functional traits of native plants and the stoichiometric characteristics of soil carbon, nitrogen and phosphorus in different habitats were explored by taking the invasive plant D. stramonium and coexisting native plants as the research object. The species, quantity and height of plants in sample plots in farmland, wasteland and roadside habitats were investigated and the specific leaf area (SLA), leaf carbon content (C), nitrogen content (N), carbon-to-nitrogen ratio (C:N), construction cost (CCmass) and stoichiometric characteristics of soil carbon (C), nitrogen (N) and phosphorus (P) were analyzed. The results showed that compared with the noninvaded area, the species and quantity of native plants decreased in the invaded area, and SLA and leaf N showed a decreasing trend. The plant height of native plants in the invaded area of the farmland and wasteland decreased by 23.19% and 15.26%, respectively, while the height of native plants along the roadside increased by 95.91%. The leaf C:N ratio of native plants in the invaded area along the roadside significantly increased by 54.07%. The plant height and leaf N of D. stramonium in the three habitats were higher than those of the native plants. The soil N in the invaded area of the three habitats increased, with the soil N in the farmland increasing by 21.05%, in the wasteland increasing by 9.82% and along the roadside significantly increasing by 46.85%. The soil carbon-to-phosphorus ratio (C:P) in the three habitats showed an increasing trend. The soil C:P ratio in the farmland increased by 62.45%, in the wasteland it increased by 11.91% and along the roadside it significantly increased by 71.14%. These results showed that invasion by D. stramonium has a great effect on the local ecosystem, and it has a high ability to capture resources. D. stramonium can improve its own competitiveness by enhancing invasiveness by changing the functional traits of native plants and the stoichiometric characteristics of soil C, N and P, which may be the reason for its invasive success.

Effect of Mycorrhizae, Azotobacter and Vermicompost Tea on Nitrogen, Phosphorus, and Potassium (NPK) Concentrations in Soil and Cucumber Plants (Cucumis sativus)

An experiment was carried out inside a greenhouse (sandy loam soil) at the College of Agriculture / University of Anbar to investigate the effect of Vesicular-Arbuscular Mycorrhizaee, Azotobacterchroococcum and Vermicompost tea on the concentration of NPK macronutrients in soil and cucumber plants. A factorial experiment consisting of two factors was designed for this purpose: the first factor is a combination of mycorrhizae (M) with 35 g plant−1, azotobacter (A) bacteria 16 ml plant−1 with a microbial density of 2.2 x 109 cfu ml−1 and phosphate Rock (R) with 40 g plant−1, added with half of the mineral fertilizer recommendation each individually with its interactions, the second factor is the addition of three concentrations (0, 5, 10%) of vermicompost tea sprayed on the plant. The experiment was designed with a completely randomized block design (RCBD) with three replications. Cucumber seeds were planted on 15/9/2022 and service operations were conducted for the crop and the experiment continued until 15/12/2022. The result showed highest percentage of phosphorus in the leaves (PIL) (0.40%), the highest potassium in the leaves (KL) (1.95%), followed by the treatment of adding mycorrhizae with phosphate Rock and half the mineral recommendation (MR) with vermicompost tea at a concentration of 10%, then the treatment of adding mycorrhizae with azotobacter bacteria with half the mineral recommendation (AR) with 10% of vermicompost tea, then the treatment of mycorrhizae with phosphate Rock plus half the fertilizer recommendation (MR) with 10% of vermicompost tea, then the treatment of mycorrhizae with azotobacter plus half of the fertilizer recommendation (MA) with 10% of vermicombe tea.