Content Of Available Phosphorus Research Articles

Effect of Exogenous Organic Matter on Phosphorus Forms in Middle-High Fertility Cinnamon Soil.

To slow down the chemical fixation of phosphate fertilizer, reduce the risk of active phosphorus leaching, stimulate the inherent phosphorus resource activity of soil, and improve phosphorus supply capacity. This study utilized a combination of field experiments and indoor chemical analysis. Six types of exogenous organic matter (fulvic acid, biochar, compound microbial fertilizer, high-energy microbial inoculum, pig manure-vermicompost, cow manure-vermicompost) were added based on conventional fertilization. The experiment was conducted under the wheat-maize rotation system in the Huang-Huai-Hai region. Compared with control (CK) without exogenous organic matter (EOM), all the other treatments with EOM had an enhancing effect on the available phosphorus of the cultivated soil. During the maize harvest, the combined application of biochar, pig manure-vermicompost and cow manure-vermicompost treatment significantly increased the content of available phosphorus in 0-20 cm soil by 45.87-56.59% compared with CK. The combined application of fulvic acid, biochar, pig manure-vermicompost and cow manure-vermicompost treatment significantly increased the content of Ca2-P in 0-20 cm soil by 34.04-65.14%. The content of Ca10-P in each treatment with EOM exhibited a lower level compared to CK. EOM could slow down the fixation of phosphorus to some degree. Correlation analysis revealed significant associations between Ca2-P, Ca8-P, Al-P, Fe-P, neutral phosphatase activity, acid phosphatase activity, and the available phosphorus content in the soil. The combined application of fulvic acid, biochar, and cow manure-vermicompost could enhance the activity of neutral and acid phosphatase in topsoil to a certain extent, thereby facilitating the conversion of phosphorus into highly available Ca2-P. EOM could enhance the soil phosphorus availability and decelerate the conversion of soil phosphorus into O-P and Ca10-P forms with low availability. Among all treatments, biochar exhibited the most pronounced efficiency in mitigating phosphorus leaching downward. All the EOMs had the potential to enhance the conversion of phosphorus into soluble phosphorus (Ca2-P), thereby mitigating the chemical fixation of soil phosphorus and ameliorating non-point source pollution caused by phosphorus. EOM enhanced the activity of neutral and acid phosphatase, which was beneficial to the conversion of organic phosphorus to inorganic phosphorus and increasing the content of available phosphorus. All EOMs had good effects on the retention of soil effective phosphorus, among which biochar had the best effect on retaining effective phosphorus in the tillage layer and blocking phosphorus leaching downward.

Effect of corn–soybean meal-based diets with low calcium and available phosphorus in male broilers on performance, tibia criteria and jejunum histomorphology

Abstract This study was conducted to determine the effect of reducing calcium (Ca) and available phosphorus (AvP) on performance, carcass yield, tibia traits and jejunum histomorphology in broilers. For this purpose, 480 one-day-old Ross 308 male chicks were distributed into four trial groups with eight subgroups. During the starter period, birds were fed with recommended or reduced Ca and AvP contents of 66.7 and 62.5 g/kg, respectively. Calcium and AvP contents of the groups were as follows: control: 8.70 g/kg Ca, 4.40 g/kg AvP for grower and 7.80 g/kg Ca, 3.90 g/kg AvP for finisher; LCP1: 8.30 g/kg Ca, 4.20 g/kg AvP for grower and 7.10 g/kg Ca, 3.50 g/kg AvP for finisher; LCP2: 7.90 g/kg Ca, 4.00 g/kg AvP for grower and 6.00 g/kg Ca, 3.00 g/kg AvP for finisher; LCP3: 7.00 g/kg Ca, 3.80 g/kg for grower and 5.00 g/kg Ca, 3.00 g/kg AvP for finisher. Performance variables have been calculated from the data of each period, and samples were obtained from the slaughtered birds on the final day of the trial (42nd day) for carcass and tibia traits and jejunum histomorphology. Reducing dietary Ca and AvP did not affect the broiler performance, carcass yield and mortality. Tibia ash decreased in LCP2 and LCP3 groups (P < 0.01). Villus width and villus surface area increased in LCP2 and LCP3. Overall, feeding with a diet 100 g/kg lower than the recommended Ca and AvP did not affect performance in broilers, but improved jejunal development.

Response of corn yield to water retaining agents, inhibitors, and corn stalks addition in semi-arid cropland,

Drought, excessive use of nitrogen fertilizer, and decline in soil organic matter threaten corn production. This study investigated the potential of water retaining agents, inhibitors, and corn stalks in enhancing soil physicochemical properties to bolster corn yield in semi-arid farmlands. In our study, polyacrylamide addition increased the content of ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3–-N) in the seedling stage, exchangeable potassium (K) in the mature stage but decreased the content of available phosphorus (P) in the seedling stage. Potassium polyacrylate addition increased the content of NH4+-N and decreased the content of available P in the seedling stage. The addition of inhibitors decreased the content of NH4+-N and available P in the seedling stage, NO3–-N and available P in the jointing stage, and NH4+-N in the mature stage, respectively. Corn stalks returning could maintain soil moisture, decrease the content of NH4+-N in the seedling stage and exchangeable K in the mature stage, and increase the content of available P and exchangeable K in the seedling stage. Combined application of inhibitors and corn stalks could increase soil organic carbon (SOC) and ensure corn yield, which was the best fertilization mode in semi-arid cropland.

Soil bacterial community structure and co‐occurrence networks in response to the succession of secondary forests in subtropical regions

AbstractA large amount of secondary successional vegetation (subtropical evergreen broadleaved forests) has formed after the extensive deforestation and cultivation of coniferous forests in Wuyi Mountain, Southeast China. However, we lack a detailed understanding of the dynamic changes in microbial community structure and its co‐occurrence network during succession. The features that are responsible for alterations in the soil bacterial community remain poorly defined. Therefore, we compared the soil physicochemical properties, enzyme activities, and bacterial diversity among three different forests (a coniferous forest [CF], early stage of succession; a mixed conifer‐broadleaf forest [CBMF], middle stage of succession; an evergreen broadleaf forest [EBF]; late stage of succession). Results indicated that the contents of soil organic carbon and microbial biomass carbon (MBC) in CBMF were higher compared with those in CF. The alpha diversity indices were the highest in CBMF. Functional annotation of prokaryotic taxa predicted the relative abundances of chemoheterotrophy and aerobic chemoheterotrophy were lower in CF than in the other two forests. Bacterial network topology was affected by forest succession, with CBMF having more complex bacterial networks. Mantel's test indicated the soil nitrate nitrogen content (P = 0.03) was the most important property that shaped the bacterial community composition, bacterial diversity was influenced by soil pH (P = 0.026), and the contents of available phosphorus (P = 0.04) and MBC (P = 0.022) during the succession process. In conclusion, the succession of secondary forests promoted soil nutrient accumulation and improved bacterial diversity and network complexity.

Exploring a path of vegetation restoration best suited for a photovoltaic plant in the Hobq desert

To investigate the soil improvement effects of different vegetation restoration measures during the operation and maintenance of photovoltaic power plants in the Hobq Desert. This study determined the soil grain size composition and soil nutrient content of 0–5 cm under four vegetation restoration measures and within the mechanical sand barriers by laser diffraction techniques and chemical experiments. The results showed that: (1) Soil particle size composition in the study area is predominantly sandy, with 1.02%, 6.63%, 5.34% and 2.61% less sand in Leymus chinensis (YC), Glycyrrhiza uralensis (GC), Artemisia ordosica Krasch (YH) and Hedysarum scoparium (HB), respectively, compared to mechanical sand barriers (CK). Soil particle distributions of YC, GC, and HB showed better sorting and more concentrated patterns, and all four vegetation restoration measures had higher fractal dimensions than CK. (2) AN (Alkali-hydrolyzable Nitrogen) content performance: The content of YC, GC, and HB was significantly higher than that of YH and CK, AP (Available Phosphorus) content did not differ significantly between measures, AK (Available Potassium) content was higher than that of CK in all measures, with YC content being the highest and SOM content being the highest for GC. (3) Soil total nutrient is unstable across vegetation restoration measures. Overall, the performance showed that the three vegetation restoration measures, YC, GC, and HB, were more evident in the soil total nutrient content improvement. Each particle size characteristic parameter and soil nutrient response vegetation restoration measures ameliorate sandy soil in PV power plants during operation and maintenance. YC and GC have the most apparent effect on soil amelioration.

The influence of biochar from animal and plant on the transformation of phosphorus during paper mill sludge composting.

Biochar has effect on phosphorus adsorption, release, and transformation. This study compared the influence of biochar derived from animal (AB) and plant (PB) during paper mill sludge composting. Results indicated AB not only accelerated sludge decomposition but also had significantly higher levels of available phosphorus (AP) than PB and CK (no biochar), with AP contents in the order of AB > PB > CK. Compared to CK, AB was found to increase the relative abundance of thermophilic bacteria, and PB diversified the microbial community. Based on Pearson and RDA results, TOC/TN ratio (C/N) and organic matter (OM) explained above 50% of the variance in microbial community and phosphorus fractions. Thermophilic bacteria with high levels of OM and C/N promoted the conversion among labile and moderately labile organic phosphorus, moderately labile inorganic phosphorus, and AP. Biochar could enhance the AP conversion pathway, leading to increased levels of AP.

Organic fertilizer prepared by thermophilic aerobic fermentation technology enhanced soil humus and related soil enzyme activities

AbstractOrganic fertilizer (OF) prepared from chicken manure in a high‐temperature aerobic fermenter contains high levels of nitrogen, phosphorus and potassium. The effect of high‐nutrient OF substitution for chemical fertilizer (CF) on soil organic carbon stability is worth exploring. We used OF to replace CFs for supplying crops, and we set five OF replacement rates as 0, 25%, 50%, 75% and 100% in the black soil zone of Northeast China. We explored the variations in soil humus carbon contents, enzyme activities and nutrient contents (0–10 cm and 10–20 cm). Two‐way ANOVA results showed that interaction between soil depth and OF substitution significantly affected soil pH, total nitrogen, organic carbon, available potassium, water‐soluble carbon substance (WSSC) and activities of soil β‐galactosidase (β‐gal), N‐acetyl‐β‐D‐glucosaminidase (NAG) and cellobiohydrolase. The treatments of OF75 and OF100 increased soil pH, and the content of soil organic carbon, humic acid carbon (HAC), fulvic acid carbon (FAC), WSSC, total phosphorus, available phosphorus (AP), total potassium and available potassium was increased in OF75 and OF100 treatment. Treatments of OF75 and OF100 increased the tested soil enzyme activities except for oxidase activities of 0–10 cm soil layer. There was a positive correlation between HAC and AP contents, and a positive correlation between FAC and soil pH, total nitrogen and available potassium contents. The key influencing factors of soil FAC were the activities of NAG, α‐galactosidase and β‐gal. It can be concluded that OF substitution promoted soil humus carbon accumulation by affecting hydrolase activity related to carbon conversion.

Effect of intercropping with legumes at different rates on the yield and soil physicochemical properties of Cyperus esculentus L. in arid land.

Intercropping has the potential to enhance yields and nutrient availability in resource-limited agricultural systems. However, the effects on crop yield nutrients and soil properties can vary considerably depending on the specific plant combinations and intercropping ratios used. In this study, the advantages and impacts of intercropping C. esculentus with legumes were investigated by measuring their biomass, nutrient content, and soil properties. The experiment included five intercropping treatments: monoculture of C. esculentus (MC), intercropping of C. esculentus with Medicago sativa L. (alfalfa) at row spacing ratios of 4:4 (4:4CM) and 8:4 (8:4CM), and intercropping of C. esculentus with Glycine max (L.) Merr. (soybean), also at row spacing ratios of 4:4 (4:4CG) and 8:4 (8:4CG). Our results demonstrated that all four intercropping treatments (4:4CM, 4:4CG, 8:4CM, and 8:4CG) significantly increased the biomass of C. esculentus by approximately 41.05%, 41.73%, 16.08%, and 18.43%, respectively, compared with monoculture cultivation alone, among which the 4:4CG treatment was optimum. However, no significant differences were observed in alfalfa or soybean biomass across different intercropping ratios. A notable increase was found in the total nitrogen (TN) and total phosphorus (TP) contents in the leaves, roots, and tubers of C. esculentus under intercropping, along with increased soil organic carbon (SOC), alkaline-hydrolyzed nitrogen (AN), available phosphorus (AP), microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), and soil water content (SWC), and significantly reduced the soil pH. Among the intercropping treatments, the 4:4CG treatment also exhibited the most favorable soil properties. In particular, compared with MC, the 4:4CG treatment resulted in significant increases of 163.8%, 394.6%, and 716.8% in SOC, AN, and AP contents, respectively. The same treatment also led to significant increases of 48.34%, 46.40%, and 208.65% in MBC, MBN, and SWC, respectively. Overall, the findings suggest that the use of 4:4CG intercropping is an effective approach for sustainable farming management in Xinjiang.

Monitoring soil quality of different land use systems: a case study in Suha watershed, northwestern highlands of Ethiopia

The problem of soil quality degradation has been becoming more severe in the highlands of Ethiopia due to soil erosion; land use and land cover change, and poor land management. The level of soil quality degradation was not well known and documented in the study area and the results of this study could provide new information to improve soil conditions. The present study was conducted to evaluate soil quality in terms of its physical and chemical fertility under different land use types in the Suha watershed, northwestern highlands of Ethiopia. A total of 27 composite surface soil samples (0–30 cm) were collected from adjacently located land-uses in three replications from two elevation gradients. Standard procedures were followed to analyze selected soil physical and chemical quality indicators. The differences in the mean values of the parameters were tested using a two-way analysis of variance. In addition, Soil Quality Degradation Index was evaluated to see the direction and magnitude of change in soil quality indicators. The analysis of variance results revealed that soil quality indicators such as index of soil aggregate stability, organic carbon (OC), total nitrogen (TN), and C:N ratio were significantly decreased in the cultivated land use system compared to other land use systems. On the other hand, the content of available Phosphorus was significantly higher in the cultivated land. Soil quality deterioration index values were highly negative for SOC (− 71.3%) and TN (− 67.7%) in the cultivated land, followed by grazing land (SOM = − 35.5% and TN = − 27.7%). Aggregated Soil Quality Index values also indicated that the status of soil quality under cultivated fields is rated as low, grazing land as optimal, and forest land as high. Generally, results indicated that land use and cover changes had adverse effects on soil quality indicators. Hence, soil management strategies, mainly Integrated Soil Fertility Management which integrates soil and water conservation strategies, are required to alleviate the problem of soil quality deterioration and improve agricultural productivity.

Impacts of Organic and Non-Organic Cultivation Practices on Soil Fertility Parameters of Selected Paddy Lands Based on the Duration of Cultivation in Wet and Intermediate Climate Zones of Sri Lanka

Sri Lanka has been practicing the cultivation of rice as its main staple food in two major agricultural techniques; organic and non-organic. The major aim of the present study was to analyze and compare the time duration-based impacts of the above two agricultural practices on paddy soil fertility indicators as the preliminary step of a long-term research project. Organic and non-organic paddy fields that have been cultivated for 2 seasons in Thorapitiya in the Matale district were selected as short-term cultivated lands. Land cultivated for 10 years organically in Homagama and land with a non-organic cultivation history of 20 years in Kottawa was selected as long-term cultivated lands. A total number of 35 samples were collected including the control samples from adjacent uncultivated land during the first phase of the Maha season 2021/2022. The samples were dried, sieved and then analyzed in their physical and chemical properties; color, texture, particle size distribution, pH, electrical conductivity (EC), organic carbon content (OCC), total nitrogen content (TNC), available phosphorus content (APC), exchangeable potassium content (EPC), and exchangeable magnesium content (EMC). The soil samples from Thorapitiya had a reddish-brown nature while most of the samples from Kottawa and Homagama had a grayish-brown color. Higher clay percentages were found in the soil samples from long-term organically cultivated lands in Homagama. The uniformity coefficient (Cu) values for soils from study areas except Homagama lie in the range for well-graded soil while the coefficient of gradation (Cc) values of all three areas were not in the above range. Short-term cultivation using organic and non-organic fertilizers did not show a significant difference in soil texture, pH, EC, APC, EPC, and EMC values. Most of their cultivated lands had a lower pH (~5.5–6.0) than the corresponding control plots (~5.8–6.4). The TNC levels in non-organically cultivated lands were significantly higher than in organic lands. Practicing agricultural activities for a prolonged period has resulted in significant differences in soil texture, pH, EC, OCC, TNC and APC between organic and non-organic lands. Higher OCC and lower pH, EC and APC values have been obtained for long-term organically cultivated lands than their non-organic counterparts. The TNC, APC and EPC levels were higher in most of the long- term organic and non-organic lands than in their control samples. Several amendments have to be made to bring the fertility parameters to an optimum level in long-term cultivated lands. 
 Keywords: Soil fertility, Paddy soil, Cultivation history, Organic cultivation, Non-organic cultivation

Isolation and Identification of Acer truncatum Endophytic Fungus Talaromyces verruculosus and Evaluation of Its Effects on Insoluble Phosphorus Absorption Capacity and Growth of Cucumber Seedlings.

The symbiosis between endophytic fungi and plants can promote the absorption of potassium, nitrogen, phosphorus, and other nutrients by plants. Phosphorus is one of the indispensable nutrient elements for plant growth and development. However, the content of available phosphorus in soil is very low, which limits the growth of plants. Phosphorus-soluble microorganisms can improve the utilization rate of insoluble phosphorus. In this study, Talaromyces verruculosus (T. verruculosus), a potential phosphorus-soluble fungus, was isolated from Acer truncatum, a plant with strong stress resistance, and its phosphorus-soluble ability in relation to cucumber seedlings under different treatment conditions was determined. In addition, the morphological, physiological, and biochemical indexes of the cucumber seedlings were assessed. The results show that T. verruculosus could solubilize tricalcium phosphate (TCP) and lecithin, and the solubilization effect of lecithin was higher than that of TCP. After the application of T. verruclosus, the leaf photosynthetic index increased significantly. The photosynthetic system damage caused by low phosphorus stress was alleviated, and the root morphological indexes of cucumber seedlings were increased. The plant height, stem diameter, and leaf area of cucumber seedlings treated with T. verruculosus were also significantly higher than those without treatment. Therefore, it was shown that T. verruculosus is a beneficial endophytic fungus that can promote plant growth and improve plant stress resistance. This study will provide a useful reference for further research on endophytic fungi to promote growth and improve plant stress resistance.

Soil fungal community is more sensitive than bacterial community to modified materials application in saline-alkali land of Hetao Plain.

Soil salinization has become a major challenge that severely threatens crop growth and influences the productivity of agriculture. It is urgent to develop effective management measures to improve saline-alkali soil. Thus, in this study, soil properties, microbial communities, and function under desulfurization gypsum (DE), soil amendment (SA), farm manure (FA), and co-application of desulfurization gypsum, soil amendment, and farm manure (TA) in a field experiment were examined by high-throughput sequencing. The results showed that the application of modified materials is an effective approach in improving saline-alkali soil, especially TA treatment significantly increased the content of available phosphorus (AP), available potassium (AK), soil organic matter (SOM), and alkaline hydrolysis nitrogen (AHN) and decreased pH, bulk density (BD), and electrical conductivity (EC). The application of modified materials resulted in notable enhancement in fungal diversity and altered the composition and structure of the fungal community. Conversely, the effect on the bacterial community was comparatively minor, with changes limited to the structure of the community. Regarding the fungal community composition, Ascomycota, Mortierellomycota, and Basidiomycota emerged as the dominant phyla across all treatments. At each taxonomic level, the community composition exhibited significant variations in response to different modified materials, resulting in divergent soil quality. The TA treatment led to a decrease in Mortierellomycota and an increase in Ascomycota, potentially enhancing the ability to decompose organic matter and facilitate soil nutrient cycling. Additionally, the sensitivity of fungal biomarkers to modified materials surpassed that of the bacterial community. The impact of modified materials on soil microbial communities primarily stemmed from alterations in soil EC, AP, AK, and SOM. FUNGuild analysis indicated that the saprotroph trophic mode group was the dominant component, and the application of modified materials notably increased the symbiotroph group. PICRUSt analysis revealed that metabolism was the most prevalent functional module observed at pathway level 1. Overall, the application of modified materials led to a decrease in soil EC and an increase in nutrient levels, resulting in more significant alterations in the soil fungal community, but it did not dramatically change the soil bacterial community. Our study provides new insights into the application of modified materials in increasing soil nutrients and altering soil microbial communities and functions and provides a better approach for improving saline-alkali soil of Hetao Plain.

Phosphorus HotSpots in Crop Plants Production on the Farm—Mitigating Critical Factors

Phosphorus resources, both in phosphate rocks and in the soil, are limited. However, effective food production is not possible without the use of P fertilizers. Recognizing and eliminating or at least ameliorating factors (hot spots) that interfere with the uptake and use of phosphorus (P) by crop plants is of key importance for effective use of both P and nitrogen (N) on the farm. Plants have developed many adaptation mechanisms to their environment, i.e., soil low in available phosphorus. The most important ones include the secretion of organic compounds into the rhizosphere and the association of plant roots with microorganisms. A classic example is mycorrhiza. These mechanisms can be used by the farmer to sequentially select plants in the crop rotation. The uptake of inorganic P (Pi) by plants from the soil is reduced by environmental (temperature and water) and soil factors (low content of available phosphorus, soil acidity, soil compaction). These factors are responsible for the growth and size of the root system. Mitigating these negative effects improves the efficiency of phosphorus uptake from the soil. The second group of critical factors, limiting both root growth and availability of phosphorus, can be effectively controlled using simple measures (for example, lime). Knowing this, the farmer must first control the level of soil fertility in the plant’s effective rooting zone and not only in the topsoil. Secondly, the farmer must multiply the productivity of applied mineral fertilizers used through targeted recycling: crop rotation, crop residues, and manure.

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.

Analysis on the Impact of Various Slope Ecological Restoration Techniques on Soil Fertility and Physicochemical Properties During the Summer Drought Period in Red Soil Area of Northeast Jiangxi Province

[Purpose] This study aims to investigate the impacts of three slope restoration techniques, namely, soil spray sowing, vegetation fiber, and vegetation concrete, on soil fertility, pH, and organic matter content during the summer drought period. The study also aims to explore the advantages of these three different restoration techniques, providing a basis for slope restoration in the Northeast Jiangxi region. [Methods] The study used experimental slopes established with three different restoration techniques: soil spray sowing, vegetation fiber, and vegetation concrete. Soil samples were collected during the rainy season in July 2022 and the drought season in September 2022. The changes in hydrolyzable nitrogen, available potassium, available phosphorus content, pH, and organic matter in the soil after restoration were comprehensively investigated. The study relies on the Qi-Wu expressway, and all the experiments are set on the slopes on both sides of the expressway. [Results]①For the soil restored using soil spray sowing during the drought season, the content of hydrolyzable nitrogen and available potassium was higher than that of the original soil, while the content of available phosphorus significantly decreased. The pH changed from acidic to weakly alkaline. ②For the soil restored using vegetation fiber during the drought season, although the content of available phosphorus increased, it was still relatively low. The content of available potassium decreased, but the total amount remained high. The content of hydrolyzable nitrogen was high and showed an increasing trend. The pH slightly decreased from weakly acidic to acidic. ③For the soil restored using vegetation concrete during the drought season, the content of hydrolyzable nitrogen, available potassium, and available phosphorus was high and showed an increasing trend. The pH slightly decreased, but it remained weakly alkaline before and after the drought. [Conclusion] Soil spray sowing, vegetation fiber, and vegetation concrete, all three restoration techniques, could demonstrate good performance during the drought period in the Northeastern Jiangxi region. In terms of their overall performance, the ranking from strong to weak is as follows: vegetation concrete > vegetation fiber > soil spray sowing. Soil spray sowing, as the most convenient and cost-effective slope restoration technique, could in the future incorporate additives that can improve local soil properties according to different regional characteristics. Vegetation fiber not only needs to improve soil acidity-alkalinity but should also appropriately incorporate phosphorus-containing additives. Vegetation concrete needs to address the issue of reducing soil acidity-alkalinity after restoration in the future.

Promotion of the symbiotic interaction between phagotrophic protists and beneficial bacteria, mediated via a balancing of soil nutrients, reduces the incidence of watermelon Fusarium wilt

Elucidating the microbial mechanisms that trigger Fusarium wilt represents a key step in addressing the barriers to sustainable cropping. However, from the perspective of the complete microbiome, the integrated role of soil nutrients and the microbial community in fields with different rate of wilt disease remains unclear. In this study, we examined the potential interrelationships among rhizosphere soil nutrients, bacteria, fungi, and protists in soils collected from fields in which watermelon had been cultivated for 8 years, and which were characterized by high (HW: 81.25%) or low (LW: 6.25%) incidence of watermelon Fusarium wilt. Soil from HW fields was found to contain a higher density of F. oxysporum (1.30-fold higher than that in the LW soil), along with higher contents of available phosphorus (1.31-fold higher), and available potassium (2.39-fold higher). In addition, the inter-kingdom correlation between protists and bacteria in the HW soil was 2.08-fold higher than that in LW soil. Furthermore, structural equation modeling revealed that an excess of soil available potassium enhances predation by potentially detrimental phagotrophic protists on potentially beneficial bacteria. Collectively, our findings indicate that a balanced nutrient input and the interaction between protists and beneficial bacteria play important roles in controlling the incidence of watermelon Fusarium wilt. These findings have implications for controlling the incidence of watermelon Fusarium wilt based on modifying the nutrient balance of soil and increasing the flora of certain beneficial protists (Cercomonas and Colpoda) that interact symbiotically with species of Bacillus.

Seasonal changes of soil microbiota and its association with environmental factors in coal mining subsidence area

As a special type of wetland, the new wetland in the coal mining subsidence area is highly sensitive to environmental changes. In recent years, more and more attention has been paid to the studies of soil microbial diversity in newly born wetlands in coal mining subsidence areas. However, there are few reports on the seasonal variation of soil microbial diversity and its relationship with soil physical and chemical properties. In this study, 16S rRNA gene sequencing technology was used to analyze the seasonal changes of soil microbial composition and functional diversity in newly formed wetlands in coal mining subsidence areas, and to determine the seasonal changes of soil nutrient elements and physical and chemical properties in coal mining subsidence areas, so as to analyze the correlation between soil microbial diversity and soil nutrient elements and physical and chemical properties in newly formed wetlands in coal mining subsidence areas. A total of 16,050 OTUs were obtained after sample gene noise reduction. Proteobacteria, Acidobacteriota and Bacteroidota were the highest abundance in the coal mining subsidence area of Jining. The two seasons gathered separately, and temperature (Temp), total phosphorus (TP), available phosphorus (AP), total organic carbon (TOC) and dry matter content (DMC) were the key factors for the seasonal change of soil microbial community in the wetland of the coal mining subsidence area of Jining. The contents of Temp, AP and TP were significantly correlated with the abundance of soil microorganisms in summer subsidence area, while the contents of DMC and TOC were significantly correlated with the abundance of soil microorganisms in winter subsidence area. Soil microbial diversity in coal mining subsidence area was correlated with the seasons. Temp, TP, AP, TOC and DMC were the key factors for the seasonal change of soil microbial community in the wetland of the coal mining subsidence area of Jining.

Soil bacterial community composition in rice-turtle coculture systems with different planting years

The rice-turtle coculture system is the most special rice-fish integrated farming system. In this study, we selected four paddy fields, including a rice monoculture paddy and three rice-turtle paddies with different planting years, to investigate the soil bacterial community composition with Illumina MiSeq sequencing technology. The results indicated that the contents of soil available nitrogen (AN), soil available phosphorus (AP) and soil organic matter (OM) in 9th year of rice-turtle paddy (RT9) were increased by 5.40%, 51.11% and 23.33% compared with rice monoculture paddy (CK), respectively. Significant differences of Acidobacteria, Desulfobacteria, Crenarchaeota were observed among the different rice farming systems. The relative abundance of Methylomonadaceae, Methylococcaceae and Methylophilaceae in RT9 was significantly higher than that in other treatments. RT9 had significantly lower relative abundance of Acidobacteria, but significantly higher relative abundance of Proteobacteria than other treatments. Redundancy analysis showed that soil AN and AP contents were the major factors influencing the abundance of the dominant microbes, wherein Methylomonadaceae, Methylococcaceae and Methylophilaceae were positively correlated with OM. The findings revealed the rice-turtle coculture system in the 9th year had higher soil nutrients and soil bacterial diversity, but there was also a risk of increasing methane emissions.

Dual Regulatory Role of Penicillium oxalicum SL2 in Soil: Phosphorus Solubilization and Pb Stabilization.

The mechanisms of the P. oxalicum SL2-mediated microbial community on phosphorus solubilization and Pb stabilization were investigated through a 90-day soil experiment. In the treatments inoculated with P. oxalicum SL2, the amount of P. oxalicum SL2-GFP remained at 77.8%-138.6% of the initial inoculation amount after 90 days, and the available phosphorus (AP) content increased 21.7%-40.8% while EDTA-Pb decreased 29.9%-43.2% compared with CK treatment. SEM-EDS results showed that P. oxalicum SL2 changed the agglomeration degree of microaggregates and promoted the combination of Pb with C and O elements. These phenomena were enhanced when applied with Ca3(PO4)2. Microbial community analysis showed that P. oxalicum SL2 improved soil microbial activity, in which the fungi absolute abundance increased about 15 times within 90 days. Correlation analyses and a partial least-squares path model showed that the activation of Penicillium, Ascobolus, Humicola, and Spizellomyces in a fungal community increased the content of oxalate and AP, which directly decreased EDTA-Pb content, while the change of Bacillus, Ramlibacter, Gemmatimonas, and Candidatus Solibacter in the bacterial community regulated Fe/Mn/S/N cycle-related functions, thus promoting the conversion of Pb to oxidizable state. Our findings highlight that P. oxalicum SL2 enhanced the microbial-induced phosphate precipitation process by activating soil microbial communities and regulating their ecological functions.

The response of nutrient cycle, microbial community abundance and metabolic function to nitrogen fertilizer in rhizosphere soil of Phellodendron chinense Schneid seedlings.

Nitrogen (N) as an essential macronutrient affects the soil nutrient cycle, microbial community abundance, and metabolic function. However, the specific responses of microorganisms and metabolic functions in rhizosphere soil of Phellodendron chinense Schneid seedlings to N addition remain unclear. In this study, four treatments (CK, N5, N10 and N15) were conducted, and the soil physicochemical properties, enzyme activities, microbial community abundances and diversities, metabolism, and gene expressions were investigated in rhizosphere soil of P. chinense Schneid. The results showed that N addition significantly decreased rhizosphere soil pH, among which the effect of N10 treatment was better. N10 treatment significantly increased the contents of available phosphorus (AP), available potassium (AK), ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N) and sucrase (SU) activity, as well as fungal diversity and the relative expression abundances of amoA and phoD genes in rhizosphere soil, but observably decreased the total phosphorus (TP) content, urease (UR) activity and bacterial diversity, among which the pH, soil organic matter (SOM), AP, NH4+-N and NO3--N were the main environmental factors for affecting rhizosphere soil microbial community structure based on RDA and correlation analyses. Meanwhile, N10 treatment notably enhanced the absolute abundances of the uracil, guanine, indole, prostaglandin F2α and γ-glutamylalanine, while reduced the contents of D-phenylalanine and phenylacetylglycine in rhizosphere soil of P. chinense Schneid seedlings. Furthermore, the soil available nutrients represented a significant correlation with soil metabolites and dominant microorganisms, suggesting that N10 addition effectively regulated microbial community abundance and metabolic functions by enhancing nutrient cycle in the rhizosphere soil of P. chinense Schneid seedlings.