Content Of Available Phosphorus Research Articles

Effect of Deep Vertical Rotary Tillage on Soil Bacterial Community Diversity and Microbial Network Structure in Cultivated Land

The aim of this study was to understand the effect of deep vertical rotary tillage on the diversity and structural distribution of a soil bacterial community in cultivated land, as well as the interactions between microbial ecological molecular network and species. In this study, the cultivated soil under different tillage methods in the Yellow River diversion irrigation area in Ningxia was selected as the research object, and two treatments were set up, namely, deep vertical rotary tillage (DVRT) and conventional tillage (CT). Then, Illumina MiSeq technology was used to analyze the molecular ecological network of soil bacterial community under different tillage methods in the Ningxia Yellow River irrigation area. The results showed that DVRT significantly increased the contents of total organic carbon (TOC), total nitrogen (TN), alkali-hydrolyzed nitrogen (AN), total phosphorus (TP), available phosphorus (AP), and total potassium (TK) in the 0-20 cm soil layer compared with those in the CT treatment. Compared with those in the CT treatment, DVRT significantly increased the contents of TOC, TN, TP, AP, TK, and available potassium (AK) in the 20-40 cm soil layer. DVRT treatment significantly increased water content (WC) by 8.13%-13.30% and decreased pH and electrical conductivity (EC) by 4.51%-5.85% and 12.5%-13.33%, respectively. In different growth stages and soil layers of maize, the Shannon and Ace indices were increased in the DVRT treatments. The dominant bacterial phyla were:Actinobacteria, Proteobacteria, Chloroflexi, Acidobacteriota, and Gemmatimonadota. The results of bacterial community β diversity showed that DVRT and CT had significant differences in bacterial community structure. The redundancy analysis and Partial Mantel test results showed that pH, EC, and TP were the key environmental factors affecting the structural diversity of bacterial communities. Molecular ecological network analysis revealed that DVRT treatment microbial networks consisted of more functionally related microbial modules, and the topological roles of key microorganisms were different from those in the CT treatment. In conclusion, DVRT can enhance soil nutrients and WC in different soil layers, reduce pH and EC, improve soil bacterial community diversity and microbial network structure, and also enhance the potential ecosystem functions in cultivated soil.

Effects of humic acid–enhanced phosphate fertilizer on wheat yield, phosphorus uptake, and soil available phosphorus content

AbstractHumic acid (HA) can improve the use efficiency of phosphate fertilizer, although its optimal proportion in fertilizers remains unknown. In this study, we conducted soil column experiments over two growing seasons to compare the effects of different HA proportions in phosphate fertilizer on wheat yield and phosphorus uptake, utilization, and soil available phosphorus. At harvest, grain yields were 0.23%–13.21% higher under HA‐enhanced phosphate (HAP) compared to treatments with conventional phosphate fertilizer (P). Among different HAPs, wheat treated with HAP with 1.0% HA (HAP10) or 2.0% HA (HAP20) had the highest 2‐year grain yield. Furthermore, total phosphorus uptake and its allocation in grains were both higher under HAP treatments compared to P treatment. The apparent use efficiency, agronomic efficiency and partial productivity of phosphorus in HAP10 and HAP20 treatments were also significantly higher than those treated with P in both growing seasons. In addition, HAP10 and HAP20 treatments resulted in the highest content of available phosphorus in the 0–60 cm soil layer compared with other HAPs or P alone. Incorporating HA into phosphate fertilizer at proportions of 0.5%–5.0% can increase wheat yield, phosphorus uptake, phosphate fertilizer use efficiency, and soil available phosphorus content, 1.0% or 2.0% HA in HAP shows the highest effects on these indexes. Given the economic benefits, 1.0% level is an optimal level for enhancing the effects of phosphate fertilizer in winter wheat crops.

Seasonal and spatial variations in soil biochemical properties in areas with different degrees of mining subsidence in Central China

Land subsidence due to underground mining results in soil nutrient loss and reduced soil fertility. Land reclamation, which refers to the improvement of soil nutrients through targeted measures, requires spatial and temporal distribution information on the soil properties. However, this has not yet been studied. Therefore, the spatial autocorrelation of soil chemical and biological properties was examined in the Pingdingshan coal mining area during four seasons in China from 80 collected and analyzed soil samples. The spatial autocorrelation was determined by the global and local Moran’s indices. Spatial clustering and variability were analyzed with ArcGIS 10.2 (Environmental Systems Research Institute, ESRI, USA) and GeoDa 7.0 software (Center for Spatial Data Science in University of Chicago, USA). Soil pH and the soil total carbon (TC) content, soil total nitrogen (TN) content, soil available phosphorus (AP) content, and soil alkali-hydrolyzable nitrogen (AN) content were measured as soil chemical properties. The soil biological properties included the quantities of bacteria, actinomycetes, and fungi. The soil chemical and biological properties showed a strong spatial autocorrelation during the four seasons. “High-high” and “low-low” were the dominant autocorrelation types that were distributed in serious and light subsidence areas. The soil properties decreased as the mining subsidence degree increased. Both the soil TC and soil AP contents were highest in spring, the soil TN content was highest in autumn, and the soil AN content was highest in summer. These results provide a reliable theoretical reference for land reclamation and ecological restoration in mining areas.

The Relationship between Core Rhizosphere Taxa and Peanut Nodulation Capacity under Different Cover Crop Amendments

Adequate exploitation of legume–rhizobia symbiosis for nitrogen fixation may help to alleviate the overuse of chemical nitrogen fertilizer and aid in sustainable agricultural development. However, controlling this beneficial interaction requires thorough characterization of the effects of soil rhizosphere microorganisms, especially core taxa, on the legume–rhizobia symbiosis. Here, we used Illumina sequencing to investigate the effects of cover crop (Raphanus sativus L. and Lolium perenne L.) residue on the rhizosphere soil microbial community and peanut nodulation ability. The results indicated that Raphanus sativus L. amendment (RS) significantly increased soil available phosphorus (AP) content and peanut nodulation ability, while the Lolium perenne L. amendment (LP) had no noticeable impact on peanut nodulation. LP and RS significantly elevated bacterial and rhizobial diversity, reduced fungal diversity, and shifted microbial community structure (bacteria, 14.7%, p = 0.001; rhizobia, 21.7%, p = 0.001; fungi, 25.5%, p = 0.001). Random forest analysis found that the core rhizosphere taxa, sharing similar ecological preferences, were the primary drivers of peanut nodulation. By least squares regression, soil AP content was found to be positively correlated with the relative abundance of key ecological clusters. Furthermore, RS was found to promote peanut nodulation by increasing the relative abundance of critical rhizosphere taxa. Overall, our findings emphasize that core microbial taxa might play an essential function in the modulation of legume nodulation and provide scientific evidence for the effective management of the plant microbiome.

Soil Salinity Weakening and Soil Quality Enhancement after Long-Term Reclamation of Different Croplands in the Yellow River Delta

Saline soils are of great concern globally. Selecting the Yellow River Delta as a model site, the influence of reclamation on soil salinity and saline soil quality was investigated. Soil quality index (SQI) was applied to statistically analyze 210 soil profile samples collected at seven depth layers in 30 sampling sites among native saline soils and three croplands (peanut, cotton, and wheat) in May 2020. After reclamation, the soil salt content (SSC) reduced from 4.52 g/kg to 1.44 g/kg after reclamation, with the degree of soil salinity reducing from severe to slight. The nitrate nitrogen (NO3−-N) contents of peanut, cotton, and wheat croplands were 1.90, 2.02, and 4.29 times higher and the available phosphorus (AP) contents were 5.43, 3.57, and 8.77 mg/kg higher than that of the saline soils, respectively, while the soil ammonium nitrogen (NH4+-N) and available potassium (AK) contents were decreased. The NO3−-N, AN, and AP contents of the three croplands showed a significant surface aggregation at depth of 0–30 cm. SQI increased by 0.10, 0.09, and 0.02 after the reclamation with the enhancement effect of wheat and cotton was more pronounced. It was discovered that reclamation notably improved the soil quality as a result of crop growth and field management of fertilization and irrigation.

Using analytical hierarchy process to determine intra-field heterogeneity zones upon implementation of precision farming

The study aimed to develop a methodology for determining zones of intra-field heterogeneity for precision farming. In this study, we took into account the Belarussian national land use system which provides for the absence of private ownership of agricultural land. The spatial distribution of intra-field heterogeneity zones within the land use area of 7549.49 thousand hectares was identified using the analytical hierarchy process (AHP). The algorithm for determining zones of spatial heterogeneity provides for: (1) the selection of indicators and their ranking; (2) developing a pairwise comparison matrix, (3) estimating relative weights and (4) assessing matrix consistency. It is recommended to use data from agrochemical soil studies which are conducted centrally every 4 years for each agricultural enterprise as input parameters. These data include the humus content in the soil, the content of available phosphorus and potassium, soil pH, and the content of B, Cu, Zn, Ca, and Mg. The data should be carefully examined using spatial statistics tools to provide a more accurate delineation of the management-zones boundaries. The developed technique makes it possible to determine fertile and marginal areas within each field and differentiate the use of fertilizers, taking into account the presence of intra-field heterogeneity. This will reduce the total cost of purchasing and applying phosphorus fertilizers by 34 $·ha-1 and potash fertilizers by 9 $·ha-1 due to the redistribution of the fertilizer dose calculated for the planned yield, taking into account the identified site-specific management zones. At the same time, the level of chemical pressure per hectare of arable land will decrease by 6.7% without loss of crops productivity.

The Application of Biochar from Waste Biomass to Improve Soil Fertility and Soil Enzyme Activity and Increase Carbon Sequestration

Biochar (BC) is a material that has many applications in agricultural and environmental activities. The aim of the study was to define the influence of BC produced in low-temperature pyrolysis from various organic waste materials, including one-month-old compost (OMOC), pine bark (PB), pine needle mulch (NM), pine cones (PC) and maple leaves (ML), on soil enzyme activity as well as its relation with organic matter properties. A 60-day incubation pot experiment was set up to investigate the influence of BC amendment on soil (S) characteristics. After incubation, we investigated the activity of soil enzymes, the content of available phosphorus (AP), potassium (AK) and magnesium (AMg), total organic carbon (TOC), total nitrogen (TN), dissolved organic matter (DOM) and its fractional composition (content and share of carbon and nitrogen of humic (CHAs, NHAs) and fulvic (CFAs, NFAs) acids and humin fractions). The effect of the amended biochars differed depending on the feedstock material. In general, the use of biochar enriched the soil with AP, AK and AMg increased the soil carbon stock, increased the intensity of nitrogen transformation and influenced the soil enzyme activity. OMOC and ML biochars significantly increased soil fertility, which was expressed by the high value of the CHA/CFA ratio.

AMF Inoculum Enhances Crop Yields of Zea mays L. 'Chenghai No. 618' and Glycine max L. 'Zhonghuang No. 17' without Disturbing Native Fugal Communities in Coal Mine Dump.

For the agricultural development of dumps, increase in land use efficiency and protection of food security, to verify the safety, efficacy and sustainability of field-applied arbuscular mycorrhizal fungi (AMF) inoculum, and to exclude the risk of potential biological invasion, in this study, we determined the effect of AMF inoculation and intercropping patterns (maize-soybean) on the temporal dynamics of soil parameters, native AMF communities and crop yields. AMF communities were analyzed using Illumina MiSeq. A total of 448 AMF operational taxonomic units (OTUs) belonging to six genera and nine families were identified. AMF inoculation treatment significantly improved the yield of intercropping maize and increased the content of available phosphorus. AMF diversity was significantly influenced by cropping pattern and growth stage, but not by the inoculation treatment. Inoculation altered the AMF community composition in the early growth stage and facilitated a more complex AMF network in the early and late growth stages. These results indicate that AMF inoculation affects native AMF only in the early stage, and its impact on yield may be the consequence of cumulative effects due to the advantages of plant growth and nutrient uptake in the early stage.

Ecological features of the formation of fertility and productivity of biocenoses on chernozem soils of the Saratov region

An analysis of the species composition of vegetation on fallow plots of different duration and virgin lands made it possible to conclude that the fallow plots succession to the state of virgin lands with increasing age. Comparison of zootechnical parameters of hay from experimental agrocenoses made it possible to state that the average content of fat, ash and fiber for fallow variants is 17.0%, 9.8% and 7.7%, respectively, higher than in hay of the virgin variant. Analysis of the chemical composition of the hay of the experimental agrocenoses showed that the average concentrations of nitrogen, carbon, calcium and magnesium in the hay were lower than in the hay of the virgin agrocenosis by 11.4%, 2.6%, 44.0% and 51 .8% respectively. At the same time, a higher content of available phosphorus and potassium in the hay of fallow agrocenoses by 9.3% and 17.1%, respectively, was observed compared to virgin agrocenosis.

Divergent linkages of soil phosphorus fractions to edaphic properties following afforestation in the riparian zone of the upper Yangtze river, China

Soil phosphorus (P) is an essential nutrient element for plant growth but it is also one of the elements of agricultural-dominated watershed pollution. While the vegetation in the riparian zone usually plays an important role in regulating P pollutants. However, how afforestation affects soil P dynamics and fractions in the riparian zone remains largely unclear. Here, we investigated soil P fractions, and associated drivers including edaphic properties, microbial attributes, and soil enzyme activities under conversion from cropland to different afforested lands in order to better understand the dynamics of soil P fractions in the riparian zone of the upper Yangtze River. We found that afforestation significantly decreased the concentrations of available phosphorus, microbial biomass P, and labile P fractions, but the moderately labile P and Stable P did not significantly differ among afforestation types. Particularly, the lowest concentration of labile P was observed in Morus alba (M.a.) forests followed by the Salix babylonica (S.b.) forests, whereas croplands generally exhibited an inverse trend with a higher labile P concentration compared to woodlands, especially in croplands nearby Morus alba forests. Generally, P fractions were negatively associated with soil pH and C:N ratio, while positively related to microbial attributes, N:P ratio, and alkaline phosphatase activities. The labile P and moderately labile P fractions were predominantly regulated by biotic factors (i.e., microbial biomass P, microbial biomass N, leucine amino peptidase), whereas the stable P was strongly related to abiotic factors (i.e., total C concentration, pH, C:N ratio). These findings indicate afforestation is conducive to intercept more labile P, resulting in reduced P leaching to rivers. Collectively, our results not only offer direct experimental insight into predicting the effects of afforestation on soil P fractions but also have important implications for agricultural pollution management and reforestation strategies in the riparian zone.

The effects of allelochemicals from root exudates of Flaveria bidentis on two Bacillus species.

To determine the allelopathic effects of root exudates from Flaveria bidentis on function of Bacillus, pot experiment was used to collect root exudates from living plants and test its allelopathic effects on function of Bacillus frigoritolerans and Bacillus megaterium, which were two dominant bacteria in the rhizosphere soil of F. bidentis. To obtain the allelopathic substances, the root exudates were successively extracted by N-hexane, dichloromethane, ethyl acetate, and N-butanol, and their allelopathic effects were tested. The results showed that B. frigoritolerans and B. megaterium considerably increased the concentration of available phosphorus and nitrogen, respectively, when the soil was treated with different concentrations of root exudates. Among the four organic solvent extracts, dichloromethane extracts significantly increased the abundances of B. frigoritolerans and B. megaterium and promoted their nitrogen-fixing and phosphate-solubilizing abilities. Phenol was detected in dichloromethane extracts by gas chromatograph-mass spectrometer (GC-MS). Meanwhile, phenol promoted the ability to fix nitrogen of B. megaterium and its growth by increasing the soil available nitrogen concentration, but phenol promoted the ability to solubilize phosphate of B. frigoritolerans only in 0.1mg/mL concentration. Therefore, phenol was an allelochemicals in the root exudates of F. bidentis that affects the growth and activities of B. megaterium.

Response of root morphogenesis of medicinal plants to low phosphorus stress and molecular mechanism

The content of available phosphorus in soil is generally low worldwide. Phosphorus, one of the necessary macroelements for plant growth and development, plays an important role in cell structure, material composition and energy metabolism, and signal transduction in plants. Phosphate transporter(PHT) genes are important for plant growth and development, root morphogenesis, secondary metabolism, hormone response, and phosphorus balance. Most of the active components in medicinal plants are secondary metabolites. Thus, it is essential to reveal the relationship between the regulation of phosphorus and the accumulation of active components in medicinal plants, especially the effect of phosphorus starvation on root morphogenesis of root medicinal materials and its coupling with hormone response. With advancement of molecular biology, scholars gradually emphasize the mechanism of PHT regulating the secondary metabolism of medicinal plants. This study summarized the strategies of plants to adapt to low phosphorus environment, such as changing root morphogenesis, inhibiting taproot growth, forming cluster root and changing physiological metabolism, PHT, its regulatory network, phenotypic biological characteristics and key genes in medicinal plants related to phosphorus starvation, and the response mechanism. The findings are expected to lay a basis for the cultivation of medicinal plants with high quality, excellent shape, and high price.

The distribution, effectiveness and environmental threshold of soil aggregate phosphorus fractions in the sub‐alpine region of Southwest China

AbstractThis article is a study of total phosphorus (TP), available phosphorus (AP) and phosphorus (P) fractions of soil aggregates along an altitude gradient in the sub‐alpine region of Southwest China. We conclude that soil aggregate TP and AP contents are higher at 3980 m and 3347 m; there are no significant differences in soil aggregate TP at any altitude (p > 0.05); the AP and phosphorus activation coefficient (PAC) are higher in 0.25–0.5 mm aggregate. Soil aggregates TPi > TPo at 3009 m and TPo > TPi at 3347, 3654 and 3980 m. Using multiple stepwise regression analysis, we conclude that NaOH‐Pi is the key fraction of AP supply, NaHCO3‐Pi and NaOH‐Pi are important fractions of CaCl2‐P. Through piecewise linear fitting of soil aggregate AP and CaCl2‐P, the soil P environmental threshold obtained is 27.766 mg kg−1 in this region. Also we got <0.25 mm, 0.25–0.5 mm aggregates at 3980 m which have high soil P loss risk. Our study fills in gap about the distribution of P fraction in aggregates and effects of soil P fraction for AP and CaCl2‐P in high‐altitude areas. Our study provides a reference and scientific basis for understanding the soil aggregate P storage capacity and the biological effectiveness of P fractions at high altitudes. Our study on the P environmental threshold provides a reference for soil P storage capacity. Our study provides a reference value for the soil P loss risk management, and sustainable development of soil ecosystems in the sub‐alpine region of Southwest China.

Effects of Oyster Shell Powder and Lime on Availability and Forms of Phosphorus and Enzyme Activity in Acidic Paddy Soil

Soil acidification improvement in the main grain production regions of southern China is an important issue to enhance the quality of cultivated land and promote grain yield. In order to explore the effects of oyster shell powder and lime on acidity and availability and inorganic forms of phosphorus in acidic paddy soil, a pot experiment was performed using oyster shell powder and lime amendments with dosages of 0.05%, 0.10%, and 0.15%. The results showed that both oyster shell powder and lime significantly (P<0.05) increased the pH and decreased exchangeable acid content of paddy soil. The improvement effects increased with the dosage of soil amendments. Under the same amendment dosage, the effects of lime on soil pH and acidity were higher than those of oyster shell powder. Both lime and oyster shell powder significantly increased the content of available P extracted using H2SO4-P, Bray-1 P, and Olsen-P techniques. The contents of inorganic P in soils decreased in the order of Fe-P>Al-P>Ca-P. The application of lime and oyster shell powder significantly increased the contents of Al-P and Fe-P in soil. Compared with the control treatment, lime and oyster shell power increased Al-P and Fe-P by 26.3%-37.4% and 7.9%-23.7%, respectively. However, there was no significant difference in Al-P content among treatments of the three amendment dosages. The contents of Fe-P and Ca-P in soils increased with an increased dosage of amendments. The activities of DHA, ALP, and IPP and the copy number of the phoD gene in soil increased with the application of lime and oyster shell powder, whereas the activities of ACP and the copy numbers of phoC and pqqC decreased. The application of lime and oyster shell powder at a rate of 0.10% and 0.15% significantly (P<0.05) increased the yield of rice. The lime and oyster shell powder treatments at the dosage of 0.15% increased rice yield by 34.2% and 46.8%, respectively, whereas the amendment had no significant effect on straw biomass of the rice crop. Correlation analysis showed that soil pH and the ALP activity were significantly positively correlated with inorganic P and available P contents, respectively. These results suggested that lime and oyster shell power could effectively increase the content of available phosphorus by eliminating soil acidity and improving the phosphatase activity, which played a positive role in increasing crop yield.

Potential Application of Paenibacillus sp. C1 to the Amelioration of Soda Saline-Alkaline Soil

In this study, a saline-alkaline-tolerant bacterial strain named Paenibacillus sp. C1 was screened and isolated, and its basic properties were characterized. Its phosphorus dissolution, organic acid production, and application on ameliorating soda saline-alkaline soil were studied, and the changes of microbial communities after adding strain C1 with or without rice straws, (NH4)2SO4 and Ca3(PO4)2 were investigated. The results demonstrated that when the nitrogen, carbon, and phosphorus sources were (NH4)2SO4, glucose, and Ca3(PO4)2, respectively, strain C1 was in the best phosphorus-dissolving condition. The strain had good characteristics of acid production and phosphorus dissolution under the condition of high salinity and alkalinity. It could secrete cellulases, decompose rice and corn straws, and produce polysaccharides effectively. Strain C1 [especially with rice straws, (NH4)2SO4 and Ca3(PO4)2] could increase the content of available phosphorus (AP), organophosphorus (OP), total organic carbon (TOC), and polysaccharide (PS) and the activity of alkaline phosphatase (ALP) in saline-alkaline soil. Furthermore, adding strain C1 [especially with rice straws, (NH4)2SO4 and Ca3(PO4)2] could alter the bacterial flora of soil to make it adapt to high salinity and alkalinity better. Our study can be an important step toward the application of Paenibacillus sp. C1 to the amelioration of soda saline-alkaline soil and the investigation of its deep mechanisms.

The Evaluation and Key-Factor Identification of the Influence of Tourism on the Soil of Mount Tai

Tourism has been proven to disturb the soil environments and stimulate heavy metal accumulation in scenic areas. Currently, research on the driving mechanisms of the impact of tourism on soil quality degradation is limited. Therefore, the aim of this study was to introduce a complex network method to comprehensively depict the impact of tourism on soil quality. To explore the key influencing factors, we collected 10 topsoil samples and 10 corresponding control samples from representative scenic areas in Mount Tai. Soil physicochemical properties (organic matter (OM), alkali dispelled nitrogen (AN), total nitrogen (TN), available phosphorus (AP), available potassium (AK), electrical conductivity (EC)), heavy metal (Cr, Cd, Pb, Hg, As, Cu) content, and microbial community diversity (by Eco-plate method) were analyzed. Additionally, complex networks of soil quality variables were established based on Pearson correlation coefficients. The results show that the OM, AN, and AP contents of scenic areas are 1.2, 1.03 and 1.18 times higher, while the AK content is 0.97 times lower, than those of the control sites, respectively (mean values of samples from scenic area vs. contorl sites). The single factor index of Hg, As, Pb, Cd, Cu, and Cr are increased from 3.65, 0.53, 0.85, 1.25, 0.78 and 0.58 to 3.69, 0.57, 1.24, 1.75, 0.97, 0.63 and 3.19, respectively, which means that tourism significantly exacerbates soil heavy metal accumulation. Additionally, the soil microbial activity and diversity are slightly reduced due to tourism. In general, the difference in the mean value of each soil quality variable between the scenic spot and the control site is not significant. However, tourism significantly reduced the connectivity and integrity of soil quality variables, which ultimately destabilized the soil, inferred from the comparison of the network’s topological parameters. Therefore, raising the content of soil OM and AN and controlling Cd pollution should be given more priority in soil ecosystem protection to counteract the negative impact of tourism on Mount Tai. It was the major limitation of the study that few typical scenic spots were selected as sampling points on Mount Tai. However, this study is sufficient to show that the complex network approach can be extended to other similar studies of soil quality degradation driving mechanisms.

Study on Soil Nutrient Change after Soil Ecological Restoration in Coal Mine Area of Northern Shaanxi Province

A field experiment was conducted to analyze the changes of soil nutrients in mining area after different microbial plant combined remediation. The results showed that the application of microbial agents could significantly increase soil total nitrogen content in coal mine area. The contents of GH, GS and GX were the highest, which were 0.54, 0.51 and 0.41 g/kg, respectively. The contents of available phosphorus and available potassium in AX treatment were the highest, reaching 57.1 and 194 mg/kg. Comprehensive analysis showed that microbial agent + mixed seed mode could effectively increase soil catalase content, among which AH had the best effect.

Humic acid and phosphorus fractions transformation regulated by carbon-based materials in composting steered its potential for phosphorus mobilization in soil

This study investigated the effects of different carbon-based additives including biochar, woody peat, and glucose on humic acid, fulvic acid, and phosphorus fractions in chicken manure composting and its potential for phosphorus mobilization in soil. The results showed that the addition of glucose effectively increased the total humic substance content (90.2 mg/g) of composts, and the fulvic acid content was significantly higher than other groups (P < 0.05). The addition of biochar could effectively improve the content of available phosphorus by 59.9% in composting. The addition of carbon-based materials to the composting was beneficial for the production of more stable inorganic phosphorus in the phosphorus fraction. The highest proportion of soluble inorganic phosphorus components of sodium hydroxide was found in group with woody peat addition (8.7%) and the highest proportion of soluble inorganic phosphorus components of hydrochloric acid was found in group with glucose addition (35.2%). The compost products with the addition of biochar (humic acid decreased by 17.9%) and woody peat (fulvic acid decreased by 72.6%) significantly increased soil humic acid mineralization. The compost products with the addition of biochar was suitable as active phosphate fertilizer, while the compost products with the addition of glucose was suitable as slow-release phosphate fertilizer.

Effects of disturbances by plateau pikas on soil microbial communities in an alpine ecosystem of the southeast Qinghai-Tibetan plateau, China

Small burrowing herbivores often disturb the grassland soil. Although the plateau pika (Ochotona curzoniae) is widespread in alpine meadows in the Qinghai–Tibet Plateau, their detailed effects on ecosystem properties are not well-established. In this study, we investigated the effects of the densities of plateau pikas on plant characteristics, soil properties, and the composition and diversity of soil microbial communities. Plant coverage, height, aboveground biomass, and belowground biomass decreased with an increase in the densities of active plateau pika burrows. Additionally, pika disturbances led to distinct changes in soil moisture, soil bulk density (SBD), total phosphorus (TP), NH4+-N, available phosphorus (AP), and available potassium (AK) contents. Soil moisture, TP and AK contents were highest under moderate plateau pika disturbance levels, whereas the SBD and AP content were highest under the highest active burrow density. However, soil microbial diversity, as determined by high-throughput sequencing, did not differ significantly among pika disturbance levels. Linear discriminant analysis Effect Size revealed that biomarker bacteria for various levels of disturbances belong to Proteobacteria, Bacteroidetes, and Firmicutes, and most biomarker bacteria were found at moderate disturbance level (D2), while biomarker fungi belong to Ascomycota and Basidiomycota, and most biomarker fungi were found in the highest plateau pika disturbance level (D4). Pika disturbances significantly influenced the microbial community, possibly via alterations in the belowground biomass, SBD, AK and TP contents. Thus, plateau pika disturbances significantly influenced the plant and soil properties and microbial community structure.

A Case Study of Initial Vegetation Restoration Affecting the Occurrence Characteristics of Phosphorus in Karst Geomorphology in Southwest China

Phosphorus (P) is one of the necessary nutrient elements in the process of plant growth and development. The temporal and spatial distribution characteristics of phosphorus content can not only reflect the soil structure and availability, but also affect the growth of wetland vegetation, the formation of the environment, and the process of vegetation succession. In this paper, taking Guizhou Caohai Nature Reserve as the research object, the temporal and spatial substitution method was used to study the distribution and influencing factors of soil total phosphorus (TP) and soil available phosphorus (AP) under different geomorphological environments (non-karst landforms, karst landforms, and geomorphology after vegetation restoration (5 years)). The results showed that (1) the TP content in the topsoil of the restored vegetation landform was generally higher than that in the topsoil of the karst landform and non-karst landform, and the distribution difference of the AP content in the three areas was slight. At the top, hillside, and foot of the mountain, the contents of TP and AP in the non-karst landform and karst landform decreased with increasing soil depth and accumulated at the foot of the mountain. (2) The results of the correlation analysis showed that the interpretation rates of TP and AP by each soil physicochemical factor were the highest, reaching 64–86%, while the interpretation rate of TP and AP by the combined action of multiple physicochemical factors was relatively small; in addition, there was a significant correlation between environmental factors and soil TP and AP (p &lt; 0.05). (3) Compared with unrepaired karst landforms, in the process of vegetation restoration (5 years), TP content has convergence between geomorphology after vegetation restoration and non-karst landforms, while AP content fluctuates greatly. The analysis showed that the changes in soil TP and AP contents were mainly affected by vegetation communities, while the changes in soil TP and AP contents in mountain areas were also affected by soil organic matter, pH, soil particle size, and climatic conditions.