Concentrations Of Different Forms Research Articles

Microorganisms Directly Affected Sediment Carbon–Nitrogen Coupling in Two Constructed Wetlands

Clarifying the carbon–nitrogen coupling pattern in wetlands is crucial for understanding the driving mechanism of wetland carbon sequestration. However, the impacts of plants and environmental factors on the coupling of carbon–nitrogen in wetland sediments are still unclear. Sediment samples from plant (Typha angustifolia and Phragmites australis)-covered habitats and bare land were collected in two constructed wetlands in northern China. The contents of different forms of carbon and nitrogen in sediments and plants, and the sediment microbial community were detected. It was found that the sediment carbon to nitrogen (C/N) ratios did not differ significantly in the bare sites of different wetlands, but did in the plant-covered sites, which highlighted the different role of plants in shifting the carbon–nitrogen coupling in different constructed wetlands. The effects of plants on the sediment carbon–nitrogen coupling differed in two constructed wetlands, so the structural equation model was used and found that sediment microorganisms directly affected sediment C/N ratios, while water and sediment physicochemical properties indirectly affected sediment C/N ratios by altering sediment microbial functions. Multiple linear regression models showed that water pH, sediment moisture content, water dissolved oxygen, and water depth had a greater influence on the carbon metabolism potential of the sediment microbial community, while sediment moisture content had the greatest impact on the sediment microbial nitrogen metabolism potential. The study indicates that variations in environmental conditions could alter the influence of plants on the carbon and nitrogen cycles of wetland sediments. Water environmental factors mainly affect microbial carbon metabolism functions, while soil physicochemical factors, especially water content, affect microbial carbon and nitrogen metabolism functions.

Publicity governance in contingency management during the COVID-19 pandemic in China: A “Government-Society” perspective

Background Publicity is a common form of governance in government and is even more important in contingency management, especially during the COVID-19 pandemic. Publicity has two sides, the main body of publicity is led by the government, the object of publicity is the response to the public. So, publicity exists in the "government-society" field. Our aim was to find out how governments have been able to achieve effective publicity in the COVID-19 and to promote the active participation of society in governance. Materials and methods We adopted a case study approach. Taking Chongqing Municipality as an example, we collected 201 messages from five forms of publicity, including cell phone SMS, village (community) broadcast, publicity placards or banners, official websites, and government media platforms during the period of 2020–2021, and described and analyzed the publicity content of different forms of publicity. Results During the whole period of the COVID-19, the publicity governance under contingency management showed the characteristics of focusing on administrative efficiency, social efficiency and post-social efficiency, and showed specific publicity governance functions such as mobilization and control, education and clarification, cultivation of public consciousness and shaping government credibility. Conclusions Publicity governance in contingency management during the COVID-19 pandemic emphasizes three effective approaches: time synchronization, organizational scale, and interaction among multiple advocacy agents. This can extend the existing government-centered research to the level of interaction between the government and society, and help the government to better use effective publicity to achieve the governance task under contingency management.

Synergy mechanism of biochar and petcoke co-combustion based on potassium migration and transformation

Co-combustion of biochar and pet-coke can reduce environmental pollution, provide fuel energy supply and improve fuel reaction characteristics. In this study, the co-combustion characteristics and synergistic behavior of rice straw char (BC) and petcoke (PC) were analyzed based on thermogravimetric analysis and kinetic analysis. The combustion corroborative experiments were conducted based on a fixed bed reactor, and the contents of different forms of potassium (K) during combustion of semi-char were characterized. Raman spectroscopy and X-ray photoelectron spectroscopy were used to characterize the carbon structure order and surface elements distribution characteristics of the semi-char after the combustion. The results showed that the co-combustion reactivity improved with the temperature and the BC blended ratio increase. Moreover, the synergistic effect increased with the temperature decrease and the BC blended ratio increase. The synergistic effect was confirmed to be related to the K migration and transformation, and its behavior was varied with active K content adsorbed by PC. The H2O-soluble K would be transformed into -COOK during PC combustion. -COOK would reduce the order of PC and increase the content of amorphous carbon during combustion.

The fate and supply capacity of potassium in biochar used in agriculture

We used chemical extraction, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) to study the potassium (K) in biochar prepared from corn straw at different temperatures (300 °C, 500 °C, 700 °C and 900 °C). The characteristics of biochar were analyzed through Fourier transform infrared spectroscopy (FTIR) and specific surface area analysis. We found that the potassium in biochar can be divided into water soluble potassium, exchangeable potassium, non-exchangeable potassium, and insoluble potassium according to the availability of agricultural potassium. The fate of potassium in straw changed as follows: with increasing pyrolysis temperature, the proportion of the sum of exchangeable and non-exchangeable potassium decreased, and the proportions of insoluble and lost potassium increased. The total, water soluble and exchangeable potassium contents in biochar were highest at 700 °C. The non-exchangeable and insoluble potassium contents were highest at 300 °C and 900 °C, respectively. Kinetics experiments were conducted to determine the different fates of potassium released from biochar at different temperatures; pot experiments were also undertaken. The release of different forms of potassium in biochar at different temperatures is mainly dominated by heterogeneous diffusion. Biochar increased not only the content of different forms of potassium in soil but also the potassium content of soybean stems and leaves. We calculated the potassium supply capacity of biochar by two strategies, measurements of the potassium content in biochar and the conversion rate of potassium in straw during pyrolysis. The most active and efficient potassium supply capacities were 33.60 g·kg−1 and 9.53 g·kg−1 at 700 °C and 300 °C, respectively. Biochar provides readily available (water soluble and exchangeable) potassium and a long-term (non-exchangeable) potassium supply to soil.

Effects of superheated steam pretreatment on phenolics and its antioxidant activity in camellia oleifera oil

Camellia oleifera oil (COO) is a high-quality woody edible oil, and the oilseed pretreatment is an important part of the oil processing in the edible oil production. This study investigated the effect of superheated steam (SHS) pretreatment on the phenolics and the corresponding antioxidant properties of COO. Results showed that SHS pretreatment time and temperature had significant impact on oil yield and the phenolic content of different forms of camellia seeds (P＜0.05). SHS pretreatment at 150 °C and 180 °C increased the free phenolics (FP) content, and the antioxidant properties of FP and conjugated phenolics (CP) in COO after SHS pretreatment under optimal condition. Then, the effect of SHS on two phenolic substances with high contents of COO, di-O-methylquercetin and 4-chloro-2-hydroxybenzoic acid was studied. SHS pretreatment had a positive effect on COO, and it may increase its biological activity and reduce its irritation. In addition, four phenolics that were significantly associated with the antioxidant properties of camellia phenolics were found. This study can provide new ideas and directions for oilseed pretreatment.

Effects of poplar intercropping systems on reducing the concentration of different forms of inorganic nitrogen in the soil profile

AbstractThis study focused on understanding how different spacing arrangements of poplar (Populus deltoides)–wheat (Triticum aestivum) agroforestry systems and the processes of the tree and wheat roots in these systems impact the elimination efficiency of inorganic nitrogen from soil. Three planting systems were tested: a monoculture wheat system (control), a widely spaced wheat–poplar system (PWW) and a narrowly spaced wheat–poplar system (PWN). Soil and root samples were collected in four different soil layers (0–20, 20–40, 40–60, and 60–100 cm) at four different sampling sites (PWN: 0, 1.5, 2.5, and 3.5 m; PWW: 0, 1.5, 3.5, and 7 m from tree row, respectively). The nitrate–nitrogen (), ammonium–nitrogen (), and nitrite–nitrogen () in the soil samples were analyzed to determine the elimination efficiency of the different systems. The results indicated that the concentration and soil accumulation content reduction of inorganic nitrogen in the two intercropping systems, especially in the PWW system, were encouraging compared to those in the control system. The and concentration reductions and poplar fine root length density (FRLD) were higher at the sampling point near the poplar row, especially in surface soil (p < 0.05), but the distribution of the wheat FRLD decreased with soil depth and proximity to the poplar trunk. Furthermore, the poplar and wheat FRLD had significant positive relationships with the concentration reduction of inorganic nitrogen. In conclusion, poplar–agroforestry systems should be considered as an important method for controlling nonpoint pollution from farmland.

Effects of heavy rain on the concentrations and forms of carbon, nitrogen and phosphorus in urban rivers of northern China.

Non-point source pollution caused by rainfall runoff is an important pollution source for river water. To explore the impact of heavy rain on urban river water environments, this paper studied the changes in carbon, nitrogen, and phosphorus levels, composition, and structure in the river water of Kaifeng, China, during the heavy rain in July 2021. The results showed that the concentrations of different forms of carbon, nitrogen, and phosphorus all increased under the effect of the heavy rain. The increase of phosphorus in the river was the largest, and that of carbon was the smallest. The most significant pollution from carbon, nitrogen, and phosphorus occurred in the HJ River. Colored dissolved organic matter (CDOM) was present in the form of macromolecules after the rain, and the degree of humification was deeper compared with before the rain. But heavy rain did not affect the CDOM composition in urban rivers. The spectral slope (SR) and the absorption coefficient at 240nm to 420nm (E2/E4) values showed that the CDOM was dominated by exogenous input after the rain, with endogenous pollution again becoming the main factor one week after the rain.

Concentration of different forms of phosphorus in soils affected by the little auk (Alle alle) and their relationship with tundra vegetation in Spitsbergen (Svalbard, High Arctic)

AbstractThe purpose of the present study was to determine the link between planktivorous little auks (Alle alle) and their soil fertilization, the concentration of total, and different forms of phosphorus in the surface layer of the High Arctic soils and the vascular plant composition of the tundra vegetation. Samples of the surface soil layer (0–10 cm) were collected along three pairs of transects (affected and unaffected by little auks) at different locations in Spitsbergen (Svalbard). The surface layer of soils affected by little auks was characterized by a significantly higher mean concentration of Ptot (1.02–1.44 g kg−1) compared to those not affected by seabirds (0.58–0.77 g kg−1). The mean concentration of different forms of P was also generally higher in soils affected by seabirds (i.e., labile P: 0.13–0.34 g kg−1, moderately labile P: 0.31–0.90 g kg−1, stable P: 0.27–0.39 g kg−1) than in unaffected soils (labile P: 0.04–0.18 g kg−1, moderately labile P: 0.30–0.37 g kg−1, stable P: 0.12–0.24 g kg−1); however, the differences were not always significant, most likely due to the high heterogeneity of specific environmental conditions at the local scale such as soil type, soil chemical composition, and vegetation type. Vascular plant cover was significantly and positively related to the concentration of the P forms studied in the soil. The phosphorus gradient significantly altered the composition of the vascular plants and explained 58.4% of its variation. Little auks are an important source of soil phosphorus in terrestrial ecosystems in the High Arctic that significantly affect the cover and composition of vascular plants.

The Effect of the Potamogeton crispus on Phosphorus Changes throughout Growth and Decomposition: A Comparison of Indoor and Outdoor Studies

Phosphorus (P) transport and transformation in water were investigated using Potamogeton crispus. To compare and evaluate our indoor experiment with outdoor data, we used the simultaneous indoor experiment and field observation approach. The effects of P. crispus growth and decomposition on P concentrations were investigated. P. crispus significantly reduced the P content of different forms in the water during the growth period, and significantly increased the P content of different forms in the water during the decomposition period, according to the findings. As a result, the P level of the water varied seasonally and regularly. The pH and dissolved oxygen (DO) of environmental factors in the water revealed an increasing trend during the P. crispus growth period and a negative trend during the decomposition period. The changing trend of chlorophyll a (Chl-a) and alkaline phosphatase activity (APA) was inverse, decreasing during the growth period of P. crispus and increasing during the decomposition period. In the P. crispus growth environment, all forms of P in water were positively related to Chl-a, APA, and pH, and negatively related to DO. The comparison of the indoor experiment with field data revealed that the indoor experiment number has a larger standard deviation, indicating that the indoor experiment data fluctuated substantially. The indoor simulation experiment has the disadvantage of large data fluctuation. As a result, this study demonstrated that P. crispus regulated the P cycle in water via absorption and changes in environmental factors during the growth period, and released nutrients via decomposition during the decomposition period, thereby influencing the migration and transformation of P in the water. This work may be used as a reference for future research into the process of P exchange between sediments and water interfaces caused by P. crispus.

Accumulation, Migration, and Transformation of Soil Phosphorus in Facility Agriculture and Its Influencing Factors

The aim of this study was to apply phosphorus fertilizer scientifically and reasonably and reduce the pollution risk to the facility agricultural environment. Taking the facility agriculture concentration area in Daxing District of Beijing as the research object, the phosphorus content in soil (0-100 cm) of the facility agriculture profile with different planting years was measured and analyzed to explore the characteristics of phosphorus accumulation, migration, and transformation. The results showed that the contents of total phosphorus and available phosphorus in the surface soil of facility agriculture varied widely, which was significantly higher than that in the surrounding grain field soil, which was mainly related to the amount of phosphorus applied by farmers in different planting years. With the increase in soil depth, the contents of total phosphorus and available phosphorus decreased gradually, showing surface aggregation ω (total phosphorus) ranging from 0.38 to 2.58 g·kg-1 and ω (available phosphorus) ranging from 1.60 to 256.00 mg·kg-1. With the increase in planting years, the contents of soil total phosphorus and available phosphorus first increased and then decreased, reached a peak in approximately 15 years, then gradually decreased, tended to be stable, and generally remained at a high level. Inorganic phosphorus was mainly concentrated in the surface soil of the facility agriculture, in which Ca-P accounted for the largest proportion of inorganic phosphorus, up to 98.38%; Ca10-P was the main form of Ca-P, up to 78.70% of Ca-P, and Ca2-P accounted for the smallest proportion, only 9.50% of Ca-P. The contents of different forms of inorganic phosphorus showed the vertical distribution characteristics of enrichment in the surface soil and a decrease downward. There were differences in the proportion of different forms of inorganic phosphorus to total phosphorus in different soil depths, in which the change in Ca-P was obvious, whereas the change in Fe-P and 0-P was not significant, indicating that the migration and transformation of Fe-P and O-P in the facility agricultural soil was poor, and the migration and transformation of inorganic phosphorus was mainly Ca-P. According to the correlation and path analysis, the direct path coefficient of Ca2-P to available phosphorus was the largest (0.787), which was not only the main source of soil available phosphorus but also the main form of inorganic phosphorus migration and transformation. Under the condition of protected cultivation, soil phosphorus showed a large accumulation trend, the availability of Ca10-P was low, and the accumulation was large. How to improve this portion of phosphorus sources is the key to the management of protected soil phosphorus.

Newsmakers and news sources in the “hybrid media system” (the case of the full-scale Russian invasion coverage)

The study aims to compare leading newsmakers’ and news sources’ usage in a professional mass media and a Telegram channel. The computer-assisted method of news processing was used. As a result, we discovered that audiences of both professional mass media and new media consume the same content in different forms, and they deal with mostly the same newsmakers, with more considerable attention towards personalities for the Telegram channel and with more quotes from other mass media and accurate references for the online mass media. Therefore, we concluded that the general observation about the coexistence of professional and new media, where the former publishes classic “hard” news and the latter entertains people with information, may be questioned.

Inoculation with Potassium Solubilizing Bacteria and Its Effect on the Medicinal Characteristics of Paris polyphylla var. yunnanensis

Potassium (K) use efficiency in Paris polyphylla var. yunnanensis production is relatively low, and the excessive use of K fertilization has negative environmental impacts. Bacterial isolates can effectively alleviate this situation. The present work aimed to analyze the effects of different combinations of three potassium-solubilizing bacteria (KSB) (Bacillus thuringiensis, B. polymyxa, and Paenibacillus amylolyticus) on K in soil and P. polyphylla var. yunnanensis. The results showed that the contents of different forms of K were increased after the application of KSB. Compared with the control group, the maximum increases of slow-acting K, available K, quick-acting K, exchangeable K, and water-soluble K were 32.6% under inoculation with both P. amylolyticus and B. polymyxa, 73.5% with B. thuringiensis, 114.0% with B. thuringiensis, 83.2% with P. amylolyticus, and 210.0% with B. thuringiensis, respectively. This promoted the conversion of soil K to the form of K with high plant availability. Pseudo-protodiosgenin and diosgenin H contents were improved by KSB inoculations, which promoted medicinal quality of P. polyphylla var. yunnanensis. Correlation analysis showed that there were significantly positive correlations among the five forms of K in the soil in all experimental groups. In conclusion, the inoculation of KSB effectively improved the plant availability of soil K and medicinal quality of P. polyphylla var. yunnanensis, providing a path for sustainable production of P. polyphylla var. yunnanensis.

A systematic review and quantitative meta-analysis of the relationships between driving forces and cyanobacterial blooms at global scale

The global expansion of cyanobacterial blooms poses a major risk to the safety of freshwater resources. As a result, many explorations have been performed at a regional scale to determine the underlying impact mechanism of cyanobacterial blooms for one or several waterbodies. However, two questions still need to be answered quantitatively at a global scale to assist the water management. One is to specify which factors were often selected as the driving forces of cyanobacterial blooms, and the other is to estimate their quantitative relationships. For that, this paper applied a systematic literature review for 41 peer-reviewed studies published before May 2021 and a statistical meta-analysis based on the Pearson's or Spearman's correlation coefficients from 27 studies. These results showed that the water quality, hydraulic conditions, meteorological conditions and nutrient levels were often considered the driving forces of cyanobacterial blooms in global freshwater systems. Among these, meteorological conditions and nutrient level had the highest probability of being chosen as the driving force. In addition, knowledge of the quantitative relationships between these driving forces and cyanobacterial blooms was newly synthesized based on the correlation coefficients. The results indicated that, at a global scale, meteorological conditions were negatively related to cyanobacterial blooms, and other driving forces, such as water quality, hydraulic conditions and nutrient levels, were positively related to cyanobacterial blooms. In addition, the measurement indicators of these driving forces had diverse forms. For example, the nutrient level can be measured by the concentration of different forms of nitrogen or phosphorus, which may lead to different results in correlation analysis. Thus, a subgroup meta-analysis was necessary for the subdivided driving forces and cyanobacterial blooms, which had a better accuracy. Overall, the synthesized knowledge can help guide advanced cyanobacteria-centered water management, especially when the necessary cyanobacterial data of targeting waterbodies are inaccessible.

Вплив удобрення та вапнування на баланс і вміст форм калію в дерново-підзолистому ґрунті

Goal. To determine the effect of plant by-products and mineral fertilizers in combination with different doses of dolomite flour on the balance and content of different forms of potassium in soddy podzolic cohesive-sandy soil. Methods. Field (the study of the effect of fertilization and liming on the change in potassium content in the soil), laboratory (the determination of the content of potassium forms in the soil), calculation (the assessment of potassium balance), statistical (the variance analysis of the reliability of research results). Results. The research during 2 rotations of a 4-field crop rotation established that liming 1.9–5.6 tons of dolomite flour with the subsequent annual entering into the soil of an average of 5 tons of by-products of crops in combination with the application of mineral fertilizers at a dose of N112P87K105 per 1 ha of the crop rotation area created the positive balance of potassium in the soil at its intensity of 167–206%. A rapid increase in the content of mobile potassium in the soil in these variants was observed only during the first 4 years of research, in subsequent years it varied within the reached level. Fertilization and liming had a positive effect on the content of all forms of potassium available to plants: water-soluble, exchangeable, and non-exchangeable. During 8 years of research, their content increased by 57.1–121, 40.5–59.5, and 7.8–12.3%, respectively. Conclusions. The use against the background of liming and fertilization of by-products of crop rotation makes it possible to return to the soil 74.0–76.3% of the economic removal of potassium and, in combination with the application of 105 kg/ha of potassium with mineral fertilizers for 1 ha of crop rotation, to create a positive balance of the element at the level of 82.8–88.1 kg/ha. The content of mobile forms of potassium in the soil layer of 0–20 cm in the first 4 years of research in the variants with fertilizer increased from 53–57 to 89–102 mg/kg of soil, in the following 4 years it almost did not increase with certain variations over the years. Under the influence of the studied components of the fertilizer system in crop rotation, the content of all forms of potassium in the soil — water-soluble, exchangeable, and non-exchangeable — increased. Compared to the control, application of N112P87K105 per 1 ha of crop rotation area contributed to an increase in their content by 21.4 and 16.2%, respectively, for a combination of 3.8 t of CaMg(CO3)2 and N112P87K105 — by 57.1–121, 40.5–59.5, and 7.8–12.3%, respectively. However, increasing the dose of dolomite flour from 3.6 to 5.8 t/ha in the crop rotation fertilizer system did not significantly increase the content of non-exchangeable potassium in the 0–20 cm layer of soddy podzolic soil.

Carbon concentrations in natural and restoration pools in blanket peatlands

AbstractOpen‐water perennial pools are common natural features of peatlands globally, and peatland restoration often results in new pool creation, yet the concentrations of different forms of aquatic carbon (C) in natural and artificial restoration pools are not well studied. We compared carbon concentrations in both natural pools and restoration pools (4–15 years old) on three blanket peatlands in northern Scotland. At all sites, restoration pools were more acidic and had mean dissolved organic carbon (DOC) concentrations in restoration pools of 23, 22, and 31 mg L−1 compared with natural pool means of 11, 11 and 15 mg L−1 respectively across the three sites. Restoration pools had a greater fulvic acid prevalence than the natural pools and their DOC was more aromatic. Restoration pools were supersaturated with dissolved CO2 at around 10 times atmospheric levels, whereas for natural pools, CO2 concentrations were just above atmospheric levels. Dissolved CH4 concentrations were not different between pool types, but were ~200 times higher than atmospheric levels. Regular sampling at one of the peatland sites over 2.5 years showed that particulate organic carbon (POC) concentrations were generally below 7 mg L−1 except during the warm, dry summer of 2013. At this regularly‐sampled site, natural pools were found to process DOC so that mean pool outflow concentrations in overland flow were significantly lower than mean inflow DOC concentrations. Such an effect was not found for the restoration pools. Soil solution and pool water chemistry, and relationships between DOC and CO2 concentrations suggest that different processes are controlling the transformation of C, and therefore the form and amount of C, in natural pools compared to restoration pools.

Cytotoxicity of three graphene-related materials in rainbow trout primary hepatocytes is not associated to cellular internalization

As a consequence of increasing production and use of graphene-related materials (GRM), their release into the aquatic environment is likely to be expected. Development of appropriate model systems to assess their potential toxicity toward aquatic organisms is undoubtedly needed. Of particular relevance are primary cultures of fish hepatocytes, since they maintain similar functionalities as those of the original tissue. Isolated hepatocytes from rainbow trout (Oncorhynchus mykiss) were exposed to ranges of concentrations of different forms of GRM, two graphene oxides (GO) of sheet-like structure and one tubular-shaped carbon nanofiber (CNF) in the presence or absence of fetal bovine serum (FBS) for 24 and 72 h. Metabolic activity, cell membrane integrity, lysosomal function, reactive oxygen species (ROS) formation and interaction with cytochrome P450 1 A enzyme were assessed by using AlamarBlue, 5-carboxyfluorescein diacetate-acetoxymethyl ester, neutral red uptake, dichlorofluorescein and 7-ethoxyresorufin-O-deethylase (EROD) assays, respectively. In the presence of FBS, GO affected metabolic activity and cell membrane integrity more than CNF, whilst absence of serum further reduced cell viability in GRM-exposed cells. GRM did not alter lysosomal function nor did it induce ROS formation or EROD activity. Intracellular uptake was observed only in the case of CNF when incubated without FBS. Primary hepatocytes from rainbow trout appear to be a suitable model to screen for cytotoxicity and to reveal any interaction with GRM. Results emphasize the role of serum proteins in the toxicological responses following exposure to GRM with important implications for the environmental risk assessment of these nanomaterials.

Sulphur Dynamics under different land uses of Outer Himalayan region of Himachal Pradesh

The knowledge of different sulphur (S) forms and their relationship with soil properties is of much relevance in assessing the short- and long-term availability of the nutrients to crops and in formulating sound fertilizer recommendations. For this purpose one hundred and one representative soil samples were collected from the study area and analyzed for various physicochemical properties and forms of sulphur (water soluble, exchangeable, available, organic, non-sulphate and total S) using standard methods. The different forms of sulphur viz., water soluble, exchangeable, available, organic, non-sulphate and total sulphur ranged from 1.1 to 7.0, 1.9 to 10.9, 3.1 to 21.1, 75.9 to 316.1, 8.0 to 41.5 and 75.5 to 372.5 mg kg-1, respectively in soils of Outer Himalayas under different land uses. The content of different forms of sulphur present in these soils were in the order of total sulphur, organic sulphur, non-sulphate sulphur, available sulphur, exchangeable sulphur and water soluble sulphur. All the forms of S correlated positively and significantly with organic carbon and clay content of soils. A negative and significant relationship was also observed between all forms of sulphur and sand content of soils. In the present study, it was also found that all forms of S present in soils were significantly and positively correlated with each other. The knowledge regarding different forms of S in soils and their availability controlled by different soil properties will be helpful for its management to optimize crop yields in the Outer Himalayas of Himachal Pradesh.

Interaction and Mechanism Between Conditioning Agents and Two Elements in the Soil Enriched with Phosphorus and Cadmium

Focusing on agricultural soil enriched in phosphorus and cadmium (total Cd=0.94 mg·kg-1 and total P=0.86g·kg-1), indoor cultivation experiments were conducted according to the length of the middle rice growth period and the following crop planting period in Hubei. The bioavailability of soil phosphorus and cadmium were examined along with their morphological changes and coupling effect under the influence of material biochar (BC), calcium magnesium phosphate fertilizer (CMP), and fly ash (FA). The results showed that:① When cultured for 140 days, the content of available phosphorus in the soil treated with the conditioning agents was significantly increased compared with the control soil, available phosphorus reached 22.47-37.81mg·kg-1, and the optimal growth requirements of rice were met without additional application of phosphate fertilizer, and adding BC had the best effect. ② The phosphorus in the test soil is mainly inorganic orthophosphate, and the content of different forms of inorganic phosphorus increased under the action of the conditioning agents. The fixed O-P and Ca10-P in the soil gradually changed to more active forms (Ca2-P, Ca8-P, Al-P and Fe-P) over time. ③ The effective Cd content of the soil treated with the conditioning agents was significantly reduced by 8.74%-17.48% relative to the control treatment, which was mainly related to the effect of the three conditioning agents on soil pH. At the same time, compared with the control, the addition of a conditioning agent significantly reduced the exchangeable Cd, and the carbonate-bound Cd and the residual Cd were increased. The abundance of active groups at the surface is related to the adsorption and chelation of Cd2+. The results showed that the three conditioners have the dual functions of phosphorus activation and cadmium passivation in phosphorus-and cadmium-enriched soil, and the effect of biomass carbon and calcium magnesium phosphate fertilizer was greatest, which persisted across the entire rice growth period to the sowing date of the next crop.

Potassium Distribution in Surface Soils of Kust Teaching, Research and Commercial Farm, Gaya, Kano State

A study was conducted on the distribution of potassium in the surface soil of Kano University of Science and Technology teaching, research and commercial farm, Gaya during 2018/2019 session. The contents of different forms of potassium were observed. Water soluble, exchangeable, non-exchangeable, mineral and total potassium were determined in surface soil (0–15cm) in KUST teaching, research and commercial farm, Gaya. The results showed that the average values for water soluble K, exchangeable K, non-exchangeable K, mineral K and total K were: 0.14, 0.18, 0.35, 1.36 and 3.92 Cmol/Kg soil respectively. The values for K saturation percentage (KSP) ranged between 0.12–019 and exchangeable K between 0.13–0.20 Cmol/Kg clay. There was a wide variation in the values of various forms of K and among indices associated with mineral composition in different soils. The results show that the values of K form in most of the studied soils are quite low. Consequently, the supplying power of potassium in these soils is low and the need for potassium fertilizer is recommended.

The Influence of Mechanical Composition and Mineral Composition of Calcareous Soil on Slope Farmland on Phosphorus Fixation

Soil erosion on slope farmland causes the degradation of soil quality and eutrophication of water bodies due to the loss of phosphorus. In order to explore the influence of soil mechanical composition and mineral composition on phosphorus fixation, we selected calcareous soil on slope farmland in the Three Gorges Reservoir area as the research object and separated the samples on the basis of particle size. Next, we determined the content of different forms of phosphorus for each particle size, and then characterized and analyzed the mineral composition. The adsorption performance of each particle size was also studied. The results show that the calcareous soil on slope farmland has a high proportion of coarse fractions, and the carbonate minerals enriched in coarse fractions will fix a large amount of phosphorus and degrade soil quality. As slope farmland is prone to soil erosion, when the soil undergoes selective migration, the loss of fine fractions will increase the proportion of coarse fractions and aggravate soil quality degradation. Meanwhile, because of the large amount of phosphorus adsorbed by fine fractions, the available phosphorus is easily lost with fine fractions, leading to eutrophication of water bodies.