Amount Of Phosphorus Research Articles

Efficient precipitation of soluble phosphorus impurities in the recycling of phosphogypsum to produce hemihydrate gypsum

Phosphogypsum (PG), a waste product of the phosphate fertilizer industry, is a source of environmental pollution. PG can be calcined to form the hemihydrate gypsum (β-CaSO4•0.5H2O, HPG), making it a potential substitute to natural gypsum. However, PG contains large amounts of soluble phosphorus(P) impurities, which pose a serious risk on the soil and groundwater, especially when they are abundantly accumulated and leached. This study systematically investigated that the pretreatment of PG by calcium hydroxide (CH) solution. Inductively coupled plasma optical emission spectroscopy (ICP) and X-ray diffraction (XRD) were used to study the precipitation of soluble P impurities in PG, differential thermal analysis (DTA) and BET (Brunauer-Emmett-Teller) were used to study the effect of CH solution on the physicochemical property of PG. In addition, the hardening characters and hydration process of HPG after stabilization with CH solution were studied in detail. The results show that pretreatment with CH solution can stabilize the soluble P impurities. However, the addition of CH solution can slightly reduce the mechanical properties of HPG and prolong the setting time. This was attributed to the production of excess CaHPO4·2H2O, which encapsulates the HPG. It is concluded that pretreatment of PG with 0.05% CH solution reduce environmental pollution without affecting the properties of the HPG produced.

Assessment of romaine lettuce cultivars grown in a vertical hydroponic system at two levels of LED light intensity

Romaine lettuce (Lactuca sativa var. longifolia) was cultivated in a hydroponic system, in the free-standing container equipped with two-shelf racks. The luminous intensity of the upper shelves was 200 µmol m−2 s−1, and that of the bottom was 160 µmol m−2 s−1. The plants were exposed to light for 16 h each day. Seven cultivars from two groups were cultivated in this study. There were four cultivars from the midi subtype (‘Casual,’ ‘Pivotal,’ ‘Delcaso,’ and ‘Airton’) and three from the mini subtype (‘Xiomara,’ ‘Coventry,’ and ‘Elizium’). The growth period of lettuce in the hydroponic chamber was 30 days. Immediately after harvest, lettuce was evaluated for plant morphological parameters and for the content of macro- and microelements and metabolites with health-promoting properties. Additionally, sensory evaluation was performed and leaf color parameters were measured.The genotype of romaine lettuce had a major impact on its extrinsic and intrinsic properties. The mini cultivars produced lower fresh mass but contained higher amounts of nitrogen, phosphorus, potassium, copper, and boron than varieties from the midi group. The contents of bioactive compounds were higher for midi romaine lettuce than for the mini type. In terms of nitrate, there were significant differences, and lower nitrate levels occurred in the mini group, except in ‘Coventry.’ The results obtained in this study did not allow us to single out any cultivar from the midi group as the best or the worst in terms of chemical composition. Among the mini cultivars, ‘Elizium’ shown the tendency to accumulate a relatively small amount of nitrate and a relatively large amount of chlorophyll, carotenoid, polyphenol and flavonoid. ‘Coventry’ with the lowest chlorophyll, carotenoid, and flavonoid contents was found to be the poorest in bioactive compounds. The sensory evaluation indicated the good quality of all mini and two midi cultivars, while ‘Delcaso’ (midi cultivar) received the worst marks, because of poor smell and crispness and a bitter aftertaste. The higher light intensity (200 µmol m−2 s−1) used for plant illumination did not unequivocally increase the content of health-promoting components or improve other characteristics of romaine lettuce compared to the light 160 µmol m−2 s−1.

Feasibility of Bio-Coagulation Dewatering Followed by Bio-Oxidation Process for Treating Swine Wastewater.

The unsatisfactory performance of the conventional swine wastewater treatment is drawing increasing attention due to the large amount of refractory chemical oxygen demand (COD), nitrogen, and phosphorus attached to the suspended solids (SS). In this study, for the first time, a novel process based on bio-coagulation dewatering followed by a bio-oxidation (BDBO) system was developed to treat swine wastewater containing high-strength SS, COD, TN, and TP. Firstly, after the bio-coagulation process, the removal efficiencies of SS, COD, NH3-N, and TP reached as high as 99.94%, 98.09%, 61.19%, and 99.92%, respectively. Secondly, the filtrate of the bio-coagulation dewatering process was introduced into the subsequent bio-oxidation process, in which the residual COD and NH3-N were further biodegraded in a sequence batch reactor. In addition, the dewatering performance of the concentrated swine slurry was substantially improved, with the specific resistance to filtration decreasing from 17.0 × 1012 to 0.3 × 1012 m/kg. Moreover, the concentrated swine slurry was pressed and filtered into a semi-dry cake after pilot-scale bio-coagulation dewatering treatment. Finally, the concentrations of COD and NH3-N in the effluent after the BDBO process, ranging between 150-170 mg/L and 75-90 mg/L, met the relevant discharge standard. Compared to traditional treatments, the BDBO system has excellent large-scale potential for improving the treatment efficiency, shortening the operation period, and reducing the processing costs, and is emerging as a cost-effective alternative for the treatment of wastewater containing high concentrations of SS, COD, TN, and TP.

The Integrated Application of Phosphorous and Zinc Affects the Physiological Status, Yield and Quality of Canola Grown in Phosphorus-suffered Deficiency Saline Soil

Despite the soil could contain high amount of phosphorus (P), salinity reduce its availability for crop plants. Hence, farmers should practice several tactics to ameliorate P deficiency in soils. The current study aimed to assess the importance of zinc (Zn) supply for mitigating the deficiency of P for canola grown in saline soil. The effects of three Zn rates (0, 150 and 300 mg L−1, Zn0, Zn150 and Zn300, respectively) under three P rates (0, 36 and 72 kg P2O5 ha−1, P0, P36, and P72, respectively) on physiological status, yield and quality of canola were measured. Treatments were arranged in the strip plot design based on completely randomized blocks with three replicates. Findings exhibited that P36 recorded the highest values of membrane stability index in the 2nd season, while statistically leveled P72 for relative water content and chlorophyll fluorescence in both seasons. Zn300 exhibited potent effect on all canola physiological traits in both seasons. In both seasons, P36 × Zn300, P72 × Zn150 and P72 × Zn300 showed the maximum chlorophyll fluorescence and performance index values. Plots treated with P72 achieved 70.0% increase in canola seed yield, greater than the untreated ones. Seed yield obtained with Zn300 were higher than Zn0 and Zn150 by1.30 and 1.10 times in 2019/20 season and 1.23 and 1.05 times in 2020/21 season. The highest oil % was recorded with P0 × Zn150 and P72 × Zn0 in the 1st season and with P72 × Zn150 in the 2nd season.

Study on the mechanism of biochar affecting the effectiveness of phosphate solubilizing bacteria.

Low phosphorus utilization and phosphorus fertilizer pollution are serious issues primarily affecting soil health. To investigate the effects of biochar on the growth, phosphorus solubilization, and metabolites of phosphorus-solubilizing bacteria (PSB), rice husk biochar (RH) and rice straw biochar (RS) were incubated with Bacillus megatherium (BM1) and Bacillus mucilaginosus (BM2), respectively. The highest phosphorus solubilization was observed in BM2 following the addition of RS. The dissolved amount of phosphorus was 244.99mg/L, which was 43.86% higher than that of the control group. Hence, biochar can improve the phosphorus solubilization capacity of PSB by affecting the organic acid and polysaccharide contents, and phosphatase activity secreted by the PSB, as the porous structure and surface characteristics of biochar ensured the adsorption of PSB. This study can help improve the functional activity of PSB and provide basis for improving the utilization of soil phosphorus, which in turn, aid in the development of biochar-based microbial fertilizers.

Evaluation of Phosphorus Storage and Performance of Broilers Using Phytase Synthetic Enzyme.

Phytic acid is a stored form of phosphorus in cereals, 65 to 70% of phosphorus in plant sources is phytate, and broilers are only able to use part of the phosphorus in plant sources. To meet the needs of chickens, it is necessary to use other artificial resources, which not only impose part of the cost of the breeding period because of its presence in the manure but is one of the factors polluting the environment. This study aimed to use different levels of phytase enzyme to reduce dietary phosphorus levels. 600 Ross 308 broilers were used in this experiment with five treatments and six replications, and in each replication, 20 chickens were used in a completely randomized design (CRD). Experimental treatments include 1) basal diet (control) 2) basal diet with 15% less phosphorus 3) basal diet with 15% less phosphorus + 1250 (FTU) phytase enzyme 4) basal diet with 15% less phosphorus + 2500 (FTU) phytase enzyme 5) basal diet with 15% less phosphorus + 5000 (FTU) phytase enzyme. The evaluated traits included weekly feed intake, weekly weight gain, feed conversion ratio, carcass characteristics, ash, calcium, and bone phosphorus. The use of phytase enzyme in different diets had no significant effect on food intake, weight gain, and feed conversion ratio (P>0.05). However, the use of phytase in different diets significantly affected the percentage of Gizzard, Heart, Liver, Proventriculus, and Spleen (P<0.05). The most changes were the increase in the ratio of feed intake and weight gain in the fourth week compared to the third week so that the changes in the ratio of feed intake ranged from 1.85 to 1.91, and this ratio for weight gain also ranged from 3.12 to 3.86 was recorded, and the lowest feed conversion ratio was obtained at the same age. The percentage of raw ash in broiler chickens was significantly increased by adding dietary phytase. The lowest amount of ash, calcium, and phosphorus belonged to the second group (diets with low phosphorus and no enzyme). The difference between the other groups and the control was not significant. Feed intake, weight gain, and feed conversion ratio with the addition of phytase enzyme were not affected by phosphorus reduction and had no significant effect on carcass characteristics. Environmental pollution can be prevented by reducing the level of dietary phosphorus and reducing excreted phosphorus.

PROTECTION OF IRRIGATED AND NON-IRRIGATED AREAS FROM WATER EROSION

Today, one of the other agronomic properties of this type of soil is that the amount of total nitrogen in the soil depends on the amount of humus in the soil. its amount varies from 0.05% to 0.15%. Typical gray soils are a very favorable medium for nitrification. The main part of nitrogen is found in the soil in the form of nitrate and is in a form that is easily absorbed by the plant. In most cases, the amount of total phosphorus is greater than the amount of total nitrogen. And in the upper layers of the soil, it is 0.1%-0.2%. Typical irrigated gray soils contain a lot of remains of roots and other parts of the plant, relatively low soil compaction, and humus is present in the plowed part of the soil. These processes have a negative impact on soil fertility. The possibilities of application to modern production, analysis of solving problems, elimination of excess water loss are the main tasks of today in the region.

Enhancement of soil fertility and yield of Capsicum frutescens (Green chilli) through application of bagasse Ash in soil

A pot experiment was conducted during 2022-23 at the research area of the Department of Environmental Science, Bareilly College, Bareilly to evaluate the effect of bagasse ash on growth, yield and quality of Capsicum frutescens (Green chilli) and also on soil fertility sugarcane. To achieve the current research work , sugar industry bagasse ash was applied to capsicum frutescens crops in pots having 1 kg soil @ 20% , 40%, 60%, 80% , 100,% respectively . When we compare the control sample. The physicochemical properties of soil under the investigation was having a pH (7.6), low in organic matter (8300 mg kg-1), and low content of Nitrogen (337 mg kg-1), Phosphorus (4.0 mg kg-1), Zinc(5.7 mg kg-1) and Iron (5.2 mg kg-1) . Bagasse ash was a rich source of micronutrients like Fe, Mn, Zn and Cu and also contained sufficient amounts of Potassium and Phosphorus. Consequently, total porosity of soil, presence P, K, Fe, Mn, Zn and Cu content in soil, increased with the levels of bagasse ash application. On the other hand, dry bulk density declined which shows a positive effect on plant growth. ECe and pH of the soil was minutely increased. After the application of bagasse ash in pots yields of capsicum frutescens crop also enhanced. It is recommended that application of 40-60% bagasse ash will result in enhanced yield of capsicum frutescens.

Characterisation of ash particles from co-combustion of bark and sludges from pulp and paper industry

Recycling phosphorus from waste streams for fertilization purposes could contribute to a sustainable society. The production in the pulp and paper industry results in several waste streams, among others nutrient-rich sludges in different forms. This study presents a detailed chemical and 3D characterization of ash from co-combustion of bark and two types of sludges from a paper mill; mixed sludge and biosludge. The combustion performance was investigated for these experiments and advanced analysis methods were used to characterise the ashes to correlate chemical and physical properties relevant for nutrient recycling. The elemental composition was determined by energy-dispersive X-ray spectroscopy; dominating crystalline phases by X-ray diffraction; and morphology, porosity, pore size distribution and active surface area of the slag were analysed with synchrotron-based X-ray micro-tomography and image analysis. Slag was formed in all combustion experiments to a large extent with increasing amounts with a higher proportion of sludge. Nutrient amounts indicate that slag particles from co-combustion of both biosludge and mixed sludge can be useful either as a soil improvement directly or for recovery processes. Slag from combustion of 30 wt% biosludge and 70 wt% bark contained the highest amount of phosphorus, 9 at% on a C and O free basis. Evaluation of tomography data showed that discrete and open pores could be distinguished on a micrometre scale. The porosity of the slag varied between the replicates and fuel mixtures, on average between 17 and 23 vol% for the bark and sludge mixtures. Open pore volume displayed large variations, on average 39–56 vol% of the pores were open pores connected to the surrounding volume. For all samples, 90 % of the pores were small, with an equivalent diameter under 30 μm, but the largest pore volume (80–90 %) consists of pores with an equivalent diameter over 75 μm. In soils, pores with a minimum equivalent diameter over 30 μm generally transmit water and the smaller pores store water. The slag particles have relatively thick walls, with few pore openings to the surroundings, indicating that the slag needs to be pre-treated by milling or crushing before application in the soil.

The Fate of Phosphorus in Experimental Burials: Chemical and Ultramicroscopic Characterization and Environmental Control of Its Persistency

The permanence of a buried body in soil always induces the formation of a decomposition island that can serve as a significant recording location to understand how the persistence of a clandestine grave affects soil. This study aims to analyze the elemental exchange from buried bodies to soil, with a focus on phosphorus content, and to determine the effects of environmental factors on its persistency. The experiment was carried out using eleven swine carcasses buried in an open site (northern Italy). The analyses were performed using the Olsen P method, which allowed for a recognition of the trend of the amount of phosphorus over time, due to the decomposition of phospholipids, followed by the transfer of the element from bone to soil. Additionally, microanalyses performed using a scanning electron microscope (SEM-EDS) on two different soil sample specimens (i.e., “dust” and “plug”) allowed for the identification of numerous phosphatic features (i.e., coatings, infillings, impregnations, and organo-mineral associations), which are the result of the interaction between soil and body fluids and can thus be used as indicators of the former presence of decomposing body (even in its absence). The ultramicroscopic analysis also shows increasing and decreasing amounts of P2O5 over time in the soil, which could be related to environmental conditions (i.e., soil moisture), due to the leaching of phosphorus induced by the percolation of natural rainwater. The study underlines the potential use of these methods to evaluate the possibility of a cadaver–soil linkage and of assessing the burial in the soil for a variable period. Moreover, the study may aid in analyzing the dynamics of phosphorus migration from buried bodies to soil during and after the decomposition process.

Comparison of Dissolved Organic Matter Composition and Microbial Distribution between Distributed-Inflow Biological Reactor and Two-Stage Anoxic/Aerobic for Piggery Wastewater Treatment

Piggery wastewater contains high amounts of feces, carbon, nitrogen, phosphorus, and other contaminants, introducing serious pollution into water, soil, and the atmosphere. Biological treatment technology is widely used in large-scale pig farms because of its high efficiency and economical advantages. In this study, two typical biological treatment systems—a distributed-inflow biological reactor (DBR) and a two-stage anoxic/aerobic (A/O/A/O)—were adopted to treat piggery wastewater to compare the treatment performance, the dissolved organic matter (DOM) composition, and the microbial distribution characteristics. The results show that the A/O/A/O system had better removal performance in terms of chemical oxygen demand (COD) compared to the DBR system, and similarly effective at removing and ammonia nitrogen (NH4+-N) and total nitrogen (TN). Using parallel factor analysis of the fluorescence excitation–emission matrix, four DOM components—namely fulvic acid-like/humic-like substances (C1), tyrosine-like substances (C2), humic-like substances (C3), and tryptophan-like substances (C4)—were tracked in piggery wastewater. Protein-like substances were significantly degraded, while humic-like substances were difficult for microorganisms to utilize. The endogenous input and humus characteristics of effluents were enhanced. Bacteroidetes (43.9% and 37.5% ) and Proteobacteria (43.1% and 56.7%) are the dominant bacteria in DBR and A/O/A/O systems. The microbial metabolites in DBR and A/O/A/O systems are mainly composed of amino acids, sugars, alcohols, and other small molecules, while those in the municipal sewage treatment plant system is mainly composed of ketones, amines, acids, lipids, and other small molecules. The results of microbial communities and metabolites can help to trace the process of biological systems treating piggery wastewater.

The effectiveness of the use of organic fertilizers in the link of crop rotation on light gray forest soil of the south of the Volga-Vyatka region

Relevance. The issues of reproduction of fertility of light gray forest soils of the forest-steppe zone and utilization of poultry industry waste as organic fertilizers are interrelated and are very relevant. Methods. The experiments studied the effect of one-time application of various doses (15, 30, 50 t/ha) of chicken manure, chicken manure compost and local organic fertilizers (sapropel and peat) on crop yields, and the aftereffect of fertilizers on the main indicators of soil fertility — amount of humus, nitrate nitrogen, phosphorus and potassium. The variants of the experiments were investigated sixfold. The Federal State Center of Agrochemical Service "Chuvashsky" was involved in laboratory analyses of soils and crop production. Mеthods of analysis of soil samples and crop production are generally accepted in agrochemical science.Results. Organic fertilizers for three years of research were introduced into the soil only once at the beginning of the experiment in doses of 15, 30 and 50 t/ha, and their effect on the yield and quality of crop production (potato tubers, spring wheat grains and peas) in 2020–2022 was positive. The agrochemical properties of the arable soil layer in the variants with the use of organic fertilizers have significantly improved. The nitrate content in the products in variants with doses of chicken manure and compost of 50 t/ha or more approached the critical level. Local fertilizers (sapropel and peat) at a dose of 30 t/ha, chicken manure and compost at a dose of 15 t/ha are good organic fertilizers with a long aftereffect.

Domestication of Wild Edible Species: The Response of Scolymus hispanicus Plants to Different Fertigation Regimes

Scolymus hispanicus L. is a wild edible species with wide distribution in the Mediterranean area. Recent research has focused on the domestication of wild edible greens, which is essential for the preservation of agroecosystems and the increase in biodiversity, especially under the adversely changing climate conditions. In the present work, the aim was to evaluate the response of S. hispanicus plants to different fertilization regimes that varied in the amounts of nitrogen, phosphorus and potassium in regard to plant growth and chemical composition of leaves. For this purpose, plants were grown in pots within an unheated greenhouse. Seven experimental treatments were used, including six fertigation regimes (SH1-SH6) and the control treatment (SHC), where no fertilizers were added. Fresh yield was beneficially affected by the treatments that included a high content of P and K (e.g., SH3 and SH5), while lesser amounts of these macronutrients (e.g., SH1 and SH4) resulted in higher chlorophyll content (SPAD index) and leaf area. In terms of mineral profile, high amounts of P and K improved dietary fiber and carbohydrates content, whereas the untreated plants had the highest content of ash, fat and crude protein. Oxalic and quinic acid were the major organic acids detected, with fertigation regimes significantly reducing their content compared to the control treatment. α-tocopherol was the only isoform of vitamin E detected in all the samples, while glucose and fructose were the most abundant sugars, with their highest content detected in control and SH4 treatments, respectively. Scolymus hispanicus leaves were rich in macro and micro minerals, while their contents varied depending on the fertigation regime. Finally, α-linolenic, palmitic, and linoleic acid were the major fatty acids detected, while their contents were beneficially affected by low nutrient inputs (e.g., untreated plants and SH1 and SH2 treatments). In conclusion, the regulation of nutrient solution seems to be an effective practice to increase fresh yield in S. hispanicus without compromising the nutritional profile of the edible product, while low inputs of macronutrients such as P and K may improve the chemical composition of the species, especially in terms of n-fatty acids.

Utilization of urban waste as liquid organic fertilizer for vegetable crops in urban farming system

Converting vegetable, fruit, food, fish offal and slaughterhouse waste that become a problem for the community in the urban areas into useful plant fertilizer is the solution. This study aims to determine (1) the potential of urban organic waste into liquid organic fertilizer and (2) the effectiveness of liquid organic fertilizer (LOF) in increasing the growth and yield of vegetable crops in urban farming systems. The study used Randomized Block Design (RBD) with some treatments P0 (control) and P1 (LOF with 6 types of waste) consisting of P2 (vegetable waste), P3 (fruit waste), P4 (sprouts waste), P5 (food waste), P6 (catfish waste) and P7 (blood waste). The treatment was repeated 3 times for a total of 28 experimental units. The three vegetable plants; eggplant, Bok Choy and mustard, were used in the experiment. The study found that liquid organic fertilizers from vegetables, fruit, sprout, food, fish, blood waste and mixed waste all contain organic matter, varying amounts of nitrogen (N), phosphorus (P), potassium (K), carbon (C), magnesium (Mg), calcium (Ca), copper (Cu), zinc (Zn), iron (Fe) and humic acid. All liquid organic fertilizer treatments increased eggplant and Bok Choy vegetable growth and yield; however, the type of organic waste used as a raw material for LOF did not affect growth but eggplant and Bok Choy yield. LOF from blood waste (P7) and fish waste (P6) has higher measured nutrients and yield from eggplant, Bok Choy and mustard vegetables than other treatments.

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.

Phosphorus extractability in relation to soil properties in different fields of fruit orchards under similar ecological conditions of Pakistan

Productivity of an orchard generally depends upon the fertility of the soil and the nutrient requirements of the fruit trees. Phosphorus (P) extractability from soils influences the P sorption, release patterns, and P bioavailability. A study was carried out to investigate P extractability via seven extraction methods in relation to soil properties in three fruit orchards. In total, 10 soil samples were collected from each fruit orchard, namely, citrus (Citrus sinensis L.), loquat (Eriobotrya japonica L.), and guava (Psidium guajava L.), located in similar ecological conditions to the Haripur district of Pakistan. Available P in the soil was extracted using deionized H2O, CaCl2, Mehlich 1, Bray 1, Olsen, HCl, and DTPA methods. Selected soil properties [pH, electrical conductivity (EC), soil organic matter (SOM)], texture, cation exchange capacity (CEC), macronutrients, and micronutrients were also determined. Soils sampled from orchards indicated significant differences in soil properties. Orchards have sequestered more amount of C stock in soil than without an orchard. The extractability of P from soils was profoundly affected by P extraction methods. The average amount of extractable P was relatively higher in those soils where the total amount of P was also higher. These methods extracted different pools of soil P with varying P concentrations regulated by the soil properties. Phosphorus amounts extracted were varied in the order of HCl &amp;gt; DTPA &amp;gt; Mehlich 1 &amp;gt; Bray 1 &amp;gt; Olsen &amp;gt; CaCl2 &amp;gt; water. Among orchards, a higher amount of P was found in soils of loquat followed by citrus and guava orchards. Regardless of the method, subsurface soil got a lower concentration of extractable P than surface soil in all orchards. The extractable P was highly associated with soil properties. DTPA extractable P was related to SOM soil clay content and CEC by R2 values of 0.83, 0.87, and 0.78, respectively. Most of the extraction methods were positively correlated with each other. This study indicated that SOM inputs and turnover associated with orchard trees exhibited a substantial quantity of extractable P in soils. Predicting available P in relation to its bioavailability using these methods in contrasting soils is required.

Ecological Role of &lt;i&gt;Onthophagus taurus&lt;/i&gt; (Schreber) in Soil Nutrient Mobilization

Dung beetles play a major role in the pasture ecosystem. The manure recycling activity of dung beetles is linked to their tunneling behavior. The present study was designed to analyze the tunnel pattern and nutrient mobilization by dung beetles, Onthophagus taurus (Schereber, 1759) in different soil types. A simple type of tunnel pattern was observed in all the four types of soil after 30th day of their introduction (10 pairs of male and female) into the experimental setup. However, the maximum number of tunnels was observed in the sandy and sandy clay loam (no. of openings - 15), followed by loamy soil (no. of openings -13). The physical (texture, water holding capacity, porosity, moisture content) and chemical parameters (pH and nutrients) of all the four types of soils were evaluated. Soil texture analysis revealed the texture to be of sandy (yellow soil), sandy clay loam (red and black soil), and loamy sand (brown soil) types. Water holding capacity and the soil porosity were recorded highest in the sandy soil, whereas moisture content was found maximum in the sandy clay loam. Soil nutrient analysis illustrated a significant increase in the amount of nitrogen (N), phosphorus (P), calcium (Ca), sulfur (S), sodium (Na), potassium (K), organic carbon and organic matter. Thus, the present study confirms that tunneling activity of O. taurus enhances the soil nutrients by carrying out dung decomposition.

Effects of phosphorus application on yield, quality and phosphorus use efficiency of edible sweetpotato: A case study of Xushu 32.

To explore the appropriate amount of phosphorus (P) fertilizer and improve economic yield and P use efficiency of edible sweetpotato, we took Xushu 32 as an example and compared the effects of different P application rates on yield, quality, P accumulation and P use efficiency of edible sweetpotato based on a two-year field experiment (soil available P content was 31.70 mg·kg-1) from 2018 to 2019. There were five P application levels (P2O5), including 0 (P0), 25 (P25), 50 (P50), 75 (P75) and 100 kg·hm-2(P100). The results showed that, 1) compared with P0, P application significantly increased the yield of fresh sweetpotao and commodity potato, with the effects being the stongest under P75 treatment, followed by P50 treatment. However, there was no significant difference between the two treatments. 2) P application significantly increased the contents of starch and reducing sugar in storage root. The contents of soluble sugar and protein increased significantly under P50 treatment. 3) Du-ring the growth period of 90 to 120 d, P fertilizer supply significantly increased P accumulation and dry matter accumulation of sweetpotato. 4) The apparent P use efficiency (APUE) decreased with increasing P application rates, while P agronomic efficiency (PAE) increased first and then decreased with the increases of P application rates, which was significantly higher under P50 than other treatments. Taking into account the yield, quality, economic yield and P utilization rate of edible sweetpotato, the optimal dosage of P2O5 is 50 kg·hm-2 under the experimental conditions.

Separation of Phosphorus from Phosphorus-concentrated Steelmaking Slag

Since 10 million tons of steelmaking slag, which contains a few percent of phosphorus, are annually produced, the phosphorus amount in the slag is equivalent to the annual import volume of phosphorus rock in Japan. Therefore, the steelmaking slag is attracting attention as a potential phosphorus resources. Phosphorus-concentrated slag obtained by the dephosphorization reaction between high phosphorus hot metal and oxidizing slag at high temperature contains phosphorous comparable to that of phosphorus rock. However, because of high FeO concentration, it is difficult to use for phosphorus resources directly. In this work, the effects of pH, acid type and leaching method on the dissolution behavior of phosphorus from P-concentrated slag were investigated. As a result, phosphorus dissolution progressed at lower pH, and was promoted by the addition of citric acid, which is known as a chelate former. When nylon mill pot stirring with citric acid and alumina mill pot stirring with nitric acid were compared to impeller stirring, respectively. By combining nylon mill pot stirring and citrate leachate, phosphorus dissolution was accelerated, because the slag was pulverized during stirring and a formation of insoluble metal-phosphate was inhibited by the formation of complex ion between leached metal cation and citrate. When the slag was leached with alumina mill pot while controlling pH by nitric acid, the phosphorus dissolution ratio lowered since phosphorus ion and aluminum ion, which is supplied by the dissolution of pot and crushing ball during leaching, constructed secondary products with low solubility along with other dissolved ions.

Changes of Nutritive Elements in Soils That Medium-Supplied With Phosphorus, Depending on Fertilizers Used in Cotton Agrocenosis

The aim is to increase the mobile nutrient content in the soil by applying optimal nitrogen and potassium fertilizers without the use of phosphorus fertilizers on irrigated typical gray soils moderately supplied with mobile phosphorus. Significant differences are observed in the amount of mobile phosphorus in the soil from the beginning and till the end of the vegetation. It ranged between 24.28-27.15 mg / kg in the driving layer and between 15.20-19.05 mg / kg in the sub-driving layer. The amount of N-NO3 increased during the vegetation to 29.1-34.4 mg / kg in the driving layer, N-NH4 in the driving layer changed to 3.1-4.2 mg / kg. Exchangeable potassium was found to fluctuate between 148.72–177.82 mg / kg in the driving layer at the end of the vegetation period and varied between 179.2–182.75 mg / kg in the sub-driving layer.