Phosphorus Leaching Research Articles

Effect of Microplastics and Straw Addition on Nitrogen and Phosphorus Leaching in Orange Orchard Soils

To explore the effects of microplastic input and straw addition on nitrogen and phosphorus leaching in orange orchard soil, indoor soil column leaching simulation experiments were conducted on orange orchard soil in Dangyang City, Hubei Province. The experiment analyzed the effects of different treatments on the leaching characteristics of soil nitrogen and phosphorus. The results showed that： ① The increase in microplastic input increased the leaching capacity of the soil （TN, NO3--N, NH4+-N, and TP） when only microplastic input was added. ② Under the addition of straw, the input of microplastics increased, which reduced the leaching amount of TN and NO3--N in the soil, and increased the leaching amount of NH4+-N and TP in the soil. ③ Under the input of microplastics, the key influencing factors of soil nitrogen and phosphorus leaching were soil bulk density and water content. Under straw addition, it was mainly affected by soil carbon and nitrogen content. Among them, microplastic input and straw addition significantly increased soil pH, but their path coefficients for nitrogen and phosphorus leaching were not significantly correlated. The results showed that the effects of polypropylene microplastic input and straw addition on soil nitrogen and phosphorus leaching were related to the amount of microplastics input and whether straw was added. The results showed that the input of microplastics would increase the amount of soil nitrogen and phosphorus leaching. Although nitrogen leaching loss caused by microplastic input could be reduced under straw addition, soil phosphorus leaching loss was significantly increased.

Environmental influences on soil phosphorus dynamics and eutrophication risks in the Three Gorges reservoir Area, Chongqing section

The spatial distribution of soil phosphorus fractions (SPFs) in the Three Gorges Reservoir area (TGRA) is crucial for evaluating water quality and lake eutrophication in the lower reaches of the Yangtze River. Besides, it is also unclear whether climate change and rising elevation will alter the risk of phosphorus loss in this region. To address this knowledge gap, soil samples were extensively collected in Chongqing section of the TGRA and extracted SPFs using a rapid sequential extraction method. Results indicated that Ustifluvents, Haplustepts, and Kanhaplustults are suitable for cultivation but also prone to the risk of phosphorus leaching due to high labile phosphorus concentration. Increased temperature positively affected labile and medium-stable phosphorus, while increased precipitation accelerated phosphorus leaching. Solar radiation has significant effects on medium-stable and stable phosphorus. Additionally, multivariate and redundancy analysis showed that different SPFs were influenced by various environmental factors, but elevation is the predominant factor affecting most SPFs in the TGRA. Northeastern TGRA and areas with lower elevations on both sides of the Yangtze River were more susceptible to phosphorus leaching. This study is expected to provide decision-makers with references and help manage the regional environment in the context of climate change.

Strength and Contaminant Toxicity Leaching Characteristics of MgO-Solidified Silt

In this study, MgO as an environmentally friendly silt-solidifying material was first mixed with silt and then carbonized by injection with CO2. The strength and contaminant leaching characteristics of the MgO-solidified silt were studied using unconfined compressive strength and toxicity leaching tests, and the results were compared with those of cement-solidified silt. The unconfined compressive strength of the silt reached 111 kPa with 9% MgO content and a 14 d curing time. The CO2 injection further increased the unconfined compressive strength of the MgO-solidified silt by approximately 25%: the values for MgO-solidified silts without and with a CO2 injection were approximately 60% and 80%, respectively, of those of the cement-solidified silts with the same additive additions. The leaching concentrations of nutrient salts and heavy metal pollutants in the silt decreased with increased MgO content. Compared with the dredged silt, MgO solidification with carbonization reduced the leaching of total nitrogen and total phosphorus by more than 10% and 50%, respectively: these values were approximately 5% points higher than those of cement-solidified silt. Of the heavy metals, the leaching concentration of Ni was reduced the most. This study provides a theoretical basis and technical support for low-carbon treatment and green resource utilization of dredging silt.

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

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

Zeolite Amendment Reduces Nitrogen and Phosphorus Leaching in Containerized Plant Production

Zeolite Amendment Reduces Nitrogen and Phosphorus Leaching in Containerized Plant Production

Loss of nutrients from meadow-brown soils during irrigation of apple trees in the conditions of the dry subtropics of Azerbaijan

The article presents the results of studies on the effect of water consumption, depending on the length (96, 144 and 192) meters of irrigation furrow with a slope of relief tg = 0.021 on the leaching of nitrogen, phosphorus and humus from irrigated soils of the dry subtropics of Azerbaijan under apple trees. Under conditions of leaching of nutrients, the effect of mineral and organic fertilizer systems on apple yields has also been studied. With a 96-meter furrow and a water consumption of 0.2 l/sec, the content of leached nutrients (N, P) and gross humus with soil was 0.01 % nitrogen and phosphorus, 0.02 % gross humus. Increase in water consumption from 0.2 l/sec. up to 0.4 l/sec. It has a negative effect on the leaching of humus, nitrogen and phosphorus from the soil. With a water consumption of 0.4 l/sec, these indicators increased markedly by 0.01 % for humus, nitrogen and phosphorus. Along the length of the irrigation furrow in both water consumption rates, the leaching of nutrients and humus from the soil increases. It was found that with an increase in the length of the furrow to 192 meters at a water consumption of 0.4 l/sec, the leaching was greater than the 96-meter furrow in humus by 0.22 %, nitrogen by 0.07 % and phosphorus by 0.04 %. The use of an organomineral fertilizer system (Background+ N120P120K90) had a positive effect on the yield of apple trees. Thus, in the non-maneuverable version on a 94–meter furrow, the yield of the apple tree was 274.2 c/ha - when the furrow was lengthened to 192 m, the yield gradually decreased due to the high content of leached nutrients and humus (268.5 c/ha). When using N120P120K90 + 10 t/ha of manure, 278.4 c/ha yield was established at 96 m furrow and 0.2 l/sec of water consumption. Whereas, when the furrow was lengthened to 192 m at the same rate of fertilizers and water consumption, the yield decreased to 278.2 c/ha, that is, furrow lengthening was ineffective at slopes tg = 0.021. It was found that at high slopes, the shorter the furrow, the less nutrients are washed out.

Contrasting effects of soil type and use of cover crops on nitrogen and phosphorus leaching in agricultural systems of the Argentinean Pampas

Agricultural systems of the Argentinean Pampas generally use rotations of summer crops under no-tillage and apply fertilization at rates that do not compensate nutrient exports with grain harvest, resulting in negative balances and soil fertility loss. However, the humid climate, long fallow periods and soil factors enhance nitrogen (N) and phosphorus (P) leaching, which has a negative impact on freshwater ecosystems. We propose to evaluate the effect of soil type and replacement of fallow periods with cover crops on drainage and N and P leaching. We used lysimeters containing two Mollisols of contrasting texture and porosity (a Typic Argiudoll and a Typic Hapludoll), and cultivated between 2014 and 2022 with a maize-soybean rotation with (M-CC-S) and without (M-S) cover crops under no tillage.The amount of drainage varied with rainfall (p<0.01), was similar between soils and higher in M-S than in M-CC-S during the intercropping period (148 vs 96 mm, p<0.05). The correlation between daily rainfall and drainage was higher for the Typic Argiudoll (r=0.46 and 0.42, for M-S and M-CC-S, respectively) than for the Typic Hapludoll (0.28 and 0.23 for M-S and M-CC-S, respectively) when considering same-day events, and it decreased for the Typic Argiudoll (r=0.31 and 0.26, for the M-S and M-CC-S, respectively) but not for the Typic Hapludoll (0.28 and 0.21 for the M-S and M-CC-S, respectively) with a 1-day lag between series. The amount of N and P lost through leaching varied with drainage (p<0.01). Cover crops reduced nitrate leaching to a greater extent in the Typic Hapludoll (from 30.4 to 3.3 kg ha−1 period−1) than in the Typic Argiudoll (from 17.6 to 2.0 kg ha−1 period−1) (p<0.05). Soil type modified P leaching in M-S (0.32 and 0.11 kg ha−1 period−1 for the Typic Argiudoll and the Typic Hapludoll, respectively) and M-CC-S had intermediate P leaching (0.17 and 0.16 kg P ha−1 period−1 for the Argiudoll and Hapludoll, respectively) (p<0.05).We conclude that: 1) water flows through different channels in each soil, the rapid flow of the Typic Argiudoll probably occurs through preferential flow channels (macropores) while the slower flow of the Typic Hapludoll is probably associated to matrix porosity, 2) P leaching is related to soil type (Typic Argiudoll > Typic Hapludoll) and drainage reduction by cover crops off-sets P leaching through macropores in the Typic Argiudoll, and 3) cover crops reduce N leaching, due to drainage reduction and N retention in cover crop biomass.

Artificial humic acid coated ferrihydrite strengthens the adsorption of phosphate and increases soil phosphate retention

Phosphorus (P) leaching loss from farmland soils is one of the main causes of water eutrophication. Thus, effective methods must be developed to maintain sustainability in agricultural soils. Herein, we design artificial humic acid (A-HA) coated ferrihydrite (Fh) particles for fixing P in soil. The experiments in water and soil are successively conducted to explore the phosphate adsorption mechanism and soil P retention performance of A-HA coated ferrihydrite particles (A-Fh). Compared with unmodified ferrihydrite (Fh), the phosphate adsorption capacity of A-Fh is increased by 15 %, the phosphate adsorption speed and selectivity are also significantly improved. The ligand exchange, electrostatic attraction and hydrogen bonding are the dominant mechanisms of phosphate adsorption by A-Fh. In soil experiments, the addition of 2 % A-Fh increases the soil P retention performance from 0.15 to 0.7 mg/kg, and A-Fh are able to convert more phosphate adsorbed by itself into soil available P to improve soil fertility. Overall, this work highlights the importance of this a highly effective amendment for improving poor soils.

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

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

Effect of Soil Amendment of Greening Waste on Leaching Loss of Soil Nitrogen and Phosphorus

It is of great practical significance for comprehensively promoting the green development of agriculture to explore practical products for preventing and controlling nitrogen and phosphorus leaching. In this study, PVC soil column experiments and field experiments were used to evaluate the interception effect of soil amendments produced by green wastes on nitrogen and phosphorus leaching. The pH value, EC value, the nutrient contents of ammonium nitrogen (NH4 +-N), nitrate nitrogen (NO3 −-N), total nitrogen (TN), and available phosphorus (AP) in different soil layers and leaching solution were determined, and the interception effects of soil amendment on nitrogen and phosphorus leaching were comprehensively evaluated. The results showed that the soil amendments of green waste had significant inhibition and control effects on the leaching of NH4 +-N, NO3 −-N, APs, and TN. The interception mechanism of the soil amendments of green waste on nitrogen and phosphorus leaching was mainly to absorb a large amount of leaching solution and various forms of nitrogen and phosphorus nutrients. The results also showed that the soil amendment of green waste had a certain nutrient content and buffering effect on acid and alkali and the main form of nitrogen leaching was NO3 −-N. This study provides a theoretical basis for the development of cheap and effective physical products to prevent and control nitrogen and phosphorus leaching from farmland.

Effect of Fertilizer, Furrow Length, and Irrigation Flow Rate on Soil Nutrient and Yield of Apple Orchard

The objective of this study was to evaluate the impact of furrow irrigation with a length of 96, 144, and 192 m and a flow rate of between 0.2 and 0.4 Ls−1 on the leaching of nitrogen, phosphorus, and humus from dry subtropical soils in Azerbaijan. Moreover, the impact of six fertilizer levels, namely, control (without fertilizer), 10 t ha−1 of cow manure, N90P90K90 + 10 t ha−1 of cow manure, N120P90K90 + 10 t ha−1 of cow manure, N120P120K90 + 10 t ha−1 of cow manure, and N120P90K120 + 10 t ha−1 of cow manure, on the performance of apple orchards, has been examined. The findings indicate that the brown soils of the irrigated grassland exhibit normal humus, total nitrogen, and weak phosphorus levels, with a gradual decline observed in the lower layers. Applicable to the agricultural and subsurface layers, the aggregates are 0.25–1.0 mm in diameter, with an agricultural value of 12.9% and 21.8%, respectively. This indicates a poor structural condition of the apple orchard soil. The elevation of the water flow rate from 0.2 to 0.4 Ls−1 resulted in a greater extraction of humus, nitrogen, and phosphorus from the soil. Both water flow rates increased the nutrients and humus leaching from the soil. By extending the furrow length to 192 m, the losses of humus (3.25%), nitrogen (0.36%), and phosphorus (0.30%) from the soil in both water flows significantly increased in comparison to the 96‐m length. By extending the length of furrows to 192 m, the yield (21.97 t ha−1) was significantly reduced in comparison to the 96‐m length (22.31 t ha−1). As a consequence of the application of N120P90K120 + 10 t ha−1 of cow manure, the yield of 27.3 t ha−1 was significantly elevated in comparison to other fertilizer treatments and the control treatment (17.9 t ha−1). Therefore, management of fertilizer systems, furrow length, and water flow can improve soil fertility and plant yield by reducing erosion in the meadow‐brown soil of Azerbaijan.

Tree dieback and subsequent changes in water quality accelerated the climate-related warming of a central European forest lake

Abstract The water temperature of many lakes has recently risen as a result of climate change. We evaluated trends in the cloudiness, solar radiation, wind, air and water temperatures, ice cover, thermocline depth, transparency, and composition of two Bohemian Forest lakes (Czech Republic) from 1998 to 2022. Lake water temperatures increased by 0.32–0.47 °C decade−1, and the ice cover periods decreased by 11.7–14.8 days decade−1. These changes were mostly associated with increasing air temperatures during most months and increasing solar radiation (due to decreasing cloudiness) especially in March and November (the months preceding ice-on/off). Decreasing snow cover in winter (by 3.8 cm decade−1) further accelerated the earlier ice melt. The number of days with water temperature ≥4 °C increased similarly in both lakes by 12–13 days decade−1. However, the number of days with water temperature ≥20 °C increased and the depth of the summer thermocline decreased more in the lake with tree dieback in its catchment. Tree dieback accelerated the leaching of organic carbon and phosphorus, increasing water brownification, algal production, and decreasing water transparency. Solar radiation was absorbed in shallower water layers. Changes in catchment forest thus contributed to the variability in the response of lake water temperatures to climate change.

Treatment of Phosphorus-Containing Raw Materials with Alkaline Solutions

The work describes a method for recovery of phosphorus compounds from phosphorus-containing raw materials. The possibility of autoclave leaching of phosphorus from phosphorite in the form of a solution of sodium phosphates with an alkaline solution was experimentally tested. The optimal process parameters were determined (temperature 250–300°C, leaching time 3 h, NaOH concentration 150–300 kg m–3), under which calcium silicate with a unique nano-sized needle-shaped structure, widely used in many industries, is formed in the solid residue. The research results make it possible to involve raw materials with low phosphorus content in waste-free processing.

Phosphorus Leaching During Potato Production in Coarse Soil

Phosphorus Leaching During Potato Production in Coarse Soil

Soil Fertility and Phosphorus Leaching in Irrigated Calcareous Soils of the Mediterranean Region

To ensure soil quality and soil health, it is necessary to improve fertilization practices while minimizing environmental impacts. The aim of this study was to record the state of the art on soil fertility related to fertilization management (organic and/or mineral) and to detect environmental challenges in highly productive fields. A soil survey was set up in a new irrigated area (c. 20 years old), in the north-eastern part of Spain, which is mainly devoted to double annual crop rotations of cereals and maize. The area also supports an important animal rearing activity. The survey covered 733 ha of calcareous soils, owned by 35 farmers. At each farm, fertilization management was recorded, and soil was analyzed for nutrients and heavy metals. Multivariate analyses were performed. Total N, P, Cu and Zn, and available P, Cu, Zn and Mn soil concentrations were associated to the use of organic amendments. Heavy metals concentrations were below established thresholds. Available P (Olsen-P) was identified as an indicator of the previously adopted fertilization management and of the potential of P leaching towards deeper soil layers. Regression analyses were performed. A displacement of available P from the uppermost layer (0–0.3 m) occurs in the breakpoint of 86 mg P kg−1 soil. Preventative actions might be established from 53 mg P kg−1 soil due to the slowdown in P immobilization. Our results reinforce the importance of setting up P threshold soil levels for best practices of fertilization, as a basis for sustainable agriculture intensification.

Enhanced nitrogen and phosphorus removal by a novel ecological floating bed integrated with three-dimensional biofilm electrode system

The ecological floating bed (EFB) has been used extensively for the purification of eutrophication water. However, the traditional EFB (T-EFB) often exhibits a decline in nitrogen and phosphorus removal because of the limited adsorption capacity of fillers and inadequate electron donors. In the present study, a series of electrolysis-ecological floating beds (EC-EFBs) were constructed to investigate the decontamination performance of conventional pollutants. EC-EFB outperformed T-EFB in terms of nitrogen and phosphorus removal. Its removal efficiency of total nitrogen and total phosphorus was 20.51–32.95% and 45.06–96.20%, which were higher than that in T-EFB.. Moreover, the plants in EC-EFB demonstrated higher metabolic activity than those in T-EFB. Under the electrolysis condition of 0.51 mA/cm2 for 24 h, the malondialdehyde content and superoxide dismutase activity in EC-EFB were 6.08 nmol/g and 22.61 U/g, which were significantly lower compared to T-EFB (38.65 nmol/g and 26.13 U/g). And the soluble protein content of plant leaves increased from 3.31 mg/g to 5.72 mg/g in EC-EFB. Microbial analysis revealed that electrolysis could significantly change the microbial community and facilitate the proliferation of nitrogen-functional microbes, such as Thermomonas, Hydrogenophaga, Deinococcus, and Zoogloea. It is important to highlight that the hydrogen evolution reaction at the cathode area facilitated phosphorus removal in EC-EFB, thereby inhibiting phosphorus leaching. This study provides a promising and innovative technology for the purification of eutrophic water.

Effects of microplastics pollution on plant and soil phosphorus: A meta-analysis

The widespread use of microplastics leads to environmental pollution, which threatens ecosystem functions (i.e., nutrient cycling). Some studies have focused on the impacts of microplastics on phosphorus from plants and soils. However, inconsistent responses of plant and soil phosphorus to microplastics have been observed. This work synthesized the results of 781 paired observations from 73 publications to explore the overall effects of microplastics on plant and soil phosphorus and whether the impacts depended on microplastics properties and experimental variables. We found the overall negative effects of microplastics on plant phosphorus and soil available phosphorus. Additionally, microplastics significantly inhibited neutral phosphatase activity but increased soil phosphorus leaching. Furthermore, the impacts of microplastics on plant and soil phosphorus varied depending on microplastics types, sizes, concentrations, and experimental durations. Soil total phosphorus and available phosphorus exhibited stronger negative responses to biodegradable than conventional microplastics. Acid phosphatase was more sensitive to biodegradable than conventional microplastics. In addition, soil total phosphorus, available phosphorus, and alkaline phosphatase were significantly correlated with microplastic concentrations and exposure time. Overall, our findings suggest that microplastics potentially threaten soil fertility and plant productivity. This work provides an important reference for predicting ecosystem functions in the context of microplastics pollution.

Long-term effects of liming on crop yield, plant diseases, soil structure and risk of phosphorus leaching

This study examined the long-term effects of applying structure lime (mixture of ~80% CaCO3 and 20% Ca(OH)2) and ground limestone (CaCO3) on soil aggregate stability and risk of phosphorus (P) losses 5–7 years after liming, incidence of soil-borne diseases and yield in winter wheat (Tritium aestivum), oilseed rape (Brassica napus) and sugar beet (Beta vulgaris). Lime was applied in 13 field trials in Sweden 2013–2015 and soil characteristics and crop yield were monitored until 2021. Seedbed (0–4 cm depth) aggregate (2–5 mm size) stability was improved to the same extent with both lime treatments compared to the untreated control, sampled 5–7 years after liming. Analyses and estimations of different P fractions (total P, PO4-P, and particulate P) in leachate following simulated rainfall events on undisturbed topsoil cores sampled 6–8 years after liming revealed lower total P and particulate P concentrations in both lime treatments compared to the untreated control. Two sugar beet trial sites with soil pH ≤7.2 before liming showed an increase in sugar yield for structure lime and ground limestone as an effect of increased concentration of soil potassium (K-AL) and/or lower Aphanomyces root rot potential compared to the untreated control. The yield of winter wheat was not affected by the application of either type of lime at sites with pH &gt;7.2 but the yield of oilseed rape decreased after the application of structure lime.

Effects of phosphate-solubilizing bacteria on phosphorus components, humus and bacterial community metabolism during spent mushroom substrate composting

To address the low conversion of effective phosphorus during previous studies on spent mushroom substrate (SMS) composting, phosphorus-solubilizing bacteria (PSB) were utilized to increase the effective phosphorus content in this study. The results demonstrated that PSB treatments exhibited higher temperature levels up to 66 °C. The TN, NH4+-N, and NO3−-N contents were higher than those of the control treatment (CK) by 9.01%, 50.01%, and 4.61%, respectively. Inoculation with PSB increased effective phosphorus, total phosphorus, and humus content in the SMS compost by 6.84%, 11.05%, and 9.10%. In addition, based on PICRUSt analysis, inoculation with PSB significantly promoted metabolic pathways associated with phosphorus conversion or the production of substances that can facilitate phosphorus conversion or phosphorus leaching, thus improving phosphorus utilization in compost. In conclusion, the addition of PSB can improve the bioavailability of P and the humus content in SMS compost to realize the green and sustainable development of the edible mushroom industry.

Study on synergistic leaching of potassium and phosphorus from potassium feldspar and solid waste phosphogypsum via coupling reactions

To achieve the resource utilization of solid waste phosphogypsum (PG) and tackle the problem of utilizing potassium feldspar (PF), a coupled synergistic process between PG and PF is proposed in this paper. The study investigates the features of P and F in PG, and explores the decomposition of PF using hydrofluoric acid (HF) in the sulfuric acid system for K leaching and leaching of P and F in PG. The impact factors such as sulfuric acid concentration, reaction temperature, reaction time, material ratio (PG/PF), liquid–solid ratio, PF particle size, and PF calcination temperature on the leaching of P and K is systematically investigated in this paper. The results show that under optimal conditions, the leaching rate of K and P reach more than 93% and 96%, respectively. Kinetics study using shrinking core model (SCM) indicates two significant stages with internal diffusion predominantly controlling the leaching of K. The apparent activation energies of these two stages are 11.92 kJ·mol−1 and 11.55 kJ·mol−1, respectively.