Excessive phosphorus emissions can result in the eutrophication of water bodies, causing severe environmental damage as well as influencing the efficiency of water treatment equipment. The impacts of carbon/phosphorus ratios on performance and mechanism of the upflow anaerobic sludge bed reactor remain unclear. Henrie, the effects of different carbon/phosphorus ratios (i.e., 80:1, 40:1, and 20:1) on the transformation of phosphorus in the biological treatment process of an upflow anaerobic sludge blanket (UASB) reactor were studied. The results showed that phosphines are of great importance in the phosphate reduction process. After a stable operation, the phosphine reached the highest 81.91 mg/m3 at a C/P ratio of 40:1. It was proved that the optimum operating condition of the reactor was carbon to phosphorus ratio of 40:1. Phosphate-reducing bacteria were present in the UASB reactor, and the relative abundance of Clostridia in the sludge was 1.90 % and 1.59 % when the C/P was 80:1 and 20:1, respectively. This implied that the low carbon to phosphorus ratio reduces the phosphorusreducing microbial activity in the reactor. Lower C/P values could inhibit the uptake and use of P in the phosphonate transport system and the transport of phosphate in the cell by the microbial Pst system, impeding the mineralization of organophosphates. The study provides new insights into improving the efficiency of treating phosphorus-rich wastewater.

Understanding how land cover and seasonal variations influence soil microbial communities and nutrient cycling is crucial for sustainable land management in tropical forests. However, such investigations are limited in Madagascar's tropical ecosystems. This study investigated the impacts of land cover types and seasonal variations on soil properties and microbial communities in the tropical forest region of Andasibe, Madagascar. Soil samples were collected from four land cover types-tree fallow (TSA), shrub fallow (SSA), eucalyptus forest (EUC), and degraded land (TM)-across three seasonal periods: the dry season, the start of the rainy season, and the end of the rainy season. Both land cover and sampling season affected soil pH and available P, whereas total nitrogen, soil organic carbon, and the C/N ratio were affected only by land cover. The soil organic carbon and total nitrogen concentrations were greater in TM. NextSeq sequencing of the 16S rRNA gene and ITS regions of the nuclear rRNA operon revealed distinct microbial community compositions across land covers, with greater diversity in the TSA and SSA. Bacteria are more sensitive to seasonal changes than are fungi, with phosphate-solubilizing (gcd) and phosphate-mineralizing (phoD) genes being more abundant in the rainy season, emphasizing the role of microbes in nutrient availability under different climatic conditions. Principal component analysis highlighted SSA as a hotspot for microbial activity, reinforcing the potential of shrub ecosystems in soil restoration. These findings reveal strong land cover and seasonal effects on soil microbial functions, with implications for nutrient cycling, ecosystem resilience, and sustainable land management in tropical forest landscapes.

Background: Fritillaria taipaiensis P.Y. Li is commonly used in Chinese medicine for its cough-suppressing and expectorant properties. Due to over-excavation and ecological damage, the wild resources of F. taipaiensis have suffered serious damage. Understanding and improving the inter-root soil environment plays an important role in improving the success rate of artificial cultivation of F. taipaiensis and the quality of medicinal herbs. Methods: This study employed a pot experiment to inoculate three strains of phosphorus-solubilizing fungi from the Aspergillus genus for a total of seven treatment groups, with sterile physiological saline serving as the control group (CK). The research aims to examine the impact of inoculating phosphorus-solubilizing fungi on the biomass of F. taipaiensis, alkaloid concentration in its bulbs, and characteristics of the rhizosphere soil environment. The specific inoculation treatments included: Aspergillus tubingensis (Z1); Aspergillus niger (Z2); Aspergillus fumigatus (Z3); a combination of A. tubingensis and A. niger (Z12); a combination of A. niger and A. fumigatus (Z13); a combination of A. tubingensis and A. fumigatus (Z23); and a combination of all three fungi, A. tubingensis, A. niger, and A. fumigatus (Z123). Results: Inoculation with phosphorus-soluble fungi significantly increased the biomass of F. taipaiensis, and the largest increase was in the Z123 group, which was 62.85% higher than that of the CK group. Total alkaloid content increased the most (0.11%) in the Z3 group, which was an 83.87% increase compared with the CK group. The total content of monomer alkaloids in the Z3, Z13, and Z123 groups increased by 10.53%, 12.48%, and 9.61%, respectively, compared with those in the CK group, indicating that the quality of F. taipaiensis could be significantly improved after applying phosphorus-solubilizing fungi. The soil environment improved after inoculation with different phosphorus-solubilizing fungi. The Z23 and Z123 groups had the greatest effect on the rhizosphere soil bacteria and Actinomyces. Overall, the soil nutrient content of the Z13 group increased the most, and the contents of available phosphorus, available potassium, available nitrogen, total phosphorus, and organic matter increased by 47.71%, 27.36%, 26.78%, 25.13%, and 31.72%, respectively, compared with those in the CK group. Conclusion: These results show that the treatment groups that included different combinations of strains were superior to the single-strain treatment groups, and the Z123 group was the best treatment group when considering bulb biomass and alkaloid and soil nutrient contents. Applying phosphorus-solubilizing fungus fertilizer is highly feasible during F. taipaiensis production in the field.

Background and AimsPrescribed burning is a widely used management technique, often employed to restore grasslands affected by woody plants encroachment. However, its interaction with pre-existing plant species in influencing soil properties remains unclear.MethodsWe conducted a diachronic soil survey to assess the evolution of several soil properties in the mid-term (up to 18 months) after burning, including physico-chemical parameters and microbial biomass carbon on soils under vegetation patches of different plant functional types and life forms. Vegetation patches included Ericaceae and legume shrubs, ferns, and biocrusts dominated by lichens. Soil samples were taken pre-burning, immediately after burning and 9 and 18 months after.ResultsOur findings indicate that while some soil properties returned to pre-burning levels in the mid-term (i. e., soil cations and NH4+), others, such as available phosphorous (P Olsen), exhibited a significant decline that persisted even 18 months later. Furthermore, soils under legumes initially displayed higher levels of soil carbon and nitrogen compared to other vegetation patches, but this distinction diminished over time. This was likely due to legumes' susceptibility to fire damage, in contrast to the greater resilience of Ericaceae shrubs.ConclusionOur study highlights the complex vegetation patch-dependent effects of prescribed burning on soil properties. While legumes initially enhance soil carbon and nitrogen, their contribution decreases over time due to fire sensitivity. Some soil parameters recover in the mid-term, but nutrients like available phosphorus continue to decline. Fire management strategies should consider plant diversity and recovery time to mitigate soil fertility loss.

Excessive boron (B) levels in soil can lead to toxicity in plants, impacting their growth and productivity. Effective strategies to reduce B uptake are important for improving crop performance in contaminated soils. This experiment aimed to investigate the effects of chicken manure incineration ash (CMA) and triple superphosphate (TSP) on B uptake in barley plants grown in B-contaminated soil. Before the experiment, the chemical composition and molecular structure of CMA were analyzed using XRF, XRD and SEM. The soil was contaminated with 15 mg kg-1 of B, and both TSP and CMA were applied at rates of 40, 80, and 160 mg kg-1 of phosphorus (P). Neither P source had a significant impact on plant dry weight. However, increasing doses of applied TSP and CMA increased plant P concentration while significantly decreasing B concentration. Particularly with CMA applied at 160 mg kg-1 P dose, plant B concentration decreased to the lowest level of 194 mg kg-1. Increasing P doses led to a slight decrease in plant silicon (Si) concentration. The pH of soil samples taken after the experiment slightly increased with CMA treatments compared to TSP. The available P concentration in soils increased with increasing P doses. The available B concentration decreased with increasing P doses, especially reducing to the lowest level of 2.52 mg kg-1 in soils with a 40 mg kg-1 P, CMA. In conclusion, in addition to the effect of P, the molecular structure of P is also important in reducing B uptake in barley.

The current work gives a snapshot of pesticide residuals, their exposure levels, and the associated potential risks of some organophosphates in Coimbatore district, Tamil Nadu. The study has significant viewpoints on food safety and pesticide management. The pesticide residual analysis was carried out on two commonly used vegetables, tomato and brinjal. The QuEChERS method is used to extract pesticides and GC-MS/SIM analyses were used to quantify pesticide residues. Among the various samples tested, organophosphorus pesticides, such as Phorate Sulfoxide, Chlorpyrifos, and Malathion, were detected in some samples. In the majority of brinjal samples analyzed, no pesticide residues were detected. However, one sample showed the presence of malathion (0.001 mg/kg). The detected level of malathion was within the acceptable safety limits, indicating that the sample is safe for consumption. Nevertheless, in one of the tomato samples tested, the residual level of phorate sulfoxide (0.34 mg/kg) is found to be higher than the MRL with a health risk index of 2.79. Except for phorate sulfoxide, all the other pesticide residuals were within MRL. Phorate residues with a soil half-life of 2 to 173 days are readily water soluble and may leach easily into groundwater, adversely affecting human health. The dietary risk of phorate can also put people at increased health risks of reproductive harm, endocrine system disruption, neurological damage, and an increased risk of certain cancers. The study's outcome suggests the need to review the strict guidelines imposed on using unsafe pesticides. Also, future investigations are necessary to validate the presence of other toxic pesticides in the study area.

Phosphorus (P) is a crucial macronutrient for plant growth, root development, and yield. Commercial P fertilizers have low efficiency of delivery and utilization and are lost from plant root zones by either low availability or leaching or surface runoff that leads to environmental damage. This review investigates how nano P fertilizers (NPFs) can overcome the current inefficiencies of conventional formulations and, thus, enhance plant yield while minimizing negative environmental impacts. NPFs have significant potential for augmenting plant germination by more effectively penetrating seed coatings and facilitating greater water and nutrient uptake. The nanoscale nature of NPF also uniquely facilitates greater P absorption by roots, which in turn enhances chlorophyll synthesis, improves light absorption, and optimizes electron transport efficiency-key factors in boosting plant photosynthesis. Additionally, it stimulates overall physiological processes (e.g., secondary metabolite production, root exudation), increases antioxidant enzyme activities, and enhances plant yield. NPFs can also minimize the accumulation of toxic elements by several mechanisms, including controlling contaminant bioavailability in soil by enhancing competing plant essential element (e.g., P, Ca) uptake. Moreover, NPFs also mediate soil pH, which has important implications for soil biogeochemistry in low-pH agricultural areas. Soil microbiomes and associated processes will often improve with NPF application relative to conventional P formulations. Although great potential has been demonstrated, a mechanistic understanding of certain aspects of NPF activity remains incomplete, including impacts across diverse crop species, environmental conditions, and soil types. However, NPFs offer great potential as an important tool in the transformation of conventional agriculture, simultaneously lessening the usage of finite P resources, reducing the environmental footprint of agriculture, and improving future food security.

The soil ecosystem has been severely damaged because of the increasingly severe environmental problems caused by excessive application of phosphorus (P) fertilizer, which seriously hinders soil fertility restoration and sustainable farmland development. Shoot P uptake (SPU) is an important parameter for monitoring crop growth and health and for improving field nutrition management and fertilization strategies. Achieving on-site measurement of large-scale data is difficult, and effective nondestructive prediction methods are lacking. Improving spatiotemporal SPU estimation at the regional scale still poses challenges. In this study, we proposed a combination prediction model based on some representative samples. Furthermore, using the experimental area of Henan Province, as an example, we explored the potential of the hyperspectral prediction of maize SPU at the canopy scale. The combination model comprises predicted P uptake by maize leaves, stems, and grains. Results show that (1) the prediction accuracy of the combined prediction model has been greatly improved compared with simple empirical prediction models, with accuracy test results of R 2 = 0.87, root mean square error = 2.39 kg/ha, and relative percentage difference = 2.71. (2) In performance tests with different sample sizes, two-dimensional correlation spectroscopy i.e., first-order differentially enhanced two-dimensional correlation spectroscopy (1Der-2DCOS) and two-trace 2DCOS of enhanced filling and milk stages (filling-milk-2T2DCOS)) can effectively and robustly extract spectral trait relationships, with good robustness, and can achieve efficient prediction based on small samples. (3) The hybrid model constrained by the Newton-Raphson-based optimizer's active learning method can effectively filter localized simulation data and achieve localization of simulation data in different regions when solving practical problems, improving the hybrid model's prediction accuracy. The practice has shown that with a small number of representative samples, this method can fully utilize remote sensing technology to predict SPU, providing an evaluation tool for the sustainable use of agricultural P. Therefore, this method has good application prospects and is expected to become an important means of monitoring global soil P surplus, promoting sustainable agricultural development.

Phosphorus (P) is one of the macronutrients that is essential for plant growth and development. Anoectochilus roxburghii (Wall.) Lindl., an important orchid species, often encounters low-phosphorus stress during cultivation. Strigolactones (SLs) or their derivatives have recently been defined as novel plant hormones that regulate plant root development. However, it remains unclear whether SLs mediate root growth in response to phosphorus deficiency in A. roxburghii. In this study, the responses of A. roxburghii under P deficiency condition to different levels of SLs were investigated. The results demonstrated that the inhibition effect of low-phosphorus stress on plant growth in A. roxburghii significantly alleviated by SLs application, especially 0.1 mu mol L-1 of SL. The group treated with SL exhibited higher root elongation and lower levels of reactive oxygen species, as well as significantly increased soluble protein content and malonaldehyde. Furthermore, the SL treatment down-regulated the expression of several phosphorus-responsive genes, such as ArPHT6 and ArAP5, suggesting that SLs may promote phosphorus uptake or utilization to mitigate low-phosphorus stress. These findings provide an important new insights into the action mechanisms of SLs' in response to low-phosphorus stress and offer potential application value for cultivation and production of A. roxburghii. Future research will focus on exploring the molecular mechanism between SLs and phosphorus uptake.

Dispersive soil is a common problem soil in engineering projects, which has the potential risk of causing serious engineering failures. In this paper, calcined waste phosphorus slag (CPS) was chosen to enhance the mechanical properties and reduce soil dispersivity. Dispersive soil samples with 1 % to 10 % CPS content were prepared and cured for 0 to 28 days. The dispersivity identification test was used to assess soil sample dispersivity. The compressive and tensile strength, conductivity, and pH were determined for the soil. Microstructural and mineral composition were analyzed using SEM/EDS, TG/DTG, and XRD analysis. The natural dispersive soil was selected to verify the effect of CPS in improving soil. Experiments show that the CPS inhibits soil dispersivity and converts it into non-dispersive soil. Both compressive and tensile strength increases significantly with the increase in the content of CPS and curing time. The tensile strength of the soil samples cured for 28 days increased by about 76 % and the compressive strength by about 61 % as the mixed content of CPS was increased from 1 % to 10 %. Results show that CPS can improve the strength and modify the dispersivity of soil, its optimal mixing content is 5 %. In addition, using CPS in dispersive soil could also solve the disposal problem of phosphate slag, which is a win-to-win solution. (c) 2024 Production and hosting by Elsevier B.V. on behalf of The Japanese Geotechnical Society. This is an open access article under the CC BY- NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).