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Lower soil phosphorus (P) availability in saline-sodic soils is due to high pH and salinity, which seriously limited crop growth. Manure application has a positive effect on soil properties and P availability. We conducted an experiment, which included five treatments with different durations of manure application: 11-, 16-, 22-, and 27-year manure treatments, and no manure as a control treatment (CK). The results showed that manure application decreased soil pH and electrical conductivity (EC) and increased soil organic matter (SOM). Soil available P content increased by 236.76 mg·kg−1 after applying manure for 27 years. Compared to the CK treatment, manure application significantly increased alkaline phosphatase (ALP) 3.36–6.05-fold and increased microbial biomass phosphorus (MBP) 3.69–15.90-fold (p < 0.05). The organic P (Po) and inorganic P (Pi) contents increased with manure application, except Ca10-P and O-P. Furthermore, we found that pH and EC were significantly negatively correlated with SOM (p < 0.05). MBP and ALP were significantly positively correlated with SOM (p < 0.05). Available P was mainly affected by Ca2-P (+0.71, p < 0.001). Overall, manure application in saline-sodic soils altered soil saline-sodic properties by increasing SOM. The results also indicated that enhanced soil available P is due to an increase in Ca2-P, Al-P, and Po mineralization, especially for Ca2-P. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is an important soil element for sustaining plant growth and the integrity of terrestrial ecosystems, and the soil P cycle is strongly influenced by climate change and agricultural activities. However, little is known about how soil P has evolved with climate change and intensive agriculture at mid‐high latitudes, where the soil P cycle is sensitive to climate change. To answer this question, an ecohydrological model (EcoHAT‐P) driven by remote sensing data was used in this study to calculate soil P concentration and loss and was calibrated and validated using 272 soil samples collected in the Sanjiang Plain, a typical mid‐high latitude region with a long history of strong agricultural activity. Soil P concentration and loss, and plant uptake of soil P, were analyzed for the years 2000–2019 and 2020–2040. The results showed that soil total P, soil P loss, and plant P uptake all increased under intensive agriculture. The soil P cycle at mid‐high latitudes was more sensitive to temperature than to precipitation. Increased temperature would increase soil P loss and plant P uptake by 93.94% and 8.16%, respectively, and soil legacy P from intensive agriculture would become the main source even if external P inputs were eliminated. The results highlight the evolution of soil P transport at mid‐high latitudes and clarify the response of soil P cycle to climate change under intensive agriculture. [ABSTRACT FROM AUTHOR]

AbstractBacillus species and organomineral fertilizers can improve various crop responses. The objective of this study was to evaluate the efficiency of organomineral fertilizer with B. subtilis and B. licheniformis, in comparison to mineral fertilizer, on soybean growth, leaf nutrient content, grain yield, and soil characteristics. Two soybean field experiments (305 km apart) were set up in southeastern Brazil. Two sources of fertilizers (inoculated granulated organomineral, 5-26-0 + 0-0-32 N-P2O5-K2O, and coated mineral fertilizer, 10-52-0 + 0-0-60 N-P2O5-K2O), and four doses of P plus K (no fertilizer, 50, 75, 100 kg ha−1 of each P2O5 and K2O) were applied. At 60 days after sowing, plant height and leaf analysis were assessed. Weight of 1000 seeds, grain yield, and soil analysis were evaluated (120 days after sowing). In both fields, there was interaction between source and P plus K dose factors for soybean grain yield. In Site 1, the highest grain yield (4,543.69 kg ha−1) was observed for 100 kg ha−1 of P2O5 and K2O dose of coated mineral fertilizer; in Site 2, the highest grain yield (4,638.55 kg ha−1) was observed for 75 kg ha−1 of P2O5 and K2O dose of organomineral fertilizer. These factors also affected N, P, and K leaf contents. Less effects were observed on plant height, weight of 1000 seeds, and soil characteristics. Inoculated organomineral fertilizer can be used for total or partial supply of nutrients without a clear difference from mineral fertilization. Smaller doses of inoculated organomineral fertilizer could be used without compromising soybean grain yield. [ABSTRACT FROM AUTHOR]

The developments and innovations in green miniaturized technologies suggest that a complete miniature approach (MA) to determine organic carbon (OC) and phosphorus (P) in soils may enable handling a large number of samples. In comparison to the conventional approach (CA), this approach also reduces waste generation and analysis costs. Here we have miniaturized all the steps of the conventional analytical procedures for OC and P analysis and carried out an in-depth validation of MA on various aspects, including linearity, biases, precision, inaccuracy, and imprecision. This rigorous assessment aimed to delineate the effect of miniaturization on the quality of determination along with its associated benefits and limitations. The findings revealed a strong correlation between the MA and CA in the OC test, indicating an R2 >0.84, with the Deming regression producing a model equation demonstrating a highly significant slope and an intercept closely approximating zero. Similarly, the P values obtained by MA and CA exhibited a correlation with an R2 > 0.99, alongside the Deming regression displaying a minimal intercept and a slope approaching one. The Bland–Altman analysis indicated a mean bias of 0.01 (95% CI, −0.51 to 0.54) for OC values and −1.7 (95% CI, −9.04 to 5.57) for P values. This cross-validation study highlights the applicability and limitations of the MA in estimating OC and P levels across a diverse range of soils. [ABSTRACT FROM AUTHOR]

Phosphorus limitation occurs in many soils as a significant amount of soil P is retained in forms inaccessible to plants, such as bound to iron (Fe) minerals. Prior studies have shown that silicon (Si) can mobilize P from the binding sites of such minerals. Several P extraction methods have been developed to account for different P pools. Nevertheless, each of those methods uses different extractants and mechanisms to extract different P pools in soils. However, there is no study comparing different P extraction methods in the presence of Si fertilization. We tested the effect of Si on P mobility and determined the efficiency of water, Calcium acetate lactate (CAL), Mehlich-III, and Bray and Kurtz extraction methods for extracting P in the presence of amorphous silica (ASi) fertilization using two soils of contrasting characteristics. Significantly higher amounts of P were found at 3% ASi treatments (10 and 21 mg P kg-1) compared to the control (4 and 10 mg P kg-1) in the water extract in the high and low-yield soil, respectively just after 6 hours of extraction and increased with time. This may be explained by Si directly competing with P for sorption to Fe minerals. Using CAL extraction, Si addition showed no effect on P extractability. In contrast, the Mehlich-III and Bray extraction methods showed decreasing P extractability, especially at 3% ASi treatment (95 and 60 mg P kg-1) compared to the control (115 and 80 mg P kg-1) for the high-yield soil. The decreasing P contents in the presence of Si found in the Mehlich-III and Bray extracts may be attributed to the decrease in extraction effectiveness of the extractants to extract P while extracting Si and Fe. Our results showed that the Mehlich-III and Bray extraction methods may not be suitable for the determination of P availability in the presence of ASi fertilization since both extractants also extract Si and this may limit the completeness of P extraction. Therefore, in the presence of Si fertilizer, the water extraction method may be suitable to determine P availability and mobilization due to ASi. [ABSTRACT FROM AUTHOR]

Aims: Afforestation is considered an effective strategy to improve soil carbon (C) and fertility in degraded drylands. However, how specific species identities (e.g., conifers or broadleaves) impact C and nutrient concentrations across deep soil layers remains uncertain. Methods: Three most important plantation forests, including plantations of native mono-species Pinus tabuliformis (coniferous species), exotic mono-species Robinia pseudoacacia (broadleaf and nitrogen-fixing species), and their mixed, were selected to explore their effects on soil organic C (SOC) and nutrient concentrations throughout soil profile (0–200 cm) in the Loess Plateau. Results: The results showed that soil C and nutrient concentrations were strongly affected by species identity. Specifically, R. pseudoacacia contained significantly higher SOC, total nitrogen (N), and ammonia N concentrations than other plantations at the top layer (0–60 cm), but R. pseudoacacia contained lower total phosphorus (P) concentrations than other plantations. In the deep layer (60–200 cm), R. pseudoacacia contained lower total N, nitrate N, and total P concentrations than other plantations. There was no significant difference in SOC concentration among plantation types in the deep layer. We found antagonistic effects of tree mixtures on soil P in the top and deep layers. Furthermore, microbial biomass C and N was the primary driver of SOC and N concentration in the top layer, respectively. Conversely, fine root biomass was the primary factor influencing N and P concentrations in the deep layer. This suggests that planting exotic R. pseudoacacia with higher root biomass has the potential to exacerbate soil N and P depletion in the deep layer. Conclusion: Our work emphasizes the key role of species identities in regulating soil nutrient concentrations, especially in the deep layer, and the importance of tree species selection in dryland afforestation. [ABSTRACT FROM AUTHOR]

By incubating the soil without living roots in situ at two spruce forest sites, we simulated the effects of tree dieback and interrupted mycorrhizal associations following forest disturbance on the soil microbiome and phosphorus leaching. We observed the retreat of ectomycorrhizal fungi and increased proportion of saprotrophs without changes in community richness and the Shannon diversity index. This was accompanied by a pronounced decomposition of organic matter, associated with an increased activity of carbon-mining hydrolases and acid phosphatase. The nonexistent phosphorus uptake and immobilization by ectomycorrhizal associations led to its substantial increase in the soil, in the labile fractions, such as microbial biomass and water-soluble reactive phosphorus, but also in the fraction bound to organometallics (extractable by oxalate), and caused considerable phosphate leaching, as estimated using ion-exchange resin traps. The results show that the retreat of the root-specific environment, characterized by the input of available carbon and effective nutrient uptake and by the specific microbiome, has profound effects on phosphorus dynamics and loss. Furthermore, we suggest that ectomycorrhiza plays an equally important role in controlling phosphorus-mining from organic matter and subsequent immobilization and/or leaching from soils concurrently to its known role in nitrogen cycling and immobilization in spruce forests. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Guilbeault‐Mayers & Laliberté (2024), 243: 636–647. [ABSTRACT FROM AUTHOR]

Coal mining causes surface subsidence, resulting in the loss of phosphorus from the soil surface and affecting crop growth. To provide a basis for the reclamation of soils in coal mining subsidence areas, using the Suntuan mine area in Huaibei City as an example, indoor soil cultivation experiments were conducted to investigate the effects of applying different types of phosphate rock powders (mechanically activated and nonmechanically activated), active minerals (zeolite, kaolin, bentonite) and phosphorus solubilizing microorganisms (Pseudomonas fluorescens, Aspergillus niger) on soil pH, available phosphorous content, and the conversion of soil phosphorus fractions. The results showed that the combined action of phosphate rock powder and phosphorus solubilizing bacteria could significantly improve the soil acidic environment. The application of phosphate rock powder, active minerals, and phosphorus solubilizing microorganisms can promote the release of available phosphorous in soil, and Aspergillus niger has a better effect than Pseudomonas fluorescens. Soil content of H2O-P, NaOH-Pi, NaHCO3-Pi, and HCl-P increased, NaOH-Po decreased, and some treatment groups had reduced Residual-P content. Together, phosphate rock powders, active minerals, and phosphorus solubilizing microorganisms can mitigate soil acidification, promote soil phosphorus release, result in the transformation of soil phosphorus fractions, and improve phosphate fertilizer utilization. [ABSTRACT FROM AUTHOR]

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Microbial necromass carbon (MNC) accounts for a large fraction of soil organic carbon (SOC) in terrestrial ecosystems. Yet our understanding of the fate of this large carbon pool under long‐term warming is uncertain. Here, we show that 14 years of soil warming (+4°C) in a temperate forest resulted in a reduction in MNC by 11% (0–10 cm) and 33% (10–20 cm). Warming caused a decrease in the content of MNC due to a decline in microbial biomass carbon and reduced microbial carbon use efficiency. This reduction was primarily caused by warming‐induced limitations in available soil phosphorus, which, in turn, constrained the production of microbial biomass. Conversely, warming increased the activity of soil extracellular enzymes, specifically N‐acetylglucosaminidase and leucine aminopeptidase, which accelerated the decomposition of MNC. These findings collectively demonstrate that decoupling of MNC formation and decomposition underlie the observed MNC loss under climate warming, which could affect SOC content in temperate forest ecosystems more widespread. [ABSTRACT FROM AUTHOR]

Nitrogen (N) and phosphorus (P) are the two most important macronutrients supporting forest growth. Unprecedented urbanization has created growing areas of urban forests that provide key ecosystem services for city dwellers. However, the large‐scale patterns of soil N and P content remain poorly understood in urban forests. Based on a systematic soil survey in urban forests from nine large cities across eastern China, we examined the spatial patterns and key drivers of topsoil (0–20 cm) total N content, total P content, and N:P ratio. Topsoil total N content was found to change significantly with latitude in the form of an inverted parabolic curve, while total P content showed an opposite latitudinal pattern. Variance partition analysis indicated that regional‐scale patterns of topsoil total N and P contents were dominated by climatic drivers and partially regulated by time and pedogenic drivers. Conditional regression analyses showed a significant increase in topsoil total N content with lower mean annual temperature (MAT) and higher mean annual precipitation (MAP), while topsoil total P content decreased significantly with higher MAP. Topsoil total N content also increased significantly with the age of urban park and varied with pre‐urban soil type, while no such effects were found for topsoil total P content. Moreover, topsoil N:P ratio showed a latitudinal pattern similar to that of topsoil total N content and also increased significantly with lower MAT and higher MAP. Our findings demonstrate distinct latitudinal trends of topsoil N and P contents and highlight a dominant role of climatic drivers in shaping the large‐scale patterns of topsoil nutrients in urban forests. [ABSTRACT FROM AUTHOR]

Various phosphorus (P) fertilizers are commonly utilized in agricultural production on the Loess Plateau. However, there exists a widespread issue of improper matching between P fertilizers, crop types, and soil types. This study proposes a scientifically based approach to managing phosphate fertilizer through a matching experiment. A field experiment was conducted to investigate the effects of different P fertilizers on soil P profiles in a wheat–corn rotation between October 2017 and September 2021. The experiment adopted a randomized block design. P fertilizer was applied as a basal fertilizer at rates of 115 kg P2O5 ha−1 during the wheat season and 90 kg P2O5 ha−1 during the maize season. Nitrogen (N) fertilizer application rates were 120 kg N ha−1 for wheat and 180 kg N ha−1 for maize. N fertilizer was divided into two applications, with 60% applied at pre-planting and 40% at the jointing stage of wheat or the V12 stage of maize. P fertilizer variants utilized in the study included ammonium dihydrogen, ammonium phosphate, calcium-magnesia phosphate fertilizer, calcium superphosphate, and ammonium polyphosphate. The transformation process of phosphate was examined, revealing that the commonly considered dominant diammonium phosphate fertilizer was not the optimal choice in this production system. Ammonium polyphosphate, calcium superphosphate, and ammonium dihydrogen were deemed more suitable for application in Loess soil. Furthermore, an analysis was conducted on the relationship between P fractions, soil properties, and soil Olsen-P. This research emphasizes the significance of strategic phosphate fertilizer use in agriculture to ensure efficient production and to help address the global P scarcity. [ABSTRACT FROM AUTHOR]

Agricultural watersheds in the North Central United States have been intensively farmed for decades with widespread application of fertilizer and extensive tilling practices. Soil phosphorus built up in sediments over time as a result of these practices may be released under anaerobic conditions, such as flood events. These floods are increasing in frequency and intensity due to climate change, leading to downstream water-quality concerns. Edge-of-field best management practices, including constructed treatment wetlands, provide a natural buffer for excess phosphorus runoff, but may only be a temporary solution if soil becomes oversaturated with phosphorus over extended periods of time. Preventing wetlands from becoming sources of phosphorus to water bodies may be essential for management in future years when considering impacts from climate change. This research assesses how wetland plant harvesting can reduce soil phosphorus accumulation (measured as Olsen phosphorus) in edge-of-field treatment wetlands, thereby preventing these systems from becoming phosphorus sources and ensuring the longevity of water-quality benefits from these systems. Using several 380 L controlled wetland mesocosm experiments in 2018–2019, we assessed above-ground plant material (S. tabernaemontani and B. fluviatilis) and soil Olsen P through the growing season and after harvest. We observed a reduction in soil phosphorus from wetland plant harvesting between 1–50% over one year, with a mean reduction of 7.9 mg/kg. B. fluviatilis initially contained higher P concentration early in the season (0.82% P content) compared to S. tabernaemontani (0.76% P), but S. tabernaemontani retained higher P later in the season (0.3% P content) compared to B. fluviatilis (0.25%). Time of season may significantly impact plant P removal potential, including accessibility of treatment wetland sites. While controlled mesocosm experiments may not always be applicable to real landscape-level management, this study highlights the potential for reductions in soil phosphorus and corresponding downstream phosphorus fluxes in edge-of-field treatment wetlands through plant harvest during the growing season. Plant harvesting can be used by land managers in edge-of-field treatment wetlands as an adaptation mechanism for shifting environmental conditions, such as increased heavy rainfall occurrences and flood events, that are exacerbated by climate change in this region. [ABSTRACT FROM AUTHOR]

Phosphorus limitation occurs in many soils as a significant amount of soil P is retained in forms inaccessible to plants, such as bound to iron (Fe) minerals. Prior studies have shown that silicon (Si) can mobilize P from the binding sites of such minerals. Several P extraction methods have been developed to account for different P pools. Nevertheless, each of those methods uses different extractants and mechanisms to extract different P pools in soils. However, there is no study comparing different P extraction methods in the presence of Si fertilization. We tested the effect of Si on P mobility and determined the efficiency of water, Calcium acetate lactate (CAL), Mehlich-III, and Bray and Kurtz extraction methods for extracting P in the presence of amorphous silica (ASi) fertilization using two soils of contrasting characteristics. Significantly higher amounts of P were found at 3% ASi treatments (10 and 21 mg P kg-1) compared to the control (4 and 10 mg P kg-1) in the water extract in the high and low-yield soil, respectively just after 6 hours of extraction and increased with time. This may be explained by Si directly competing with P for sorption to Fe minerals. Using CAL extraction, Si addition showed no effect on P extractability. In contrast, the Mehlich-III and Bray extraction methods showed decreasing P extractability, especially at 3% ASi treatment (95 and 60 mg P kg-1) compared to the control (115 and 80 mg P kg-1) for the high-yield soil. The decreasing P contents in the presence of Si found in the Mehlich-III and Bray extracts may be attributed to the decrease in extraction effectiveness of the extractants to extract P while extracting Si and Fe. Our results showed that the Mehlich-III and Bray extraction methods may not be suitable for the determination of P availability in the presence of ASi fertilization since both extractants also extract Si and this may limit the completeness of P extraction. Therefore, in the presence of Si fertilizer, the water extraction method may be suitable to determine P availability and mobilization due to ASi.

Soil phosphorus (P) is pivotal for crop health and growth. We collated a dataset spanning 65 studies from 19 countries to quantify the effects of both natural and anthropogenic factors on P dynamics (dataset provided). Our meta-analysis encompassed five variables: the type of fertilizer (chemical or organic fertilizer), tillage practices (tillage or no-till), land use (cultivated or forest), soil texture (either loam soil or sandy loam soil) and soil depth (surface or subsurface). The interplay between soil management strategies, especially those encompassing fertilizer application and tillage, and soil phosphorus dynamics is well established. Our quantitative data suggests the use of organic fertilizers relates to a significant 82% increase in soil Olsen-P content. Additionally, while the no-till method has resulted in only a slight 1.6% increase in Total-P, it has brought about a remarkable 60% increase in organic phosphorus, especially NaHCO3-Po, in contrast to conventionally tilled soils. Further, we found that the concentrations of Total-P and Olsen-P in surface loam soils is elevated, being 24.8% and 1023.6% higher, respectively, compared with subsurface loam soils. In sandy loam soils, these values are 35.3% and 872.2% higher, respectively. These meta-analysis data highlight how soil management practices can cause variation in P species in soil. They not only underscore potential strategies for refined phosphorus use in diverse farming contexts but also pave the way for further research focusing on agricultural P management. [ABSTRACT FROM AUTHOR]

Considerable amounts of residual fertilizer phosphorus (P) have accumulated in the agricultural soils of Finland since the 1960s, and the P fertilizer application recommendations have been lowered. It is unknown how much P intensively managed silage grass can obtain from the accumulated reserves without a loss of yield. In two field experiments on sandy loam conducted in 2003-2020, four consecutive grass (70% timothy, 30% fescue) rotations were performed (4 or 5 years each, including the establishment year). The grass received mineral P fertilizers (PF; 16 kg P ha-1 year-1), cattle slurry (PS; 11 kg P ha-1 year-1) or no P (P0). The organic P (Po) and inorganic P (Pi) pools in 2003 and 2020 samples were determined following the Hedley procedure using H2O, NaHCO3, NaOH and HCl as sequential extractants. Soil test P (STP) was monitored annually using ammonium acetate extraction. The results showed that the cumulative P balance (P0: -344 to -412 kg ha-1; PF and PS: -101 to -198 kg ha-1) was highly negative, resulting in declining STP. Still, after 18 years, the grass showed no consistent yield response to P fertilizer application. The most significant Pi decline occurred in the Pi-NaHCO3 (~30%) and Pi-NaOH (~50%) pools, while the changes in Po were negligible. This study and international comparisons, Mehlich-3, degree of P saturation and the result of Hedley in other studies, suggest that these soils, initially above the critical STP level, contain plenty of legacy P and can provide perennial grass with sufficient P for a long time. [ABSTRACT FROM AUTHOR]

Purpose: Nanoparticles (NPs) have been considered to improve phosphorus (P) availability and activation of soil P in agroecosystems. However, the effects of NPs addition on soil P fractions, microbial characteristics, and plant growth are not well-understood. This study aims to investigate the influences of titanium dioxide (TiO2NPs) and iron oxide (Fe3O4NPs) addition on soil P fractions, microbial characteristics, and plant growth of oilseed rape (Brassica napus L.). Materials and methods: Pot experiment was conducted in 2020 and 2021 years. The exposure of TiO2NPs/Fe3O4NPs (1000 mg kg−1 dry soil) to oilseed rape cultivated was investigated in two contracting calcareous soils (i.e., vegetable field (VF) and cotton field (CF)) for 86 days. Soil pH, Olsen-P, available-Ti/Fe, and Fe-oxides were determined. Different P fractions (CaCl2-P, Citrate-P, Enzyme-P, and HCl-P) were tested by biologically based P fractionation method (BBP). Soil microbial biomass phosphorous (MBP) and alkaline phosphatase activity (ALP) were analyzed. The numbers of bacteria and fungi count were measured by flow cytometry method. Plant biomass and total P uptake were examined in the TiO2NPs/Fe3O4NPs treatments. Results and discussion: Compared with the CK treatment, soil pH was decreased by 12.0–18.0% in the TiO2NPs- and Fe3O4NPs-added treatments in both the VF and CF soils. In contrast, soil Olsen-P was increased by 12.0–19.0%, respectively, implying that TiO2NPs/Fe3O4NPs addition improved soil P availability. The addition of TiO2NPs/Fe3O4NPs significantly affected different soil P fractions. For example, the TiO2NPs/Fe3O4NPs treatments increased CaCl2-P and Citrate-P while decreased Enzyme-P content, indicating that a great portion of soil Enzyme-P was transformed into CaCl2-P and Citrate-P in the TiO2NPs/Fe3O4NPs-treated soils. However, TiO2NPs/Fe3O4NPs addition had no significant influences on HCl-P. Soil microbial biomass phosphorus (MBP), ALP activity, and available-Ti/Fe contents were almost unaffected by TiO2NPs/Fe3O4NPs addition. In addition, the addition of TiO2NPs/Fe3O4NPs had no influence on the numbers of soil bacteria and fungi and plant biomass and total P uptake of oilseed rape. Conclusions: This study demonstrated that the addition of TiO2NPs/Fe3O4NPs in calcareous soils improved soil P availability, and promoted insoluble P transformed to labile-P (CaCl2-P and Citrate-P). However, TiO2NPs/Fe3O4NPs addition at dose of 1000 mg kg−1 dry soil had no toxic effect on oilseed rape (Brassica napus L.). The proper application dosage should be further explored to activate soil P and promote crop growth. Our results provide theoretical basis for the effects of nanoparticles addition on soil P activation, microbial characteristics, and plant growth of Brassica napus L. [ABSTRACT FROM AUTHOR]

Soil microorganisms play crucial roles in maintaining material circulation and energy flow in desert ecosystems. However, the structure and function of soil microorganisms in different forestlands are currently unclear, restricting the use of sand-fixing plants and the understanding of forest ecosystem functions. In this study, Artemisia ordosica, Caragana korshinskii, and Salix psammophila, three types of sand-fixing forests widely distributed in the Mu Us Sandy Land, were used to explore the effects of sand-fixing forests on soil physicochemical properties, soil enzyme activity, soil microbial biomass, microbial community structure, and inter-microbial species relationships. Soils of forestlands showed higher soil organic carbon (SOC), total phosphorus (TP), and total nitrogen (TN) contents than bare sandy land. The SOC in bare sandy soil was only 0.84 g kg−1, while it remained 1.55–3.46 g kg−1 in forestland soils. The TN in bare sandy land soil was 0.07 g kg−1, which was significantly lower than that in forestland soils (0.35–0.51 g kg−1). The TP in bare sandy soil was 0.18 g kg−1, significantly lower than that in forestland soils (0.46–0.69 g kg−1). Afforestation of bare sandy land improved soil microbial carbon and nitrogen contents and increased microbial enzyme activities of acid phosphatase and N-acetyl-β-D-glucosaminidase. Significant differences were observed between the three forestlands and bare sandy land in terms of soil microorganisms and community composition. With the establishment of a sand-fixing forest, the alpha diversity of soil bacteria significantly improved, whereas that of soil fungi remained stable. The bacterial community comprised 33 phyla, 106 classes, 273 orders, 453 families, and 842 genera. While five fungal phyla were detected by OTUs at a similarity of 97%, bacterial and fungal community structures were affected by the organic carbon content, sand particle content, soil pH, total nitrogen, and total phosphorus contents of soils. This study is helpful for vegetation construction and protection on sandy lands from the perspective of plant-microbe interactions. [ABSTRACT FROM AUTHOR]

The response of lowland tropical forest on highly weathered P-limited soils to changes in atmospheric composition is likely to be regulated by P-availability from litter and soil. Our aim was to gain insight into possible mechanisms that may affect P-availability and C sequestration. We collected litter and soil samples along a transect in Central Amazonia. We examined litter and soil properties, determined C, N, and P contents and performed density fractionation to obtain organic-C, -N and -P fractions. To assess microbial demand and mineralization, we analysed C, N and P associated enzyme activities. The litter layer has an estimated turnover time of about one year or less and C, N and P contents were much smaller than in the mineral soil. Total soil C, N and P decreased with depth, while P was depleted relatively more. Most organic-C, -N and -P is stabilized by adsorption onto mineral surfaces. Non-adsorbed organic matter fractions were depleted of P. Nearly all organic-P appeared to be present in the mineral-associated fractions from where it, despite high phosphatase activities, appears not to be available for mineralization. Enzyme activities revealed that microbial C-demand in litter is higher than in soil, while P-demand was relatively high in soil and increased with depth. Hypothesized higher phosphatase activity under increasing atmospheric CO2 concentrations may probably not alleviate P-limitation in these terra firme forests due to the limited availability of mineralizable organic-P. [ABSTRACT FROM AUTHOR]

Soil phosphorus (P) limitation in karst areas has severely constrained soil quality and land productivity. To enhance silage maize yield and quality and alleviate and/or balance the low phosphorus availability in the karst areas of China, the experiment investigated the effects of different tillage and residue retention practices on silage maize yield and quality and soil phosphorus in this region. The treatment set included: conventional tillage (CT), conventional tillage and root stubble retention (CTH), conventional tillage and mulch (CTM), conventional tillage and crushing and incorporation of hairy vetch by tillage (CTR), no tillage (NT), no tillage and root stubble retention (NTH), no tillage and mulch (NTM), and no tillage and living mulch (NTLM). The results showed that CTM, NTM, CTR, and NTLM significantly increased the height and LAI of silage maize compared with the CT, NT, and NTH treatments. CTM, CTR, and NTM significantly enhanced maize yield. Compared with conventional tillage, not tilling had a more pronounced improvement in silage quality, whereas residue retention hardly affected corn quality. In addition, although not tilling does not significantly increase acid phosphatase activity, it appeared to be advantageous in increasing soil microbial phosphorus and available phosphorus content when combined with cover crop measures. Ultimately, we concluded that NTM and NTLM are beneficial for silage maize yield and quality and soil phosphorus content in karst areas and verified the advantages of combining no tillage and residue retention practices for silage maize production and soil phosphorus improvement in the karst areas of China. [ABSTRACT FROM AUTHOR]

Freeze and thaw cycles (FTCs) influence the process of nutrient transformation and migration in soils; however, it is still not clear how soil available phosphorus (AP) distribution changes after FTCs at the watershed scale. In this study, 750 soil samples were collected at 0–50 mm, 50–100 mm, and 100–200 mm soil depths before and after FTCs in a Mollisol watershed in Northeast China. Factorial analysis, structural equation modeling, geostatistical analysis and random forest model were used to detect the changes in the AP and the main driving mechanisms after FTCs. The results showed that, after FTCs in the watershed, (1) the AP in 51.2–55.2% of areas decreased in the 0–200 mm soil depth, and the mean value decreased by 2.3–8.5%, while the spatial autocorrelation (Moran's I) of AP typically increased at all soil depths. (2) The AP decrease was higher in forestland than in farmland at all soil depths and was higher on the south-facing slope than on the north-facing slope. (3) Slope steepness, as the key factor interacting with slope position, slope aspect, land use type, crop type, and tillage method, influenced the AP change. (4) AP, pH and the ratios among carbon, nitrogen and phosphorus were the key factors influencing the AP change in the watershed after FTCs, and this process was also influenced by the original distribution of soil erosion and deposition. Generally, the AP change in the 0–200 mm soil layer was severely influenced by landscape pattern and soil properties, which was deeply driven by snowmelt erosion in the watershed. [ABSTRACT FROM AUTHOR]

Context: Despite being a crucial factor in plant growth and fitness, the nutritional requirements of non-native invasive plants are poorly understood and rarely considered when assessing invasion risk; yet, they are particularly relevant in many parts of the world with nutrient-poor soils. Aims: We investigated the growth response of a native South American tree species (Tipuana tipu), to soil concentrations of phosphorus (P). T. tipu is widely introduced in some regions of western Australia and South Africa, and we aimed to determine whether soil P availability constrains establishment, naturalisation or invasion of the species. Methods: We grew T. tipu (Benth.) Kuntze (Fabaceae), a species that is invasive in some regions, from seed in a glasshouse. All treatments were supplied baseline nutrients, and P from 0 to 640 μg P g−1 dry substrate. Plant height and the number of mature leaves were recorded regularly. Plant biomass, P, and nitrogen (N) concentrations were analysed following destructive harvest. Key results: Phosphorus availability had a significant effect on all measured aspects of plant growth. Seed P resources were sufficient to support growth for about 7 weeks, with plants at very low soil P availability (≤5 μg P g−1 dry soil) unable to sustain growth beyond that time. P-toxicity symptoms were observed when substrate P exceeded optimum concentrations (40–160 μg P g−1 dry soil). Conclusions: Growth of young T. tipu seedlings was very slow at very low soil P concentrations. Under these conditions, seeds may germinate, and seedlings may survive for a short time, but self-sustaining populations are unlikely to be established. Our study adds to a growing body of research that shows that nutrient requirements of introduced plants and soil nutrient availability influence invasion risk and should be considered in risk assessments for managing species invasions at the landscape level. Non-native invasive plants have a range of impacts on native species, communities and ecosystems, and there is evidence that soil nutrient availability affects the likelihood of plant species invasions. A glasshouse study of seedlings of a non-native tree (Tipuana tipu) showed that soil phosphorus availability had a significant effect on plant growth, with plants grown in conditions similar to those in south-western Australia unable to survive and establish. This infers that soil nutrient availability may be a limiting factor for species invasions. [ABSTRACT FROM AUTHOR]

【Objective】 Phosphorus (P) leaching from soils is not only an environmental concern but also a financial loss to farmers. Understanding the mechanisms underlying mobility of P in different soils is essential to alleviating its loss to surface runoff and leaching to groundwater. 【Method】 We studied the physical and chemical properties of typical soils in Shanxi province, including chestnut-cinnamon soil, regosol soil, loessial soil and fluvo-aquic soil, which combine to cover 88.51% of the land surface across the province. For each soil, we measured its organic matter, particle size in the range of >0.002 mm, 0.002~0.05 mm and 0.05~2 mm, texture, active Fe (Al), Olsen-P and CaCl2-P. Soluble P at different concentrations was added to each soil, and it was allowed to reach equilibrium. The contents of Olsen-P and CaCl2-P were then determined using NaHCO3 and CaCl2, and the threshold that resulted in P starting to leach was calculated from the relationship between Olsen-P and CaCl2-P. 【Result】 The critical P content beyond which P leached is 73.50 mg/kg for cinnamon soil, 7.0 mg/kg for chestnut-cinnamon soil, 23.30 mg/kg for neutral regosols soil, 39.4 mg/kg for loessial soil and 61.36 mg/kg for fluvo-aquic soil. The critical Olsen-P content in all soils increased with the increase in organic matter content but not significantly (p>0.05). Logarithm of the critical Olsen-P content is significantly correlated to the logarithm of clay and active Fe content (p0.05). 【Conclusion】 Vulnerability of the main five soils to P leaching is ranked in the order of neutral regosol soil>loessial soil>fluvo-aquic soil>chestnut-cinnamon soil>cinnamon soil. Clay and active Fe contents are the edaphic factors affecting P leaching the most.

Background: Predicting soil phosphorus (P) needs and P fertilizer requirements are important for plant nutrition and reducing environmental risk. Thus, the precise estimation of available soil P (ASP) is required for the better management of environmental resources and improving agricultural productivity. Yearly, direct measurements of most nutrients at large scales are time‐consuming and expensive within the economic point of view. Aim: Therefore, to tackle such limitations indirect measurement of them in an accurate estimating manner is a possibility. Methods: Thus, during this study, an exponential regression model for predicting ASP was suggested, and it was estimated as a function of soil organic carbon (OC). OC and ASP were used to investigate and analyze the soil to determine empirical relationships between them. Determination of the mentioned nutrient within the laboratory is somewhat difficult and time‐consuming. Therefore, an exponential regression model for predicting ASP from soil OC was suggested, and it was estimated as a function of soil OC. The ASP predicted from the ASP‐OC model was compared to the ASP determined by laboratory test using the paired samples t‐test and the Bland–Altman approach using SPSS. Results: The ASP predicted by the ASP‐OC model was not significantly different from the ASP determined by laboratory test since (p > 0.05). Conclusions: The findings of the study indicated that the ASP‐OC model provides a simple, economic, and brief methodology to estimate ASP, and so to predict ASP‐supported soil OC using the exponential regression model (Y = aebX), the suggested model based on the findings for ASP is ASP = 9.786 e0.486 OC with R2 = 0.901 often suggested. [ABSTRACT FROM AUTHOR]

The spatial distribution of soil phosphorus (P) is important to both biogeochemical processes and the management of agricultural landscapes, where it is critical for both crop production and conservation planning. Recent advances in the availability of large environmental datasets together with big data analytical tools like machine learning have created opportunities for evaluating and predicting spatial patterns in complex environmental variables like soil P. Here, we apply a random forest machine learning model to publicly available soil P datasets together with nearly 300 geospatial attributes summarizing aspects of soil type, land cover, land use, topography, nutrient inputs, and climate to predict total soil P at a 100 m grid scale for the Upper Mississippi River Basin (UMRB), USA. The UMRB is one of the most intensively farmed regions in the world and is characterized by widespread water quality degradation arising from P-associated eutrophication. Although potentially complex interacting drivers determine total soil P, the predictive accuracy of our random forest model was relatively high (R2 = 0.58 and RMSE = 129.3 for an independent validation dataset). At the regional scale represented by our model, the variables with the greatest comparative importance for predicting soil P included a combination of soil sample depth, land use/land cover, underlying soil physical and geochemical properties, landscape features (such as slope, elevation and proximity to the stream network), nutrient inputs, and climate-related factors. An important product of this research is a fine-scale (100 m) raster data layer of predicted total soil P values for the UMRB for public use. This dataset can be used to improve conservation planning and modeling efforts to improve water quality in the region. [ABSTRACT FROM AUTHOR]

Mountainous river bars are natural shoals formed in rivers as a result of bank slumping, undercutting, and sediment deposition. We investigated total phosphorus (TP) and available phosphorus (P) spatial variation in soil, factors influencing soil P spatial variation, and the environmental buffering capacity of mountainous river bars. Soil samples were collected at the head, middle, and tail transects of nine bars. Soil TP and available P contents ranged as 357.5–1256.48 mg kg-1 and 5.02–45.79 mg kg-1, respectively. Soil TP content was at a low level in the study area, whereas soil available P content was at a high level in some bars. Soil TP exhibited an increasing trend from head to tail transects in bars, but a decreasing trend was observed from upper to lower reaches, influenced by location of bars in the river, location of soil in the bar and soil texture. Soil available P showed an increasing trend from head to tail transects in bars and a fluctuation variation trend from upper to lower reaches, influenced by land use and vegetation biomass. The environmental buffering capacity of the bar is the capacity of bar to intercept P migrate from soil to river. Bars in lower reach, with lower height above water surface and narrower width could lead to weaker environmental buffering capacity in mountainous rivers, so more attention should be paid to these bars in order to reduce P pollution effectively. [ABSTRACT FROM AUTHOR]

The size of particles determines the adsorption reaction. In this study, three different particle sizes of biochar (0.25-1 mm, 0.075-0.25 mm, <0.075 mm) were produced from rapeseed straw (SBC) and chicken manure (MBC). The biochar was mixed with high phosphorus (P) soil and low P soil and then incubated for 30 days. We conducted isothermal P sorption and desorption experiments to evaluate the effects of biochar particle size on sorption-desorption characteristics of soil P, and analyzed soil properties associated with P sorption. The results showed that P sorption capacity of SBC and MBC in the water system was highest for the smallest particle size (<0.075 mm) (SBC: 43125 mg ⋅ kg-1, MBC: 20083 mg ⋅ kg-1), followed by the intermediate particle size (0.075-0.25 mm) (SBC: 37376 mg ⋅ kg-1, MBC: 13199 mg ⋅ kg-1) and the largest particle size (0.25-1 mm) (SBC: 27749 mg ⋅ kg-1, MBC: 12251 mg ⋅ kg-1). However, there was little difference in soil P sorption between the three particle sizes of the same biochar in the soil system. In comparison with no biochar treatment, the addition of SBC increased the Langmuir P sorption maximum (Smax) by 236.8%-755.7%, and decreased soil P desorption rate. The addition of MBC increased Smax, but the enhancement was less than that of SBC. Soil P desorption rate was increased by 7.2%-295.9%. Both SBC and MBC significantly increased the contents of soil total P, available P, and exchangeable calcium (Ca) and magnesium (Mg). The increases in Ca and Mg contents due to biochar addition was 64.0%-257.1% (SBC) and 39.1%-205.3% (MBC), respectively. The contents of soil exchangeable Ca and Mg were positively correlated with Smax. These results suggested that biochar particle size had little effect on soil P sorption, but the enrichment of Ca and Mg due to biochar addition played a critical role in regulating soil P sorption. The rapeseed straw biochar had a high adsorption capacity for soil P, making it suitable for improving the P fixation capacity of soil rich in P and reducing the loss of excess P. Chicken manure biochar could be used to improve the P availability of low P soils and increase the contents of available P. [ABSTRACT FROM AUTHOR]

[Display omitted] • Antibiotics can affect the mineralization capacity of organic phosphorus (OP). • Ciprofloxacin, erythromycin and ampicillin negatively affect OP mineralization. • Sulfadiazine positively regulates OP mineralization capacity. • EPS and microbial phenotype are direct causes of differences in OP mineralization. • Microbial diversity and network complexity indirectly regulate OP mineralization. Understanding the impacts and mechanisms of different antibiotics on organic phosphorus (OP) mineralization is crucial for promoting the rational utilization of resources and protecting the ecological environment. In this study, the effects of four commonly used antibiotics (sulfadiazine, ciprofloxacin, erythromycin, and ampicillin) on the mineralization of OP were explored using16S rRNA gene sequencing technology. The results showed that ciprofloxacin, erythromycin, and ampicillin negatively affected the mineralization capacity of OP, whereas sulfadiazine positively influenced OP mineralization. The content and composition of extracellular polymeric substances (EPS) and microbial phenotypes (biofilm formation and stress tolerance) were directly correlated with differences in OP mineralization capacity. Microbial diversity, network complexity and stability, and key microorganisms indirectly influenced OP mineralization by regulating EPS content and composition and microbial phenotypes. In summary, this study reveals specific impacts of different antibiotics on OP mineralization, offering valuable insights for addressing "phosphorus limitation" and "phosphorus load" amid various antibiotic stresses. [ABSTRACT FROM AUTHOR]

【Background】 Nutrient cycling and kinetic in soil is mediated by biogeochemical processes which in turn is modulated by soil water and temperature. The aim of this paper is to investigate the hydrothermal effects on bioavailability of phosphorus (P) in different soils. 【Method】 We studied soils with different cultivations using culture experiments: paddy field, upland, vegetable and forest in the same region. There were three moisture treatments for each soil by keeping the soil water content at 40% (W40), 70% (W70) and 100% (W100) of the saturated water content, respectively. For each soil water, there were further three temperature treatments by keeping the soil temperature at 15 ℃ (T15), 25 ℃(T25) and 35 ℃(T35), respectively. All soils were incubated for 15 days, after which we measured the contents of P in different forms. 【Result】 When temperature and soil moisture were the same, the contents of bioavailable P and Olsen-P in different soils were ranked in the order of forest > vegetable > upland > paddy field. When the temperature was the same, soil water content up-regulated HCl-P, Citrate-P, Enzyme-P and Olsen-P, regardless of the soils. When soil moisture content was the same, the temperature positively impacted HCl-P and Olsen-P, negatively affected Citrate-P (p moisture > temperature -moisture coupling. 【Conclusion】 Increasing soil moisture increased HCl-P, Citrate-P, Enzyme-P and Olsen-P in all soils. Increasing soil temperature increased HCl-P and Olsen-P, while reducing Citrate-P. Among all P forms we measure, only CaCl2-P and Enzyme-P were jointly affected by soil water and temperature. In a certain range, the effects of temperature and moisture on bioavailability of different P forms are integrative in all four soils we studied.

Simultaneous measurement of plant functional traits and the regeneration environment should shed light on the plant-environment interactions and feedbacks as secondary forest regenerates. However, little of such work has been done in the wet tropics, and even fewer studies have examined soil nutrients. We investigated whether plant functional traits and environmental variables explain the varied recovery of secondary forests in Singapore. Our study plots included three primary forest plots and eight approximately 60-year-old secondary forest plots regenerating from intensive agricultural activities. Using 35 seedling quadrats, we asked: Q1) How do environmental variables explain the variation in seedling functional traits observed in primary and secondary forests? Q2) How do seedling traits, adult traits and environmental variables relate and explain variation in species richness and stem density in secondary forests? We found that both light and soil fertility explained the shifts in plants functional traits from poorly recovering secondary forests to primary forests. Poor forest regrowth was correlated with high soil aluminum levels and lower leaf nitrogen concentrations. Low nutrients and high aluminum saturation were also negatively correlated with seedling species richness, but not stem density, in the secondary forests. Forest recovery is probably slowed by positive feedback between slower nutrient returns from slow decaying litter and further recruitment of nutrient conserving species, as indicated by positive correlations among adult leaf CN ratio, litter depth, soil CN ratio and quadrat level CN ratio. Plant functional traits are indicative of the strategies of successful seedlings and do not necessarily relate to overall forest recovery. Hence, while some specialist plant species are able to accrue high nutrients on degraded soils with aluminum toxicity and low nutrients, species richness on these soils was poor. This underscores the need to concurrently measure environmental variables and plant traits when investigating the mechanisms driving changes during forest recovery.

"Least‐cost theory" posits that C3 plants should balance rates of photosynthetic water loss and carboxylation in relation to the relative acquisition and maintenance costs of resources required for these activities. Here we investigated the dependency of photosynthetic traits on climate and soil properties using a new Australia‐wide trait dataset spanning 528 species from 67 sites. We tested the hypotheses that plants on relatively cold or dry sites, or on relatively more fertile sites, would typically operate at greater CO2 drawdown (lower ratio of leaf internal to ambient CO2, Ci:Ca) during light‐saturated photosynthesis, and at higher leaf N per area (Narea) and higher carboxylation capacity (Vcmax 25) for a given rate of stomatal conductance to water vapour, gsw. These results would be indicative of plants having relatively higher water costs than nutrient costs. In general, our hypotheses were supported. Soil total phosphorus (P) concentration and (more weakly) soil pH exerted positive effects on the Narea–gsw and Vcmax 25–gsw slopes, and negative effects on Ci:Ca. The P effect strengthened when the effect of climate was removed via partial regression. We observed similar trends with increasing soil cation exchange capacity and clay content, which affect soil nutrient availability, and found that soil properties explained similar amounts of variation in the focal traits as climate did. Although climate typically explained more trait variation than soil did, together they explained up to 52% of variation in the slope relationships and soil properties explained up to 30% of the variation in individual traits. Soils influenced photosynthetic traits as well as their coordination. In particular, the influence of soil P likely reflects the Australia's geologically ancient low‐relief landscapes with highly leached soils. Least‐cost theory provides a valuable framework for understanding trade‐offs between resource costs and use in plants, including limiting soil nutrients. [ABSTRACT FROM AUTHOR]

A soil's responses to phosphorus (P) input differs based on its chemical composition. Soil acidity and the presence of metallic cations dictate a soil's chemical composition. Currently, soil P application recommendations are universal and do not account for differing soil composition. A targeted soil‐specific approach is required to optimize P efficiency and availability. A pot incubation experiment was established to explore the effects of contrasting lime and P application rates across a range of soils (25), characterized by fine particle size and high levels of soil organic matter. Three contrasting rates of P were applied (0, 50, and 150 kg P ha−1) both with and without ground lime (CaCO3) at 5 tonne ha−1 over a 140‐day incubation period. The addition of lime buffered the soil, increasing nutrient availability and reducing P fixation. The 50 kg P ha−1 treatment rate was required to achieve sufficient plant available P in both mineral soil textural classes. Current legislative recommendations however do not allow the application of such rates, which has an impact on agronomic performance. Loam soils experienced a greater increase in M3 soil P in comparison to clay and organic soils. Organic soils posed a major threat to water quality due to poor P retention. A re‐evaluation of P recommendations is required to account for soil variability as current P allowances are insufficient on these particular soils. [ABSTRACT FROM AUTHOR]

The rapid invasion of Spartina alterniflora threatens the ability of soils to store carbon (C), nitrogen (N) and phosphorus (P) in coastal wetlands. This study analyzed the temporal and spatial distribution characteristics of soil C, N and P in Spartina alterniflora wetland in the Dafeng Elk Nature Reserve of Yancheng, China, in different invasion stages from 1995 to 2020. The results suggest that: (1) the invasion of Spartina alterniflora increased the content and storage of soil C and N, and decreased the content and storage of soil P; (2) altered soil properties caused by Spartina alterniflora invasion also indirectly affected the accumulation of soil C, N and P in wetland ecosystem. Organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) were positively correlated with soil moisture content (SMC) and electrical conductivity (SEC), and negatively correlated with bulk density (SBD) and pH; (3) Spartina alterniflora invasion increased soil C/P and N/P, and decreased soil C/N. In conclusion, Spartina alterniflora invasion has changed the ecosystem, increased the storage capacity of soil C and N in the invasive ecosystem, but reduced the storage capacity of soil P to a certain extent. [ABSTRACT FROM AUTHOR]

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Losses of phosphorus from soil to surface waters in agricultural areas have been linked to substantial declines in water quality. Riparian wetlands can potentially intercept phosphorus mobilized from upland soils before it reaches connecting waterways, but the capacity of wetlands to buffer against downstream losses of P is poorly understood, especially in northern temperate zones. In these regions, the spring freshet releases large volumes of water from snowmelt and soil pore water during the time when microbial productivity, which transfers available P into biomass, is low. In addition, losses of P in runoff may be exacerbated by freeze-thaw cycling (FTC) in soil during late winter and early spring through the physical degradation of organic matter. We investigated P dynamics from late fall through spring thaw and into summer to assess P transfers between inorganic, organic and microbial biomass pools, as functions of season and distance from a river. The site is located on the Grand River in southern Ontario, which discharges to Lake Erie, and consists of riparian wetland and wooded areas. Reactive P (Olsen P) and microbial biomass P (PMBIO) increased with distance from the river and varied more over time in the wetland soil compared to the adjacent wooded area, reflecting higher variability in vegetation, topography and hydrology. The positive correlation between microbial biomass P and microbes linked to ammonification supports the release of N and P through mineralization pathways as spring progresses, with microbial biomass decreasing in June as plant growth increases. There was evidence for leaching of Fe and Al, and lower concentrations of total P, in the transect proximate to the river. Seasonal flooding during spring thaw contributed to a pulse of dissolved reactive P, but temperature monitoring showed that the wetland soil did not experience freeze-thaw cycling. Investigation of FTC using wetland soil in mesocosms indicated that multiple FTC (>3) were necessary to increase the pool of reactive soil P, with the highest amount of soil reactive P observed after six FTC, when dissolved reactive P also tended to increase.

Copyright of Journal of Henan Agricultural Sciences is the property of Editorial Board of Journal of Henan Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Questions: Traditional pastoralists attribute high numbers of plateau pikas (Ochotona curzoniae) to impoverished soils that favor more and better forage for pika, suggesting a bottom-up control of pika density. Conversely, government policies focus on excessive numbers of this small mammalian herbivore as the primary top-down cause of degradation in Tibetan rangeland. Despite concerted campaigns to reduce pika abundance in recent decades, the sustainability of Tibetan rangelands remains uncertain. Location: Alpine meadows on the Tibetan Plateau. Methods: We proposed a conceptual model based on indigenous knowledge that predicted pika numbers from soil condition and plant traits. At three alpine meadow sites lightly grazed by livestock, we tested whether spatial variation in pika burrow density could be explained by changes in the functional composition of the plant community attributable to species turnover and intraspecific trait variation associated with changes in soil fertility. Results: Due primarily to intraspecific trait variation, changes in the functional composition of the meadow community accounted for 56%-68% of the spatial variation in pika density, changes in the proportion of plant functional groups for 62%-74%, and changes in edaphic conditions for 71%-82%. Greater pika density was associated with a decline in soil phosphorus availability and a lower-growing vegetation profile enriched in both the quantity and quality of forage preferred by pikas. Conclusions: These results, which are in accord with indigenous knowledge, suggest that compensating soil phosphorus losses and maintaining a well-calibrated grazing rotation can better manage pika populations and improve the sustainability of Tibetan rangelands. By combining trait-based ecology and traditional knowledge, our study provides new insight into both understanding the dynamic complexity of grazing regimes and managing rangeland sustainability. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Ciências Agrárias is the property of Sociedade de Ciencias Agrarias de Portugal and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Aims: To identify soil phosphorus (P) mobilization and wheat agronomic performance in response to the P mobilizer Ceriporia lacerata HG2011 could provide a new strategy for improving fertilizer P efficiency in wheat cultivation. Methods and Results: Liquid culture showed that C. lacerata HG2011 converted Ca3(PO4)2, FePO4, AlPO4, phytate, lecithin and ribonucleic acid into soluble inorganic P, which was stimulated by ammonium and urea but less influenced by P supply. In the incubation experiment, this fungus colonized on wheat roots, and mobilized P in the soils regardless of Olsen P levels. The efflux of protons, organic acids and phosphatase could be involved in insoluble P mobilization. In the greenhouse pot experiment, C. lacerata HG2011 increased soil Olsen P under different P fertilization levels, improved wheat P uptake by 15.39%–28.70%, P fertilizer use efficiency by 4.26%–13.04% and grain yield by 12.24%–22.39%. Conclusions: Ceriporia lacerata HG2011 was able to colonize on wheat roots, mobilize P in soils and improve wheat agronomic performance irrespective of P fertilization levels. Significance and Impact of the Study: Ceriporia lacerata HG2011 could be used to enhance the quality of compost or as a bio‐fertilizer for P mobilization in modern sustainable agriculture. [ABSTRACT FROM AUTHOR]

Paddy fields have alternating wet and dry hydrological cycles at different growth stages of rice, driving changes in soil environment and phosphorus (P) transformation and transport. In-situ measurements of dissolved oxygen (DO), iron (Fe), and P concentrations were conducted to determine the vertical distribution of these concentrations together with the hydrological and meteorological data during the whole growth stage. The results demonstrate that soil vertical DO concentrations at different growth stages were greatly influenced by the water level and temperature of the paddy field at the soil-water interface. A strong negative correlation between soil DO and DGT-labile Fe has been observed, whereas a strong positive correlation has been observed between soil Fe concentration and vertical P. In the paddy field, soil DO concentrations were lower during tillering, booting, and heading to flowering than during the other stages. Thus, soluble P fluxes from soil water interfaces (SWIs) to overlying waters were most significant during these three stages. Furthermore, soils in these three stages are capable of sustained release of P and are highly able to buffer P. Consequently, water management in paddy fields should take into account the hydrological environment during these three stages in order to minimize soil P release. The results of our study provide a valuable reference point for controlling soil P and Fe during rice growth.

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)