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Phosphorus accumulation in agricultural soils is a growing concern worldwide, but terminology on this issue is confusing. The accumulated phosphorus is often described as residual phosphorus. However, agronomists use this term for the fertilizer not taken up by the crop, and soil scientists use it to describe the phosphorus remaining in soil after sequential extraction, a procedure used to characterize the chemical nature of soil phosphorus. These different uses of residual phosphorus are mutually incompatible because phosphorus accumulated in the soil is often readily soluble, while phosphorus remaining after sequential extraction is extremely stable. To resolve this, we endorse the term legacy phosphorus to describe the phosphorus accumulated in soil through human activity, based on the definition of legacy as something received from the past or carried over from past actions. This allows the term residual phosphorus to be reserved for the unextractable phosphorus in sequential extraction schemes (i.e., in the residue, leftover or remaining). Finally, we recommend the term surplus phosphorus for the fertilizer not taken up by the crop, based on the definition of surplus as an excess of supply over demand. This clarification of terminology will reduce confusion as research progresses on this interdisciplinary topic. [ABSTRACT FROM AUTHOR]

Ectomycorrhizal (ECM) fungi are functionally important in biogeochemical cycles in tropical ecosystems. Extracellular enzymatic activity of ECM on a ground-area basis is the product of two attributes; exploration capacity (ECM surface-area) and specific enzymatic activity. Here, we elucidated which attribute better explained the ECM enzymatic activity in response to different levels of soil phosphorus (P) and Nitrogen (N) availability in five Bornean tropical rainforests. We determined the surface area of ECM root tips as well as the enzymatic activities per ECM surface area for carbon (C), N and P degrading enzymes in each site. We evaluated the relationship of ECM enzyme activities with the resource availabilities of C (Above-ground net primary production; ANPP), N, and P of ECM by a generalized linear mixed model. The ECM enzymatic activities on a ground-area basis were more significantly determined by specific enzymatic activity than by the exploration capacity. Specific enzymatic activities were generally negatively affected by C (ANPP) and soil P availability. ECM fungi enhance the specific enzyme activity rather than the exploration capacity to maintain the capacity of nutrient acquisition. The less dependence of ECM fungi on the exploration capacity in these forests may be related to the limitation of C supply from host trees. We highlighted the adaptive mechanisms of ECM fungi on nutrient acquisition in tropical ecosystems through the response of enzymatic activity to nutrient availability across the elements. [ABSTRACT FROM AUTHOR]

The desert ecosystem of the Qinghai–Tibet Plateau (QTP) is an important component of China's desert ecosystem. Studying the mechanisms shaping the taxonomic, phylogenetic, and functional beta diversity of plant communities in the QTP desert will help us to promote scientific conservation and management of the region's biodiversity. This study investigated the effects of environmental (including altitude, climate factors, and soil factors) and geographic distances on three facets of beta diversity as well as their turnover and nestedness components based on field survey data. The results showed that turnover components dominate the three facets of beta diversity. However, the turnover contributions to phylogenetic and functional beta diversity were lower than for taxonomic beta diversity. Environmental distance had a greater influence than geographic distance, with the former uniquely explaining 15.2%–22.8% of beta diversity and the latter explaining only 1.7%–2.4%. Additionally, the explanatory power of different factors for beta diversity differed between herbs and shrubs, with environmental distance being more important for the latter. Distance‐based redundancy analysis suggested that soil total potassium content had a substantial impact on the beta diversity of three dimensions, with mean temperature of the coldest month and soil total phosphorus content having a substantial impact on taxonomic and functional beta diversity as well. Our results support that environmental sorting plays a predominant role in shaping plant community composition across QTP desert ecosystems. To maintain the plant diversity of this region, it is crucial to prioritize the conservation of its diverse environmental conditions and actively mitigate its degradation by anthropogenic pressures. [ABSTRACT FROM AUTHOR]

Background: Over the years, the excessive P fertilizer application to crop fields resulted in the build up of insoluble phosphorus pool in soil known as legacy phosphorus. This represents a vast and largely untapped resource in soil. The current study was conducted to evaluate the potential of some P activators (Phosphorus solubilising bacteria, phytase, humic acid, farmyard manure) on increasing the plant availability of legacy P in calcareous soil. Methods: A field experiment was conducted with maize hybrid COH(M) 6. The P activators were combined and applied along with the different doses of P fertilizer (100%, 75% and 50% soil test dose of single super phosphate). Result: Farmyard Manure (FYM) application with Humic acid (HA) showed the increased Olsen P under 100% and 75% of P application. The phosphorus activation response of FYM+HA applied plots showed a higher value than other treatments. The maize yield and P uptake obtained with FYM and HA were statistically comparable at 100% and 75% soil test dose of P. The findings have illustrated that even the reduced amount of P fertilizer application can support the crop growth due to the release of legacy P if they are applied along with P-activators such as FYM and HA. [ABSTRACT FROM AUTHOR]

Although the application of biological materials has shown potential in improving the environment of salinized soil, the impact on the transformation of soil phosphorus forms in salinized soil, especially when combined with B. mucilaginosus (BM), has rarely been studied. Therefore, this study investigated soil's properties and phosphorus forms, as well as their relationship, in salinized soil after the application of different biological materials, including rice straw (RS), biochar (B), acidified biochar (AB), BM, RS+BM, B+BM, and AB+BM. A sequential extraction procedure was employed to determine the soil organic/inorganic phosphorus forms (Po/Pi). In our study, the contents of the soil's resin-P, NaHCO3-Pi, NaOH-Pi, and HCl-P increased by 50–341.66%, 4.08–184.63%, 37.45–163.45%, and 10.19–38.29%, respectively, with the application of the biological materials compared to with conventional fertilization (CK1). However, the contents of the soil's NaHCO3-Po, NaOH-Po, and residual-P significantly decreased in comparison to with CK1, particularly in the soils that received a combined application with biological materials and BM. Furthermore, the results from the statistical analysis revealed that the application of biological materials could increase the level of soil stable phosphorus, facilitate the transformation from soil stable phosphorus and soil unstable Po to soil unstable Pi, and enhance the effectiveness of soil phosphorus, especially when combined with BM, particularly in soil with AB+BM. [ABSTRACT FROM AUTHOR]

The symbiosis between endophytic fungi and plants can promote the absorption of potassium, nitrogen, phosphorus, and other nutrients by plants. Phosphorus is one of the indispensable nutrient elements for plant growth and development. However, the content of available phosphorus in soil is very low, which limits the growth of plants. Phosphorus-soluble microorganisms can improve the utilization rate of insoluble phosphorus. In this study, Talaromyces verruculosus (T. verruculosus), a potential phosphorus-soluble fungus, was isolated from Acer truncatum, a plant with strong stress resistance, and its phosphorus-soluble ability in relation to cucumber seedlings under different treatment conditions was determined. In addition, the morphological, physiological, and biochemical indexes of the cucumber seedlings were assessed. The results show that T. verruculosus could solubilize tricalcium phosphate (TCP) and lecithin, and the solubilization effect of lecithin was higher than that of TCP. After the application of T. verruclosus, the leaf photosynthetic index increased significantly. The photosynthetic system damage caused by low phosphorus stress was alleviated, and the root morphological indexes of cucumber seedlings were increased. The plant height, stem diameter, and leaf area of cucumber seedlings treated with T. verruculosus were also significantly higher than those without treatment. Therefore, it was shown that T. verruculosus is a beneficial endophytic fungus that can promote plant growth and improve plant stress resistance. This study will provide a useful reference for further research on endophytic fungi to promote growth and improve plant stress resistance. [ABSTRACT FROM AUTHOR]

Purposes: Developing the cultivation and utilization of tiger nuts on marginal land is an effective approach to tackle the shortage of arable land in northern China. However, key information on their growth is unclear. This study aims to reveal the adaption potential of tiger nuts to on marginal land to help improve and adjust management practices. Methods: Three treatments were arranged to plant tiger nut in marginal land: no fertilization (N:P = 0:0), traditional fertilization (N:P = 15:15), and additional nitrogen fertilizer (N:P = 60:15). Functional traits of tiger nut and soil nutrients over three growth periods were investigated. Results: Under no fertilization, tiger nuts extended roots and toughened leaves to maximize nutrient absorption, and then quickly transported those nutrients to tubers. However, the lack of available phosphorus in the soil prevented the expansion of tubers. With the addition of fertilizers, tiger nuts produced more individuals, and their abundant belowground tissues resulted in soil organic matter increase. Under traditional fertilization, the tuber remains the main reproductive organ for tiger nuts, and phosphorus has a significant effect on the expansion of tubers. But under additional nitrogen fertilizer, the main reproductive organ changed to the stolon, nitrogen and phosphorus acted on stolons to promote their extension. Conclusion: Tiger nuts outstandingly adapt to marginal land environments and adjust their adaptation strategies according to varying soil nutrient conditions, Best tuber production will be achieved in soils with higher phosphorus availability, and a significant nitrogen proportion increase in fertilizers is necessary for enhancing aboveground production. [ABSTRACT FROM AUTHOR]

Soil organic carbon (SOC) not only contributes to maintain soil health, but is also important in regulating global climate change. How atmospheric nitrogen (N) deposition and phosphorus (P) addition affects SOC dynamics remains unclear, especially in subtropical forests. The response of SOC in three layers to N deposition and P addition in this study is estimated by analyzing the soil aggregates and C chemical stability composition fertilized with N (100 kg N hm−2 a−1) and/or P (50 kg P hm−2 a−1) over 9 years in a Chinese fir (Cunninghamia lanceolata) plantation. Treatments involving N deposition increased the SOC concentration, while P addition alone decreased the SOC concentration in soil layers above 10 cm. The addition of N significantly increased the mean diameter of topsoil aggregates, macroaggregates SOC concentration, and the contribution of N to total SOC. P addition decreased the relative abundances of aromatic and aliphatic functional groups while decreasing the chemical stability of SOC in the topsoil. A structural equation model indicated that N deposition promoted SOC concentration by mainly improving the physical protection of soil aggregates, while P addition reduced SOC sequestration by decreasing the chemical stability of SOC. Our research suggested that elevated N deposition might promote the soil C sink, while P fertilization would not be recommended under increased N deposition to protect soil C storage in subtropical forests. [ABSTRACT FROM AUTHOR]

As an important part of terrestrial ecosystems, the forest soil nutrient content is easily affected by thinning. However, the effects of thinning on soil phosphorus (P) stocks and dynamics have not yet been systematically analyzed. In this study, we aimed to investigate the effects of thinning on the soil P stock and rate of soil P stock change in the 0–30, 30–60, and 0–60 cm soil layers by integrating 237 data points on a global scale. In addition, we aimed to determine whether these factors are regulated by forest type, recovery time, and thinning intensity. The results indicated that thinning increased the soil P stock in the 0–30, 30–60, and 0–60 cm soil layers by 9.0, 13.2, and 10.2%, respectively, and the soil P stock change rates were 0.017, 0.013, and 0.025 Mg ha−1 yr−1, respectively. Furthermore, the promoting effect of thinning on soil P stocks was greater in coniferous forests than in broadleaf and mixed forests. In addition, the stocks and change rates of soil P increased with recovery time and decreased with thinning intensity and mean annual precipitation. This study highlights the effects of thinning on forest soil P accumulation on a global scale. The results are of great significance for understanding soil nutrient cycling and sustainable forest management. [ABSTRACT FROM AUTHOR]

Soil phosphorus (P) partitioning could contribute to species diversity and structure in plant communities, but field-scale evidence for P partitioning remains scarce. We hypothesized that the presence of P partitioning could be inferred from statistical associations between the spatial distributions of plants and chemical forms of bioavailable soil P. We investigated this in a diverse tropical tree community on Barro Colorado Island, Panama. We quantified potentially bioavailable forms of soil P by extraction in 2 mM citric acid followed by treatment with phosphatase enzymes. We then linked these P forms to the distribution of 189 tree species in a 50 ha forest dynamics plot by testing species–P associations against null models of random dispersal. We found that 20% of tree species were significantly (α = 0.05) associated with the depletion of at least one soil organic P fraction, although around half of these associations might be false rejections of the null hypothesis due to type I error. Species in the Fabaceae (legumes), which are known to express high rates of phosphatase in their roots, were most frequently associated with soil P fractions. We interpret our findings as evidence of widespread P partitioning at the community scale, affecting a relatively small proportion of tree species in this moderately fertile forest. We predict that stronger evidence of partitioning will be found at sites with lower P availability. [ABSTRACT FROM AUTHOR]

Moso bamboo (Phyllostachys edulis (Carrière) J.Houz.) is a fast-growing species that commonly invades neighboring broadleaf forests and has been widely reported in subtropical forest ecosystems. However, little is known about the effect on soil phosphorus (P) bioavailability and its potential influence factor during the P. edulis expansion. Here, the four soil P bioavailable fractions (i.e., CaCl2-P, Citrate-P, Enzyme-P, and HCl-P), acid phosphatase activity, iron and aluminum oxides (Fed and Ald), and soil total P pool at depths of 0–10 cm, 10–20 cm, and 20–40 cm were measured in three expanding interfaces (a broadleaf forest, a mixed bamboo–broadleaf forest, and a pure P. edulis forest) in subtropical forests of southern China. Regardless of soil depths, the CaCl2-P content was significantly lower in the mixed bamboo–broadleaf forest than the other two forest types, with contents ranging from 0.09 to 0.16 mg/kg, whereas the HCl-P content was significantly lower in the broadleaf forest, with contents ranging from 3.42 to 14.33 mg/kg, and the Enzyme-P content and acid phosphatase activity were notably lower in P. edulis forest with contents of 0.17–0.52 mg/kg and 68.66–74.80 μmol MUF released g−1 min−1, respectively. Moreover, the soil total P pool was enhanced in the mixed bamboo–broadleaf forest in 0–10 cm depth compared to broadleaf and P. edulis forests, with increases of 27.40% and 31.02%, respectively. The redundancy analysis showed that soil pH plays an important role in regulating soil P bioavailability during the P. edulis expansion (p < 0.01). From the above results, the invasion of P. edulis into broadleaf forests has resulted in soil P bioavailability and storage capacity. The results of this study suggest that when P. edulis invades broadleaf forests, it could affect the soil P bioavailability by elevating soil pH, which in turn drives and facilitates the completion of the expansion. This is important for understanding P cycling during the P. edulis forest expansion in subtropical regions. [ABSTRACT FROM AUTHOR]

Introduction: Straw return has been widely recognized as an important carbon (C) enhancement measure in agroecosystems, but the C-phosphorus (P) interactions and their effects on plants in saline soils are still unclear. Methods: In this study, we investigated the effects of straw return and three P application levels, no P fertilizer (Non-P), a conventional application rate of P fertilizer (CP), and a high application rate of P fertilizer (HP), on maize growth and soil C and P fractions through a pot experiment. Results and discussion: The results revealed that the dry matter weight of maize plant was no difference between the two straw return levels and was 15.36% higher under HP treatments than under Non-P treatments. Plant nutrient accumulations were enhanced by straw addition and increased with increasing P application rate. Straw application reduced the activities of peroxidase (POD), superoxide dismutase (SOD), catalase, and the content of malondialdehyde (MDA) in maize plants by 31.69%, 38.99%, 45.96% and 27.04%, respectively. P application decreased SOD, POD activities and MDA content in the absence of straw. The contents of easily oxidized organic carbon (EOC), particulate organic carbon (POC) and the ratio of POC/SOC in straw-added soils were 10.23%, 17.00% and 7.27% higher, respectively, than those in straw-absent soils. Compared with Non-P treatments, HP treatments led to an increase of 12.05%, 23.04% in EOC, POC contents respectively, while a decrease of 18.12% in the contribution of MAOC to the SOC pool. Straw return improved the P status of the saline soil by increasing soil available P (14.80%), organic P (35.91%) and Ca2-P contents (4.68%). The structural equation model showed that straw and P applications could promote maize growth (indicated by dry matter weight, P accumulation, antioxidant enzyme activity and MDA content) through improving soil C and P availabilities. Conclusion: This study provides evidence that straw return together with adequate P supply in saline soil can promote crop nutrient accumulation, attenuate the oxidation damage on crop growth, and be beneficial for SOC turnover and soil P activation. [ABSTRACT FROM AUTHOR]

Purpose: Phosphorus, an essential limiting nutrient for plant growth, has been a significant challenge due to its low utilization efficiency in recent years. The application of organic acids has become one of the most effective means to activate insoluble soil phosphorus. This study aims to elucidate the global mechanism of soil phosphorus activation by organic acids and provide guidance for maximizing its effectiveness. Methods: A meta-analysis of 7870 samples from 37 studies worldwide was done. The structural equation model was used to test two hypotheses based on meta-analysis results. Results: Our study demonstrates that organic acids enhance soil phosphorus availability, primarily by promoting the transformation of phosphorus into plant-available forms. This transformation process is collectively influenced by organic acid types, soil properties, and treatment conditions (ranging from −14.58 to 185.77%). Acetic acid exhibits the strongest effect, increasing available phosphorus by 185.77%. Furthermore, soil and treatment conditions are found to have significant impacts on the transformation of available phosphorus by organic acids through the structural equation model, and excess organic acids are detrimental to this process. Conclusion: This study unequivocally demonstrates that organic acids significantly enhance soil phosphorus availability. The application of organic acids, particularly acetic acid, promotes the conversion of phosphorus into plant-available forms. Low concentrations of organic acids in neutral loam maximize this effect. This research contributes to the advancement in identifying more effective ways of utilizing organic acids as phosphorus activators and improving nutrient management strategies, ultimately paving the way for sustainable agricultural practices. Graphical bstract: [ABSTRACT FROM AUTHOR]

The ecology of plant species relies on the synchronous functioning of leaves and roots, but few studies have simultaneously examined the community trait dispersion (CTD) patterns of both organs. We measured 16 analogous leaf and root traits on 44 co-occurring woody species in a subtropical forest in southern China, aiming to examine whether leaf and root traits were coordinated, organized into parallel trait axes, exhibited similar CTD, and displayed consistent responses in CTD and community-weighted means of (CWM) traits over environmental gradients. While the first axes of leaf and root trait variation similarly exhibited a fast–slow continuum, leaf traits covered a secondary "carbon economics" axis, contrasting to root traits depicting a collaboration axis reflecting species' mycorrhizal dependency. Analogous leaf and root chemical traits were generally coordinated but less so for morphological traits. At the community level, changes in the CWM of the first axes were generally consistent among organs with more conservative traits found as increasing elevation but not for the second axis. While root traits became thinner and more conservative as soil phosphorus concentration decreased, leaf traits rarely varied. When different trait axes were combined, leaf traits were overdispersed but tended to converge with increased elevation and soil potassium and phosphorus levels, whereas root traits were clustered but tended to diverge along the same gradients. Our study highlights fine filtering of different suites of traits above- and belowground, which in turn might reduce overall niche overlap among species and promote coexistence with diverse functional designs. [ABSTRACT FROM AUTHOR]

Converting natural forests to agricultural lands has been widespread globally due to increasing population and the demand for food. Phosphorus (P) is often applied to agricultural lands in excessive amounts which can saturate the natural P sorption capacity of the soil, leading to P leaching and subsequent off‐site water eutrophication. We studied the effect of land‐use conversion from natural forests to tea plantations on total soil P, P fractions, and P sorption capacity in subtropical China. Compared to natural forests, total soil P concentrations increased significantly in both 0–20 and 20–40 cm depths in tea plantations, indicative of the accumulation of P fertilizer. The increases in total soil P were primarily found in NaOH‐extractable inorganic P and residual P fractions in both depths, suggesting that P fertilizer was sorbed and occluded into more stable forms due to the high abundance of sorbents (i.e., iron [Fe], aluminum [Al] minerals, and clay). Across all soil samples, oxalate‐extractable Fe was the best predictor of soil maximum P sorption capacity (r = 0.94, p < 0.001). Surprisingly, the conversion from natural forests to tea plantations decreased both oxalate‐extractable Fe concentration and soil maximum P sorption capacity, hereby increasing the degree of P saturation in soils. Depletion of P sorbents (i.e., soil amorphous Fe) is likely a consequence of Fe removal through tea production and soil erosion, indicating soil degradation. Plantation soils have also shown other signs of degradation including the loss of nutrients (e.g., total soil nitrogen and oxalate‐extractable calcium) and soil organic matter. Our results demonstrate that the conversion of natural forests to tea plantations reduced the ability of the soil to sorb P by both saturating the natural P sorption capacity and depleting P sorbents. Soil degradation resulting from land‐use conversion has increased the environmental risk of P leaching loss, emphasizing the need for improved P fertilization management. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal fungi (AMF) are ancient and ecologically important symbionts that colonize plant roots. These symbionts assist in the uptake of water and nutrients, particularly phosphorus, from the soil. This important role has led to the development of AMF inoculants for use as biofertilizers in agriculture. Commercial mycorrhizal inoculants are increasingly popular to produce onion and carrot, but their specific effects on native mycorrhizal communities under field conditions are not known. Furthermore, adequate availability of nutrients in soils, specifically phosphorus, can reduce the diversity and abundance of AMF communities in the roots. The type of crop grown can also influence the composition of AMF communities colonizing the plant roots. This study aimed to investigate how AMF inoculants, soil phosphorus levels, and plant species influence the diversity of AMF communities that colonize the roots of onion and carrot plants. Field trials were conducted on high organic matter (muck) soil in the Holland Marsh, Ontario, Canada. The treatments included AMF-coated seeds (three to five propagules of Rhizophagus irregularis per seed) and non-treated onion and carrot seeds grown in soil with low (~46 ppm) and high (~78 ppm) phosphorus levels. The mycorrhizal communities colonizing the onion and carrot roots were identified by Illumina sequencing. Five genera, Diversispora, Claroideoglomus, Funneliformis, Rhizophagus, and Glomus, were identified in roots of both plant species. AMF communities colonizing carrot roots were more diverse and richer than those colonizing onion roots. Diversispora and Funneliformis had a 1.3-fold and 2.9-fold greater abundance, respectively, in onion roots compared to carrots. Claroideoglomus was 1.4-fold more abundant in carrot roots than in onions. Inoculation with R. irregularis increased the abundance and richness of Rhizophagus in AMF communities of onion roots but not in carrot roots. The soil phosphorus level had no effect on the richness and diversity of AMF in the roots of either crop. In summary, AMF inoculant and soil phosphorus levels influenced the composition of AMF communities colonizing the roots of onion and carrot plants, but the effects varied between plant species. [ABSTRACT FROM AUTHOR]

Introduction: Soybean adapts to phosphorus-deficient soils through three important phosphorus acquisition strategies, namely altered root conformation, exudation of carboxylic acids, and symbiosis with clumping mycorrhizal fungi. However, the trade-offs and regulatory mechanisms of these three phosphorus acquisition strategies in soybean have not been researched. Methods: In this study, we investigated the responses of ten different soybean varieties to low soil phosphorus availability by determining biomass, phosphorus accumulation, root morphology, exudation, and mycorrhizal colonization rate. Furthermore, the molecular regulatory mechanisms underlying root phosphorus acquisition strategies were examined among varieties with different low-phosphorus tolerance using transcriptome sequencing and weighted gene co-expression network analysis. Results and discussion: The results showed that two types of phosphorus acquisition strategies--"outsourcing" and "do-it-yourself"--were employed by soybean varieties under low phosphorus availability. The "do-it-yourself" varieties, represented by QD11, Zh30, and Sd, obtained sufficient phosphorus by increasing their root surface area and secreting carboxylic acids. In contrast, the "outsourcing" varieties, represented by Zh301, Zh13, and Hc6, used increased symbiosis with mycorrhizae to obtain phosphorus owing to their large root diameters. Transcriptome analysis showed that the direction of acetyl-CoA metabolism could be the dividing line between the two strategies of soybean selection. ERF1 and WRKY1 may be involved in the regulation of phosphorus acquisition strategies for soybeans grown under low P environments. These findings will enhance our understanding of phosphorus acquisition strategies in soybeans. In addition, they will facilitate the development of breeding strategies that are more flexible to accommodate a variety of production scenarios in agriculture under low phosphorus environments. [ABSTRACT FROM AUTHOR]

The intricate decomposition pathways within soil micro-food webs are vital for cycling soil organic carbon and nutrients, influencing the quality, productivity, and sustainability of soil systems. However, the impact of diverse phosphorus addition on these organic decomposition pathways still needs to be explored. In an 8-year experiment, phosphorus (P) fertilizer was added at varying levels (0 kg ha-1, CK; 60 kg ha-1, P60; 120 kg ha-1, P120; and 180 kg ha-1, P180), to investigate the response of the soil micro-food web. The results revealed a significant effect of phosphorus addition on soil microorganisms and nematodes, with P60 exerting a greater influence than other treatments. At P60, the Shannon index of nematodes and fungi surpassed other treatments, indicating higher diversity, while the Shannon index of bacteria was lower. The Chao1 index of bacteria and fungi at P60 was higher, contrasting with the lower index for nematodes. Metabolic footprints of bacterivores and omnivores-predators (BFMF and OPMF) were higher at P60, while metabolic footprints of fungivores and plant parasites (FFMF and PPMF) were lower, signifying altered energy flow. Functional metabolic footprints and energy flow analysis unveiled a stable soil micro-food web structure at P60, with enhanced energy conversion efficiency. Network analysis illustrated positive correlations between fungi, fungivorous nematodes (FF), and omnivorous-predatory nematodes (OP) at P60, while P120 and P180 showed positive correlations among bacteria, bacterivorous nematodes (BF), and OP. Path analysis underscored the higher contribution rate of BF-C, FF-C, and OP-C to soil organic carbon at P60 compared with P120 and P180. These findings suggest that nutrient interactions between fungi and nematodes regulate soil micro-food web decomposition under low phosphorus concentrations. In contrast, interactions between bacteria and nematodes dominate at high phosphorus concentrations. The study indicates that adding phosphorus has nuanced bottom-up effects, intricately shaping the structure and activity of the pathways and underscoring the need for a comprehensive understanding of nutrient dynamics in soil ecosystems. [ABSTRACT FROM AUTHOR]

The soils of the Brazilian Cerrado have phosphorus as the most limiting element, as it has a low quantity and a high retention capacity in the solid phase, thus, the P is mostly adsorbed to the soil. The use of bacteria represents a sustainable alternative to mobilize phosphorus in soils. This study aimed to prospect bacteria with phosphorus solubilizing activity with the potential to be used to promote the growth of soybean plants and the biocontrol of S. sclerotiorum. Bacterial isolations were carried out from different soils and locations in MT. Afterward, the isolates with the highest phosphate solubilizing capacity were selected, to test in an experiment with soybean plants in a greenhouse in DIC, with 11 treatments, nine of which were isolates VG09, VG27, VG42, VG46, VG47, VG68, VG82, VG89, VG91, fertilization (NPK) and the control without phosphate fertilization. Root length, plant height, and fresh and dry weight of roots and shoots were evaluated. Finally, the seeds health test was realized with S. sclerotiorum, evaluating the nine bacteria, the chemical fungicide Certeza N (thiophanate-methyl and fluazinam), and the treatment control. The bacterial isolates VG91, VG09, and VG27 stood out for providing increases in most of the soybean plant growth promotion parameters evaluated. Biological seed treatment with the bacteria VG42, VG 27, VG46, VG47, and VG91 provided satisfactory control of S. sclerotiorum in soybean seeds. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is a key limiting nutrient in tropical and subtropical soils but with unknown responses to climate change. We hypothesized that storage and distribution of P pools differ between reference soil groups, but P availability increases with an increase in precipitation in native sub‐Saharan Africa, an underrepresented region in the global P database. To test these hypotheses, we sampled topsoils (0–10 cm; Arenosols, Lixisols, Acrisols) of uncultivated Savannah woodlands along climate gradients stretching from Mozambique to Zambia. Mean annual precipitation (MAP) ranged from 365 to 1227 mm. We extracted P fractions using Hedley's sequential fractionation, yielding resin‐exchangeable P, P in 0.5 M NaHCO3, 0.1 M NaOH, 1 M HCl and aqua regia. Extracts were analysed for total P using inductively coupled plasma–optical emission spectroscopy and inorganic P using the colorimetric molybdenum blue method. We found that total P contents were highest in Acrisols (235 ± 76 mg kg−1), followed by Lixisols (214 ± 45 mg kg−1) and Arenosols (133 ± 74 mg kg−1). Beside P storage, also P distribution differed between soils. Mean annual temperature (MAT) did not reveal significant correlations with P fractions. However, with increasing MAP, concentrations of almost all P pools increased; available Pi (Resin‐P) increased significantly in Arenosols while potentially bioavailable P (NaHCO3‐Po) increased in all soils, with MAP explaining 43% of data variability in Arenosols, 74% in Lixisols and 85% in Acrisols. Hence, P availability increased with an increase in MAP to different degrees, that is, climatic effects on P dynamics were soil‐group‐specific. Therefore, different regions in the native sub‐Saharan woodlands are likely prone to different soil fertility responses when climate changes. [ABSTRACT FROM AUTHOR]

The degradation and desertification of grassland ecosystems have garnered significant attention both domestically and internationally. Grassland restoration techniques are widely considered a principal measure to promote the sustainable utilization of grasslands, with soil nutrient content being a core indicator for assessing the effectiveness of restoration in degraded grasslands. This study aims to explore the differential impacts of various grassland restoration methods on soil nutrient distribution in degraded Stipa grandis grasslands. Three major restoration methods, i.e., root cutting, enclosure, and fertilization, were applied in the study area. The soil nutrient content was measured and analyzed under the different restoration methods and at varying depths. The results revealed that under all three restoration methods and at different soil depths (0–10 cm, 10–20 cm, 20–30 cm), the organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, alkali-hydrolyzable phosphorus, and available potassium contents were significantly higher than those in the control group (p < 0.05). Furthermore, as soil depth increased, the contents of organic matter and all nutrients gradually decreased. Specifically, regarding the contents of different nutrients, the order of organic matter, total nitrogen, total phosphorus, alkali-hydrolyzable nitrogen, and available phosphorus was as follows: fertilization > enclosure > root cutting > control, while the contents of total potassium and available potassium followed the sequence: fertilization > enclosure > control > root cutting. Additionally, based on the canonical correlation analysis (R2 = 0.88), the total phosphorus content in soil had the greatest impact on soil nutrients, while vegetation cover and plant height contributed the most to vegetation characteristics. In grassland restoration, the increase in soil total phosphorus led to higher vegetation cover and height, mildly influenced plant diversity and density, and simultaneously promoted biomass accumulation. These research findings provide a solid theoretical foundation for the application of grassland restoration techniques, contributing to the sustainable development of grassland ecosystems. [ABSTRACT FROM AUTHOR]

Phosphorus deficiency in soil due to cation-mediated fixation reduces agricultural output from otherwise fertile lands. Phosphate solubilizing bacteria can solubilize this immobilized phosphate. The goal of this study was to use random UV mutagenesis to improve the phosphate solubilizing efficiency of the bacterial strains isolated from agriculture soils of Jaipur, Rajasthan. The phosphate solubilizing capacity was determined using the colorimetric chlorostannous reduced molybdo phosphoric acid blue method. When UV treated for 40, 50, and 60 min. Strain B5 depicted 58.54 %, 133.27 %, and 159.09 % enhanced phosphate solubilization, respectively, in the phylogenetic tree constructed using 16S rRNA gene sequencing, the isolate B5 clustered with Pseudomonas putida strains. Thus wild strains such as Pseudomonas sp. and Bacillus sp. can be mutagenically exploited to avail incapacitated phosphorus in soil. This can be an ecologically desired elucidation; however, more research is needed to investigate the underlying mechanisms involved and their repercussions. [ABSTRACT FROM AUTHOR]

Phosphorus (P) is recognized as an important driver of terrestrial primary productivity across biomes. Several recent developments in process-based vegetation models aim at the concomitant representation of the carbon (C), nitrogen (N), and P cycles in terrestrial ecosystems, building upon the ecological stoichiometry and the processes that govern nutrient availability in soils. Thus, understanding the spatial distribution of P forms in soil is fundamental to initializing and/or evaluating process-based models that include the biogeochemical cycle of P. One of the major constraints for the large-scale application of these models is the lack of data related to the spatial patterns of the various forms of P present in soils, given the sparse nature of in situ observations. We applied a model selection approach based on random forest regression models trained and tested for the prediction of different P forms (total, available, organic, inorganic, and occluded P) – obtained by the Hedley sequential extraction method. As input for the models, reference soil group and textural properties, geolocation, N and C contents, terrain elevation and slope, soil pH, and mean annual precipitation and temperature from 108 sites of the RAINFOR network were used. The selected models were then applied to predict the target P forms using several spatially explicit datasets containing contiguous estimated values across the area of interest. Here, we present a set of maps depicting the distribution of total, available, organic, inorganic, and occluded P forms in the topsoil profile (0–30 cm) of the pan-Amazon region in the spatial resolution of 5 arcmin. The random forest regression models presented a good level of mean accuracy for the total, available, organic, inorganic, and occluded P forms (77.37 %, 76,86 %, 75.14 %, 68.23 %, and 64.62% respectively). Our results confirm that the mapped area generally has very low total P concentration status, with a clear gradient of soil development and nutrient content. Total N was the most important variable for the prediction of all target P forms and the analysis of partial dependence indicates several features that are also related with soil concentration of all target P forms. We observed that gaps in the data used to train and test the random forest models, especially in the most elevated areas, constitute a problem to the methods applied here. However, most of the area could be mapped with a good level of accuracy. Also, the biases of gridded data used for model prediction are introduced in the P maps. Nonetheless, the final map of total P resembles the expected geographical patterns. Our maps may be useful for the parametrization and evaluation of process-based terrestrial ecosystem models as well as other types of models. Also, they can promote the testing of new hypotheses about the gradient and status of P availability and soil-vegetation feedback in the pan-Amazon region. The reference maps can be downloaded from 10.25824/redu/FROESE (Darela-Filho and Lapola, 2023). [ABSTRACT FROM AUTHOR]

Large amounts of use of mineral fertilizers (MF) have brought about environmental pollution and soil problems, like soil degradation and acidification. The partial substitution of MF with organic fertilizer is considered eco-friendly and more efficient in improving soil fertility. In our study, the effects of MF alone and the combination of MF and organic fertilizers (MOF) on soil phosphorus (P) availability in infertile soil with P deficiency were studied with the initial soil without any addition as the control. The addition of MF and MOF increased the soil labile P (resin-P and NaHCO3-Pi) by 101.8% and 320.1%, respectively, compared to the control after 180 days of treatment. Resin-P was the predominant P fraction in MOF, accounting for 28.0% of the total P. The proportions of residual-P in MOF were 5.6% and 8.3% lower than those in MF and control, respectively. The P activation coefficient in MOF was the highest (15.0%), and was the main contributor to soil P fractions based on redundancy analysis. Our results suggest that the combined application of organic and mineral fertilizers is more efficient in improving soil P availability than mineral fertilizer alone. We highlight the joint application was beneficial to improve soil P activation coefficient. [ABSTRACT FROM AUTHOR]

Phosphorus (P) availability in soil is often limited, posing a challenge for sustainable agricultural production. Phosphate solubilizing microorganisms (PSMs) have emerged as a promising biological approach to enhance soil P availability while minimize negative environmental impacts. Exploring the impact of PSMs on increasing soil available P is crucial for optimizing the utilization of insoluble P in soil and promoting sustainable agricultural practices. In this article, we provide a comprehensive review on the dynamics of soil available P, including its input, loss and transformation processes. Additionally, we draw a conclusion about how PSMs increase the availability of P in soil, including solubilizing inorganic P (Pi) and organic P (Po) by secreting substances such as protons, organic acids, inorganic acids, exopolysaccharides, hydrogen sulfide, siderophores and phosphatases. Notably, the factors influencing the P solubilizing activity of PSMs in soil are thoroughly discussed. Moreover, practical applications of PSMs for increasing soil P availability are summarized. Future research should focus on exploring novel PSM isolates, conducting long-term field experiments to assess the effects and potential risk of PSMs under diverse conditions, and investigating synergistic approaches with other P activators or beneficial microorganisms. This review will advance our understanding of PSMs and their practical application, enabling their widespread adoption in agricultural systems. [ABSTRACT FROM AUTHOR]

Future phosphorus (P) shortages could seriously affect terrestrial productivity and food security. We investigated the changes in topsoil available P (AP) and total P (TP) in China's forests, grasslands, paddy fields, and upland croplands during the 1980s–2010s based on substantial repeated soil P measurements (63,220 samples in the 1980s, 2000s, and 2010s) and machine learning techniques. Between the 1980s and 2010s, total soil AP stock increased with a small but significant rate of 0.13 kg P ha−1 year−1, but total soil TP stock declined substantially (4.5 kg P ha−1 year−1) in the four ecosystems. We quantified the P budgets of soil–plant systems by harmonizing P fluxes from various sources for this period. Matching trends of soil contents over the decades with P budgets and fluxes, we found that the P‐surplus in cultivated soils (especially in upland croplands) might be overestimated due to the great soil TP pool compared to fertilization and the substantial soil P losses through plant uptake and water erosion that offset the P additions. Our findings of P‐deficit in China raise the alarm on the sustainability of future biomass production (especially in forests), highlight the urgency of P recycling in croplands, and emphasize the critical role of country‐level basic data in guiding sound policies to tackle the global P crises. [ABSTRACT FROM AUTHOR]

Deforestation of tropical rainforests is a major land use change that alters terrestrial biogeochemical cycling at local to global scales. Deforestation and subsequent reforestation are likely to impact soil phosphorus (P) cycling, which in P‐limited ecosystems such as the Amazon basin has implications for long‐term productivity. We used a 100‐year replicated observational chronosequence of primary forest conversion to pasture, as well as a 13‐year‐old secondary forest, to test land use change and duration effects on soil P dynamics in the Amazon basin. By combining sequential extraction and P K‐edge X‐ray absorption near edge structure (XANES) spectroscopy with soil phosphatase activity assays, we assessed pools and process rates of P cycling in surface soils (0–10 cm depth). Deforestation caused increases in total P (135–398 mg kg−1), total organic P (Po) (19–168 mg kg−1), and total inorganic P (Pi) (30–113 mg kg−1) fractions in surface soils with pasture age, with concomitant increases in Pi fractions corroborated by sequential fractionation and XANES spectroscopy. Soil non‐labile Po (10–148 mg kg−1) increased disproportionately compared to labile Po (from 4–5 to 7–13 mg kg−1). Soil phosphomonoesterase and phosphodiesterase binding affinity (Km) decreased while the specificity constant (Ka) increased by 83%–159% in 39–100y pastures. Soil P pools and process rates reverted to magnitudes similar to primary forests within 13 years of pasture abandonment. However, the relatively short but representative pre‐abandonment pasture duration of our secondary forest may not have entailed significant deforestation effects on soil P cycling, highlighting the need to consider both pasture duration and reforestation age in evaluations of Amazon land use legacies. Although the space‐for‐time substitution design can entail variation in the initial soil P pools due to atmospheric P deposition, soil properties, and/or primary forest growth, the trend of P pools and process rates with pasture age still provides valuable insights. [ABSTRACT FROM AUTHOR]

Soils in hyper‐arid climates, such as the Chilean Atacama Desert, show indications of past and present forms of life despite extreme water limitations. We hypothesize that fog plays a key role in sustaining life. In particular, we assume that fog water is incorporated into soil nutrient cycles, with the inland limit of fog penetration corresponding to the threshold for biological cycling of soil phosphorus (P). We collected topsoil samples (0–10 cm) from each of 54 subsites, including sites in direct adjacency (<10 cm) and in 1 m distance to plants, along an aridity gradient across the Coastal Cordillera. Satellite‐based fog detection revealed that Pacific fog penetrates up to 10 km inland, while inland sites at 10–23 km from the coast rely solely on sporadic rainfall for water supply. To assess biological P cycling we performed sequential P fractionation and determined oxygen isotope of HCl‐extractable inorganic Pδ18OHCl−Pi$$ \mathrm{P}\ \left({\updelta}^{18}{\mathrm{O}}_{\mathrm{HCl}-{\mathrm{P}}_{\mathrm{i}}}\right) $$. Total P (Pt) concentration exponentially increased from 336 mg kg−1 to a maximum of 1021 mg kg−1 in inland areas ≥10 km. With increasing distance from the coast, soil δ18OHCl−Pi$$ {\updelta}^{18}{\mathrm{O}}_{\mathrm{HCl}-{\mathrm{P}}_{\mathrm{i}}} $$ values declined exponentially from 16.6‰ to a constant 9.9‰ for locations ≥10 km inland. Biological cycling of HCl‐Pi near the coast reached a maximum of 76%–100%, which could only be explained by the fact that fog water predominately drives biological P cycling. In inland regions, with minimal rainfall (<5 mm) as single water source, only 24 ± 14% of HCl‐Pi was biologically cycled. We conclude that biological P cycling in the hyper‐arid Atacama Desert is not exclusively but mainly mediated by fog, which thus controls apatite dissolution rates and related occurrence and spread of microbial life in this extreme environment. [ABSTRACT FROM AUTHOR]

With limited phosphorus (P) supplies, increasing P demand, and issues with P runoff and pollution, developing an ability to reuse the large amounts of residual P stored in agricultural soils is increasingly important. In this study, we investigated the potential for residual soil P to maintain crop yields while reducing P applications and losses in Canada. Using a P cycling model coupled with a soil P dynamics model, we analyzed soil P dynamics over 110 years across Canada's provinces. We found that using soil residual P may reduce mineral P demand as large as 132 Gg P year−1 (29%) in Canada, with the highest potential for reducing P applications in the Atlantic provinces, Quebec, Ontario, and British Columbia. Using residual soil P would result in a 21% increase in Canada's cropland P use efficiency. We expected that the Atlantic provinces and Quebec would have the greatest runoff P loss reduction with use of residual soil P, with the average P loss rate decreasing from 4.24 and 1.69 kg ha−1 to 3.45 and 1.38 kg ha−1, respectively. Ontario, Manitoba, and British Columbia would experience relatively lower reductions in P loss through use of residual soil P, with the average runoff P loss rate decreasing from 0.44, 0.36, and 4.33 kg ha−1 to 0.19, 0.26, and 4.14 kg ha−1, respectively. Our study highlights the importance of considering residual soil P as a valuable resource and its potential for reducing P pollution. [ABSTRACT FROM AUTHOR]

Lagoons, significant coastal wetlands, stand out for their vital role in the cycles and transformations of phosphorus. However, the relationship between the spatial distributions of various phosphorus forms in the soil and sediments of lagoon areas remains unclear. This study investigated the phosphorus fractions and distribution patterns in the soil and sediments from Shimei Inland Sea, Hainan Province, China, and identified the factors controlling phosphorus distribution and its relationship with lagoon eutrophication. The results revealed significant enrichment of inorganic phosphorus (IP) in the Shimei Inland Sea (64.1–679.0 mg/kg) and offshore areas (56–627.2 mg/kg), while organic phosphorus (OP) was relatively concentrated in land (60–744.3 mg/kg), suggesting that the productivity of the terrestrial ecosystem controlled the OP content and IP formed from the mineralization of OP was more likely to leach into the water and combine with minerals. Total phosphorus (TP) content was negatively affected by pH, and organic matter, cation exchange capacity and iron/aluminum oxides showed significant positive correlations with TP content. These findings highlighted the coupled impact of soil and sediment physicochemical properties on phosphorus enrichment and transformation, providing theoretical support for the ecological restoration of ecosystems in tropical coastal wetlands. [ABSTRACT FROM AUTHOR]

Utilization of insoluble P in soils of salt–alkali regions is key to increasing available P content. P-solubilizing bacteria (PSB) dissolve inorganic phosphates or mineralize organic phosphates in the soil to promote plant growth. In this study, we analyzed the growth kinetics and salt–alkali tolerance of the halophilic PSB Kushneria sp. YCWA18. Suaeda salsa was used for assessing seed germination rate and growth of plants after inoculation with this PSB. Our results showed that the maximum P solubilized by the bacterium was 616.98 mg/L at 48 h. The available P content increased with time, with a simultaneous reduction in pH. YCWA18 grew well under 5% NaCl but exhibited average alkali resistance. YCWA18 promoted the seed germination of S. salsa which was otherwise inhibited under NaCl–alkali stress, but it had no effect under low NaCl or high alkali conditions. The addition of YCWA18 to salt–alkali soil led to a reduction in soil pH and a 1.5–tenfold increase in available P, plant height and biomass. Thus, YCWA18 improved P availability in salt–alkali soil and promoted plant growth. The results of our study provide a theoretical basis for the application of PSB in salt–alkali soils. [ABSTRACT FROM AUTHOR]

Management practices, such as tillage and cropping diversification, influence soil phosphorus (P) dynamics. The aim was to evaluate the long-term effect of tillage systems (no tillage, NT; vertical tillage, VT; conventional tillage, CT) on total (TP) and extractable (Pe) soil P distribution under different crop sequences (corn-wheat/soybean, C-W/S; wheat/soybean, W/S; corn-corn, C-C; soybean-soybean, S-S). TP and Pe were measured up to 50 cm deep. The TP distribution was associated to soil organic carbon (SOC) (r = .89, p < .01) and tend to increase near soil surface under NT as compared with CT and VT. The Pe was sensitive to the crop residues pattern of accumulation and their quality in the topsoil. Crop sequences that included corn had lower Pe concentration under NT. Conversely, in W/S, Pe concentration was lower under VT with no differences between NT and CT and, in S-S sequence, there were no differences in Pe concentration. However, under NT the increase in the above-ground biomass in sequences without corn (p < .001) increased Pe concentration in 0-5 cm layer, while the opposite occurs in sequences with corn (p < .06). In S-S under NT, the low crop residue input (1.6 Mg of dry matter ha-1) and the high Pe concentration in 0-5 cm layer (40 mg kg-1) might increase the risk of P loss to adjacent ecosystems. Intensified sequences presented more negative P balances than corn/soybean monoculture. This study demonstrates that it's necessary to develop management strategies that improve P supply in synchrony with the crop demand and decrease P loss, while keeping productivity. [ABSTRACT FROM AUTHOR]

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]

The aim of this study was to evaluate the influence of organic fertilizers on some soil agrochemical indicators, such as: soil reaction (pH), content of soil in organic carbon, humus, total nitrogen, total phosphorus and total potassium. Research was carried out in an apple demonstrative plot established in 2010 at Maracineni, in a private farm from Arges County. In 2022 the following fertilization variants were applied: V1 - Unfertilized; V2 - Biohumus - 0.5 l/tree, soil application + Macys BC 28 - 2 l/ha, foliar application + Cifamin BK - 1 l/ha, foliar application; V3 - Biohumus - 0.7 l/tree, soil application + Macys BC 28 - 2 l/ha, foliar application + Cifamin BK - 1 l/ha, foliar application; V4 - Biohumus - 0.9 l/tree, soil application + Macys BC 28 - 2 l/ha, foliar application + Cifamin BK - 1 l/ha, foliar application; V5 - manure - 20 t/ha. The following determinations were carried out: pH in aqueous solution mix soil:water = 1:2.5 (potentiometric method); organic carbon according to the Walkley Black method, respectively the humus by calculation; the total nitrogen was determined by the Kjeldahl method; the total phosphorus was determined spectrophotocolorimetric, the Egner-Riehm-Domingo method; the total potassium was determined flamphotometrically from the same extract obtained when determining the phosphorus. Fertilization with manure in a dose of 20 t/ha (V4), has led to an improvement of soil acidity, increased soil content in humus, nitrogen, phosphorus and potassium compared to the unfertilized variant and with the other fertilization variants. [ABSTRACT FROM AUTHOR]

The relevance of the study lies in the need to maintain optimal levels of mobile phosphorus in carbonate soils to support healthy plant growth and development, as it can be converted into less mobile forms in such soils. The purpose of the study was to assess the impact of various long- term fertilisation strategies on the content of various forms of phosphorus in the soil to improve this availability. The research was conducted in 2019-2022 as a stationary experiment in a separate division of the National University of Life and Environmental Sciences of Ukraine "Agronomic Experimental Station" in Kyiv Oblast on meadow chernozem carbonate low-humus coarse-sawn light loamy soil in a five-field crop rotation, where the influence of different levels of fertiliser saturation (no fertiliser, minimum, average, and optimal) on soil phosphate status and yield of Etana winter wheat variety and Sumiko sunflower hybrid was investigated. Soil samples were taken from the 0-20 and 20-40 cm layers, and the group and fractional composition of phosphates was determined using the Chang-Jackson method and the content of mobile phosphates using the Chirikov and Machigin methods. According to the analysis of the group and fractional composition of soil phosphates, it was found that in meadow chernozem carbonate low-humus coarse-sawn light loamy soil, the content of iron phosphates prevails among all fractions during long-term fertilisation. The results showed an increase in the content of aluminium phosphates in the 0-20 cm surface layer of the soil of two variants with long-term fertilisation, and an increase in the content of the second fraction of soluble calcium phosphates (Ca-PII), with the minimum saturation (N27P18K20) with the highest available phosphate fraction for plants (Ca-PI) is observed The content of mobile phosphates was maximal at optimal fertiliser saturation (N81P54K62) and was 4.8 and 8.5 mg/100 g of soil, the aftereffect of organic fertilisers positively affected the accumulation of mobile phosphates in the soil. The highest yield of winter wheat (7.55 t/ha) and sunflower (4.28 t/ha) was obtained with optimal fertiliser saturation, the lowest - without the use of fertilisers, where it was 4.45 t/ha for winter wheat and 2.23 t/ha for sunflower. The results of the study can be used to develop more sustainable and effective strategies for using phosphorus in soils, which can help preserve soil resources and prevent possible contamination of water sources due to excessive phosphorus intake [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]

Long-term unsystematic use of near-settlement pastures in the desert zone of South Kazakhstan had a negative impact on the physic-chemical parameters of Calcisol. Excessive grazing leads to trampling of soil and reduction of soil fertility. The aim of the study was to develop a technology to improve the productivity of degraded near-settlement pastures. The tasks of the research were to determine the effect application of environmental safe biostimulator and biofertilizer on microbial communities, the content of carbon and phosphorus in the soil, the effectiveness of biostimulator application on degraded pastures in order to increase green mass. For this purpose, geobotanical, bacteriological and helminthological methods of analysis were used. The result of the used proposed technology is the activation of soil microorganisms, which leads to the prevention of degradation of arid pastures. The results of the conducted research contribute to the introduction of a better technology to increase the productivity of arid near-settlement pastures. Statistical analysis of the experiments showed that all manipulations on soil microorganisms increase the number and green mass of arid plants. [ABSTRACT FROM AUTHOR]

Today, the use of chemical fertilisers is significantly determined by their production and purchase costs, which are high. In contrast, phosphorus (P) is present in sewage sludge in a form that is easy for plants to absorb. Good quality sewage sludge compost (SSC) could contain a high quantity of P, together with other macro- and microelements and organic matter. The effect of regular SSC application on soil characteristics as well as plant parameters has been studied since 2003 in Nyíregyháza in a small plot experiment. Focusing on the P in the soil-plant system, our hypothesis was that SSC covers plants' P demand through enhancing soil P content and its plant availability in the acidic sandy soil. The effect of the SSC was examined at the doses of 0, 9, 18, and 27 t ha-1 on rye as a test crop. Some soil chemical parameters (pH, soil organic matter - SOM, ammonium lactate (AL) extractable P2O5), and the relationship between plant development (green weight, shoot length), physiological parameters (SPAD index), plant shoot P content, and soil available P content were studied. The obtained data indicated that the SOM content, pH, and available P content of the treated plots increased as a result of the long-term applied SSC compared to the control. Measurement of the relative chlorophyll content showed a strong correlation with the available P content of the soil, but surprisingly less correlation with shoot P content was found. The results of plant biomass and soil P content proved that SSC could be used as a low-cost and good source of P for plants. [ABSTRACT FROM AUTHOR]

The study was enforced to probe the conversion and migration behavior of phosphorus speciation in sludge and the biochar received from pyrolysis of municipal sludge (MS), town sludge (TS), and slaughterhouse sludge (SS). This study creatively used fractionation of soil phosphorus to further differentiate speciation of phosphorus in three sludges (MS, TS, and SS). According to the x-ray diffraction (XRD) analysis and sequential extraction, the study proved the dependence of P speciation conversion on pyrolysis temperature and different types of raw sludge. The results of P-fractionation indicated that Ca-bound IP (Ca-IP) content in all biochars significantly increased at pyrolysis temperature of 350-800 °C, and the proportion of soluble and loosely bound IP (SL-IP), aluminum-bound IP (Al-IP), and Fe-bound IP (Fe-IP) of MS and SS decreased. The difference is that the Al-IP in the TS increased slightly as the pyrolysis temperature increased. Among the three kinds of sludge, the Olsen-P of TS is the lowest because the content of Olsen-P in sludge will decrease with the decrease of pH in the process of sewage treatment after acidification. In addition, XRD patterns of three sludges and biochar further confirmed the low crystallinity of AlPO4 minerals. Through in-depth research on the environmental behavior of phosphorus, this study might additionally provide essential knowledge for the recovery and utilization of phosphorus in sludge. [ABSTRACT FROM AUTHOR]

Introduction: The Songnen Plain is one of the three major saline-alkali areas in China, covering a vast area, where drought and overgrazing have exacerbated the salinization trend, andwill have great potential for development if utilized rationally. Phosphorus, as one of important soil nutrients, plays a crucial role in plant growth. Howtominimize its loss andmigration has become a current research hotspot. The objective of the present study was to elucidate the adsorption properties of phosphorus in soils affected by salinization and to establish the correlation between the potential for phosphorus release and soil properties. Methods: A batch treatment test was conducted in this study using three soils with the various salinization degrees to examine the impact of environmental factors on the adsorption properties and potential release of phosphorus. Results and discussion: It was found that the maximum phosphorus adsorption by the three salinization soils in 0-360 minutes accounted for 86.8%-90.5% of the total adsorption capacity; the equilibrium adsorption capacity was: HS> MS> LS. In cases where the phosphorus level in the surrounding liquid is low, the three levels of salinized soils exhibited varying levels of phosphorus discharge, with the adsorbent acting as the origin of contaminants. The Pseudo-second-order model kinetics and Langmuir equation can well describe the adsorption process, and the adsorption process is spontaneous heat absorption with entropy increase. Increasing the pH led to an increase in the adsorption of phosphorus from the three salinized soils. Additionally, the adsorption was enhanced by introducing varying concentrations of Na+, Ca2+, and Al3+ to the background solution. The phosphorus eutrophication release risk (ERI) demonstrated a gradual decline as temperature increased. Correlation analysis revealed a noteworthy positive correlation between TN, TP, and ERI, as well as a significant negative correlation between CEC, K+, and ERI. Furthermore, there was a highly significant negative correlation between coarse silt and fine silt. Considering local climatic and environmental factors is crucial for controlling the adsorption capacity of phosphorus in various salinized soils, as it can unveil the mechanism of phosphorus adsorption and impact its migration and release risk. [ABSTRACT FROM AUTHOR]

Functional traits play an important role in studying the functional niche in plant communities. However, it remains unclear whether the functional niches of typical forest plant communities in different climatic regions based on functional traits are consistent. Here, we present data for 215 woody species, encompassing 11 functional traits related to three fundamental niche dimensions (leaf economy, mechanical support, and reproductive phenology). These data were collected from forests across four climatic zones in China (tropical, subtropical, warmtemperate, and cold-temperate) or sourced from the literature. We calculated the functional niche hypervolume, representing the range of changes in the multidimensional functional niche. This metric quantifies how many functional niche spaces are occupied by existing plants in the community. Subsequently, we analyzed differences in functional niche hypervolume and their associated environmental factors across different types of forest vegetation. The results indicate that the functional niche hypervolume and the degree of forest vegetation overlap decrease with increasing latitude (e.g., from tropical rainforest to cold temperate coniferous forest). The total explanatory power of both climate and soil factors on the variation in functional niche hypervolume was 50%, with climate factors exhibiting a higher explanatory power than soil factors. Functional niche hypervolume is positively correlated with climate factors (annual mean temperature and annual precipitation) and negatively correlated with soil factors (soil pH, soil organic matter content, soil total nitrogen content, and soil total phosphorus content). Among these factors, annual mean temperature, soil pH, and soil total nitrogen content most significantly affect the difference in functional niche hypervolume among forest vegetation. Our study emphasizes the significant variation in the functional niche hypervolume among typical forest vegetation in China. [ABSTRACT FROM AUTHOR]

Volcanic soils are well-known to have a high agronomical value, and in Sumatra, Mt. Kerinci volcanic soils produce one of the highest quality tea and rice. Declining soil organic carbon (C) and high phosphorus (P) retention are two main issues in volcanic soils in the area. Thus, this study aimed to study the dynamic of C) and P content in volcanic soils and to find the main controls of their variation from geochemical signatures. The soils of Mt Kerinci present a unique environment as one part of the area was converted from forest to tea plantation for about 100 years, and a nearby field had been used for paddy rice cultivation for about 200 years. The study was conducted in the Mt Kerinci area covering 5,922 ha in the north comprise of paddy soils (ps) and north tea soils (nts) and the south slope (south tea soils= sts). Soil samples were collected on a grid of 500 × 500 m under tea and paddy (n = 206 samples) at 0–20 and 20–40 cm depth. All soils have similar pH in H2O, but pH in KCl paddy soils (ps) > north tea soils (nts) > south tea soils (sts). The average content of soil organic Carbon (SOC) in paddy soils was 50% less than in the soils of tea plantations. The labile organic carbon content in paddy soils were lower than in soils of tea plantations. Most C was chemically bound to the metal complex. Higher P retention occurred in all soils. The CaO/TiO2 index indicated a weathering sequence of ps > nts > sts. Soil weathering controlled P retention with an increasing P retention as the soils weathered. Overall, the study suggests that cultivation in volcanic soils influenced the geochemical properties of the soils and subsequently their C and P contents. [ABSTRACT FROM AUTHOR]

Contrasting fertilization modifies soil phosphorus (P) transformation and bioavailability, which impact crop P uptake and P migration in the soil profile. A long-term (25-year) fertilizer experiment was employed to investigate crop yield, P uptake and changes in sequentially extracted P fractions in the soil profile, and their relationships on a calcareous soil derived from loess material under a winter wheat and summer maize double-cropping system. The experiment involved seven nutrient management treatments: control (CK, no nutrient input), N, NK, NP, and NPK, representing various combinations of synthetic nitrogen (N), phosphate (P), and potassium (K) applications, as well as combinations of NPK fertilizers with either crop residues (SNPK, where S refers to maize stalk or wheat straw) or manure (MNPK, where M refers to dairy manure). Wheat and maize yields were significantly higher with P input fertilizer relative to the P-omitted treatments. Long-term application of P-containing fertilizers markedly raised the contents of inorganic (Pi) and organic (Po) P fractions at 0–20 cm depth compared with the P-omitted treatments. Moreover, both Pi and Po fractions were markedly higher under MNPK than under NPK and SNPK treatments. For achieving high yield for wheat and maize, the critical contents of labile P were 54 and 63 mg kg−1, and those of moderately labile P were 48 and 49 mg kg−1, respectively, defined by the linear plateau model. In addition, the change points of labile P and moderately labile P were 99 and 70 mg kg−1, above which CaCl2-P content significantly increased. Moreover, long-term P input significantly accumulated different P fractions in the deeper soil layers up to 100 cm, with large portions of organic P being a composite of labile and moderately labile P, especially in MNPK treatment. Our results suggest that excessive P supply with organic manure resulted in massive P accumulation in the topsoil and promoted soil P fraction transformation and availability in the deep soil layers, especially in an organic P form that has often been neglected. [ABSTRACT FROM AUTHOR]

Returning crop straw to the soil is an effective measure to increase soil fertility and maintain crop yield in agroecosystems. In this study, we conducted a 34-year field experiment (1984–2017) to investigate the relationships among the impacts of straw return on soil nutrients, phosphorus (P) fractions, phosphorus transformation-related functional microbial communities, and key genes in black soil. The results of the soil chemical properties showed that straw return could slow the decline in soil pH and increase soil nutrients, i.e., soil organic carbon (SOC), available K (AK), and available P (AP) concentrations, with the straw addition (PKS) treatment resulting in the highest soil AP and AK contents. Compared with conventional fertilizer (NPK) and conventional fertilizer with straw (NPKS), straw return alone (S) significantly increased the soil AP and AK contents by 1.1–42.8 and 38.3–114.3 mg/kg (p < 0.05), respectively. The results of the phosphorus fraction experiment indicated that long-term straw return promoted labile and moderately stable phosphorus content by altering the composition and increasing the relative abundances of functional genes regulating soil P activation (ugpQ, ppk, phoD, and gcd). The compositional changes in the phosphorus-cycling-related functional genes of the soil were affected mostly by soil total P (TP), AK, and NO3−-N, whereas pH, SOC, and available N (AN) were the main environmental factors influencing the phosphorus-cycling-related microbial community composition. These direct measurements provide insight into the soil phosphorus fractions, phosphorus-cycling-related functional genes, and microbial communities associated with straw returning, which enhances our understanding of the chemical and biogeochemical behavior of soil phosphorus upon straw incorporation. [ABSTRACT FROM AUTHOR]

Maize (Zea mays sp.) is one of the most important basic grains in our diets, and it requires high levels of nitrogen and phosphorus for optimum growth. However, phosphorous transitions in forms inaccessible to plants. The Lupinus genus, and more specifically, Lupinus albus, through its root clusters, or proteoid roots, has the ability to solubilize portions of phosphorous when it is found in a limited environment. The objective of the current study was to evaluate the effect of Lupinus montanus under phosphorous stress conditions intercropped with maize, utilizing sandy soils with calcium phosphate bands. Work was conducted in growth chambers using rhizotrons, which allowed the authors to observe the growth and root behavior of both species (Lupinus montanus and maize). The phosphorus analysis in the plant tissue indicated that its concentration in maize was slightly higher in intercropping conditions than in monoculture planting. From this, we concluded that Lupinus montanus is capable of solubilizing portions of phosphorus, making it available for other crops; likewise, we also observed that the proteoid structures did not develop, leaving the study open for other wild species. In conclusion, the use of Lupinus montanus will be as an alternative in favor of more sustainable agricultural methods since it improve soil fertility in phosphorus deficient soils. [ABSTRACT FROM AUTHOR]

BACKGROUND: Soil fumigation can change soil nutrient cycling processes by affecting soil beneficial microorganisms, which is a key issue for soil fertility. However, the effect of combined application of fumigant and fungicide on soil phosphorus (P) availability remains largely unclear. We investigated the effects of the fumigant chloropicrin (CP) and the fungicide azoxystrobin (AZO) on soil phosphatase activity and soil P fractions in ginger production using a 28‐week pot experiment with six treatments: control (CK), a single application of AZO (AZO1), double applications of AZO (AZO2), CP‐fumigated soil without AZO (CP), CP combined with AZO1 (CP + AZO1) and CP combined with AZO2 (CP + AZO2). RESULTS: AZO application alone significantly increased the soil labile P fractions (Resin‐P + NaHCO3‐Pi + NaOH‐Pi) at 9 weeks after planting (WAP) but decreased the soil phosphatase activity at 28 WAP. CP fumigation significantly reduced the soil phosphatase activity but increased the proportions of soil labile P fractions (Resin‐P + NaHCO3‐Pi + NaHCO3‐Po) to total P (TP) by 9.0–15.5% throughout the experiment. The combined application of CP and AZO had a synergistic effect on soil phosphatase activity and soil P fractions compared with a single application. CONCLUSION: Although AZO application and CP fumigation can increase soil available P in the short term, they might negatively affect soil fertility in the long run by inhibiting soil phosphatase activity. Soil microbial activities, especially microorganisms related to P cycling, may be responsible for the variations in soil P availability, but further research is needed. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]