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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]

BACKGROUND RESULTS CONCLUSION The relationship between phosphorus (P) related enzymatic activity and organic P turnover remains unclear, particularly in the context of biochar application. Field experiments were conducted on Phaeozem and Luvisol soil types to investigate the effects of biochar application rates – 0 t ha−1 (CK), 22.5 t ha−1 (D1), 67.5 t ha−1 (D2), and 112.5 t ha−1 (D3) – on soil organic fractions using 31P nuclear magnetic resonance (NMR) spectroscopy and relevant phosphatase activity.The application of biochar increased the soil organic carbon (SOC), pyrophosphate (pyro), and orthophosphate (ortho) content, as well as the acid phosphomonoesterase (AcP), alkaline phosphomonoesterase (AlP), inorganic pyrophosphatase (IPP), and phosphodiesterase (PD) activities. Biochar application also increased soil organic P (OPa), the sum of inorganic P forms (IP), ortho, monoesters, and myo‐IHP contents, the pH value, AlP and PD activities in Phaeozem, but it significantly reduced diesters, polyphosphate (poly) contents, and IPP and AcP activities compared to those in Luvisol. Acid phosphomonoesterase and PD activities also showed an opposite trend in Luvisol. The structural equation model showed that the potential mechanism of organic P turnover in response to biochar application differed depending on the soil types, potentially influenced by P availability.Overall, the findings of this study enhance the comprehension of the variation of P fractions and their availability in the context of biochar application for agricultural production in northeastern China. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The accumulation of secondary metabolites in Panax ginseng Meyer (P. ginseng) exhibits significant geographical variation, normally due to environmental factors. The current study aimed at elucidating the key environmental factors modulating the accumulation of secondary metabolites in P. ginseng. Plant and the associated soil samples were collected from ten geographical locations within the latitudinalrange of 27.09°N − 42.39°N and longitudinal range of 99.28°E − 128.19°E. 12 secondary metabolites in P. ginseng toots were measured. And the correlation between secondary metabolites with a series of soil properties and 7 climatic factors were investigated through Pearson's correlation, mantel test, random forest and pathway analysis. The results revealed that climatic factors were stronger drivers of ginseng secondary metabolite profile than soil nutrients. Specifically, temperature seasonality (TS) and soil available phosphorus (AP) were the most effective environments to have significantly and positively influence on the secondary metabolites of ginseng. This findings contribute to identifying optimal cultivation areas for P. ginseng, and hopefully establishing methods for interfering/shaping microclimate for cultivating high-quality P. ginseng. [ABSTRACT FROM AUTHOR]

Phosphorus is a very important plant nutrient for the development of plants and its production is not unlimited in the world. In addition, excessive use can lead to soil and water pollution. In this respect, phosphorus should be used effectively in plant production, especially in calcareous soils. The aim of this study was to comparatively determine the effects of phosphorus-enriched organomineral fertilization (p-OMF), chemical phosphorus fertilization (CF), and organic fertilization (OF) on some chemical properties of a calcareous soil. The experiment was established in Söke county of Aydın province in the Southwest of Türkiye. In this study, four doses of dairy manure (DM1: 10, DM2: 20, DM3:30, and DM4: 40 t ha−1) in OF, four phosphorus doses (P1: 10, P2: 20, P3:30, and P4: 40 kg P ha−1) in the CF system, and sixteen different doses of OMF formed by the combinations of these two fertilizers were applied excluding control. According to the main research findings, p-OMFs increased the soil organic matter (SOM), salinity, total nitrogen (N), available phosphorus (P), and potassium (K) by 60.1%, 20.9%, 22.1%, 140%, and 17.2%, respectively. They also decreased soil pH by 4%. As a result, it was determined that the most effective organomineral fertilizer combination that maintains soil properties at appropriate levels in calcareous soils is DM3+P2 (30 t ha−1 dairy manure +20 kg P ha−1). [ABSTRACT FROM AUTHOR]

Soil legacy phosphorus (P) accumulated due to the long-term continuous application of P fertilizers in agricultural fields accumulated in the soil for years, as sparingly soluble forms. This can be made as a possible soil P source using P-activators. In this study, a laboratory incubation and a pot experiment were conducted to evaluate the potential of some P activators (Phosphorus solubilizing bacteria, phytase, humic acid, oxalic acid) in increasing the availability of residual phosphorus in calcareous soil. For the incubation experiment, the P activators were applied alone and in combination. Soil samples were analyzed at subsequent intervals for soil available P, alkaline phosphatase activity, and sequential P fractions. The results showed that phytase application with humic acid (HA) increased the available soil P (12.4 kg ha−1) and alkaline phosphatase activity (47.42 µg p-nitrophenol released g−1 soil hr−1) followed by phosphorus solubilizing Bacteria (PSB) with humic acid and PSB with phytase treatments. All treatments have a significant effect on different soil P-fractions. A greater reduction in calcium phosphate fraction was noted in phytase and humic acid application. The combined application of P-activators performed better than their sole application. The best three treatments selected from the laboratory incubated experiment were used for the pot experiment with maize, along with the different dosages of P fertilizer. The morphological parameters were observed on the 30th and 60th days of the maize crop. The results of plant height, chlorophyll index, and dry matter production showed that the application of phytase and HA with 100% recommended dose of P was statistically comparable with phytase and HA with 75% recommended dose of P. The findings have illustrated the extent of P release by different P activators in increasing the legacy P availability. The application of phytase and HA with 25% reduced dose of P fertilizers will promote the availability of legacy P in calcareous soils through solubilization. [ABSTRACT FROM AUTHOR]

Summary: The antagonistic interplay between phosphorus (P) and zinc (Zn) in plants is well established. However, the molecular mechanisms mediating those interactions as influenced by arbuscular mycorrhizal (AM) symbiosis remain unclear.We investigated Zn concentrations, root AM symbiosis, and transcriptome profiles of maize roots grown under field conditions upon different P levels. We also validated genotype‐dependent P–Zn uptake in selected genotypes from a MAGIC population and conducted mycorrhizal inoculation experiments using mycorrhizal‐defective mutant pht1;6 to elucidate the significance of AM symbiosis in P–Zn antagonism. Finally, we assessed how P supply affects Zn transporters and Zn uptake in extraradical hyphae within a three‐compartment system.Elevated P levels led to a significant reduction in maize Zn concentration across the population, correlating with a marked decline in AM symbiosis, thus elucidating the P–Zn antagonism. We also identified ZmPht1;6 is crucial for AM symbiosis and confirmed that P–Zn antagonistic uptake is dependent on AM symbiosis. Moreover, we found that high P suppressed the expression of the fungal RiZRT1 and RiZnT1 genes, potentially impacting hyphal Zn uptake.We conclude that high P exerts systemic regulation over root and AM hyphae‐mediated Zn uptake in maize. These findings hold implications for breeding Zn deficiency‐tolerant maize varieties. [ABSTRACT FROM AUTHOR]

Specific leaf area (SLA) and leaf dry matter content (LDMC) are key leaf functional traits often used to reflect plant resource utilization strategies and predict plant responses to environmental changes. In general, grassland plants at different elevations exhibit varying survival strategies. However, it remains unclear how grassland plants adapt to changes in elevation and their driving factors. To address this issue, we utilized SLA and LDMC data of grassland plants from 223 study sites at different elevations in China, along with climate and soil data, to investigate variations in resource utilization strategies of grassland plants along different elevational gradients and their dominant influencing factors employing linear mixed-effects models, variance partitioning method, piecewise Structural Equation Modeling, etc. The results show that with increasing elevation, SLA significantly decreases, and LDMC significantly increases (P < 0.001). This indicates different resource utilization strategies of grassland plants across elevation gradients, transitioning from a "faster investment-return" at lower elevations to a "slower investment-return" at higher elevations. Across different elevation gradients, climatic factors are the main factors affecting grassland plant resource utilization strategies, with soil nutrient factors also playing a nonnegligible coordinating role. Among these, mean annual precipitation and hottest month mean temperature are key climatic factors influencing SLA of grassland plants, explaining 28.94% and 23.88% of SLA variation, respectively. The key factors affecting LDMC of grassland plants are mainly hottest month mean temperature and soil phosphorus content, with relative importance of 24.24% and 20.27%, respectively. Additionally, the direct effect of elevation on grassland plant resource utilization strategies is greater than its indirect effect (through influencing climatic and soil nutrient factors). These findings emphasize the substantive impact of elevation on grassland plant resource utilization strategies and have important ecological value for grassland management and protection under global change. [ABSTRACT FROM AUTHOR]

The plant-available soil phosphorus rate and methods for applying phosphatic fertilizer and soil P-fixation capacity are critical factors for lower cotton productivity in Southern Punjab, Pakistan. Hence, a two-year study was conducted in Central Cotton Research Institute (CCRI), Multan, Pakistan, to examine the effects of various P rates and application methods on cotton crop output during the growing seasons of 2014 and 2015. Phosphorus was applied in four rates (0, 40, 80, and 120 kg ha−1 P2O5) using broadcast, band application, and fertigation methods. Results indicated that the impact of P rates was statistically significant on plant height, the number of nodes, monopodial and sympodial branches, leaf area index, harvest index, and seed cotton yield. The greater P application (120 kg P2O5 ha−1) had a better effect on cotton productivity than the lower application rates (0, 40, and 80 kg P2O5 ha−1). The band application responded better on nodes plant−1, sympodial branches plant−1, boll weight, leaf area index, lint yield, and harvest during the growing season 2015. Therefore, by adopting the band application coupled with 120 kg P2O5 ha−1 rather than the conventional method of broadcast, productivity of cotton crops could be increased. [ABSTRACT FROM AUTHOR]

This study investigates soil phosphorus (P) partitioning and transformations through chemical fractionation and modeling across various land uses to elucidate their impact on P dynamics and the potential for eutrophication. Geo-referenced soils (0–30 cm at various depth intervals) were collected from diverse land uses, including corn, soybean, wheat stubble, modified relay intercropping, corn-soybean with rye under conventional tillage and no-till systems, and sheep pastures, alongside an adjacent forest (control). Processed soils were sequentially extracted to quantify soluble reactive (SRP), exchangeable (EP), Ca and Mg bound (CaMgP), Fe and Al bound (FeAlP), particulate organic (POP), residual (RP), and total P pools. Results showed significant effects of land use and soil depth on extracted P pools. Notably, corn-soybean with rye exhibited a higher SRP accumulation (2.8 mg/kg) compared to the forest. The labile (SRP + EP), moderately labile (FeAlP + CaMgP + POP), and non-labile P (RP) pools accounted for 1 to 2, 23 to 29, and 65 to 76% of total P, respectively. The structural equation model elucidated soil P transformation, indicating the contribution of labile, moderately labile, and non-labile P pools to SRP accumulation in various land uses. Our findings underscore the critical link between land use, soil P dynamics, and eutrophication risk, offering valuable insights for developing agricultural management practices aimed at mitigating edge-of-field P loss and protecting water quality against eutrophication. [ABSTRACT FROM AUTHOR]

Biochar-based fertilizers can be prepared to mix or compound with the fertilizers and biochar as a carrier. The nutrients can also be provided for the crops. The function of slow-release to conventional fertilizers can also reduce the soil nutrient leaching, in order to improve the efficiency of fertilizer utilization. However, urea is normally used as the nitrogensupplying fertilizer in most biochar-based fertilizers at present. Only a few studies have reported on biochar-based fertilizers for ammonium sulphate. This study aims to investigate the effect of biochar addition on the nitrogen slow-release performance of ammonium sulfate fertilizer. Soil nitrogen loss and soil nutrient sequestration were determined by soil column leaching simulation. Fourier infrared (FIR) spectroscopy and scanning electron microscopy (SEM) were used to observe the surface morphology and structure of biochar-ammonium sulfate fertilizer. A systematic investigation was made on the nitrogen loss of biochar-ammonium sulfate fertilizers (BC-AS1/3, BC-AS1/4, BC-AS1/5) that were prepared under different charcoal-fertilizer ratios (the mass ratios of biochar to ammonium sulfate fertilizer were 1:3, 1:4 and 1:5). The results showed that: 1) Addition of biochar was effectively adsorbed the ammonium sulfate fertilizer, and then slowed down the nitrogen release rate of ammonium sulfate. According to the three charcoal-fertilizer ratios, the BC-AS1/4 treatment shared the smoothest and tightest surface structure, while the combination of biochar and ammonium sulfate had the best molding properties. 2) Compared with the conventional ammonium sulfate treatment AS, the different biochar-ammonium sulphate treatments significantly improved the soil water and fertilizer retention performance, but reduced the soil inorganic nitrogen leaching. Among them, the cumulative ammonium and nitrate nitrogen leaching of BC-AS1/4 treatment was reduced by 80.83% and 11.56%, respectively, compared with the AS treatment, which showed the smallest leaching rate and cumulative leaching amount, and the best slow-release effect. 3) Various treatments of biochar-ammonium sulphate significantly increased the soil nitrogen accumulation in the soil column, compared with the conventional AS treatment. Among them, the BC-AS1/4 treatment showed that the best nutrient sequestration increased nitrogen accumulation in the soil column, compared with the AS treatment. There was a significant increase in the content of nitrate nitrogen in the soil layers of 0-10 cm and 10-20 cm compared with the AS treatment. 4) In the leaching test, the content of soil organic carbon in each soil layer was positively correlated with the soil's total nitrogen, quickacting potassium content, and soil conductivity. There was a positive correlation with the content of soil effective phosphorus in the 0-20 cm soil layer, whereas, a negative correlation was observed with the content of soil effective phosphorus in the 20-40 cm soil layer. The input of carbon in the biochar-ammonium sulfate fertilizer effectively improved the nutrient-holding capacity of the soil. In conclusion, the biochar-ammonium sulfate fertilizer effectively slowed down the release rate of nitrogen nutrients, indicating better slow-release performance and soil nutrient-holding capacity. The nitrogen nutrient leaching was reduced to improve the fertilizer utilization for the less risk of environmental pollution. At the same time, the biocharammonium sulfate fertilizer can be applied to increase the content of soil organic carbon, holding nitrogen, phosphorus, and potassium nutrients, in order to cultivate the effect of fertility. Among them, the combination of biochar and ammonium sulphate performed the best, when the charcoal-fertilizer ratio was 1:4, indicating the best slow-release performance and fertilizer-building. It is of great significance to realize the efficient use of industrial by-product ammonium sulphate fertilizer. [ABSTRACT FROM AUTHOR]

Soil phosphorus (P) availability is a crucial factor determining primary productivity in terrestrial ecosystem. Plant functional traits and microbes under P‐deficient conditions can respond positively to increase soil P bioavailability. Whether and/or how the fine‐root traits (FRTs) of deep‐rooted desert species affect the rhizosphere and bulk soil community of phoD‐harbouring bacteria and thus improve the availability of soil P, however, remains unclear. We conducted a three‐year artificial outdoor pot experiment of P supply using Alhagi sparsifolia Shap. (hereafter Alhagi) to address this gap. Fine‐root samples from 1‐ and 3‐year‐old Alhagi seedlings and samples of the rhizospheres and bulk soil were collected. High‐throughput sequencing, sequential extraction and root system scanning were used to determine soil phoD‐harbouring bacteria community, Hedley‐P fractions and the FRTs. Fine‐root surface area (RSA), specific root length, foliar Mn concentration (indicating the quantities of root carboxylates that are released) and acid phosphatase (APase) activity were significantly higher in the no‐P supply compared with the high‐P supply conditions. APase activity was significantly higher by 27%, but the foliar Mn concentration was remarkably lower by 26%, in the 3‐ than the 1‐year‐old seedlings. The rhizospheric concentrations of labile P, moderately labile P, inorganic P and organic P in the no‐P supply condition were 5%, 11%, 10% and 21% higher, respectively, in the 3‐ than the 1‐year‐old seedlings. RSA and the foliar Mn concentration were dominated root predictors for the rhizospheric phoD‐harbouring bacteria community for the 1‐year‐old seedlings, whereas fine‐root P concentration was the dominated root predictor for the rhizospheric and bulk soil phoD‐harbouring bacteria communities for the 3‐year‐old seedlings. Soil water content, as the most dominant soil factor driving the variation of phoD‐harbouring bacteria community, notably could not be ignored. FRTs were the main factors that directly and positively determined rhizospheric phoD‐harbouring bacteria community and thus influenced soil P availability, but bulk soil phoD‐harbouring bacteria community were dominated by inorganic P concentration. The importance of fine‐root morphological traits to soil P availability gradually increased as the plants grew. Overall, our results emphasize the significance of rhizospheric phoD‐harbouring bacteria determined by the effect of FRTs on the bioavailability of soil P. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Agricultural productivity is significantly hindered by the limited availability of phosphorus in acidic soils due to the presence of aluminum and iron phosphates. Soil liming is commonly employed to enhance soil fertility. However, modifying the pH might also impact the interactions involving existing soil organic matter, leading to changes in the effective concentrations of competing low-molecular-weight acids (LMWOACs) participating in phosphorus adsorption. This study explored the impacts of citric, oxalic, and malic acids in acidic soils from tea cultivation regions within the Eastern Black Sea. These soils had undergone various levels of liming and were incubated for 15 months to assess their effects on phosphorus (P) adsorption in 7 acidic soils. The experimental sorption data were utilized to calculate the soil Langmuir and Freundlich adsorption parameters. In addition, the influences of organic acids and liming levels on the Freundlich and Langmuir model parameters were subjected to ANOVA analysis. The findings indicated that citric acid demonstrated the highest efficiency in diminishing phosphorus adsorption among the tested organic acids, followed by oxalic and malic acids. Three carboxyl groups (−COOH) in citric acid facilitated the formation of more complexes with adsorbed phosphorus on the soil surface. Furthermore, the 100% LR ratio of liming notably decreased phosphorus adsorption, especially in the lower end of the isotherms. Therefore, it can be concluded that the combination of LMWOACs and liming treatments could be used to overcome P deficiency in acid soils with very high P sorption ability. [ABSTRACT FROM AUTHOR]

Rapeseed–rice rotation is a cropping system that improves the land-use rate. The present study conducted a field experiment with winter planting of rapeseed as treatment (WR) and winter fallow as control (CK) to investigate the effects of winter planting of rapeseed on growth, yield formation, and 2-acetyl-1-pyrroline (2-AP) biosynthesis of fragrant rice in the two subsequent cropping seasons. The results show that WR treatment improved alkali-hydro nitrogen and rapidly available phosphorus contents in soil. Compared with CK, WR treatment significantly increased grain yield and effective panicle number per plant by 21.16–27.26% and 7.33–21.24%, respectively. Higher net photosynthetic rate, leaf area index, and dry matter accumulation of fragrant rice plants were recorded in WR treatment and CK. Furthermore, compared with CK, WR treatment significantly increased grain 2-AP content, which could be explained by increased content of pyrroline-5-carboxylic acid, methylglyoxal, 1-pyrroline, and enhanced activity of proline dehydrogenase. In addition, future studies should be conducted at a molecular level to reveal the regulation mechanism in 2-AP biosynthesis of fragrant rice under conditions of winter planting of rapeseed. [ABSTRACT FROM AUTHOR]

The application of a diammonium phosphate coating effectively mitigates direct contact between the phosphate fertilizer and the soil, thus minimizing phosphorus fixation. Humic acid holds a pivotal role in augmenting soil quality and activating the soil's phosphorus reserves. Notably, when combined with humic acid, diammonium phosphate significantly enhances the utilization efficiency of phosphate fertilizer. However, there is a paucity of literature exploring the dynamics of nutrient transport in soil when humic acid is paired with coated phosphate fertilizers. To assess the impact of the combined application of coated diammonium phosphate and humic acid on wheat yield enhancement, we conducted pot experiments along with leaching and ammonia volatilization simulation tests, aiming to elucidate the effects of this combination on nutrient transport. The study explored the effects of three distinct treatments: coated diammonium phosphate (CP), coated diammonium phosphate combined with humic acid (PHA), and coated diammonium phosphate combined with humic acid (CPHA). The investigation focused on analyzing their impacts on wheat yield, ammonia volatilization, soil-available phosphorus, nitrate nitrogen, ammonium nitrogen, soil-available potassium, as well as the mobilization and transport of calcium and magnesium in the soil. (1) Compared to the P treatment, the PHA and CP treatments significantly increased grain yield by 17.2% and 13.5%, respectively. The PHA treatment also increased effective panicle number by 12.9%. Overall, the CP, PHA, and CPHA treatments improved grain yield by 13.5%, 17.2%, and 19.1% compared to the P treatment. (2) The CP and PHA treatments reduced available phosphorus by 95.6% and 49.2%, calcium by 2.0% and 67.0%, and magnesium by 11.6% and 46.1% compared to the P treatment. Ammonium nitrogen decreased by 37.0% and 64.3%, while nitrate nitrogen increased by 14.0% in CP and slightly decreased by 0.8% in PHA. In the leaching solution, PHA and CP treatments reduced available phosphorus by 96.7% and 62.5%, increased calcium by 5.0% and 78.9%, decreased ammonium nitrogen by 2.2% and 43.4%, and decreased nitrate nitrogen by 10.6% and 13.0%. The PHA and CPHA treatments increased available phosphorus in the 0–20 cm soil layer by 1.4 times and 25.8%, respectively. (3) The CP treatment reduced ammonia volatilization by 87.0% compared to the P treatment, while the CPHA treatment further reduced it by 87.5% compared to the PHA treatment. The application of coated diammonium phosphate efficiently delays nutrient release and reduces nutrient leaching in the soil. Additionally, the integration of humic acid significantly improves the availability of phosphorus in the soil, minimizing phosphorus loss. Notably, the combined application of humic acid and coated diammonium phosphate leads to a significant increase in soil phosphorus content, subsequently enhancing soil nutrient availability, conserving fertilizer, and ultimately resulting in an improved wheat yield. [ABSTRACT FROM AUTHOR]

Aims: Plant and soil nitrogen (N) isotope ratios (δ15N) have been used as indicators of N cycling processes of ecosystems. However, the effects of N and Phosphorus (P) addition on δ15N values and their indicative roles in N-cycling in legume-dominated tropical forests remain poorly understood. Methods: We compared leguminous (Acacia auriculiformis) and non-leguminous (Eucalyptus urophylla) forests in terms of N concentration and δ15N in the leaf–litter–soil continuum under long-term N and P addition. Typical soil N-cycling processes, including rates of mineralization, nitrification, and N loss, were also examined to determine the differences between the corresponding 15N signatures observed in the leguminous and non-leguminous forests. Results: The plants in both tropical forests were found to be 15N-depleted. N addition significantly increased the foliage δ15N in understorey species in the non-leguminous but not the leguminous forest. In both forests, the addition of N resulted in an increase in nitrate (NO3−) leaching and nitrous oxide (N2O) emission. Conversely, P addition led to a decrease in NO3− leaching and N2O emission. Additionally, foliage δ15N was positively correlated with soil N loss rates (N2O emission and NO3− leaching) in the non-leguminous forest but showed no correlation in the leguminous forest. Conclusions: In contrast to the traditional convention derived from non-leguminous forests, our results suggest that foliar 15N isotope signals are not applicable for indicating the soil N dynamic status of leguminous forests. This study highlights the importance of distinguishing legumes from other plant species in terrestrial N-cycling models when incorporating 15N isotope signals. [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]

Background and aims: Increased nitrogen (N) deposition may exacerbate soil phosphorus (P) deficiency, which alters soil greenhouse gas (GHG) emissions by changing soil properties and understory vegetation in subtropical forests. However, the effects of N addition, P addition, and understory vegetation interactions on soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions in forest ecosystems and their underlying mechanisms remain unclear. Methods: We conducted a continuous N and P addition experiment in a subtropical Chinese fir plantation. The effects of N and P addition on soil CO2 and N2O emissions with different understory vegetation were examined using a structural equation model. Results: The addition of N and P did not directly affect soil CO2 emission of the understory, which was affected by understory species (F = 2.86; p = 0.05). N indirectly and positively affects soil CO2 emission through plant elements, and directly affect N2O emission of understory soil. Compared with CK, the addition of N2 promoted the N2O cumulative emission by 74.3%. N has a direct positive effect on soil N2O emissions, while P addition indirectly exerts a negative influence on N2O emissions through its impact on soil properties. Plant elements and soil properties were explained in 26.3% of soil CO2 emissions, of which 17.6% and 16.0% variations were explained by plant elements and soil properties, respectively. Leaf total N was the most important factor for predicting CO2 emissions. Conclusions: Our results suggested that soil CO2 emission was more dependent on plant elements, and soil N2O emission was directly dependent on N addition rather than plant elements. Thus, different patterns of soil GHG emissions and associated controls following N and P addition provided novel insights into predicting the effects of understory vegetation on climate change mitigation outcomes. [ABSTRACT FROM AUTHOR]

Human activities have profoundly altered the Earth's phosphorus (P) cycling process and its associated microbial communities, yet their global distribution pattern and response to human influences remain unclear. Here, we estimated the abundances of P‐cycling genes from 3321 global soil metagenomic samples and mapped the global distribution of five key P‐cycling processes, that is, organic phosphoester hydrolysis, inorganic phosphorus solubilization, two‐component system, phosphotransferase system, and transporters. Structural equation modeling and random forest analysis were employed to assess the impact of anthropogenic and environmental factors on the abundance of P‐cycling genes. Our findings suggest that although less significant than the climate and soil profile, human‐related factors, such as economic activities and population, are important drivers for the variations in P‐cycling gene abundance. Notably, the gene abundances were increased parallel to the extent of human intervention, but generally at low and moderate levels of human activities. Furthermore, we identified critical genera, such as Pseudomonas and Lysobacter, which were sensitive to the changes in human activities. This study provides insights into the responses of P‐cycling microbes to human activities at a global scale, enhancing our understanding of soil microbial P cycling and underscoring the importance of sustainable human activities in the Earth's biogeochemical cycle. [ABSTRACT FROM AUTHOR]

Grass cover in orchards has been proposed as a sustainable management system with greater ecological and economic benefits than open pastures. However, few studies have compared the ecological impact of grass-covered orchards with that of traditional tilled systems. Therefore, this meta-analysis was focused on evaluating the ecological benefits of grass cover in orchards on the soil physicochemical properties under different establishment modes and construction period in China. In total, 492 paired data points were extracted from 29 references, and effect values (ES) were calculated to show the effect of grass cover on soil physicochemical properties. The results showed that grass cover in orchards improved soil physicochemical properties by decreasing the soil bulk density (ES: -0.0659) of three soil layers (0–20 cm, 20–40 cm and 40–60 cm depth) and by decreasing soil pH in the alkaline areas (ES: -0.0219) of 0–20 cm and 20–40 cm soil layers. Grass cover in orchards also significantly improved the nutrient contents of the topsoil layer (0–20 cm depth), having the greatest effect on the total nitrogen content (ES: 0.1416), followed by that on the total phosphorus content (ES: 0.1002), and the weakest effect was observed on the total potassium content (ES: 0.0832). Grass cover in orchards significantly increased the soil available nitrogen content at all three soil depths (ES: 0.1608) and the soil available phosphorus content at the 0–40 cm soil depth (ES: 0.0788). However, no significant effect on the soil available potassium content was detected. Grass cover in orchards significantly increased soil organic matter content at all three soil depths (ES: 0.3734; P < 0.01), with the greatest effect occurring in the 40–60 cm soil layer (ES: 0.7972). Subgroup analysis of available nutrients in the 0–20 cm soil layer showed that 2–3 years after grass covering in orchards greatest promoting on the soil available nitrogen (ES: 0.2967) and phosphorus contents (ES: 0.1815), while the soil available potassium content decreased with construction period. In summary, grass cover in orchards has various effects on soil physicochemical properties, and these effects are closely related to soil layer depth, construction period, plant species and geographical region. Moreover, long-term monitoring is required to confirm the ecological influence of diverse types of grasses on soil properties in orchards. [ABSTRACT FROM AUTHOR]

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The growth of cover crops can contribute to the increase in phosphorus content at depth by root decomposition. The aim of this work was to verify the effect of cover crops on soil phosphorus availability and use by successive plants, and the accumulation of soil P in a no-tillage system conducted for 14 years. This research was carried out during the 2016/2017 and 2017/2018 crop seasons, whose treatments have been installed and maintained since 2003. The experimental design was a randomized block design, and the plots consisted of spring crops: pearl millet, forage sorghum, sunn hemp, and additionally, a fallow/chiseling area. The evaluation of available P was determined by P fractionation. In general, in the two years of evaluation, the accumulation of P in the shoot dry matter was higher in sunn hemp growth, on average 25% higher than pearl millet in 2016 and 40% higher than sorghum in 2017. The highest contents of labile inorganic P were in the sorghum–soybean and fallow/chiseling–soybean successions, with values higher than 50 mg kg−1 of P in the 0–0.1 m soil layer. However, in the other layers analyzed, the cover crops obtained higher availability of labile inorganic P. The systems using cover crops recovered 100% of the P fertilized in soybean. [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]

In order to evaluate the effects of continuous cropping of millet on soil nutrients and soil enzyme activities, the present study was based on four treatments of 2 years of continuous cropping (T1), 3 years of continuous cropping (T2), 4 years of continuous cropping (T3) and rotational cropping (CK), based on 4 years of no fertilizer positioning experiments, and the soil nutrients, soil enzyme activities and millets yields were determined, respectively. The results showed that with the increase of continuous cropping years, the millet yield decreased and was significantly lower than that of rotating with legume crops, and compared with CK, the yields of T1, T2 and T3 treatments were reduced by 8.92%, 13.73% and 37.60%, respectively; the soil nitrogen and phosphorus contents were reduced, the quick-acting potassium content did not change obviously, and the soil pH was increased; Soil urease, alkaline phosphatase, sucrase and catalase activities generally showed a decreasing trend and the decrease was more significant with the increase in the number of years of continuous cropping. Therefore, in order to maintain the soil fertility and increase the millet yield, it is necessary to practice crop rotation and stubble reversal between millets and leguminous crops such as kidney beans, and to apply certain fertilizers. [ABSTRACT FROM AUTHOR]

While the positive species–area relationship on islands is frequently observed, the mechanisms underlying this pattern remain poorly studied. By analyzing insular community diversity across spatial scales and the soil properties within the islands, we were able to explore potential mechanisms leading to the island species–area relationship of plants, as well as associated soil bacteria and fungi, from a tropical archipelago. We found that both plant and soil microbial communities showed similar positive species–area relationships across scales and the greater taxonomic diversity on larger islands was mainly driven by the higher richness within samples. These patterns arose primarily due to shifting habitat quality with island area, rather than spatial processes generally attributed to species–area relationships. Specifically, for plants, changes in soil total phosphorus content with island area were most explanatory, while changes in soil pH appeared to play the most important role in shaping soil bacteria and fungi patterns. By contrast, we found little evidence for the role of spatial processes (i.e. dispersal limitation or soil heterogeneity) within the island. Overall, this study highlights the importance of dissecting potential mechanisms underlying multi‐trophic community dynamics to explain patterns of biodiversity and its variation on islands. [ABSTRACT FROM AUTHOR]

Background: Transforming coniferous plantation into broadleaved or mixed broadleaved-coniferous plantations is the tendency of forest management strategies in subtropical China. However, the effects of this conversion on soil phosphorus (P) cycling microbial functional genes are still unknown. Methods: Soil samples were collected from 0-20, 20-40, and 40-60 cm (topsoil, middle layer, and subsoil, respectively) under coniferous Pinus massoniana (PM), broadleaved Erythrophleum fordii (EF), and their mixed (PM/EF) plantation in subtropical China. Used metagenomic sequencing to examine the alterations of relative abundances and molecular ecological network structure of soil P-cycling functional genes after the conversion of plantations. Results: The composition of P-cycling genes in the topsoil of PM stand was significantly different from that of PM/EF and EF stands (p < 0.05), and total phosphorus (TP) was the main factor causing this difference. After transforming PM plantation into EF plantation, the relative abundances of P solubilization and mineralization genes significantly increased in the topsoil and middle layer with the decrease of soil TP content. The abundances of P-starvation response regulation genes also significantly increased in the subsoil (p < 0.05), which may have been influenced by soil organic carbon (SOC). The dominant genes in all soil layers under three plantations were phoR, glpP, gcd, ppk, and ppx. Transforming PM into EF plantation apparently increased gcd abundance in the topsoil (p < 0.05), with TP and NO3--N being the main influencing factors. After transforming PM into PM/EF plantations, the molecular ecological network structure of P-cycling genes was more complex; moreover, the key genes in the network were modified with the transformation of PM plantation. Conclusion: Transforming PM into EF plantation mainly improved the phosphate solubilizing potential of microorganisms at topsoil, while transforming PM into PM/EF plantation may have enhanced structural stability of microbial P-cycling genes react to environmental changes. [ABSTRACT FROM AUTHOR]

Despite fertilization efforts, phosphorus (P) availability in soils remains a major constraint to global plant productivity. Soil incorporation of biochar could promote soil P availability but its effects remain uncertain. To attain further improvements in soil P availability with biochar, we developed, characterized, and evaluated magnesium-oxide (MgO) and sepiolite (Mg4Si6O15(OH)2·6H2O)-functionalized biochars with optimized P retention/release capacity. Field-based application of these biochars for improving P availability and their mechanisms during three growth stages of maize was investigated. We further leveraged next-generation sequencing to unravel their impacts on the plant growth-stage shifts in soil functional genes regulating P availability. Results showed insignificant variation in P availability between single super phosphate fertilization (F) and its combination with raw biochar (BF). However, the occurrence of Mg-bound minerals on the optimized biochars' surface adjusted its surface charges and properties and improved the retention and slow release of inorganic P. Compared to BF, available P (AP) was 26.5% and 19.1% higher during the 12-leaf stage and blister stage, respectively, under MgO-optimized biochar + F treatment (MgOBF), and 15.5% higher under sepiolite-biochar + F (SBF) during maize physiological maturity. Cumulatively, AP was 15.6% and 13.2% higher in MgOBF and SBF relative to BF. Hence, plant biomass, grain yield, and P uptake were highest in MgOBF and SBF, respectively at harvest. Optimized-biochar amendment stimulated microbial 16SrRNA gene diversity and suppressed the expression of P starvation response and P uptake and transport-related genes while stimulating P solubilization and mineralization genes. Thus, the optimized biochars promoted P availability via the combined processes of slow-release of retained phosphates, while inducing the microbial solubilization and mineralization of inorganic and organic P, respectively. Our study advances strategies for reducing cropland P limitation and reveals the potential of optimized biochars for improving P availability on the field scale. Article Highlights: MgO and sepiolite doping optimized biochar's surface properties for phosphorus (P) retention and slow release The potential formation of Mg-PO4 phases on the optimized biochar surface regulated P retention and release MgO and sepiolite-ptimized biochars increased soil available P by promoting microbial P mineralization and solubilization. [ABSTRACT FROM AUTHOR]

In biogeochemical phosphorus cycling, iron oxide minerals are acknowledged as strong adsorbents of inorganic and organic phosphorus. Dephosphorylation of organic phosphorus is attributed only to biological processes, but iron oxides could also catalyze this reaction. Evidence of this abiotic catalysis has relied on monitoring products in solution, thereby ignoring iron oxides as both catalysts and adsorbents. Here we apply high-resolution mass spectrometry and X-ray absorption spectroscopy to characterize dissolved and particulate phosphorus species, respectively. In soil and sediment samples reacted with ribonucleotides, we uncover the abiotic production of particulate inorganic phosphate associated specifically with iron oxides. Reactions of various organic phosphorus compounds with the different minerals identified in the environmental samples reveal up to ten-fold greater catalytic reactivities with iron oxides than with silicate and aluminosilicate minerals. Importantly, accounting for inorganic phosphate both in solution and mineral-bound, the dephosphorylarion rates of iron oxides were within reported enzymatic rates in soils. Our findings thus imply a missing abiotic axiom for organic phosphorus mineralization in phosphorus cycling. Iron oxides serve as both adsorbents and catalysts to generate inorganic phosphorus from organic phosphorus in environmental matrices. This abiotic dephosphorylation, which is comparable to enzymatic rates, is a missing piece in phosphorus cycling. [ABSTRACT FROM AUTHOR]

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

Summary: Soil phosphorus (P) is a growth‐limiting nutrient in tropical ecosystems, driving diverse P‐acquisition strategies among plants. Particularly, mining for inorganic P through phosphomonoesterase (PME) activity is essential, given the substantial proportion of organic P in soils. Yet, the relationship between PME activity and other nutrient‐acquisition root traits remains unclear.We measured root PME activity and commonly measured root traits, including root diameter, specific root length (SRL), root tissue density (RTD), and nitrogen concentration ([N]) in 18 co‐occurring species across soils with varying P availability to better understand trees response to P supply.Root [N] and RTD were inversely related, and that axis was not clearly related to soil P supply. Both traits, however, correlated positively and negatively with PME activity, which responded strongly to P supply. Conversely, root diameter was inversely related to SRL, but this axis was not related to P supply.This pattern suggests that limiting similarity influenced variation along the diameter–SRL axis, explaining local trait diversity. Meanwhile, variation along the root [N]–RTD axis might best reflect environmental filtering. Overall, P availability indicator traits such as PME activity and root hairs only tended to be associated with these axes, highlighting limitations of these axes in describing convergent adaptations at local sites. See also the Commentary on this article by Dallstream & Soper, 243: 509–512. [ABSTRACT FROM AUTHOR]

The fermentation process for Jiang-flavored baijiu using sorghum as the raw material involves a variety of microorganisms. However, the specific physicochemical characteristics of sorghum and microbial composition on its surface have not been fully elucidated. We aimed to perform a comprehensive comparative analysis of the variations in physicochemical properties and surface microflora in waxy sorghum samples from three prominent production regions in China (Renhuai, Jinsha, and Duyun). Multivariate statistical assessments were conducted that incorporated local soil and climate variables. The results showed that Cyanobacteria, unclassified bacteria, Proteobacteria, Firmicutes, and Bacteroidota were the dominant bacteria in these regions. These bacteria were associated with ethyl acetate, ethyl caprylate, ethyl lactate, and butyl groups, which synergistically produce flavorful compounds. The surface bacterial communities were affected by soil total phosphorus, altitude, diurnal temperature range, monthly mean temperature, precipitation, and effective accumulated temperature. The findings of this study provide a new perspective on microorganisms related to Jiang-flavored baijiu and can help establish a reference for the stability of liquor quality. [ABSTRACT FROM AUTHOR]

AbstractPhytoextraction is an attractive method to extract excess soil phosphorus (P) builds up from the soils. The crops potential to extract an enriched P in soil is still lacking. Therefore, four crops were grown in three different soils with variable P levels (0 to 200 mg P/kg soil) and screened for P acquisition potentials. Total P accumulation in roots and shoot was high with enriched P levels in all soils, for example in soil A at 200 mg P/kg soil, the values were 0.44% for cucumber (Cucumis sativus), 0.40% for sunflower (Helianthus annus), and ∼0.30% for cabbage (Brassica oleracea) and 0.20% for Indian mustard (Brassica juncea). The cucumber and sunflower showed a greater biomass production (>6.0 g/pot) with enriched P levels and exhibited more prominent root characteristics, suggests more favorable for P acquisition from the P enriched soils. More prominent enhanced phosphomonoesterase and phytase activities in these crops possibly contributing to their P accumulation ability under high soil P conditions. This study shows that, cucumber and sunflower can generate high dry matter content and can accumulate greater quantity of P from the soils through different mechanisms and they can be potential candidates for phytoextraction of P from the soil P enriched areas. [ABSTRACT FROM AUTHOR]

Forest management changes the physical environments and nutrient dynamics and then regulates the forest productivity. Soil phosphorus (P) availability is critical for productivity in tropical and subtropical forests. However, it was still poorly understood howsoil P content and fraction respond to various forest management practices in these regions. Here, we measured the soil total P, available P, and Hedley's P fractions, including inorganic and organic P (Pi and Po), in subtropical pine plantations treated with understory removal (UR), non-dominant species thinning (NDST) and dominant species thinning (DST) after nine years. Compared to plantations without management (CK), treatments such as UR, NDST, and DST decreased soil total P at 0--10 cm and soil available P at 0-- 10 cm and 10--20 cm. Increases in resin-Pi, NaOH-Pi, and C.HCl-Pi resulted in a higher total Pi in 0--10 cm (p < 0.05) in treated plots (UR, NDST, and DST) than in CK plots. UR, NDST, and DST treatments increased NaHCO3-Po and NaOH-Po (p < 0.05) but decreased C.HCl-Po at a depth of 0--10 cm. Regardless of management treatments, soil total P, available P, and P fractions in 0--10 cm showed higher contents than those in 10--20 cm. There were positive relationships between total P and total Po (p < 0.01) and between available P and total Pi. There were also positive relationships between total P, available P, NaHCO3-Pi, and NaOH-Pi (p < 0.05). In conclusion, forest management such as UR, NDST, and DST decreased soil total P and available P, and transforming soil P fractions to available P will meet the P demand following management in the pine plantations of subtropical China. [ABSTRACT FROM AUTHOR]

Efficient utilization of agricultural soil phosphorus (P) and mitigation of loss risks necessitate a precise evaluation of soil P storage capacity (SPSC). This study compared the effectiveness of four soil test P methods (Oxalate, Bray, Olsen, and Mehlich-1) to accurately estimate SPSC and simplify P loss risk assessment of soils located in a typical red soil in the Sunjia Watershed, Yingtan, Jiangxi Province, China. The extraction efficiencies of these methods for Fe, Al, P, and P saturation ratio (PSR) were compared, and conversion equations between SPSCOx (extracted using Oxalate) and soil test P (Bray, Olsen, and Mehlich-1) were derived through fitting analysis. The results underscored Oxalate as the optimal extractant for gauging P loss risk in red soils. Structural equation modeling (SEM) unveiled the substantial impact of amorphous iron-aluminum oxides (Feo, Alo) on SPSC, with Feo exerting a more pronounced influence than Alo. Among soil physicochemical properties, total carbon emerged as the most influential, and a strong interaction was noted between the physicochemical properties and Feo and Alo. The study delineated three crucial P concentration ranges for practical P management in red soils. When Bray-P < 48.2 mg kg–1, the soil acted as a P sink with no P loss risk, allowing for continued P application to augment crop yield. Conversely, within 48.2 mg kg–1 < Bray-P ≤ 55.2 mg kg–1, the soil attained its maximum secure P capacity; further P application significantly escalated the peril of P loss. Subsequently, when Bray-P > 55.2 mg kg–1, the soil turns into a source of P release. This signifies an escalated risk of P loss, demanding the immediate implementation of environmental protective measures. [ABSTRACT FROM AUTHOR]

Phosphorus is one of the major constraints to karst grassland productivity. Understanding the effects of different fertilization practices on soil phosphorus dynamics is essential for enhancing phosphorus bioavailability and rational management of soil phosphorus in karst grasslands. Here, we investigated the effects of fertilizers and manures on soil bioavailability of phosphorus fractions and explored the relationship between soil properties and soil phosphorus fractions. The four fertilizer application designs were as follows: control (CK; no fertilizer or manure); fertilization (F); manure application (M); fertilization and manure application (FM). The results showed that total phosphorus (TP) concentration was elevated by 23%, 1%, and 42% in F, M, and FM treatments, respectively, compared with CK. F and FM treatments enhanced the total inorganic phosphorus (Pi) concentration by 65% and 66%, respectively, while M and FM treatments enhanced the total organo-phosphorus (Po) concentration by 21% and 35%, respectively. FM treatment elevated bioavailable P, active Po, secondary mineral P, primary mineral P, and occluded P by 69%, 39%, 50%, 31%, and 41%, respectively. Fertilizers inhibited soil acid phosphatase activity, whereas alkaline phosphatase did not respond significantly to fertilizer management in low-latitude karst regions. SOM, TN, AP, and MBP are the key factors affecting the bioavailability of phosphorus fractions. The combined application of fertilizer and manure is the most beneficial measure for enhancing soil phosphorus bioavailability. This research helps deepen our understanding of soil phosphorus dynamics in the karst areas and provides a basis for further enhancement of nutrient availability and vegetation productivity of grassland ecosystems. [ABSTRACT FROM AUTHOR]

Organic fertilizers produced from agricultural waste materials using earthworms have many advantages. The impact of vermicompost bio-organic fertilizer (VcF) prepared from waste mushroom bran on the quality of Chinese herbal medicine and soil health deserves attention. We conducted a field experiment to explore the quality of Rhizoma atractylodis and soil, using chemical fertilizer and VcF at dosages of 30 t·ha−1 and 40 t·ha−1. The results demonstrated that VcF significantly increased the contents of atractylenolide II, β-eudesmol, atractylenol, and atractylenolone by 34%, 175%, 72%, and 24%, respectively, along with a 70% increase in yield compared to the control. VcF significantly increased the available phosphorus content and the activity of the soil enzymes (α-Galactosidase, β-Galactosidase, and peroxidase), while reducing the nitrate nitrogen content. The addition of vermicompost did not change the soil bacterial diversity, while it significantly increased the soil fungal diversity. VcF improved the soil fungal diversity and significantly enhanced the relative abundance of the bacterial phylum Actinobacteriota and WPS-2, as well as the fungal phylum Ascomycota. Vermicompost significantly increased the relative abundance of bacteria phylum Actinobacteriota and WPS-2, as well as the fungi phylum Ascomycota. Actinobacteria mainly participate in the decomposition of detritus and the heterotrophic nutrient cycle. A Principal Coordinates Analysis of the soil bacterial and fungi communities suggested a significant impact of vermicompost application on the community structure of the soil bacteria. Conversely, no significant variance was detected in the bacterial community composition across the two levels of vermicompost. This study contributes to the enhancement of fertilization strategies for Atractylodes macrocephala, broadens the application scope of vermicompost, and advances the growth of organic agriculture. [ABSTRACT FROM AUTHOR]

Alpine grassland ecosystems are the most important ecosystem type, exhibiting a high sensitivity to anthropogenic nitrogen (N) and phosphorus (P) inputs into terrestrial ecosystems and significantly affecting the carbon (C) cycle within these ecosystems. However, the effects of N and P additions on soil C stability and the processes of organic C transformation remain unclear. This study measured the soil enzyme activities and oxidizable C fractions over a 9-year period following N and P additions to an alpine meadow in the Qinghai–Tibet Plateau. It included four treatments: control (CK), N addition, P addition, and combined N and P addition (NP), utilizing statistical methods such as analysis of variance (ANOVA), correlation analysis, and redundancy analysis. The findings indicated that NP addition significantly increased the non-labile soil oxidizable C fraction in the topsoil layer. Redundancy and correlation analyses revealed strong associations between the vegetation characteristics, C-cycling enzyme activities, soil-oxidized C fractions, and SOC stability index. These results underscore the role of NP addition in enhancing SOC accumulation and stability in grassland ecosystems, with the soil vegetation properties and C source enzyme activities serving as key regulators of the SOC stability. This study offers valuable insights into predicting the SOC dynamics amid rising N and P availability, thereby elucidating the effect of nutrient addition on soil C-cycling mechanisms. [ABSTRACT FROM AUTHOR]

Land use changes and reforestation impact soil phosphorus (P) distribution over extended periods. This study examines P distribution in forest development from 1957 to 2017 at the Calhoun Critical Zone Observatory in South Carolina. Tracking changes in 0–60 cm mineral soil P fractions through six samplings in eight continuously uncut plots and eight plots cut in 2007 (replanted in 2009), we hypothesized an increase in soil organic P (Po) over time in uncut plots, at the expense of HCl‐extractable P (i.e., Ca‐P). This hypothesis is based on the expectation of a transfer of P from easily accessible forms, possibly from historic fertilization to organic reservoirs within the soil. Meanwhile, we expect to lose Po in cut plots due to disturbance and residue decomposition, and increase bioavailable Mehlich‐III extractable P (Mehlich‐III P), resin inorganic phosphorus (Pi), and HCO3 Pi. Results revealed a continued decrease in Mehlich‐III P in uncut (38.7–15.7 µg g−1) and cut plots (25.2–17.7 µg g−1) within the 0–7.5 cm range. NaOH‐Po in uncut plots remained stable, while in cut plots, it increased by ∼4 µg g−1 in the 0–7.5 cm soil layer. Slowly cycling Po (NaOH‐Po) increased during forest regrowth in the cut plots, aligning with rising soil organic carbon and decreasing soil pH. Soil P changes indicate minor declines in available fractions during the initial three decades, with the HCl extractable (Ca‐P) fraction experiencing the highest depletion. In the later three decades, P associated with NaOH extraction (i.e., iron [Fe] and aluminum [Al] bound P) declined, although estimated mineral soil P removals during this period were less than accumulated P in tree biomass and forest floor. The total soil P decline from 1990 to 2017 was 34 kg ha−1, suggesting a growing role of P recycling from debris decomposition in supplying soil P to plants. Core Ideas: Phosphorus distribution in mineral soils is dynamic across a forest's developmental timeline from 1957 to 2017.Phosphorus recycling from forest floor and soil organic P contributes to plant nutrient supply.An agricultural fertilization legacy is still influencing long‐term phosphorus cycling.The decadal timescale of this study highlights the role of slowly cycling phosphorus fractions over extended time scales. [ABSTRACT FROM AUTHOR]

Manure relocation strategies are needed to mitigate excessive phosphorus (P) application to agricultural land in areas of intensive animal agricultural production. This requires conceptual frameworks such as the manureshed, which categorizes agricultural areas according to the potential to export or receive manure for P fertilization. To further understand how the manureshed concept could be utilized, assessments of the potential implementation and necessity of the manureshed model are needed. With North Carolina at the center of the largest manureshed in the United States, North Carolina is an ideal test case to identify areas of concern for manure relocation under the manureshed framework. Swine and poultry dominate North Carolina's agricultural production, and because the vast majority of North Carolina producers are not required to limit manure applications to a P‐based rate, P accumulates. Therefore, soil test data from samples submitted to the North Carolina Department of Agriculture and Consumer Services (NCDA&CS) from 2017 to 2019 were used to determine how manureshed classes defined by Spiegal et al. correspond to current soil test P levels. It was determined that 36% of counties experience very high (>100 mg P kg−1; N = 36) median P concentrations in soil. Furthermore, fields cultivated with warm‐season forages had the highest mean P concentration (188 mg kg−1) and high median P trended toward counties with high animal production. Lastly, while mean soil P for all manureshed classifications fell into the very high category, manure source counties had the highest mean soil P concentrations (188 mg kg−1), which was 39%–52% higher than the other classifications. This suggests that, in addition to manuresheds classification, soil test data are needed to design and promote manure redistribution strategies. Core Ideas: Soil tests confirm the accumulation of phosphorus in areas of intense livestock production.Redistribution of manure based on the manuresheds concept should include counties identified for within county transfers adjacent to manure source counties.Soil test reports add valuable context when making decisions regarding manure relocation strategies. [ABSTRACT FROM AUTHOR]

Closed depressions are common landscape features across glaciated landscapes. Erosion and runoff from depression hillslopes may result in phosphorus (P) accumulation near the bottom of the depression, with this "legacy P" potentially at risk of loss to surface waters when drained via tile drainage. We assessed spatial patterns of soil P within a tile‐drained watershed in northeastern Indiana as a function of landscape position and agricultural management practices. Paired soil samples (depression bottom vs. hillslope contributing area) were collected from agricultural (n = 14) depressions at four depths (0–60 cm). Water‐extractable phosphorus (WEP), Mehlich‐3 extracted phosphorus (M3‐P), total phosphorus (TP), Hedley P fractions, and other physical and chemical characteristics were determined. To assess the risk of P loss, P desorption from surface soils (0–5 cm) was quantified using flow‐through experiments. Results showed that WEP, M3‐P, and TP were 2–10 times greater in the depression bottom compared to hillslopes across all depths. Long‐term management practices such as P application history and tillage influenced the magnitude of soil P concentration, degree of P saturation, and vertical stratification of soil P. Flow‐through experiments highlighted that the risk of P loss was highly dependent on M3‐P concentration for both hillslope and depression soils. Findings therefore indicate that closed depressions may act as hotspots for P cycling and loss in tile‐drained watersheds. Including low‐lying depressional areas as part of a routine soil sampling strategy combined with variable rate P application could lessen P accumulation in depressions and reduce P loading to surface waters. Core Ideas: Phosphorus accumulation in closed depressions of a tile‐drained watershed was assessed.WEP, Mehlich‐3 extracted phosphorus (M3‐P), and total P were significantly greater near the depression bottom compared to hillslopes.Topography and agricultural management influenced P accumulation within depressions.Phosphorus desorption during flow‐through experiments showed that P loss was dependent on M3‐P concentration.Soil sampling in depressions combined with variable rate P application could reduce the risk of P loss. [ABSTRACT FROM AUTHOR]

Purpose: Selection for root traits has become a target in (pre-)breeding programs aiming at improving crop ability to capture soil resources. However, the benefit of selected traits in heterogeneous target environments will depend on spatial and temporal interactions between root systems, the soil environment (fertility and water supply) and management (fertiliser placement). Methods: We assessed growth and phosphorus acquisition of durum wheat (Triticum durum L.) lines defined by contrasting seminal root angles (41° 'Narrow' vs 82° 'Wide'), in response to different soil phosphorus placements and seasonal water dynamics. Responses were evaluated in clear pots (seedlings), rhizoboxes (late-tillering stage) and a custom lysimeter system (flowering stage). Results: The Narrow genotype increased deep soil exploration (down to 50 cm) during early growth, with a tendency to more rapidly acquire phosphorus placed as a deep fertiliser band (25 cm depth). However, genotypic differences in shoot biomass or phosphorus uptake were not apparent at anthesis, in part due to phosphorus-induced changes in phenological development. Contrastingly, the wide genotype increased root growth in the topsoil (0–10 cm) when phosphorus was stratified in this layer and produced greater biomass at anthesis under these conditions. Shoot and root biomass and phosphorus uptake decreased when the topsoil dried out, with the greatest effect observed for phosphorus stratified in this layer. Conclusion: The benefits of the selected root angle trait strongly depend on nutrient and water distributions and dynamics in the target environment. Ideotype breeding efforts and farmer selection of genotypes should consider the context in which genotypes will be deployed. Highlight: The interaction between root system architecture and heterogeneous distributions of phosphorus and available water determine the relative performance of durum wheat genotypes with contrasting root angles. [ABSTRACT FROM AUTHOR]

Phosphorus (P) limitation in acidic soils is well known and P-use and -recovery efficiency (PUE and PRE) is quite low. Rhizosphere-based P management has been considered as a means of enhancing PUE in acidic rice soils, but no clear dynamic study on this context. Rice was grown in pots using different P-sources [rock-phosphate (RP), single-super-phosphate (SSP), compost, P solubilizing bacteria (PSB), PSB + RP, PSB + compost, and compost + PSB + RP] in acidic Inceptisols (pH 4.31). Additionally, a micro-plot field experiment validated the results, using control, SSP, RP, PSB, and PSB + RP. Available-P (AvlP) and pH were analyzed every 10-days, while acid-phosphomonoesterases activity (PHA) and P-uptake in every 30-days until harvest. AvlP was peaked at 20 days after transplanting (DAT) and decreased until harvest. Compost + PSB + RP maintained significantly higher AvlP, soil pH and PHA, while root volume was highest in SSP throughout the growing period, and Soil pH showed an asymptotic trend. The P-content and uptake in biomass showed the highest peak at 60DAT and gradually declined until harvest. The effects of SSP and compost + PSB + RP on grain yield, chlorophyll concentration index (CCI), grain P content and uptake were comparable, but PUE and PRE were higher in compost + PSB + RP. Similar result was also observed in micro-plot field experiment, wherein grain yield and P uptake were comparable in SSP broadcast and PSB + RP. The study clearly shows that the combined application of PSB with RP, compost, or both in a 50% reduced amount can maintain higher AvlP in rice in acidic soil compared to full dose SSP while achieving a comparable yield. [ABSTRACT FROM AUTHOR]

Organic phosphorus(Po)is an important part of soil phosphorus reservoir. In order to investigate the effects of soil aggregate Po distribution properties in Pinus massoniana plantations after close-to-nature transformation, the pure P. massoniana plantations(PP)and P. massoniana-broad-leaved mixed plantations(CP)after close-to-nature transformation were investigated in southern subtropical China. Soil samples collected from 1-10 cm were screened into >2 mm, 0. 25-2 mm and <0. 25 mm three-part aggregates using the dry-sieving method. The Po fraction, microbial biomass phosphorus(MBP)content and acid phosphatase(ACP)activity in the bulk soil and aggregates were measured to understand the distribution of the Po fraction and its drivers. The results were as follows: (1)Soil Po fractions changed in CP compared to PP, with highly recalcitrant organic phosphorus(HRO-P)and moderately labile organic phosphorus(MLO-P)significantly greater in the bulk soil and soil aggregates than in PP(P<0. 05), while labile organic phosphorus(LO-P)and moderately recalcitrant organic phosphorus(MRO-P)were not significantly different in CP and PP. In addition, there was no consistent pattern of change in Po fractions in the bulk soil and soil aggregates between PP and CP. (2)The size of the proportion of each form of Po in PP was HRO-P>MRO-P>MLO-P>LO-P, while CP was HRO-P>MLO-P>MRO-P>LO-P. (3)The MBP content and ACP activity in CP were significantly greater than that of PP in the bulk soil and soil aggregates, and there was a tendency for the ACP activity to increase with the decrease in the size of aggregates. (4)Redundancy analysis revealed that soil available phosphorus(AP), soil aggregate mean weight diameter(MWD), MBP and total nitrogen(TN)were the main drivers of soil Po fractions. In conclusion, the close-to-nature transformation is beneficial to the accumulation and transformation of soil phosphorus in P. massoniana plantation. This study provides a theoretical reference for the improvement of soil quality and productivity in P. massoniana plantations. [ABSTRACT FROM AUTHOR]

The objective of this study was to compare the effects of grazing and non-grazing on the physicochemical properties, stoichiometry, ecto-enzyme activities, and microbial element limitations of soils at five depths in subtropical grassland, China, and to identify the influencing factors of enzyme activities and element limitations. Results showed that grazing, soil depth, and the interaction between grazing and depth remarkably changed soil available phosphorus (AP), available potassium (AK), available calcium (ACa) and available magnesium contents (AMg), bulk density (BD), water content (WC), and β-glucosidase activity (βGC) (p = 6.702e-9 - 0.04739). Compared with no g razing, g razing remarkably declined the 0-5 cm soil AP by 73.10% (p = 0.0250), the 0-5, 5-10, 10-20 cm soil WC by 47.19% (p = 0 .0042), 3 7.19% ( p = 0 .0090), a nd 3 0.80% ( p = 0.0034), however, grazing remarkably increased the 0-5, 5-10, 10-20, 20-30 cm soil ACa by 188.76% (p = 7.9e-05), 93.24% (p = 0.0177),84.18% (p = 0.00067), and 38.77% (p = 0.01368), the 0-5, 5-10 cm soil AMg by 186.69% ( p = 0.0016), 78.89% (p = 0.0109), t he 0-5, 5-10, 1 0-20 c m s oil pH b y 0 .51 ( p = 0.0013), 0.37 (p = 0.0006), and 0.27 (p = 0.0114) units, the 0 -5, 5-10, 10-20 cm soil BD by 59.03% ( p = 0.0077), 44.14% ( p = 0.0147), and 35.55% (p = 0.0071), the 30-50 cm soil WC by 22.88% (p = 0.0241), the 0-5 cm soil βGC by 89.49% (p = 0.0011), the 0-5, 5-10 cm soil ACP by 7.87% (p = 0.0300), 6.57% (p = 0.0240), respectively. Grazing exacerbated the microbial C limitation of 0-5 and 10-20 cm soils by 20.51% (p = 0.0078) and 40.38% (p = 0.0209) and switched the soil microbiome from under N limitation to under P limitation at 5-10 cm (p = 0.0390). Specific soil available cations were identified as the important factors that significantly explained the variation of soil ecto-enzyme activities and soil microbial carbon and nutrient limitations. These findings present basic information for the future improvement management of subtropical grassland and understanding the impact of grazing on microbial element limitation. [ABSTRACT FROM AUTHOR]

In view of the lack of considering index weight and less nutritional status classification in maize crop’s nutritional status identification, an identification method of maize crop’s nutritional status based on index weight is studied. Based on the five aspects of Agronomic and soil properties, 15 identification indexes such as plant height and soil available phosphorus content are selected to construct the identification index system of maize crop’s nutritional status. Through the evidence fusion process, the subjective weight calculation method is combined with the objective weight calculation method to calculate each identification index system. The nutritional status of maize crops is divided into nine grades: extreme poor nutrition to extreme severe eutrophication. Samples are generated by random interpolation between the values of grade standard domain. The probabilistic neural network recognition model is constructed, and the randomly generated samples are used to train and test the model to obtain the recognition model architecture that meets the accuracy requirements. The weight of each index and the normalized sample index matrix are calculated and input into the trained recognition model to obtain the recognition results of nutritional status of corn crop samples. The test results show that the index weight obtained by this method has higher reliability and can meet the application needs of maize crop’s nutritional status identification. [ABSTRACT FROM AUTHOR]

AbstractPhosphatic fertilizers applied to soil, with time, alters into different insoluble soil phosphorus fractions. Since P fertilizers are expensive and raw material supplies are limited, it is essential to evaluate changes in phosphorus fractions and balance in soil in order to determine appropriate phosphorus fertilizer management strategies for sustainable yields. A long-term experiment (20 years) was conducted in an inceptisol with rice-rice cropping system. Soil samples were collected from six treated plots and one fallow; analyzed for phosphorus fractions using sequential extraction method. Phosphorus balance was computed. The results reveled that yield was 51.5, 112.0, 147.7 and 116.7% higher under 50% NPK, 100% NPK, 150% NPK and 100% NPK + FYM over control. Irrespective of the treatments, the abundance of the various fractions of phosphorus (P) in soil as follows: Organic P (32.4% of total P) > Calcium-P (27.76% of total P) > Mineral P (24.17% of total P) > Iron-P (6.65% of total P) > Aluminum-P (3.46% of total P) > Reductant soluble P (3.22% total P) > Occluded P (1.44% of total P) > Saloid P (0.89% total P). Phosphorus activation coefficient (%) was recorded higher under 150% NPK followed by 100% NPK + FYM > 100% NPK > 50% NPK > 100% N > control > Fallow. Hence, 100% NPK + FYM treatment has maintained phosphorus fractions in a good proportion and sustainable yields under rice-rice cropping system. [ABSTRACT FROM AUTHOR]

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Anthropogenic inputs of nitrogen (N) and phosphorus (P) to terrestrial ecosystems alter soil nutrient cycling. However, the global‐scale responses of soil P fractions to N and P inputs and their underlying mechanisms remain elusive. We conducted a global meta‐analysis based on 818 observations of soil P fractions from 99 field N and P addition experiments in forest, grassland, and cropland ecosystems ranging from temperate to tropical zones. Our global meta‐analysis revealed distinct responses of soil P fractions to N and P enrichment. For studies using the Chang and Jackson inorganic (Pi) method, we found that high N addition promoted the transformation of immobile Pi fractions into Ferrum/Aluminum‐bound Pi and available Pi in surface soils through soil acidification. However, this acid‐induced transformation of Pi fractions by N addition was observed only in Calcium‐rich soils, while in acidic soils, further acidification led to increase P binding. In contrast, additions of P alone or combined with N significantly increased all soil Pi fractions. Regarding the Hedley P fractions, N addition generally decreased labile organic P by enhancing soil acid phosphatase activity. The responses of other P fractions were influenced by soil pH, fertilization rates, ecosystem type, and other factors. P addition increased most soil P fractions. Overall, both P fractionation methods consistently demonstrate that N inputs deplete soil P and accelerate P cycling, while P inputs increase most soil P fractions, alleviating P limitation. These findings are crucial for predicting the effects of future atmospheric N and P deposition on P cycling processes. Plain Language Summary: Human activities have increased the amount of nitrogen (N) and phosphorus (P) in the environment, which has led to changes in the soil nutrients cycle. This study examined the global‐scale responses of soil P fractions to N and P inputs using a data set from 99 field experiments worldwide. The findings revealed distinct responses of soil P fractions to N and P enrichment. High N input resulted in the transformation of immobile inorganic P (Pi) fractions into available Pi in surface soils. This transformation was observed in calcium‐rich soils due to soil acidification. In contrast, in acidic soils, the acidification led to increased Pi binding. Moreover, N input generally decreased labile organic P, potentially by enhancing soil enzyme activity. Addition of P alone or combined with N significantly increased soil P fractions. These findings have important implications for predicting the effects of future N and P deposition on P cycling processes in the terrestrial ecosystems and understanding the impacts of nutrient enrichment on soil carbon storage and eutrophication. Key Points: Nitrogen inputs can accelerate phosphorus (P) transformation in Calcium‐rich soils but promote P binding in acidic soilsSoil acidification reduces inorganic P bioavailability by increasing the P fixation of Ferrum and Alumiium oxidePhosphorus input increases soil labile, moderately labile, and occluded inorganic P, enhancing soil available P [ABSTRACT FROM AUTHOR]

Pinus thunbergii and Euonymus japonicus are two species commonly found in arid and semi-arid areas; however, their responses in terms of physiological traits and soil properties under drought and cadmium (Cd) stress are not clear. In this study, we carried out single and combined stress treatments consisting of drought and Cd on saplings of P. thunbergii and E. japonicus and investigated the responses in terms of the physiological traits and soil properties of both species. For both species, under single Cd stress, Cd was observed in both the xylem and phloem, while the root Cd2+ flow rate fluctuated at different levels of Cd stress. Under both single and combined stress, as the stress level increased, the abscisic acid (ABA) content of the leaves and roots increased significantly, while the indole-3-acetic acid (IAA) content of the leaves and roots decreased significantly. Moreover, the non-structural carbohydrate (NSC) content of the leaves, stems, and roots, as well as the leaf chlorophyll content, decreased significantly. Under drought stress, the xylem water potential and hydraulic conductivity significantly decreased, which was exacerbated by Cd stress; this led to a more significant decrease in water potential and hydraulic conductivity under the combined stresses. Meanwhile, no significant changes in the conduit lumen diameter and double-wall thickness were observed, except for the double cell wall thickness of the P. thunbergii tracheid, which increased. In addition, both the single stresses and the combined stress of drought and Cd induced significant changes in the soil properties of the two species, i.e., the ammonium nitrogen, nitrate nitrogen, and effective phosphorus of the soil increased significantly, and the increase in content was more significant under combined stress. The diversity of the soil microbial community of P. thunbergii saplings significantly increased, while no change was found in its microbial community abundance under the single stresses and combined stress; however, the diversity and abundance of the soil microbial community in E. japonicus saplings showed the opposite pattern, which indicates that the effect of Cd on soil microorganisms is more significant than the effect of drought. The activity of sucrase and catalase in P. thunbergii soil fluctuated under the single stress and combined stress when compared, and the activity of sucrase in the soil of the E. japonicus species decreased. However, its catalase activity increased significantly under the single drought and Cd stress and combined stress when compared. We found that the combined stresses exacerbated the effects of the single stress in both species. Our study provides more detailed information on the responses in terms of the physiological traits and soil properties of the two species under single and combined stress consisting of drought and Cd. [ABSTRACT FROM AUTHOR]

Agricultural activities contribute significantly to the pollution of groundwater through the incomplete absorption of nitrogen (N) and phosphorus (P). Understanding the vertical migration patterns of N and P in soil solution is crucial for controlling groundwater quality. This study is based on monitoring data of soil solution nitrogen and phosphorus at different depths (30 cm, 60 cm, 100 cm) in the Huixian Wetland Experimental Area in the Li River Basin from March to December 2021. The vertical distribution patterns of nitrogen and phosphorus in soil solution in the study area are elucidated from three aspects: seasonal variations, karst types, and land use. The results indicate that the following: (1) NO3−-N is the predominant form of nitrogen, generally decreasing with increasing soil depth, while NH4+-N concentrations show slight increases and TP concentrations remain relatively stable. Overall, NO3−-N and TN concentrations tend to accumulate at 30 cm and 60 cm depths during both irrigation and non-irrigation seasons, with no distinct distribution patterns observed for NH4+-N and TP. (2) During the irrigation season, the migration distance of NO3−-N in non-karst landforms is mainly at 60 cm, while in peak forest plains, it is mainly at 100 cm, with no clear trend observed in NO3−-N concentrations in peak cluster depressions. In non-irrigation seasons, the distribution of NO3−-N content in non-karst landforms and peak cluster depressions is mainly 30 cm > 60 cm > 100 cm. The downward migration distance of NH4+-N generally follows the order of peak cluster depressions > peak forest plains > non-karst landforms. (3) During the irrigation season, NO3−-N concentrations in paddy fields remain relatively high at 100 cm, while in drylands, NO3−-N concentrations generally follow the pattern of 30 cm > 60 cm > 100 cm but may exhibit anomalous increases or decreases at 60 cm and 100 cm depths during heavy rainfall. [ABSTRACT FROM AUTHOR]