Inorganic Phosphorus Fractions Research Articles

Fractionation of Inorganic Phosphorus in Cold Temperate Forest Soils: Associating Mechanisms of Soil Aggregate Protection and Recovery Periods after Forest Fire Disturbance

The soil aggregate is the fundamental unit of soil structure. The fractionation characteristics and influencing factors of phosphorus (P) in soil aggregates inherently link its geochemical characteristics and recycling mechanism. This work investigated the fractionation characteristics of inorganic P in cold temperate forest soils and studied the impacts of recovery periods after forest fires and soil aggregate protection mechanisms on P fractionation. Our results showed that the TP, active P, stable P, and total organic carbon (TOC) contents varied with increasing recovery years after forest fire disturbance. The TP content in the coarse particulate organic matter fraction (cPOM) exhibited an increasing trend with the number of recovery years. Redundancy analysis (RDA) and correlation analysis indicated that TOC played a crucial role in influencing the dynamics of P fractionation during the recovery process. The order of TP levels in different soil aggregate fractions was as follows: μClay > dClay > LF > cPOM > dSilt > μSilt > iPOM, with significant contributions from the cPOM and dSilt fractions. The ranking of P fractions in bulk soils was as follows: ACa-P > Fe-P > Oc-P > Or-P > De-P > Al-P > Ex-P. The protective mechanism of soil aggregates had a more significant effect on TOC than TP, with the order of protective abilities being: Phy×biochem-protected > Biochem-protected > Phy-protected > Non-protected mechanism. TOC and recovery years emerged as critical factors influencing the dynamics of different P fractions during post-fire recovery. Soil aggregate protection mechanisms demonstrated significantly higher effects on TOC than on TP. This study provides insights into the fractionation mechanisms of P in the soil–forest ecosystem of the Greater Khingan Mountains, contributing to the sustainable development and utilization of cold temperate forest ecosystems.

Exogenous carbon addition soil mediated phosphorus dynamics under eight years continuous input of swine manure in a wheat-rice rotation

The study investigated the prolonged impact of swine manure application on soil inorganic phosphorus (P) fractions over an 8-year continuous, randomized field trial involving rotating wheat (wet conditions) and rice (flooded conditions) crops. The trial comprised six treatments: triplicate control plots receiving only chemical fertilizers, and triplicate plots receiving chemical fertilizers and/or swine manure ranging from 150 to 1200 kg P2O5 ha−1. The continuous application of swine manure increased soil P content and availability. Initially, P primarily accumulated in the soil as Fe-P during the first four years of manure application, transitioning to Ca8-P over the following four years. The main driver of these changes in P fractions was soil total organic carbon (TOC) was identified as the main driver of these changes in P fractions, contributing 31.5% to the observed variations. TOC increased steadily throughout the trial, with a faster rising in years 1–4 compared to years 4–8. Laboratory-scale soil incubation experiments were conducted, involving the addition of glucose or cellulose as exogenous carbon sources to test their effects on soil P dynamics and mitigate environmental damage from P leaching. The addition of cellulose to soil that had received high quantities of swine manure for eight years resulted in increased the moderately labile and moderately resistant organic P fractions while decreasing the Ca8-P and Olsen-P fractions. This promoted adsorption of high-activity inorganic P to organic matter, consequently limiting the accumulation of Ca8-P. The long-term application of swine manure altered soil P fractions and enhances P lability, enhancing P lability and availability. This study identified an optimized the risk of leaching of labile P from soil under a fertilization regime applying 10,300 kg ha−1 yr−1 swine manure. To further mitigate the risk of P leaching, the inclusion of additional cellulose-based organic matter (e.g., straw) in swine manure fertilization regimes is recommended.

Integrated agroforestry system affects the dynamics of inorganic phosphorus fractions in the savanna of Brazilian Northeast

The savanna (Cerrado) of northeastern Brazil has undergone significant transition in land use to expand agricultural activities. In this region, soils are highly weathered, with phosphorus (P) commonly bound to aluminum (Al) and iron (Fe), creating conditions that demand the supply of P fertilizers to build soil fertility. Conservation systems, such as integrated agroforestry, can increase the inorganic P lability. The aim of this study was to evaluate soil P availability in components of an integrated agroforestry system. Four systems were studied from a 3-year experiment: eucalyptus ( E. urophylla × E. tereticornis) rows (ER), sabiá ( Mimosa caesalpiniifolia) rows (SR), inter-planted maize, and inter-planted soybean in addition to an area of native Cerrado (NC) used as a control. Inter-planted soybean and maize components showed an increase in available P in relation to NC, as a response to a liming-induced increase in soil pH and phosphate fertilization. Eucalyptus and sabiá row components showed an increase in available P in soil because of higher P recycling promoted by forest species and lower P adsorption onto Fe and Al due to the high concentrations of organic matter. Phosphorus forms, following a descending order for all components of the agroforestry system, are P–Al > P–Fe > P–Ca. This information can be used to improve management and soil quality of agricultural production in the Cerrado of the Brazilian northeast region.

Inorganic phosphorus fractions and phosphorus availability in long term fertilizer cum manurial trials under coconut cultivation

Phosphorus is one of the major nutrients required for coconut production. The information about the fate of native and applied phosphorus in soil is essential for better management of the nutrient. The changes on inorganic P fractions and P availability in soil after 43 years of coconut cultivation were studied from a long term fertilizer cum manurial experiment at CPCRI, Kasaragod. There were 6 treatments viz. tillage with organic and inorganic fertilizer, tillage with inorganic fertilizer, inorganic fertilizers with basin forking, tillage alone, herbicide application without tillage and fertilizer and the control. Soil samples were taken at two depths (0-30 and 30-60 cm) from coconut basin for analysis. Phosphorus was fractionated into Easily Soluble P (ES-P), Aluminium P (AI-P), Iron P (Fe-P), Calcium P (Ca-P) and Reductant Soluble P (RS-P) through sequential extraction. The dominant phosphorus fraction in the coconut basin at 0-30 cm depth was Ca-P and the trend is as follows: Ca-P> Fe-P> RS-P>Al-P>ES-P. However, at 30-60 cm depth, Fe-P became the dominant fraction and the trend is Fe-P>Ca-P>RS-P>Al-P>ES-P. Long-term phosphorus fertilization would facilitate the accumulation of soil Ca-P, and thus improve soil P availability. In the interspaces, Fe-P was the dominating fraction in both the depths followed by Ca-P and RS-P. The difference in P fractions in fertilized and non-fertilized plots clearly showed that the fertilized plots have high content of all the inorganic phosphorus fractions in both the depths. Application of mineral P along with forking in basin showed a high concentration of all the inorganic P fractions compared to other fertilizer applied treatments.

Interaction between P and Zn on the Changes in Different Inorganic Phosphorus Fractions under Waterlogged Soil Treated with and Without Organic Matter

Background: Phosphorus and zinc are two essential nutrients which are required for normal plant growth. These nutrients are mutually antagonistic in certain circumstances which can cause yield reductions in many crops due to either P or Zn deficiencies. Organic matter causes soil to clump and form soil aggregates, which improves soil structure. With better soil structure, permeability improves, in turn improving the soil’s ability to take up and hold water. The addition of organic manure may reduce the mobility of Zn in soil by forming stable chelates thereby may affect the formation of Zn-P complexes in soil. Thus, the present study was undertaken to find the interaction between P and Zn on the changes in different inorganic phosphorus fractions under waterlogged soil treated with and without organic matter. Methods: An incubation experiment has been conducted in the laboratory of Department of Agricultural Chemistry and Soil Science, University of Calcutta to find the interaction between P and Zn on the changes in different phosphorus fractions under waterlogged soil treated with and without organic matter. Treatments details: P0Zn0 - No Phosphorus + No Zn, P0Zn1 - No Phosphorus + Application of Zn at 2.5 mg/kg soil, P0Zn2 - No Phosphorus + Application of Zn at 5 mg/kg soil , P1Zn0 - Application of P at 10 mg/kg soil + No Zn, P1Zn1 - Application of P at 10 mg/kg soil + Application of Zn at 2.5 mg/kg soil,P1Zn2 - Application of P at 10 mg/kg soil + Application of Zn at 5 mg/kg soil, P2Zn0 - Application of P at 15 mg/kg soil + No Zn, P2Zn1 - Application of P at 15 mg/kg soil + Application of Zn at 2.5 mg/kg soil, P2Zn2 - Application of P at 15 mg/kg soil + Application of Zn at 5 mg/kg soil. The same treatment combination was studied with application of organic matter where organic matter was applied @1% by soil weight basis and another set of treatment combination were conducted in absence of organic matter. After application of all treatments, maintaining waterlogged condition, the soils were allowed to incubate at room temperature (30±2)°C for a period of 10, 20, 30, 40, 50 days interval and analyzed for different fractions of P. Result: The amount of Soluble and Loosely bound P fractions has been recorded highest (47.50 mg kg-1) in the treatment P2OM2 at 30 days of incubation in presence of organic matter. As regards to the interaction effect between P and organic matter it was observed that the amount of Al-P was recorded enhanced, being highest with their highest level of application. The individual application of P increased the amount of Fe-P content, being highest (56.96 mg kg-1) at 30 days of incubation with its highest level, while the application of organic matter at its highest level recorded highest amount of Fe-P (55.30 mg kg-1) content. The absolute amount of Reductant soluble P was recorded a lower value than Fe-P. The results suggest that Ca-P fraction was the dominant inorganic P fraction among other fractions and there is a synergistic effect was found between P and organic matter where there is an antagonistic effect found between P and Zn.

Changing the Phosphate Regime of Soils in the Middle Taiga When Using Biochar

The influence of wood biochar on the content of various forms of phosphates was studied in laboratory experiments on soils with different phosphorus availability. Soils of the middle taiga subzone of Karelia were used in this work: a sandy Umbric Podzol and a heavy loamy Umbric Retisol. The tests studied the effect of two fractions of biochar (3–5 and ≤2 mm) in an amount of 2% and 5% of soil mass on pHKCl, the content of available and total phosphorus, the inorganic phosphorus fractions (Chang-Jackson method), and the total phosphatase activity of soils, as well as the effect of separate and combined application of biochar and fertilizer (NPK) on the content of available phosphorus in a pot experiment with spring barley. The research revealed that biochar significantly increased the content of available phosphorus by 20–40%, increased the content of the fraction of Ca-bounded P, Al-bounded P and loosely-bounded P, and also increased the phosphatase activity in the Umbric Podzol. In pot experiment was noted a higher content of P2O5 in variants with biochar ≤2 mm, in variants with fertilizer, and a significant mutual influence factors of biochar and fertilizer. Biochar increased the content of available phosphorus by 2–6%, increased the content of Ca-bounded P and loosely-bounded P (with biochar ≤2 mm at 5% dosage), and had no significant effect on the phosphatase activity in the Umbric Retisol. Only combination of biochar ≤2 mm and fertilizer had a significant effect in pot experiment with Umbric Retisol. In general, the most noticeable effect on almost all studied indicators was provided by ≤2 mm fraction of biochar in a 5% dosage. The use of biochar led to statistically significant increase in pHKCl values, and did not affect the content of total phosphorus in both soils. Biochar had a greater effect on the phosphate regime of coarse-textured soil with an initially lower pH and a less content of available and total phosphorus.

Influence of cropping sequences on labile carbon and phosphorus fractions in a wheat-based conservation agriculture system

While conservation agriculture (CA) has largely been successful in many areas, some reports suggest that certain farmers have not realised the benefits they had hoped for, especially in Africa. The benefits of CA could depend on the cropping sequences involved. This study determined the short-term effects of wheat (Triticum aestivum L.)/ maize (Zea mays L.) and wheat/ soybean (Glycine max L.) cropping sequences on fractions of soil organic carbon (SOC), inorganic phosphorus and other soil quality parameters in the 0–200 and 200–400 mm depths on CA farms. Water-soluble carbon (C) and available phosphorus (P) (NaHCO3 Pi) were significantly higher and NaOH I Pi was lower in maize/wheat than in soybean/wheat sequences. SOC, extractable P, and NaHCO3 Pi were significantly higher in the 0–200 mm than in the 200–400 mm depth. Extractable P correlated positively with particulate organic carbon (OC) fractions under both sequences. In addition, soil pH, exchangeable potassium (K), calcium (Ca), magnesium (Mg) and cation exchange capacity (CEC) were significantly higher while acid saturation and Ca:Mg was lower in maize/wheat than in soybean/wheat sequences. The findings imply that short-term cropping sequences do not affect SOC sequestration but a wheat crop preceded by maize could benefit from higher soil pH and labile C fractions making P more available, with the additional benefit of available K in these CA systems.

The Phosphorus Availability in Mollisol Is Determined by Inorganic Phosphorus Fraction under Long-Term Different Phosphorus Fertilization Regimes

Understanding the effects of a fertilization regime on the long-term accumulation and transformation of soil phosphorus (P) is essential for promoting the development of sustainable management of soil P. Based on a 29-year field experiment in Mollisol, the compositions and changes of P forms using a modified Hedley sequential extraction method, solution 31P-NMR and P K-edge XANES and soil properties were investigated under continuous mono maize with and without manure (NPKM and NPK). Results showed a stronger positive related coefficient between soil total P and labile P, and mid-labile P fraction was found in NPKM than in NPK treatment. It indicated NPKM could improve the availability of soil accumulated P and reduce its transformation to stable P. Accumulated inorganic P (Pi) was dominated by aluminum phosphate (Al-P) and monobasic calcium phosphate monohydrate (MCP) for NPK treatment, Al-P, MCP, and tricalcium phosphate for NPKM treatment with XANES analysis, which contributed to the P availability in Mollisol. Moreover, the proportion of IHP with XANES and ratio of orthophosphate diesters to monoesters in NPK compared to NPKM indicated the higher Po lability with NPK treatment. Pi, especially NaHCO3-Pi and NaOH-Pi, were the potential sources of resin-Pi. Soil organic matter (SOM), organic-bound iron, and alumina oxide (Fep + Alp) showed significant influence on the transformation of P forms. Our research suggested that due to the rise in SOM and Fep + Alp, the fertilization regime significantly increased most highly active soil P fractions, especially in NPKM treatment. This work gives new insight into sustainable P management, which benefits the reduction in soil P accumulation.

Isolation of Inorganic-Phosphate-Solubilizing Bacteria and Analysis of their Effect on Phosphorus Release from Lagoon Sediments

Internal phosphorus (P) loading from sediments is an important cause of eutrophication, and inorganic-phosphate-solubilizing bacteria (IPB) are known to play a vital role in the process of sediment P release. In this study, 10 IPB strains were isolated from the sediments of a lagoon suffering from macroalgal blooms dominated by Chaetomorpha linum – Rongcheng Swan Lagoon, China – and their taxonomy was determined by 16S rRNA sequence analysis. The phosphate-solubilizing characteristics of the obtained IPB strains were evaluated using a liquid medium, and the ability of IPB strains to dissolve P from sediments and the transformation of inorganic phosphorus (IP) fractions were investigated by inoculating IPB strains into a sediment–water experimental system. The 10 isolated IPB strains belonged to one family, two genera, and four species. All IPB strains in the liquid medium culture dissolved tricalcium phosphate, but the phosphate-solubilizing ability of IPB varied greatly between strains and appeared to be promoted when the strains were grown in mixed-strain cultures. Bacillus megaterium showed the strongest phosphate-solubilizing ability. The IPB inoculation experiment showed a large decrease in the Ca-bound P (HCl-P) concentration of sediments in various IPB inoculation treatments, especially in sediments from the central lake. Our results indicate that, under the action of IPB, there is great potential for the release of HCl-P, which is the primary IP fraction of lagoon sediments, and more attention should be given to the endogenous P pollution in Swan Lagoon Wetland.

Characteristics of inorganic phosphorus fractions and their correlations with soil properties in three non-acidic soils

Understanding the characteristics and influences of various factors on phosphorus (P) fractions is of significance for promoting the efficiency of soil P. Based on long-term experiments on black soil, fluvo-aquic soil, and loess soil, which belong to Phaeozems, Cambisols, and Anthrosols in the World Reference Base for Soil Resources (WRB), respectively, five fertilization practices were selected and divided into three groups: no P fertilizer (CK/NK), balanced fertilizer (NPK/NPKS), and manure plus mineral fertilizer (NPKM). Soil inorganic P (Pi) fractions and soil properties were analyzed to investigate the characteristics of the Pi fractions and the relationships between Pi fractions and various soil properties. The results showed that the proportion of Ca10-P in the sum of total Pi fractions was the highest in the three soils, accounting for 33.5% in black soil, 48.8% in fluvo-aquic soil, and 44.8% in loess soil. Long-term fertilization practices resulted in periodic changes in soil Pi accumulation or depletion. For black soil and fluvo-aquic soil, the Pi accumulation was higher in the late period (10–20 years) of fertilization than in the early period (0–10 years) under NPK/NPKS and NPKM, whereas the opposite result was found in loess soil. The Pi accumulation occurred in all Pi fractions in black soil; mainly in Ca8-P, Fe-P, and Ca10-P in fluvo-aquic soil; and in Ca2-P, Ca8-P, and O-P in loess soil. Under CK/NK, the soil Pi was depleted mainly in the early period in each of the three soils. In addition to the labile Pi (Ca2-P) and moderately labile Pi (Ca8-P, Fe-P, Al-P), the Ca10-P in black soil and fluvo-aquic soil and O-P in loess soil could also be used by crops. Redundancy analysis showed that soil properties explained more than 90% of the variation in the Pi fractions in each soil, and the explanatory percentages of soil organic matter (SOM) were 43.6% in black soil, 74.6% in fluvo-aquic, and 38.2% in loess soil. Consequently, decisions regarding the application of P fertilizer should consider the accumulation rate and the variations in Pi fractions driven by soil properties in non-acidic soils.

Application of phosphate solubilizing fungi and lime altered the soil inorganic phosphorus fractions in an Ultisol of north-eastern India

ABSTRACT The gradually dwindling reserves of rock phosphate, the primary material used in the manufacturing of phosphatic fertilizers, encourages researchers to look for ways to exploit the accumulated fixed P pool in soil. Phosphate solubilizing microorganisms (PSM) could be a viable option for addressing the problem at a lower cost. Keeping these in mind, the present study was undertaken to evaluate the changes in the distribution of P in soil as affected by P fertilization, phosphate solubilizing fungi (PSF) and liming vis-à-vis the contribution of these fractions toward P nutrition of a test crop soybean (Glycine max L.). A bulk surface soil sample (0–15 cm) was obtained from Negheriting tea estate of Golaghat district of Assam, India (Ultisol, pH = 4.23) and after processing, three levels of P [0, 50, and 100% of recommended dose of P (RDP)], two levels of lime [No lime, 1/10th of Lime Requirement (LR)] and two levels of PSF (No-PSF, PSF) were applied in a completely randomized design with three replications. Sequential P fractionation was done in the post-harvest soil. On an average, the abundance of different P fractions in the soil, expressed as % of total P, followed the order: residual P (67.5%)> Fe bound P (12.1%)> reductant soluble P (8.85%)> Al bound P (4.04%)> occluded P (3.79%)> Ca bound P (3.11%)> soluble and loosely bound P (0.46%). All the inorganic P fractions except the residual P, increased significantly with P fertilization. Either liming or PSF application significantly increased the soluble and loosely bound P fraction and decreased the Al bound and Fe bound P fractions in soil. Positive growth response of soybean was obtained due to the application of P, lime, and PSF. Liming increased the P uptake by 30.4% and dry matter yield of soybean by 18.5% over no liming. On the other hand, PSF inoculation increased the P uptake by 16.7% and dry matter yield by 7.77% over no inoculation. So, it is evident that in short term, either liming or PSF was able to solubilize the native soil P. Phosphorus×lime and lime×PSF interactions should also be exploited in future endeavors.

Can dark septate endophytic fungi (DSE) mobilize selectively inorganic soil phosphorus thereby promoting sorghum growth? A preliminary study

Phosphate fertilizers tend to precipitate with soil components, affecting fertilization efficiency and causing negative environmental effects. Soil microorganisms have been used to solve this problem. However, the ability of dark septate endophytic fungi (DSE) to dissolve phosphates and increase crop yield are not well known. The activity of DSE fungi capable of solubilizing reagent grade phosphates was studied in a Typic Hapludoll (Hapludol típico). The effect of the fungi on the inorganic phosphorus fractions was evaluated and an experiment was conducted in pots with sorghum as a crop. No fungal structures were found in the roots. Curvularia sp. aerial biomass and root length increased; however, P concentration was not affected. Although the results are not conclusive, they represent an advance in the potential use of DSE fungi as P solubilizers to treat crop nutrition.

Changes in inorganic phosphorus fractions in weathered soils under long-term intensive cultivation and irrigation

ABSTRACT Conventional intensive cultivation tends to modify the interactions of phosphorus in soil, favoring inorganic forms transformations. The aim of the study was to evaluate the status of inorganic phosphorus and correlate with the chemical, physical and mineralogical soil properties in areas under natural vegetation and different cultivation periods: 1, 17, 22, 28, 32 and 43 years. Soil P was extracted using Chang and Jackson method (Al-P, Fe-P, Ca-P and Residual-P). The micro-chemical map of P concentrations within the representative aggregates was determined by electron probe. Results showed that biofertilizers application in the area under intensive cultivation for 32 years of use significantly increased all soil P fractions (4.249 mg kg−1 in upper soil layer). There was a slight increase in the P at the edges of the aggregates in the first year (0.23%), but at 43 years, there was an increase in contents within the aggregates (0.32%). The intensive cultivation promoted the increase of P content in soil fractions in the arable layer of the soil over time. However, the decline in inorganic P contents after a few years of cultivation suggests that the soils of the studied areas tend to exceed their maximum adsorption capacities in the future.

The Conversion of Inorganic Phosphorus Fractions, Phosphatase Activity, and Some Biological Properties in Sandy Soil Enriched with Minerals, Organic Matter, and Microbial Modifiers under Two Months of Incubation

The Conversion of Inorganic Phosphorus Fractions, Phosphatase Activity, and Some Biological Properties in Sandy Soil Enriched with Minerals, Organic Matter, and Microbial Modifiers under Two Months of Incubation

Toward a Global Model for Soil Inorganic Phosphorus Dynamics: Dependence of Exchange Kinetics and Soil Bioavailability on Soil Physicochemical Properties.

The representation of phosphorus (P) cycling in global land models remains quite simplistic, particularly on soil inorganic phosphorus. For example, sorption and desorption remain unresolved and their dependence on soil physical and chemical properties is ignored. Empirical parameter values are usually based on expert knowledge or data from few sites with debatable global representativeness in most global land models. To overcome these issues, we compiled from data of inorganic soil P fractions and calculated the fraction of added P remaining in soil solution over time of 147 soil samples to optimize three parameters in a model of soil inorganic P dynamics. The calibrated model performed well (r 2 > 0.7 for 122 soil samples). Model parameters vary by several orders of magnitude, and correlate with soil P fractions of different inorganic pools, soil organic carbon and oxalate extractable metal oxide concentrations among the soil samples. The modeled bioavailability of soil P depends on, not only, the desorption rates of labile and sorbed pool, inorganic phosphorus fractions, the slope of P sorbed against solution P concentration, but also on the ability of biological uptake to deplete solution P concentration and the time scale. The model together with the empirical relationships of model parameters on soil properties can be used to quantify bioavailability of soil inorganic P on various timescale especially when coupled within global land models.

Effects of nutrient and water addition on soil inorganic phosphorus fractions in an old-field grassland

Reasonable nutrient and water management is effective ways to improve productivity and biodiversity of degraded grasslands. However, little is known about the effects of nutrient and water addition on soil inorganic phosphorus (P) fractions in old-field grasslands. Based on a field experiment with nutrient addition (N: 10 g·m-2·a-1, P: 10 g·m-2·a -1) and water addition (180 mm water irrigated during plant growing season) in Duolun County, Inner Mongolia in 2005, we examined the changes of inorganic P fractions and Olsen-P contents in the topsoil (0-10 cm). Results showed that 11-year P addition significantly increased total inorganic P (TIP) content, and that exogenous P was mostly transformed into calcium phosphate (Ca-P: 62.6%-69.2%), and then into aluminium phosphate (Al-P: 19.9%-25.1%), ferric phosphate (Fe-P) and occluded P (O-P). Phosphorus incorporated with nitrogen (N) addition significantly increased Fe-P and Al-P contents by declining soil pH and activating Fe3+ and Al3+ in soil. Water addition alone significantly increased Fe-P, Al-P, and decalcium phosphate (Ca10-P) fractions, and the contents of Fe-P, Al-P, octacalcium phosphate (Ca8-P), and Ca10-P were greater in P incorporated with water treatment than in P addition alone. There was no difference of each inorganic P fraction between P incorporated with N and water treatment and P incorporated with N treatment. Phosphorus and P incorporated with N additions significantly increased soil Olsen-P content, while water addition significantly decreased soil Olsen-P content under P addition alone and P incorporated with N treatment. In the calcareous soils, calcium superphosphate addition could enhance soil inorganic P pool through increasing Ca-P fraction.

缙云山4种林分土壤无机磷与活性铝的含量及分布

PDF HTML阅读 XML下载 导出引用 引用提醒 缙云山4种林分土壤无机磷与活性铝的含量及分布 DOI: 10.5846/stxb202101090092 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 重庆市社会民生类重点研发项目（cstc2018jscx-mszdX0080）；国家自然科学基金项目（31570599） Content and distribution of inorganic phosphorus and labile aluminum in soil of four forest types in Jinyun Mountain Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探索不同林分对土壤中无机磷与活性铝的含量及分布的影响，以及无机磷与活性铝之间的相互关系，以在我国西南地区酸性土壤上的农林经营管理提供理论和实践依据。研究以缙云山广泛分布的4种林分类型：山莓、马尾松、楠竹和柑橘林土壤为对象，采用酸性土壤无机磷分级方法和铝试剂比色法测定了土壤剖面A、B和C层中各形态的无机磷与活性铝的含量，分析了不同林分土壤中无机磷和活性铝的含量和分布特征。结果表明，林分类型显著影响土壤中无机磷与活性铝的含量与分布，且铁磷（Fe-P）、交换态铝（Ex-Al）和羟基铝（Hy-Al）的含量和比例还受到土壤层次的影响。4种林分相比，山莓林能促进闭蓄态磷（O-P）的形成，而马尾松、楠竹和柑橘林则有利于Al-P、Fe-P和Ca-P的形成；柑橘林有利于低活性的腐殖酸铝（Al-AH）形成，而山莓、马尾松和楠竹林促进高活性的Ex-Al或Hy-Al溶出；Ex-Al、Al-P和Fe-P在土层的分布上有表层富集现象，而Hy-Al集中分布于B层。此外，土壤Ex-Al和Al-P与Fe-P之间，Hy-Al和Ca-P之间均呈显著（P<0.05）正相关。因此，林分类型显著影响土壤无机磷与活性铝的含量与分布，高活性铝的溶出显著影响Al-P、Fe-P和Ca-P含量。 Abstract:Phosphorus (P) is an essential element for plant growth, development and metabolism. Soil is a direct donor of phosphorus for plants. Generally, total phosphorus (TP) is plenty in most soils, but its availability to plants is very low. Aluminum (Al) is the most abundant metal element in the earth's crust. When the soil is getting acidified, Al in the forest soil can be activated into Al3+ (exchangeable Al, Ex-Al) or Al (OH)2+, Al (OH)2+ (hydroxyl-Al, Hy-Al), which might precipitate HPO42-, H2PO4-, and PO43- into hard-to-dissolve P and reduce the P availability in consequence. How to prevent the decrease of P availability caused by the dissolution of Al from acidic soil, which is one of the urgent problems to be solved in forest land management. Forest type and soil layer might affect the characteristics and relationships between inorganic phosphorus (IP) and labile Al, which remains poorly understood up to now. The present study aimed to determine the influence of forest type and soil layer on the concentration and distribution of IP and labile Al in soil, in addition to the correlation between labile Al and IP. The soil was collected by digging in three soil layers (A, B and C layer) of four forest types of Rubus corchorifolius, Pinus massoniana, Phyllostachys pubescens and Citrus reticulata forest in Jinyun Mountain, Chongqing, China. Concentrations of IP and labile Al fractions were measured using the traditional method. Results showed that concentrations and proportions of IP and labile Al in soil were significantly affected by forest types and that of iron-bound P (Fe-P), Ex-Al and Hy-Al in soil were significantly different in soil layers. Among the four forest types, Rubus corchorifolius promoted the formation of occluded P (O-P). Whereas, Pinus massoniana, Phyllostachys pubescens and Citrus reticulata were in favor of the formation of aluminum-bound P (Al-P), Fe-P and calcium-bound P (Ca-P). Citrus reticulata was favorable for the formation of low-active Al species (humic acid-Al, Al-AH), while Rubus corchorifolius, Pinus massoniana and Phyllostachys pubescens contributed the dissolution of labile Al from low-active into high-active species (Ex-Al or Hy-Al). In soil layers, Ex-Al, Al-P and Fe-P mainly enriched in the surface among the three soil layers. Hy-Al concentrated in the second soil layer. Meanwhile, the correlations were significantly positive between Ex-Al and Al-P and Fe-P or between Hy-Al and Ca-P in the soil of four forest types. The concentration and distribution of IP and labile Al fractions in soil were significantly affected by forest types. The dissolution of labile Al from low-active into high-active species significantly affected the concentrations of Al-P, Fe-P and Ca-P. This study can provide theoretical and practical basis for the management of agriculture and forestry on acid soils in southwest China. 参考文献 相似文献 引证文献

The Phosphorus Availability in Black Soil is Determined by Inorganic Phosphorus Fraction Under Long-Term Different Phosphorus Fertilization Experiments

The Phosphorus Availability in Black Soil is Determined by Inorganic Phosphorus Fraction Under Long-Term Different Phosphorus Fertilization Experiments

引种降香黄檀和顶果木对石漠化山区土壤磷素转化及其有效性的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 引种降香黄檀和顶果木对石漠化山区土壤磷素转化及其有效性的影响 DOI: 10.5846/stxb202012223252 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31960240）；广西自然科学基金项目（2017GXNSFAA198207，2018GXNSFAA294139，2019GXNSFAA185023） Effects of introducing Dalbergia odorifera and Acricarpus fraxinifolius on soil phosphorus transformation and availability in rocky desertification mountainous regions Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:我国西南岩溶区石漠化严重，植被覆盖率低，土壤贫瘠。植被恢复作为一项重要的生态治理措施，在提高土壤养分有效性，增加生物多样性和改善生态环境等方面发挥着极其重要的作用。以广西马山县经过8年植被恢复的4种样地类型（降香黄檀纯林；顶果木纯林；降香黄檀/顶果木混交林；相邻的天然灌草丛作为对照组）为研究对象，探讨了引进固氮树种（降香黄檀和顶果木）及其种植模式对石漠化山区土壤磷素转化及其有效性的影响。研究结果表明：（1）降香黄檀/顶果木混交林土壤的有机质（SOM）、硝态氮（NO3--N）、有效磷（AP）、微生物生物量碳（MBC）、微生物生物量氮（MBN）和微生物生物量磷（MBP）含量均显著高于对照（P<0.05）；降香黄檀/顶果木混交林、顶果木纯林和降香黄檀纯林的全磷（TP）相比于对照组更易转化为AP，其中以降香黄檀/顶果木混交林的效果最佳。（2）相关分析结果表明，土壤NH4+-N、NO3--N和MBN与AP分别呈显著线性正相关（P<0.05），MBN与MBP呈极显著线性正相关（P<0.01）。（3）引种降香黄檀和顶果木后，各林分的土壤无机磷组分均发生变化，其中降香黄檀/顶果木混交林和顶果木纯林的各种无机磷含量显著增加（P<0.05）。（4）最后，冗余分析表明MBP、SOM和MBN可能是影响土壤无机磷组分变化的最主要因素（P<0.05）。研究表明降香黄檀和顶果木在一定程度上能改善石漠化山区土壤的养分状况和提高土壤磷的有效性，其中以二者混交种植模式的效果最显著，以期为珍贵固氮树种在石漠化生态恢复与重建中的推广应用提供理论依据和实践支持。 Abstract:Rocky desertification is serious in karst areas in southwest China, with low vegetation coverage and poor soil. As an important ecological management measure, vegetation restoration plays an extremely important role in improving the availability of soil nutrients, increasing biodiversity, and improving the ecological environment. In this study, four types of site (the pure plantation of Dalbergia odorifera; the pure plantation of Acricarpus fraxinifolius; the mixed plantation of D. odorifera and A. fraxinifolius; the adjacent natural weed field as the control) in Mashan, Guangxi were selected as the research objects after 8 years of vegetation restoration. The effects of introducing N2-fixing tree species (D. odorifera and A. fraxinifolius) and their planting patterns on the soil phosphorus transformation and availability in rocky desertification mountainous regions were discussed. The results showed that:(1) the contents of soil organic matter (SOM), nitrate nitrogen (NO3--N), available phosphorus (AP), soil microbial biomass carbon (MBC), soil microbial biomass nitrogen (MBN), and soil microbial biomass phosphorus (MBP) in the mixed plantation of D. odorifera and A. fraxinifolius were significantly higher than those of the control (P<0.05). The total phosphorus (TP) of the mixed plantation of D. odorifera and A. fraxinifolius, the pure plantation of A. fraxinifolius and the pure plantation of D. odorifera could be easily transformed into AP than control, among which the mixed plantation of D. odorifera and A. fraxinifolius had the best effect. (2) The results of correlation analysis showed that NH4+-N, NO3--N, and MBN had significant linear positive correlation with AP respectively (P<0.05), while MBN and MBP had extremely significant linear positive correlation (P<0.01). (3) After introducing D. odorifera and A. fraxinifolius, the soil inorganic phosphorus fractions in all sites changed, and the contents of various inorganic phosphorus in the mixed plantation of D. odorifera and A. fraxinifolius and the pure plantation of A. fraxinifolius increased significantly (P<0.05). (4) Finally, the redundancy analysis (RDA) indicated that MBP, SOM, and MBN would be the main factors affecting the changes of soil inorganic phosphorus fractions (P<0.05). Overall, D. odorifera and A. fraxinifolius could improve soil nutrient and phosphorus availability in rocky desertification mountain regions to a certain extent, among which the mixed planting pattern (the mixed plantation of D. odorifera and A. fraxinifolius) had the most significant effect. The purpose of the study could provide theoretical basis and practical support for the application of N2-fixing tree species in the ecological restoration and reconstruction of rocky desertification. 参考文献 相似文献 引证文献

Land-Use Change Affects Inorganic Phosphorus Fractions in Sandy Soils from the Northeastern Cerrado, Brazil

Land-Use Change Affects Inorganic Phosphorus Fractions in Sandy Soils from the Northeastern Cerrado, Brazil