The chemical fractionation of soil zinc and its specific and total adsorption by Egyptian alluvial soils

Summary The Zn contents of twenty-nine alluvial soils from Egypt were chemically fractionated into: water soluble+exchangeable, weakly bound to inorganic sites, organically bound, occluded as free oxide material, and residual mainly in the mineral structure. On the average these fractions constituted about 0.01, 1.20, 28.6, 21.5 and 45.5% of the total soil Zn respectively which averaged 76.25 ppm. Significant correlations were obtained between each individual Zn-fraction and some soil variable.Zinc adsorption isotherms were developed for seven soils suspended in dilute ZnCl₂ solution in the presence of either 0.05M CaCl₂ solution (Specific adsorption) or deionized water (Total adsorption). The Langmuir constants (adsorption maximum and bonding energy) were calculated. The average value of specific adsorption maximum was 1.94 mg Zn/g soil and of total adsorption maxima was 11.54 mg Zn/g soil. Correlation analysis showed that CEC, free Fe₂O₃ and clay content were the dominant soil variables contributing towards specific Zn adsorption. The (Zn) (OH)₂ ion concentration products in the solutions when Zn adsorption corresponded to the Langmuir adsorption maxima were 0.92×10^–17 in the specific adsorption treatment, and 1.35×10^–15 in the total adsorption treatment. These values are within the solubility range of Zn (OH)₂ and ZnCO₃. The values of Langmuir bonding energy constants showed that Zn was more strongly adsorbed by low carbonate or carbonate-free soils than by carbonate-rich soils.     

Phosphate adsorption and availability plant of phosphate

Summary The effects of phosphate buffer capacity on the plant-availability of labile soil phosphate, when measured as intensity (I) or quantity (Q), are described and tested using results from a greenhouse experiment on 24 Sherborne soils. In multiple regression studies, phosphate buffer capacity with I or Q measurements as independent variables accounted for up to 94% of the variance in P uptake by ryegrass, the maximum buffer capacity being generally more useful than the equilibrium buffer capacity.When the quantity of soil P is measured (Q), its availability (i.e. ease of desorption) to plant roots is inversely related to the Langmuir bonding energy parameter and the buffer capacity. When the intensity of soil P is measured (I), its availability (i.e. resistance to change) is directly related to the adsorption and buffer capacities. The levels of Q or I, therefore, which are optimal for plant uptake vary with the buffer capacity of the soil. There is little or no correlation between the adsorption capacity and the bonding energy in many soils and consequently phosphate buffer capacity is only poorly correlated with the total adsorption capacity.     

Effect of clay,organic matter and CaCO3 content on zinc adsorption by soils

Summary Zinc adsorption was studied in suspensions of six soils of different physicochemical characteristics in dilute ZnSO₄ solutions. At low concentrations, Zn²⁺ adsorption was described by the Langmuir adsorption equation. The calculated Langmuir adsorption maxima were related positively to clay and carbonate content and negatively with organic matter content of soils. Multiple regression analysis revealed that zinc adsorption maxima can be predicted with good precision from information in soil survey reports. When the added Zn²⁺ exceeded the adsorption maximum, the solid phase of zinc controlling its concentration in solution was either zinc hydroxide or carbonate so long as soil carbonates were present. The values of zinc potential also indicated that soils retain Zn²⁺ more strongly than Zn(OH)₂ or carbonate. Postgraduate student Professor of Soils. Professor of Soils.     

Phosphorus adsorption characteristics of Hawaiian soils and their relationships to equilibrium phosphorus concentrations required for maximum growth of Millet

Summary Phosphorus adsor tion isotherms were constructed for six Latosols and one calcareous soil from Hawaii which differed greatly in their phosphorus adsorption capacities. Equilibration was in 0.01M CaCl₂ at 25°C for 6 or 8 days. P adsorption properties of the soils were characterised employing the linear form of Langmuir's equation and also by calculating the amount of P adsorbed between equilibrium concentrations of 0.25 to 0.35 ppm (estimates of P buffering capacities), following the procedure of Oaanne and Shaw¹³. The isotherms of all the soils were found to fit the Langmuir equation at low equilibrium concentrations (< 5 ppm) and the P adsorption maxima ranged from 520 to 10 500 ppm. The buffering capacity estimates correlated closely (r = 0.950) with the adsorption maxima of soils. However, in two soils, the estimates were much lower than expected from their adsorption maxima.Millet (Pennisetum typhoides) was grown in these soils in pots, at 6 phosphorus levels corresponding to 6 equilibrium concentrations chosen from the phosphorus adsorption isotherms. Equilibrium concentrations at maximum growth of millet (C_max) in Latosols varied inversely with the adsorption maxima of the soils. The relationship between these two parameters was expressed by the equation CmaX = a,b^–k, where C_max = equilibrium P concentration at maximum growth of millet, b = P adsorption maximum and a and k are constants. Quantitative expression of the constants are useful as they enable predictions of CmaX for a particular crop from the phosphorus adsorption maximum. This relation was found to hold also for the data on limed acid soils published by Woodruff and Kamprath²⁰.A part of the Ph.D. Thesis approved by the University of Hawaii, Honolulu, Hawaii, U.S.A. (1971).     

几种粉煤灰对磷素吸附与解吸特性的研究

通过吸附解吸和培养试验, 研究了几种粉煤灰对磷素吸附与解吸特性.结果表明,粉煤灰的全磷含量和有效磷含量分别为0.545～4.540 g·kg^-1和19.55～163.0 mg·kg^-1,显著高于土壤,粉煤灰对磷吸附量随着加入溶液磷浓度的增加而增加,但其吸附率随着加入溶液磷浓度的增加而减少;粉煤灰的吸磷率比土壤高,但其解吸率低.这主要是由于粉煤灰比土壤存在更多的磷吸附位点且结合能大,不易解吸.Langmuir方程、Freundlich方程和Temkin方程都能很好地拟合粉煤灰对磷吸附,其中Langmuir方程的MBC、Freundlich方程的a和Temkin方程的k2都可以表征粉煤灰对磷吸附能力, MBC、a和k2值越大,则吸磷能力越强.不同来源的粉煤灰的MBC、a和k2值不同,其大小顺序为：湘潭电厂(5 167.7,4 056.2,831.5)>岳阳纸厂(1 650.7,2 803.4,711.9)>华能电厂(303.0,1 677.6,368.7)>株洲电厂(76.2,464.2, 211.0) > 洞庭氮肥厂(34.7,413.48,213.8).粉煤灰对磷吸附固定作用随粉煤灰含水量的增加有增大的趋势.粉煤灰对磷吸附主要是专性吸附和化学沉淀反应,所以在施用粉煤灰改良土壤或利用粉煤灰制造复混肥时,须考虑粉煤灰对磷的固定作用及粉煤灰含水量的影响.     

Prediction of fertilizer phosphate requirement using the Langmuir adsorption maximum

The phosphate adsorption maximum as calculated by the Langmuir equation was used to predict the fertilizer P requirement of wheat (Triticum aestivium, cv. Caldwell) on both virgin and cultivated Decatur clay loam (clayey, kaolinitic, thermic, Rhodic Paleudult) and Hartsells sandy loam soils (fine-loamy, siliceous, thermic, Typic Hapludult). Soils with higher adsorption maximum were found to require more fertilizer P than soils with lower adsorption maximum. For soils 25% saturation of the adsorption maximum gave the optimum dry matter yield. This corresponded to equilibrium P concentration of 0.45 mg L⁻¹ for Decatur cultivated and 0.31 mg L⁻¹ for Decatur and Hartsells virgin soils for optimum dry matter yield. These values are within the range of those reported previously by other investigators working with different soils.     

Influence of pH,exchangeable aluminium and 0.02M CaCl2-extractable aluminium on the growth and nitrogen-fixing activity of white clover (Trifolium repens) in some New Zealand soils

The effects of soil acidity on the growth and N₂-fixing activity of white clover in seven acid topsoils and subsoils of New Zealand were investigated using a glasshouse experiment.The application of phosphate (Ca(H₂PO₄)₂) to the soils resulted in very large increases in white clover growth on all soils. The application of phosphate, as well as increasing P supply, also decreased 0.02M CaCl₂-extractable Al levels, but had little effect on exchangeable Al levels.Where adequate phosphate was applied, increasing rates of lime (CaCO₃) resulted in increased plant growth on most soils. N₂[C₂H₂]-fixing activity was increased by the first level of lime for one soil, but generally remained approximately constant or declined slightly at higher rates of lime. Up to the point of maximum yield, white clover top weight was more highly correlated with 0.02M CaCl₂-extractable soil Al than with exchangeable Al or pH. At pH values greater than 5.5, plant yield declined on some soils, apparently because of Zn deficiency. The data suggest that white clover is unlikely to be affected by Al toxicity at 0.02M CaCl₂-extractable Al levels of less than about 3.3 g g^–1. However, there were differences between soils in apparent plant tolerance to 0.02M CaCl₂-extractable Al, which appeared to be caused by differing C levels in the 0.02M CaCl₂ extracts.     

Beneficial effects of combination of P and Zn for green gram (Phaseolus aureus L.)

Summary Dicalcium phosphate dihydrate and potassium dihydrogen phosphate were applied to calcareous soil in combination with zinc sulphate in the molar ratio of 100∶0, 100∶1, 100∶2 and 100∶4. Increasing addition of zinc sulphate into P sources gradually increased KCl (0.01M) soluble P and Zn, NaHCO₃ (0.5M, pH 8.5) extractable P and DTPA extractable Zn from soil and grain and straw yields of green gram.     

Mycorrhizal symbiosis and phosphorus fertilization effects on Zea mays growth and heavy metals uptake

Arbuscular mycorrhizal fungi (AMF) can promote plant growth and reduce plant uptake of heavy metals. Phosphorus (P) fertilization can affect this relationship. We investigated maize (Zea mays L.) uptake of heavy metals after soil AMF inoculation and P fertilization. Maize biomass, glomaline and chlorophyll contents and uptake of Fe, Mn, Zn, Cu, Cd and Pb have been determined in a soil inoculated with AMF (Glomus aggregatum, or Glomus intraradices) and treated with 30 or 60 µg P-K₂HPO₄ g^?1 soil. Consistent variations were found between the two mycorrhizal species with respect to the colonization and glomalin content. Shoot dry weight and chlorophyll content were higher with G. intraradices than with G. aggregatum inoculation. The biomass was highest with 30 µg P g^?1 soil. Shoot concentrations of Cd, Pb and Zn decreased with G. aggregatum inoculation, but that of Cd and Pb increased with G. intraradices inoculation. Addition of P fertilizers decreased Cd and Zn concentrations in the shoot. AMF with P fertilization greatly reduced maize content of heavy metals. The results provide that native AMF with a moderate application rate of P fertilizers can be exploited in polluted soils to minimize the heavy metals uptake and to increase maize growth.     

Interactions between aluminium,phosphorus and pH in the response of barley to soil acidity

Summary Two acid soils showing different Al solubility as a function of pH were limed to a range of pH values (in 10^–2 M CaCl₂) between 4.1 and 5.6. The apparent critical pH for the growth of barley in pots was 0.25 lower in the soil showing lower Al solubility. The addition of phosphate reduced exchangeable and soluble Al in the soils, and lowered the apparent critical pH by 0.35 while maintaining the difference between the soils. The Al concentration at the critical pH, measured after cropping to take account of the treatment effects on soil Al, also varied with soil and with phosphate addition. These apparent critical values of both pH and soluble Al varied linearly with available phosphate, over the range 18 to 73 mg P/kg soil, as follows: pH from 4.9 to 4.3; soluble Al, from 0.010 mM to 0.056 mM; and the soluble Ca/Al mole ratio, from 1270 to 214.     

Evaluation of Iodide and Iodate for Adsorption–Desorption Characteristics and Bioavailability in Three Types of Soil

Adsorption–desorption of iodine in two forms, viz., iodide (I⁻) and iodate (IO₃⁻), in three types of soil were investigated. The soils were: red soil developed on Quaternary red earths (REQ)— clayey, kaolintic thermic plinthite Aquult, Inceptisol soil (IS) and alluvial soil (AS)—Fluvio-marine yellow loamy soil. The isothermal curves of iodine adsorption on soils were described by Langmuir and Freundlich equation, and the maximum adsorption values (y _m) were obtained from the simple Langmuir model. As compared with the iodide, the iodate was adsorbed in higher amounts by the soils tested. Among three soils, the REQ soil adsorbed more iodine (I⁻ and IO₃⁻) than the IS and AS. The distribution coefficient (K _d) of iodine in the soils decreased exponentially with increasing iodine loading concentration. Desorption of iodine in soil was increased correspondingly with increasing adsorption values. The REQ soil had a greater affinity for iodine than the IS and AS at the same iodine loadings. In the pot experiment cultivated with pakchoi (Brassica chinensis L.) and added with two exogenous iodine sources, the iodide form was quickly taken up by pakchoi and caused more toxicity to the vegetable. The rate of iodine loss from soil was higher for iodide form as compared with the iodate. The iodine bioavailability was the highest but the persistence was the weakest in AS among the three soils tested, and the REQ soil showed just the opposite trend to that of the AS soil. This study is of theoretical importance to understand the relationship between iodine adsorption–desorption characteristics and their bioavailability in different soils and it also has practical implications for seeking effective alternatives of iodine biofortification to prevent iodine deficiency disorders.     

A model for the behaviour of labile phosphate in soil

Summary The Langmuir two-surface adsorption equation is used to derive a phosphate adsorption characteristic, the maximum buffer capacity, which integrates the intensive and extensive components of adsorption and is independent of P saturation. Changes in the intensities and quantities of labile P and equilibrium buffer capacities resulting from fertilization of a group of 24 soils are shown to be related to the Lamgmuir high-energy adsorption parameters and in particular the maximum buffer capacity.     

广东省主要母质发育水稻土对磷的吸附特性

对广东省5种不同母质上发育的水稻土进行了P素等温吸附试验.结果表明,供试土壤的等温吸附数据与Langmuir、Freundlich和Temkin 3个方程都能很好地拟合,但以Langmuir方程拟合程度最好(相关系数从0.995^**到0.999^**).利用Langmuir方程计算的P最大吸附量(Xm)和吸附强度因子(K)的乘积(KXm:P吸附特性值)可以作为水稻土吸附P素的综合指标,KXm的大小可以表明水稻土施P次序.试验结果还表明供试水稻土对P素吸附存在两种不同的吸附区.     

An investigation of the anion-exchange resin method for soil phosphate extraction

Summary The anion-exchange resin method for soil-phosphate extraction was investigated on 4 different soils under varying experimental conditions. The variables were: (a) the type of anion-exchange resin, (b) the anionic form of the resin, (c) the ratio between the amounts of resin, soil, and water, and (d) the time of shaking. The amount of P extracted was dependent on the anionic form of the resin. For resins in the chloride form both the amount of P extracted psr soil unit and the pH of the soil suspension varied with the type of resin and the soil-water ratio. Resins in the bicarbonate form stabilized the system, so that the amount of P extracted and the suspension pH were almost independent of the type of resin and the soil-water ratio. The results indicated that the rate-determining step in the overall process of P transport from the soil phase through the water phase to the resin phase is the P desorption from the soil phase to the water phase, provided the resin is added in excess. The rate of this P desorption is dependent on the chemical composition of the water phase, which in turn is governed by the type of soil, the soil-water ratio, the time of shaking and the anionic form of the resin. In a final experiment a resin was used in the chloride- and the bicarbonate form, respectively, for extraction of phosphate from 34 soils. The available P of these soils had been determined 15 years before in a pot experiment with ryegrass and by different laboratory methods². The degree of correlation between the ryegrass P uptake and the P. determined by the laboratory methods decreased according to the following order: resin (bicarbonate form), resin (chloride form), 0.5M sodium bicarbonate, L value, E value, ammonium lactate solution, sodium zeolite, 0.01M calcium chloride, phosphate potential, and 0.1M sulphuric acid. It is recommended that resins in the bicarbonate form should be used for both routine as well as more advanced analyses of the ability of soils to supply phosphate to plants. A final procedure for the analysis is given in the paper.     

Phosphorus availability under alley cropping and mulched and unmulched sole cropping systems in Costa Rica

Phosphorus availability was measured in soils under five cropping systems: alley cropping with Erythrina poeppigiana, alley cropping with Gliricidia sepium, sole cropping with Erythrina poeppigiana mulch applied, sole cropping with Gliricidia sepium mulch applied, sole cropping with no mulch. The following parameters were measured: 1) plant-available soil P assessed by P uptake of maize and bean bioassay plants; 2) phosphate desorbable by anion exchange resin; 3) adsorption of added P into isotopically exchangeable and non-exchangeable pools.In the bioassay, P uptake of beans declined in the order: mulched sole-cropped>unmulched sole-cropped>alley-cropped soils. For maize the relative uptake was: mulched sole-cropped>unmulched sole-cropped = alley-cropped soils. These results suggest trees had not incorporated a significant quantity of P into the system after seven years and, probably, there was a decrease in available soil P due to the sequestration of P in the tree biomass. Potentially resin-desorbable P was higher in alley-cropped and mulched sole-cropped soils than in unmulched sole-cropped soils. The adsorption and desorption of added P into and from exchangeable and non-exchangeable pools did not differ between alley-cropped and unmulched sole-cropped soils.Crop yield and crop N, P and K uptake were all higher in the alley crops than in the unmulched sole crop. The supply of P to the crop under alley cropping seems to be dependent on P cycled and released from the mulch. The P cycle in alley cropping appears to be self-sustaining at least under conditions of moderate P fertiliser input.     

Evaluation of elemental allelopathy in Acroptilon repens (L.) DC. (Russian Knapweed)

Although Acroptilon repens (L.) DC. (Russian knapweed) is known to concentrate zinc (Zn) in upper soil layers, the question of whether the elevated Zn has an allelopathic effect on restoration species has not been addressed. Experiments were conducted to investigate whether soils collected from within infestations of A. repens (high-Zn) inhibit the germination or growth and development of desirable restoration species, compared to soils collected adjacent to an A. repens infestation (low-Zn). Four bioassay species [Sporobolus airoides (Torrey) Torrey (alkali sacaton), Pseudoroegneria spicata (Pursh) A. Love (bluebunch wheatgrass), Psathyrostachys juncea (Fischer) Nevski (Russian wildrye) and A. repens] were germinated in a growth chamber and grown in a greenhouse in both soils and received treatments for the alleviation of Zn toxicity (P, Fe, Fe-oxide, and soil mixing) to isolate the effects of elevated soil Zn on plant performance. Percent germination, total plant biomass, tiller and stem number, inflorescence number, and tissue metal levels were compared among soil types and treatments for each species. There was no evidence from any of the indicators measured that high-Zn soils reduced plant performance, compared to low-Zn soils. Tissue Zn levels barely approached the lower range of phytotoxic levels established for native grasses. Older plants with longer exposure times may accumulate higher Zn concentrations. S. airoides and A. repens both had higher biomass in the high-Zn soil, most likely due to increased macronutrient (N and P) availability. As the Zn levels in the soils used in this study were much higher than any levels previously reported in soils associated with A. repens, it is unlikely that the elevation of soil Zn by A. repens will hinder germination or growth and development of desirable grasses during establishment.     

The use of indigenous plant species and calcium phosphate for the stabilization of highly metal-polluted sites in southern Poland

Highly metal-polluted (Pb, Cd, Zn) soil from a non-ferrous mine and smelter site in southern Poland, further referred to as Waryski soil, was used to test indigenous plant species for stabilization effectiveness of heavy metals in soils. Results of pilot investigations with commercially available cultivars of plant species showed that these cultivars could not grow on this highly polluted soil even with the application of soil amendments to stabilize the heavy metals. Based on these results, mesocosm and field experiments with an indigenous, metal-tolerant ecotype of Deschampsia cespitosa from the Waryñski site were carried out. The mesocosm experiment showed that applications of calcium phosphate (3.8% w/w) as a heavy metal-stabilizing amendment decreased Cd and Zn concentrations 2 and 3-fold respectively in leachates, whereas lead content was not significantly changed. This decrease in the concentration of heavy metals in leachates was correlated with a lower accumulation of Pb, Cd and Zn in the roots and shoots of D. cespitosa, ecotype Waryñski. In the field experiment, lower accumulations of Cd in roots and shoots and Zn in shoots in the amendment added plot were observed during the second year of investigations. In the first growing season, D. cespitosa plant cover in the amendment enriched mesocosms ranged from 95 to 100%, compared to 10% in mesocosms without calcium phosphate. In the second year of the experiment, in non-amendment enriched mesocosms D. cespitosa was substituted with Cardaminopsis arenosa(95% cover). C. arenosa is an undesirable species for phytostabilization, as it accumulates high amounts of zinc and cadmium in its shoots, even thought it provided better growth cover in not amended soils. However, in amended mesocosms, soil surface cover by D. cespitosa was still very high (90%). Similar results were obtained in field experiments. Addition of calcium phosphate to the soil also resulted in excellent D. cespitosa root system development when compared to soils without amendment. In amended mesocosms, high plant cover and root system development significantly decreased the volume of leachates and improved water retention. These results indicate that the use of D. cespitosa, ecotype Waryski in combination with calcium phosphate as a heavy metals immobilizing agent is sufficient to restore a dense vegetative cover to highly heavy metal-polluted soil.     

Some aspects of the chemistry of lithium in soils

Summary A method for the determination of exchangeable lithium using 0.5M NH₄Cl is described. The range of exchangeable Li in the fifty Papua New Guinea (PNG) soils analyzed was 0.002 to 0.409 gg^–1 in contrast to five Australian soils which ranged from 0.032 to 0.830 gg^–1. The PNG soils were divided into hill and alluvial soils with average exchangeable Li contents of 0.062 and 0.263 gg^–1 respectively. No significant correlation between total and exchangeable Li was found in either group of soils althoughr=0.67 for the comined data and was significant at the 5% level. From the analysis of three profiles exchangeable Li was found to be at least twice as high (0.27 gg^–1) in surface soils as in subsurface samples (0.10 gg^–1). The average value of the deeper subsoil samples was 0.18 ppm.R mode cluster analysis of the data for village garden soils collected on a sampling grid showed that exchangeable Li was more strongly assoicated with Ca and Mg than with pH, 0.05M EDTA soluble Zn, 0.5M NaHCO₃ soluble P or exchangeable Na and K. Computer constructed isographs using the analyses of grid samples from a garden illustrated the association between Li, Ca and Mg and the inverse association with Na.The correlation coefficient between Ca and Li in the ash of three food plants (Gnetum gnemon, Hibiscus abelmoschus andStenochlaena plustris) while not significant on an individual basis, was significant when the data was combined suggesting that the association between these elements in the soil may reflect an association in the ash returned to the soil when the garden was cleared. The correlation coefficient between soil exchangeable Li and Li in plant ash was positive, but not significant.Adsorption experiments over a five-day period demonstrated that Li was strongly adsorbed from solution. On average 63–75% of the adsorbed Li was fixed in a form which was not exchangeable with 0.5M NH₄Cl or soluble in 0.05M EDTA.     

Moisture retention properties of a mycorrhizal soil

The water relations of arbuscular mycorrhizal plants have been compared often, but virtually nothing is known about the comparative water relations of mycorrhizal and nonmycorrhizal soils. Mycorrhizal symbiosis typically affects soil structure, and soil structure affects water retention properties; therefore, it seems likely that mycorrhizal symbiosis may affect soil water relations. We examined the water retention properties of a Sequatchie fine sandy loam subjected to three treatments: seven months of root growth by (1) nonmycorrhizal Vigna unguiculata given low phosphorus fertilization, (2) nonmycorrhizal Vigna unguiculata given high phosphorus fertilization, (3) Vigna unguiculata colonized by Glomus intraradices and given low phosphorus fertilization. Mycorrhization of soil had a slight but significant effect on the soil moisture characteristic curve. Once soil matric potential (_m) began to decline, changes in _m per unit change in soil water content were smaller in mycorrhizal than in the two nonmycorrhizal soils. Within the range of about –1 to –5 MPa, the mycorrhizal soil had to dry more than the nonmycorrhizal soils to reach the same _m. Soil characteristic curves of nonmycorrhizal soils were similar, whether they contained roots of plants fed high or low phosphorus. The mycorrhizal soil had significantly more water stable aggregates and substantially higher extraradical hyphal densities than the nonmycorrhizal soils. Importantly, we were able to factor out the possibly confounding influence of differential root growth among mycorrhizal and nonmycorrhizal soils. Mycorrhizal symbiosis affected the soil moisture characteristic and soil structure, even though root mass, root length, root surface area and root volume densities were similar in mycorrhizal and nonmycorrhizal soils.     

Phosphorus mining for ecological restoration on former agricultural land

To restore species‐rich terrestrial ecosystems on ex‐agricultural land, establishing nutrient limitation for dominant plant growth is essential because in nutrient‐rich soils, fast‐growing species often exclude target species. However, N‐limitation is easier to achieve than P‐limitation (because of a difference in biogeochemical behavior), biodiversity is generally highest under P‐limitation. Commonly used restoration methods to achieve low soil P‐concentrations are either very expensive or take a very long time. A promising restoration technique is P‐mining, an adjusted agricultural technique that aims at depleting soil‐P. High biomass production and hence high P‐removal with biomass are obtained by fertilizing with nutrients other than P. A pot experiment was set up to study P‐mining with Lolium perenne L. on sandy soils with varying P‐concentrations: from an intensively used agricultural soil to a soil near the soil P‐target for species‐rich Nardus grassland. All pots received N‐ and K‐fertilization. The effects of biostimulants on P‐uptake were also assessed by the addition of arbuscular mycorrhiza (Glomus spp.), humic substances or phosphate‐solubilizing bacteria (Bacillus sp. and Pseudomonas spp.). In our P‐rich soil (111 µg P_Olsen/g), P‐removal rate was high but bioavailable soil‐P did not decrease. At lower soil P‐concentrations (64 and 36 µg P_Olsen/g), bioavailable soil‐P had decreased but the P‐removal rate had by then dropped 60% despite N‐ and K‐fertilization and despite that the target (<10 µg P_Olsen/g) was still far away. None of the biostimulants altered this trajectory. Therefore, restoration will still take decades when starting with ex‐agricultural soils unless P‐fertilization history was much lower than average.