scholarly journals Sensitivity of Three Phosphate Extraction Methods to the Application of Phosphate Species Differing in Immediate Plant Availability

Agronomy ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 29 ◽  
Author(s):  
Tobias Hartmann ◽  
Iris Wollmann ◽  
Yawen You ◽  
Torsten Müller
Keyword(s):  
Soil Phosphorus ◽  
Extraction Methods ◽  
Available P ◽  
Plant Availability ◽  
Soil P ◽  
Low Concentrations ◽  
High Sorption ◽  
Phosphate Species ◽  
Different Characteristics ◽  
Plant Available P

Extractive tests for determining the plant-availability of soil phosphorus (P) give varying results due to the inherently different characteristics of the extraction solution. Generally, classical soil P tests such as the Olsen or calcium acetate/lactate (CAL) method do not give an indication on the total amount of plant available P, but merely give an indication of the equilibrium between soil and extraction solution. It is also not entirely clear which fractions of P are directly determined through the various methods of extraction, i.e., determined P must not be immediately plant available, as is the case for rock phosphate. It is therefore possible that extraction methods either over or under estimate the amount of P available for plant consumption. In this research, we compared three methods of soil P determination (CAL, Olsen and diffusive gradients in thin films (DGT)) with regards to their ability to determine P species (Ca(H2PO4)2, CaHPO4, Ca3(PO4)2 and Inositol-6-hexakisphosphate) added to soils of high sorption capacity, immediately after as well as two weeks after application. For each of the methods, it could be shown that sorption processes in the soil immediately (0 days incubation) fix P to a point where it is not extractable through any of the described methods. These sorption processes continue over time, leading to a further decrease of determined P. The acidic CAL extraction method gives higher results of extractable P compared to the Olsen method. Due to the extraction of Ca3(PO4)2, the CAL method may overestimate immediately plant-available P. The most suitable methods for the determination of immediately plant available P may therefore be the Olsen and DGT methods. Organic IP6 is not determined by any of the extraction methods. At low concentrations of soil P, the DGT method may fail to give results.

Depletion, accumulation and availability of soil phosphorus in the Askov long-term field experiment

Soil Research ◽  
2020 ◽  
Vol 58 (2) ◽  
pp. 117 ◽  
Author(s):  
Musibau O. Azeez ◽  
Gitte Holton Rubæk ◽  
Ingeborg Frøsig Pedersen ◽  
Bent T. Christensen
Keyword(s):  
Rock Phosphate ◽  
Soil Phosphorus ◽  
Available P ◽  
Soil P ◽  
Olsen P ◽  
Extractable P ◽  
P Application ◽  
Plant Available P ◽  
Water Extractable

Soil phosphorus (P) reserves, built up over decades of intensive agriculture, may account for most of the crop P uptake, provided adequate supply of other plant nutrients. Whether crops grown on soils with reduced supply of other nutrients obtain similar use-efficiency of soil P reserves remains unclear. In treatments of the Askov Long-Term Experiment (initiated in 1894 on light sandy loam), we quantified changes in soil total P and in plant-available P (Olsen P, water extractable P and P offtake in wheat grains) when P-depleted soil started receiving P in rock phosphate and when P application to soil with moderate P levels ceased during 1997–2017. Additionally we studied treatments with soil kept unfertilised for >100 years and with soil first being P depleted and then exposed to surplus dressings of P, nitrogen (N) and potassium in cattle manure. For soil kept unfertilised for >100 years, average grain P offtake was 6 kg ha–1 and Olsen P averaged 4.6 mg kg–1, representing the lower asymptotic level of plant-available P. Adding igneous rock phosphate to severely P-depleted soil with no N fertilisation had little effect on Olsen P, water extractable P (Pw), grain yields and P offtake. For soils with moderate levels of available P, withholding P application for 20 years reduced contents of Olsen P by 56% (from 16 to 7 mg P kg–1) and of Pw by 63% (from 4.5 to 1.7 mg P kg–1). However, the level of plant-available P was still above that of unfertilised soil. Application of animal manure to P-depleted soil gradually raised soil P availability, grain yield and P offtake, but it took 20 years to restore levels of plant-available P. Our study suggests symmetry between rates of depletion and accumulation of plant-available P in soil.

Comparison of Mehlich 3, AL and artificial root exudates containing extractants for soil phosphorus analysis

2020 ◽  
Author(s):  
Tonu Tonutare ◽  
Gert Kaldmae ◽  
Tiina Köster ◽  
Kadri Krebstein ◽  
Ako Rodima
Keyword(s):  
Root Exudates ◽  
Soil Phosphorus ◽  
Extraction Methods ◽  
Solution Chemistry ◽  
Soil Science ◽  
Available Phosphorus ◽  
Plant Analysis ◽  
Soil P ◽  
Fertilizer Recommendations

<p>Due to increase of fertilizers prices and tightening of environmental protection requirements the need for efficient use of fertilizers has increased. At moment over the word huge number of different methods for determination of soil plant available phosphorus (PAP) are in use. Due to unequal extraction ability of extractants have each method own specific gradation to evaluate the soil P class. Allmost all widely used PAP extraction methods are developed in last century, mostly more than fifty years ago and often there is not possible to found information how the P status classes and fertilizer recommendations are determined for each method is determined.</p><p>The content of PAP in soil is difficult to estimate because soil pH has a strong effect to soil  - solution chemistry. Therefore extracting  soils with higly buffered solutions as for example Mehlich 3 can give overestimated results. The acidic Mehlich  3 extactant can solubilize relatively insoluble Ca- Fe- and Al phosphates. Also the AL (acetate-lactate) method uses the buffered extraction solution and may influence the amount of extracted PAP. The most realistic conditions for PAP extraction can give the extraction solution which mimic the soil environment that has actively growing roots. </p><p>The aim of our research was to investigate the extraction of PAP with extragent similar by chemical composition to soil solution with root exudates proposed by Haney et al (2010).  The obtained results were compared with Mehlich 3 and AL methods results.    </p><p>Ref.: Haney, R.L., Haney, E.B., Hossner, L.R., Arnold, J,G. 2010. Modification to the New Soil Extractant H3A-1: A Multinutrient Extractant. Communications in Soil Science and Plant Analysis, 41:1513-1523.</p>

Bayesian spatio-temporal modeling of soil phosphorus in Britany in western France (1995-2014) with INLA-SPDE

2020 ◽  
Author(s):  
Bifeng Hu ◽  
Nicolas Saby ◽  
Hocine Bourennane ◽  
Thomas Opitz ◽  
Pascal Denoroy ◽  
...  
Keyword(s):  
Temporal Variation ◽  
Soil Phosphorus ◽  
External Validation ◽  
Soil Management ◽  
Available P ◽  
Validation Dataset ◽  
Related Factors ◽  
Soil P ◽  
Soil Available P ◽  
Spatio Temporal

<p>Soil phosphorus (P) is one of the most critical elements for Earth’s ecosystem. P is a component of the complex nucleic acid structure of plants, which regulates protein synthesis, plants deficient in P are stunted in growth and lead to diseases. In practice, P is most often the element responsible for eutrophication problems in freshwater meanwhile, and it is considered the macronutrient most frequently as the element limiting eutrophication because many blue-green algae are able to use atmospheric N<sub>2</sub>. Since the Second World War overuse application of fertilizer P has leaded to lots of serious environmental problems such as eutrophication of water body.</p><p>Soil P was affected by several factors including climate, geology, time, anthropogenic activities (irrigation, industrial emission, fertilizer application, crop planting pattern etc.) and so on. This makes soil P varied in a very complex manner on both spatial and time dimension and thus increases the difficulty of estimating spatio-temporal variation of soil P. Therefore, a flexible framework is necessary for modelling spatio-temporal variation of soil P.</p><p>To explore spatio-temporal variation of soil available P, we propose a Bayesian hierarchical spatio-temporal model using Integrated Nested Laplace Approximation with Stochastic Partial Differential Equation approach (INLA-SPDE). The study was conducted on phosphorus measured by Olsen (P Olsen) and Dyer (P Dyer) methods in Britany (western France) from 1995 to 2014 with data of more than 30,000 samples of France national soil test database (BDAT).</p><p>The INLA-SPDE method exploits the Laplace approximation in Bayesian latent-Gaussian models and does not require generating samples from the posterior distribution. Hence, it can often be used for quite large data sets at reasonable computational expense. It could provide approximate marginal (posterior) distributions over all states and parameters. In this study, the constructed model includes of several components such as spatial varying trend, space varying temporal trend, effects of covariates, and residual with space-time dependent variation.</p><p>Regardless the method of quantifying phosphorus, the results indicated that the mean content of soil available P decreased between 1995 and 2014 in Britany. Our model explained 49.5% of variance of spatio-temporal variation of P Olsen in Britany in external validation dataset. For P Dyer, our model explained 50% of variance in external validation dataset. The purely spatial effects shown that the available P in west of Britany was higher than east part. Our study could contribute to better soil management and environmental protection. Further study still needed to include more related factors into the model to improve the model performance and detected more related factors (such as soil management measures) which have important effects on spatio-temporal variation of available P in soil.</p>

A comparison of four resin extractions and 32P isotopic exchange for the assessment of plant-available P

1992 ◽  
Vol 72 (3) ◽  
pp. 281-294 ◽  
Author(s):  
T. Sen Tran ◽  
R. R. Simard ◽  
J. C. Fardeau
Keyword(s):  
Anion Exchange ◽  
Isotopic Exchange ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Relative Yield ◽  
Available P ◽  
Multiple Regression Equation ◽  
Fertilizer Response ◽  
Soil P ◽  
Plant Available P

Resin extraction procedures are widely used to simulate nutrient uptake by plant roots. The objective of this study was to compare an anion exchange resin in three forms: F, Cl and HCO3, and a mixed anionic-cationic exchange resin in H-OH form to a 32P isotopic exchange method in their ability to extract soil P, and to predict plant-available P for oat (Avena sativa L.) grown in the glasshouse. Thirty-four soils varying widely in chemical and physical properties, and in P contents, were extracted for 24 h at a soil-to-solution ratio of 1:80 with 1 g resin. Increasingly higher P quantities were obtained by isotopic exchange after 1 min (E1 7.61 mg kg−1), Cl-resin (27.3 mg kg−1), HCO3-resin (40.5 mg kg−1), F-resin (75.1 mg kg−1) and H-OH resin (130 mg kg−1). The Cl and HCO3 resins extracted a constant ratio of E1-P in strongly acidic and weakly acidic to neutral soils; this was not the case for the other resins. The pH values of the resin-soil-solution system were related to the natural logarithm of the amount of rapidly exchangeable Ca. The Cl and HCO3 resins best predicted P uptake and relative yield of oat growing on 34 soils. These two methods were superior to chemical methods in evaluating soil P status and fertilizer response of oats. The relationships between the amount of soil P desorbed by the HCO3 and F resins and by plant uptake were improved when the P buffering capacity (MBC) was included in the multiple regression equation. The P intensity factor was most important for the H-OH and Cl resins. In general, desorption of soil P with exchange resins improves, compared to chemical extradants, the evaluation of the P-supplying power of soils. Key words: 32P, anion exchange resin, available P, extraction method

scholarly journals Penentuan Metode Terbaik Uji Fosfor untuk Tanaman Tomat pada Tanah Inceptisols

2013 ◽  
Vol 22 (2) ◽  
pp. 139
Author(s):  
L Izhar ◽  
A D Susila ◽  
B S Puswoko ◽  
A Sutandi ◽  
I W Mangku
Keyword(s):  
Extraction Method ◽  
Soil Phosphorus ◽  
Block Design ◽  
Dry Weight ◽  
Extraction Methods ◽  
Soil P ◽  
Soil P Test ◽  
Coefficient Corrélation ◽  
P Fertilizer ◽  
Nutrient Extraction

ABSTRAK.  Fosfor merupakan salah satu hara penting tanah dan aplikasi hara tersebut pada konsentrasi yang sesuai sangat berpengaruh terhadap pertumbuhan tomat. Penelitian tentang studi analisis fosfor tanah dan aplikasi pupuk fosfor pada budidaya tomat pada tanah Inceptisols dilakukan di Kebun Percobaan dan Rumah Kaca di Cikabayan, Institut Pertanian Bogor, dari bulan Maret sampai dengan November 2010. Tujuan penelitian ialah untuk mendapatkan  metode  ekstraksi  fosfor tanah yang terbaik guna menentukan dosis pupuk fosfor pada budidaya tomat  pada tanah Inceptisols. Penelitian menggunakan rancangan acak kelompok dengan perlakuan pemberian pupuk fosfor pada beberapa tingkat dosis yaitu  0X, ¼ X, ½ X, ¾ X, dan 1X, di mana nilai X ialah 368,5 kg/ha P2O5 dengan empat ulangan. Perlakuan pemupukan fosfor diterapkan pada 6 bulan sebelum penanaman tomat. Analisis korelasi dilakukan antara kandungan P tanah dan pertumbuhan tanaman yang ditanam di dalam rumah kaca menggunakan media inkubasi berasal dari tanah yang diberi perlakuan dan dianalisis. Uji  fosfor  tanah menggunakan lima metode ekstraksi, yaitu metode Bray I (NH4F 0,03 N + HCl 0,025 N, nisbah 1:7); Bray II (NH4F 0,03 N + HCl 0,10 N ); Mehlich I (HCl 0,05 N + H2SO4 0,025 N); Morgan Wolf (NaC2H2H3O2.3H2O; pH 4,8); dan Truogh [HCl 0,10 N + (NH4)2SO4; pH 3]. Hasil penelitian menunjukkan adanya perbedaan yang nyata antara pengaruh perlakuan pupuk P terhadap parameter  tinggi tanaman,  jumlah daun, dan diameter batang tomat. Bobot segar biomassa dan bobot kering tomat juga menunjukkan  perbedaan pengaruh yang signifikan antarperlakuan. Nilai korelasi terbaik ditunjukkan oleh metode pengekstrak Mehlich I melalui parameter bobot kering dan bobot basah relatif tanaman. Dengan demikian, metode uji P tanah yang menggunakan Mehlich I dapat digunakan sebagai metode ekstraksi yang paling tepat untuk menganalisis unsur hara fosfor dengan koefisien korelasi 0,88, sehingga metode Mehlich I dapat diusulkan sebagai rekomendasi pemupukan P pada budidaya tomat pada tanah Inceptisols (nilai r = 0,89).  <br /><br />ABSTRACT. Izhar, L, Susila, AD, Purwoko, BS, Sutandi, A,  and  Mangku, IW. 2012. Determination of the Best Method of Soil P Test for Tomato (Lycopersicon esculentum Mill. L) on Inceptisols Soil. Phosphorus is one of important soil elements and application of the element in suitable concentration give high effect on tomato growth. A study on phosphorus analysis and its application for recommendation of soil fertilization of tomato cultivation on Inceptisols soil was conducted at the field and Greenhouse of Cikabayan, Bogor Agricultural University, from March to November 2010. The objective of this research was to obtain the best extraction method of soil-P test for determining phosphorus nutrient required for tomato cultivation on Inceptisol soil. Rate of phosphorus of 0X, ¼ X, ½ X, ¾ X, and 1X, where X was 368.5 kg/ha P2O5 with four replications, was applied in the study. The treatments were applied 6 months before planting date. The research was arranged in randomized complete block design. Analysis of correlation between soil-P and plant growth based on data collected from the plants grown in the greenhouse using incubation media in treated-soil was  analyzed. Soil-P test was carried out by using five extraction methods i.e. Bray I (HCl 0,025 N + NH4F 0.03), Bray II (NH4F 0.03 N + HCl 0.10 N), Mehlich I (HCl 0.05 N + H2SO4 0.025 N), Morgan Wolf (NaC2H2H3O2.3H2O; pH 4.8), and Truogh [HCl 0.10 N + (NH4)2SO4; pH 3]. The results showed that there were significant differences among the treatments of P fertilizer on the variables of plant height, leaf number, and stem diameter of tomato. Biomass fresh and dry weight of tomato also showed significantly different between the treatments applied. The highest correlation was shown on Mehlich I extraction reagent between plant dry and fresh weight. It means that, this P-nutrient extraction method was the most appropriate in determining phosphorus nutrient for tomatoes on Inceptisols soil with a coefficient correlation of 0.88. Mehlich I can also be used to develop a comprehensive phosphorus fertilizer recommendation for tomato cultivation on Inceptisols soil (r value = 0.89).<br /><br />

scholarly journals Comparison of soil phosphorus and phosphatase activity under long-term no-tillage and maize residue management

2019 ◽  
Vol 65 (No. 8) ◽  
pp. 408-415 ◽  
Author(s):  
Xiaozhu Yang ◽  
Xuelian Bao ◽  
Yali Yang ◽  
Yue Zhao ◽  
Chao Liang ◽  
...  
Keyword(s):  
Soil Phosphorus ◽  
Soil Layer ◽  
Residue Management ◽  
Available P ◽  
No Tillage ◽  
Organic P ◽  
Inorganic P ◽  
Phosphatase Activities ◽  
Soil P ◽  
Soil Available P

The migration and transformation of soil phosphorus (P) are essential for agricultural productivity and environmental security but have not been thoroughly elucidated to date. A 10-year field study was conducted to explore the effects of conventional tillage (CT) and no-tillage with maize residue management (NT-0, NT-33%, NT-67% and NT-100%) on P contents and phosphatase activities in soil layers (0–5, 5–10, 10–20 and 20–40 cm). The results showed that soil available P content and phosphatase activities were higher in no-tillage with maize residue than CT. Soil moisture and pH were significantly positively correlated with soil available P. Higher organic P contents and lower inorganic P contents in the 0–5 cm soil layer were found in the treatment NT-67% compared with other treatments. According to the structure equation model, the source of available P was inorganic P in NT-33%, while organic P in NT-67%. This study demonstrated that the variation of dominant mechanisms involved in soil P migration and transformation were dependent on residue input amounts, and NT-67% might play an important role in the maintenance and transformation of soil organic P.

Changes in soil phosphorus balance and phosphorus-use efficiency under long-term fertilization conducted on agriculturally used Chernozem in Germany

2018 ◽  
Vol 98 (4) ◽  
pp. 650-662 ◽  
Author(s):  
Tetiana Medinski ◽  
Dirk Freese ◽  
Thomas Reitz
Keyword(s):  
Soil Phosphorus ◽  
Spring Barley ◽  
Farmyard Manure ◽  
Available P ◽  
Phosphorus Use Efficiency ◽  
P Fertilization ◽  
Mineral N ◽  
Efficient Treatment ◽  
Soil P ◽  
Use Efficiency

This study investigates changes in soil phosphorus (P) in different fertilization treatments applied since 1902 on Chernozem soil at a “Static Fertilization Experiment” in Germany. Total and plant-available soil P, and soil P balances were assessed at 0–30, 30–60, and 60–90 cm depth layers in unfertilized “Zero”, mineral “NK” and “NPK”, and combined mineral and organic “FYM + NK” (farmyard manure + NK) and “FYM + NPK” fertilization treatments. P-use efficiencies were determined for each crop in rotation (sugar beet, spring barley, potato, and winter wheat). The 110 yr of P fertilization at rates between 22 and 55 t ha−1 yr−1 resulted in a significant increase of available P contents. P stocks increased up to 60 cm depth. Total P accumulation comprised 1.4 t ha−1 for NPK, 1.3 t ha−1 for FYM + NK, and 3.1 t ha−1 for FYM + NPK. Crops cultivation without P fertilization in Zero and NK treatments resulted in negative P balances and reduction of available P below recommended levels. Reduction of mineral P application rates after 1981, along with crop variety-dependent yield increases, resulted in an improved P-use efficiency. An organic fertilization combined with mineral N and K fertilizers (FYM + NK) was found to be the most P-efficient treatment for Chernozem soils.

scholarly journals Forest Soil Colloids Enhance Delivery of Phosphorus Into a Diffusive Gradient in Thin Films (DGT) Sink

2021 ◽  
Vol 3 ◽  
Author(s):  
Alexander Konrad ◽  
Benjamin Billiy ◽  
Philipp Regenbogen ◽  
Roland Bol ◽  
Friederike Lang ◽  
...  
Keyword(s):  
Thin Films ◽  
P Uptake ◽  
Parent Material ◽  
Plant Roots ◽  
Bulk Soil ◽  
Available P ◽  
Soil Extraction ◽  
Soil P ◽  
Freeze Dried ◽  
Plant Available P

Phosphorus (P) is preferentially bound to colloids in soil. On the one hand, colloids may facilitate soil P leaching leading to a decrease of plant available P, but on the other hand they can carry P to plant roots, thus supporting the P uptake of plants. We tested the magnitude and the kinetics of P delivery by colloids into a P sink mimicking plant roots using the Diffusive Gradients in Thin-Films (DGT) technique. Colloids were extracted with water from three forest soils differing in parent material using a method based on dispersion and sedimentation. Freeze-dried colloids, the respective bulk soil, and the colloid-free extraction residue were sterilized and mixed with quartz sand and silt to an equal P basis. The mixtures were wetted and the diffusive fluxes of P into the DGTs were measured under sterile, water unsaturated conditions. The colloids extracted from a P-poor sandy podzolic soil were highly enriched in iron and organic matter compared to the bulk soil and delivered more P at a higher rate into the sink compared to bulk soil and the colloid-free soil extraction residue. However, colloidal P delivery into the sink was smaller than P release and transport from the bulk soil developed on dolomite rock, and with no difference for a soil with intermediate phosphorus-stocks developed from gneiss. Our results provide evidence that both the mobility of colloids and their P binding strength control their contribution to the plant available P-pool of soils. Overall, our findings highlight the relevance of colloids for P delivery to plant roots.

scholarly journals Relative Suitability of Phosphorus Extraction Procedures for F Tropical Ferralsol

2020 ◽  
pp. 27-35
Author(s):  
J. S. Tenywa ◽  
E. Odama ◽  
A. K. Amoding
Keyword(s):  
Soil Phosphorus ◽  
Extraction Methods ◽  
P Uptake ◽  
Strong Positive Correlation ◽  
Predictive Capacity ◽  
Soil P ◽  
Application Rates ◽  
Plant P Uptake ◽  
Phosphorus Extraction ◽  
P Application

Purpose: To evaluate the predictive capacity common procedures for soil P extraction and testing in laboratories in the region. Materials and Methods: A pot study with treatments viz. soil phosphorus extraction methods (Bray I, Bray II and Mehlich 3), and six P application rates (0, 20, 40, 60, 80 and 100 kg P ha-1). Maize (Zea mays L.) variety Longe IV was the test crop. A Ferralsol from northwestern Uganda (West Nile) was used in this study. Results and Conclusion: Mehlich 3 correlated most with plant P uptake by presenting the highest correlation coefficient with plant P content (r = 0.254) and a number of leaves per plant (r = 0.733). A strong positive correlation existed between Bray I and Mehlich 3 extractable P values (r = 0.975), suggesting lack of a marked difference between them; implying that either of the two procedures could be applied for soil P extraction in Ferralsols. However, Mehlich 3, being a multi-nutrient extractant, was recommended as the most suitable for P extraction for the Ferralsol used in this study.

Evaluation on a Novel Phosphorus Fractionation Method in Acid Soils

2012 ◽  
Vol 204-208 ◽  
pp. 272-278
Author(s):  
Hong Jun Lei ◽  
Xin Liu ◽  
Bei Dou Xi ◽  
Duan Wei Zhu
Keyword(s):  
Soil Phosphorus ◽  
Acid Soils ◽  
Phosphorus Fractionation ◽  
Red Soil ◽  
Water Bath ◽  
Available P ◽  
Control Treatment ◽  
Available Phosphorus ◽  
Soil P ◽  
The Difference

Phosphorous fractionation is a method developed to estimate sizes of readily soil available P pool, soil P sub-pools and their ability to replenish the available P. Three types of acid soils (1aterite red soil, yellow red soil and brown red soil) were used in pot experiment under a rain-shelter condition to investigate the effect of lime amendment on P fractions and their bioavailability by plant of broad bean. A novel phosphorus fractionation scheme was developed and used to study the phosphorus fractionation of the tested soils compared with the two typical soil phosphorus fractionation schemes, adopting a series of extractants such as 0.25mol L-1 NaHCO3, 1h (for Ca2-P), 0.5mol L-1 NH4F (pH8.5), 1h (for Al-P), 0.7mol L-1 NaClO, pH 8.05, 85°C water bath 30min (for Org-P), 0.1mol L-1 NaOH-0.1Na2CO3, 4h (for Fe-P), 1mol L-1 NaOH, 85°C water bath 1h (for O-Al-P), 0.3 mol L-1 Na-citrate-0.5 g Na2S2O4 -0.5 mol L-1 NaOH, 85°C water bath 15min (for O-Fe-P), 0.25mol L-1 H2SO4, 1h (for Ca10-P). Main results are obtained just as follows: besides Ca2-P, Al-P, Fe-P and O-Fe-P are potentially available phosphorus resource. Although O-P reflects the difference of P between lime and control treatment well, when it appears as a whole, it needs further subdivision to reflect soil phosphorus biologically availability difference better.

Sign in / Sign up

Export Citation Format

Share Document