Changes in the forms and distribution of soil phosphorus due to long-term corn production

1995 ◽  
Vol 75 (3) ◽  
pp. 311-318 ◽  
Author(s):  
John E. Richards ◽  
Thomas E. Bates ◽  
S. C. Sheppard

Long-term fertilizer-P application affects soil-P distribution and forms. These effects must be characterized to use fertilizer P most efficiently. In three southern Ontario soils of varying texture, we determined changes in soil organic P (Po) and inorganic P (Pi) caused by fertilizer P application (0–90 kg broadcast P ha−1 yr−1 during 10 yr of corn production. Soil P was characterized by (1) annual measurement of 0.5 M NaHCO3-extractable P (Olsen-P) and (2) sequential extraction from soil taken at the beginning of the experiment and after receiving 0 to 90 kg broadcast P ha−1 yr−1 for 10 yr. Fertilizer P increased Olsen-P concentrations in all soils. The increases were proportional to the cumulative amount of P applied. Based on all three soils, 16 kg P ha−1 was required to increase Olsen-P concentrations by 1 mg L−1 soil. After 10 yr of 90 kg broadcast P ha−1 yr−1, labile Pi fractions (resin P and NaHCO3 P) were increased, as was NaOH-extractable Pi in all soils. On the most P-deficient soil (Conestogo SiL), where corn grain yields were increased by fertilizer P, P fertilization also increased HCl-Pi, residual P (H2O2-H2SO4 extractable P) and labile Po (NaHCO3-Po and NaOH-Po). A P balance was calculated, which accounted for additions to, removals from, and changes in the total P status of the 0–20 cm layer. When no broadcast P was applied, there was an unaccounted-for input (possibly from the subsoil), of 20.9 kg P ha−1 yr−1 on the Conestogo SiL. When 90 kg broadcast P ha−1 yr−1 was applied to the Fox SL, the coarsest soil studied, there was a deficit of 30.9 kg P ha−1 yr−1 and elevated Olsen-P concentrations in the 25–36 cm depth, suggesting downward movement on fertilizer P. It appears that subsoil P was involved in the P cycle of these two soils. Key words: Continuous corn, P fertilization, sequential extraction, organic phosphorus, inorganic phosphorus, labile phosphorus, subsoil P, leaching

Soil Research ◽  
2020 ◽  
Vol 58 (2) ◽  
pp. 117 ◽  
Author(s):  
Musibau O. Azeez ◽  
Gitte Holton Rubæk ◽  
Ingeborg Frøsig Pedersen ◽  
Bent T. Christensen

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.


1997 ◽  
Vol 77 (4) ◽  
pp. 685-691 ◽  
Author(s):  
T. Q. Zhang ◽  
A. F. MacKenzie

Phosphorus from fertilized agricultural land may contribute to ground or surface water inputs and accelerate eutrophication. With increases in soil P saturation and organic P in long-term fertilized soils, soil P leaching losses may increase. The effect of long-term P fertilization (6 to 11 yr) on inorganic and organic P in soil solutions at zero tension was studied on two soils, a Chicot sandy clay loam (Grey Brown Luvisol) and a Ste. Rosalie clay (Humic Gleysol). Soil solution samples were collected using a cylinder technique and analyzed for total dissolved P (TDP), dissolved inorganic P (DIP), and dissolved organic P (DOP). Levels for DIP ranged from 0.15 to 1.01 mg P L−1 and TDP ranged from 0.33 to 1.19 mg P L−1 in the Chicot soil. In the Ste. Rosalie soil, values of DIP ranged from 0.04 to 0.23 mg P L−1 and TDP ranged from 0.15 to 0.36 mg P L−1. Increasing fertilizer P applications from 44 kg ha−1 to 132 kg ha−1 increased DIP and TDP in soil solutions in both soils. There was no effect of P fertilization rate on DOP values. Soil P movement below 45 cm during the non-growing season was estimated at 633 to 2732 g ha−1 yr−1 in the Chicot soil and from 312 to 974 g ha−1 yr−1 in the Ste. Rosalie soil. Soil solution DIP was found to be linearly related to soil P extractable with 0.5 M NaHCO3, but levels of NaHCO3-extractable P required to produce 0.05 mg P L−1 DIP varied with soil, ranging from 70 to 110 mg P kg−1 soil. The critical level of extractable P has to be considered in association with soil type to predict potential water contamination. Key words: Continuous corn, long-term fertilization, soil solution, dissolved inorganic and organic P, NaHCO3 extractable P


2011 ◽  
Vol 60 (2) ◽  
pp. 343-358
Author(s):  
Péter Csathó ◽  
Marianna Magyar ◽  
Erzsébet Osztoics ◽  
Katalin Debreczeni ◽  
Katalin Sárdi

A szabadföldi trágyázási (tartam)kísérletek eredményeit talaj-, illetve diagnosztikai célú növényvizsgálatok segítségével tudjuk kiterjeszteni, általánosítani – figyelembe véve természetesen a kiterjesztés korlátait is. Célszerűnek láttuk ezen túl a talaj könnyen oldható tápelem-, közöttük P-tartalmát is meghatározni a hazánkban hivatalosan elfogadott AL- (ammónium-laktátos) módszer mellett az Európai Unióban és Észak-Amerikában alkalmazott P-tesztekkel is (CaCl2-, H2O-, Olsen-, Bray1-, LE-, Mehlich3- stb.) a hazai OMTK kísérletek talajmintáiban. A kísérleti helyek talajtulajdonságaiban megnyilvánuló jelentős különbségek lehetőséget adnak rá, hogy a talaj P-teszteket – és a növényi P-felvételt – jellegzetes hazai talajokon, sokszor szélsőséges talajparaméterek mellett vizsgáljuk. Az egyes P-szintek között a 28 év átlagában mintegy évi 50 kg P2O5·ha-1volt a különbség. A P0-szinten mért P-tartalmak jól jelezték az egyes kísérleti helyek talajának eltérő P-ellátottságát, illetve, közvetve, fizikai féleségében, pH és mészállapotában meglévő különbségeket. A P2-szinten – a hazai talajokra, P-igényes növényekre a hazai szabadföldi P-trágyázási tartamkísérleti adatbázisban talált összefüggésekre alapozott – új AL-P határértékek szerint csupán a bicsérdi csernozjom barna erdőtalajon nem javult a P-ellátottság legalább a „jó” szintig. Vizsgálataink megerősítették az AL-módszer függőségét a CaCO3-tartalomtól: a Mehlich3 módszerrel való összefüggésben a karbonátmentes és a karbonátos talajok csoportja erőteljesen elkülönült egymástól. Az AL-P korrekció elvégzése, azaz az AL-P értékeknek egy standard talajtulajdonság-sorra való konvertálása (KA: 36; pH(KCl): 6,8; CaCO3: 0,1%) látványosan csökkentette az AL-módszernek a talaj CaCO3-tartalmától való függőségét. Az AL-P és Olsen-P, valamint a korrigált AL-P és Olsen-P tartalmak összehasonlításában ugynakkor ugyanez az összefüggés nem volt állapítható, ami arra utal, hogy az Olsen módszer bizonyos fokig szintén pH- és mészállapot függő. Kísérleti eredményeink megerősítették a Sarkadi-féle AL-P korrekciós modell helytálló voltát. Fenti megállapításunkat ugyanakkor a növényi P-tartalmakkal való összefüggéseknek is igazolniuk kell. Szükséges tehát a talajvizsgálati eredményeknek a diagnosztikai célú növényvizsgálatokkal, valamint a terméseredményekkel való összevetése. A tartamkísérletek talajai lehetőséget nyújtanak a környezetvédelmi célú P-vizsgálatok értékelésére, a talaj P-feltöltöttsége környezeti kockázatának becslésére. Ezekkel a kérdésekkel a cikksorozat további részeiben kívánunk foglalkozni.


Soil Research ◽  
2007 ◽  
Vol 45 (4) ◽  
pp. 255 ◽  
Author(s):  
Ebrahim Adhami ◽  
Hamid Reza Memarian ◽  
Farzad Rassaei ◽  
Ehsan Mahdavi ◽  
Manouchehr Maftoun ◽  
...  

Inorganic phosphorus (P) sequential fractionation schemes are applicable techniques to interpret soil P status. The present study was initiated to determine the origin of various P fractions in highly calcareous soils. Inorganic P forms were determined by a sequential fractionation procedure extracting with NaOH (NaOH-P), Na citrate-bicarbonate (CB-P), Na citrate 2 times (C1-P and C2-P), Na citrate-ascorbate (CAs-P), Na citrate-bicarbonate-dithionite (CBD-P), Na acetate (NaAc-P), and HCl (HCl-P). Results showed that NaOH-P was negatively correlated with active iron oxides. CB-P was positively correlated with silt content and negatively related to citrate-bicarbonate-dithionite extractable Fe (Fed). This result illustrates the weathering effect on Ca-P, with Ca-P content declining as a consequence of weathering. A negative correlation was observed between C1-P and citrate ascorbate extractable Fe (FeCAs). Second citrate extractable P (C2-P) was negatively related to calcium carbonate equivalent and positively related to hydroxylamine-hydrochloride and neutral ammonium acetate-hydroquinone extractable Mn (Mnh and Mnq). Fine silt (Fsilt) was the most influential factor affecting CAs-P. It seemed citrate-dithionite-bicarbonate extractable Al (Ald), Mnh, and Mnq have been sinks for CBD-P, while free iron oxide compounds (Feo, Fec, and FeCAs) were a major contributing factor for the formation of NaAc-P. Stable P compounds (HCl-P) of highly calcareous soils originated from coarse silt (Csilt) and hydroxylamine-hydrochloride extractable Mn (Mnh).


2014 ◽  
Vol 38 (5) ◽  
pp. 1487-1495 ◽  
Author(s):  
Ciro Antonio Rosolem ◽  
Alexandre Merlin

Phosphorus fixation in tropical soils may decrease under no-till. In this case, P fertilizer could be surface-spread, which would improve farm operations by decreasing the time spend in reloading the planter with fertilizers. In the long term, less soluble P sources could be viable. In this experiment, the effect of surface-broadcast P fertilization with both soluble and reactive phosphates on soil P forms and availability to soybean was studied with or without fertilization with soluble P in the planting furrow in a long-term experiment in which soybean was grown in rotation with Ruzigrass (Brachiaria ruziziensis). No P or 80 kg ha-1 of P2O5 in the form of triple superphosphate or Arad reactive rock phosphate was applied on the surface of a soil with variable P fertilization history. Soil samples were taken to a depth of 60 cm and soil P was fractionated. Soybean was grown with 0, 30, and 60 kg ha-1 of P2O5 in the form of triple phosphate applied in the seed furrow. Both fertilizers applied increased available P in the uppermost soil layers and the moderately labile organic and inorganic forms of P in the soil profile, probably as result of root decay. Soybean responded to phosphates applied on the soil surface or in the seed furrow; however, application of soluble P in the seed furrow should not be discarded. In tropical soils with a history of P fertilization, soluble P sources may be substituted for natural reactive phosphates broadcast on the surface. The planting operation may be facilitated through reduction in the rate of P applied in the planting furrow in relation to the rates currently applied.


Soil Research ◽  
2007 ◽  
Vol 45 (5) ◽  
pp. 397 ◽  
Author(s):  
David Nash ◽  
Murray Hannah ◽  
Kirsten Barlow ◽  
Fiona Robertson ◽  
Nicole Mathers ◽  
...  

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.


HortScience ◽  
2004 ◽  
Vol 39 (4) ◽  
pp. 795E-796
Author(s):  
P.R. Johnstone ◽  
T.K. Hartz*

Heavy P fertilization of vegetable crops in the Salinas Valley of California have increased soil P levels, with > 50 mg·kg-1 bicarbonate-extractable P (Pbc) now common. To evaluate the response of lettuce (Lactuca sativa L.) to P fertilization in fields with elevated soil P levels, 12 trials were conducted in commercial fields during 2002-2003. Pbc at the trial sites varied from 53-171 mg·kg-1. In each trial four replicate plots receiving the growers' P application were compared with paired plots in which no P was applied. Leaf P was monitored at cupping stage and at harvest. At harvest mean whole plant mass and % of marketable plants were recorded. The correlation of Pbc to bioavailable P (Pba) was evaluated using 30 representative Salinas Valley soils; Pbc varied among these soils from 15-177 mg·kg-1. Pba was estimated by P adsorption on an anion resin membrane during a 16 h incubation. The effect of temperature on P bioavailability in 6 of these soils was estimated by conducting the Pba incubation at 5, 15 and 25 °C. A significant increase in lettuce yield with P fertilization was achieved at only one trial site, a spring planting where Pbc was 54 mg kg-1 ; at all other sites, including 3 with Pbc < 60 mg kg-1, P application resulted in no agronomic benefit. P application resulted in only a marginal increase in plant P uptake. Pba was highly correlated with Pbc (r = 0.89). Pba increased approximately 40% across soils with each 10 °C increase in soil temperature.


2002 ◽  
Vol 51 (1-2) ◽  
pp. 167-176 ◽  
Author(s):  
Marianna Magyar ◽  
P. Csathó ◽  
K. Debreczeni ◽  

Five soil P-test methods were compared on the soils of the network of unified Hungarian P fertilization long-term field trials. The effect of P application on the soil P-test values was significant on the different P levels and sites. The average effect of the sites varied between 1.5-fold (H 2 O method) and 3.7- fold (AL-method). The amounts of extracted P increased in the order of H 2 O-P < Olsen-P < Pi-P < AERM-P < AL-P < Corrected AL-P. For studying the relationships between the P values extracted by the different methods, acidic, calcareous and all soils groups were taken into account as a basis. A good correlation was found between the Pi- and AERM-methods in each soil group. Within the acidic soil group, pH has a much less expressed effect on AL-P values, presumably this was the reason why the strongest correlation in this soil group was found between the AL- and the Corr. AL-P methods  The next step in our research will be to calibrate these soil-P tests with plant P uptake and yield responses.


2021 ◽  
Vol 9 ◽  
Author(s):  
Wenjia Yu ◽  
Haigang Li ◽  
Peteh Mehdi Nkebiwe ◽  
Guohua Li ◽  
Torsten Müller ◽  
...  

Modern phosphate (P) fertilizers are sourced from P rock reserves, a finite and dwindling resource. Globally, China is the largest producer and consumer of P fertilizer and will deplete its domestic reserves within 80 years. It is necessary to avoid excess P input in agriculture through estimating P demand. We used the legacy P assessment model (LePA) to estimate P demand based on soil P management at the county, regional, and country scales according to six P application rate scenarios: (1) rate in 2012 maintained; (2) current rate maintained in low-P counties and P input stopped in high-P counties until critical Olsen-P level (CP) is reached, after which rate equals P-removal; (3) rate decreased to 1–1.5 kg ha−1 year−1 in low-P counties after CP is reached and in high-P counties; (4) rate in each county decreased to 1–8 kg ha−1 year−1 after soil Olsen-P reached CP in low P counties; (5) rate in each county was kept at P-removal rate after reduction; (6) P input was kept at the rate lower than P-offtake rate after reduction. The results showed that the total P fertilizer demand of China was 750 MT P2O5, 54% of P fertilizer can be saved from 2013 to 2080 in China, and soil Olsen-P of all counties can satisfy the demand for high crop yields. The greatest potential to decrease P input was in Yangtze Plain and South China, which reached 60%. Our results provide a firm basis to analyze the depletion of P reserves in other countries.


1998 ◽  
Vol 131 (2) ◽  
pp. 187-195 ◽  
Author(s):  
I. R. RICHARDS ◽  
C. J. CLAYTON ◽  
A. J. K. REEVE

The effects of four rates of fertilizer phosphorus (P) application (0, 9·8, 19·6 and 39·2 kg P/ha per year) on soil and crop P and cadmium (Cd) contents were measured in a field trial begun in 1968 and cropped each year with barley in south west England. In 1996, available and total soil P and Cd were measured in seven soil layers (0–20, 20–25, 25–30, 30–35, 35–40, 40–45 and 45–50 cm). Offtake of P in the crop was measured, or could be estimated, throughout the trial period. There was a linear relationship between P balance (total applied − total offtake) and P application rate with a balance of zero at a rate equivalent to 17 kg P/ha per year. The rate of P required for the economically optimum grain output was equivalent to 30 kg P/ha per year. No evidence was found for available P enrichment of soil layers below 25 cm. There was no evidence of Cd enrichment of either soil or crop after 29 years of P applications.


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