Published in Soil Sci. Soc. Am. J. 68:1421-1428 (2004).
© 2004 Soil Science Society of America
677 S. Segoe Rd., Madison, WI 53711 USA
DIVISION S-8—NUTRIENT MANAGEMENT & SOIL & PLANT ANALYSIS
Differences in Phosphorus Retention and Release in Soils Amended with Animal Manures and Sewage Sludge
Muhammad Tariq Siddique and
J. Stephen Robinson*
Dep. of Soil Science, The Univ. of Reading, Whiteknights, P.O. Box 233, Reading RG6 6DW, UK
* Corresponding author (j.s.robinson{at}reading.ac.uk).
 |
ABSTRACT
|
|---|
Excessive levels of P in agricultural soils pose a threat to local water quality. This study evaluated (i) time-dependent changes in soil P sorption (expressed as a phosphorus sorption index, PSI) and P availability (as resin P) during incubation (100 d) with poultry litter, cattle slurry, sewage sludge, or KH2PO4, added on a P-equivalent basis (100 mg P kg–1), and (ii) the subsequent kinetics of P release, measured by repeated extractions with a mixed cation-anion exchange resin. Soil exchangeable Ca and ammonium oxalate-extractable Fe and Al were also determined at 100 d of incubation. The small decrease in P sorption in the litter and sludge treatments (25%), compared with that in the slurry and KH2PO4 treatments (52%) between 20 and 100 d of incubation was attributed partly to the formation of new adsorption sites for P. Subsequent P release was described by a power equation: Resin P = a(extraction number)b, where the constants a and b represent resin P obtained with a single extraction and the rate of P release per resin extraction, respectively. On average, the rate of P release decreased in the order: KH2PO4 and slurry > litter > sludge, and was inversely related to exchangeable Ca content of the incubated soils (R2 = 0.57). The slower rates of P release in the litter and sludge treatments (P < 0.001) are attributed to the large values for exchangeable Ca (1050–2640 and 1070–2710 mg kg–1, respectively) in these amended soils. Future research concerned with short-term declines in environmentally harmful levels of P in recently amended soils should consider the differential effects of the amendments on soil P dynamics.
Abbreviations: PSI, phosphorus sorption index
|
INTRODUCTION
|
|---|
THE ACCUMULATION OF plant-available P in topsoils, either from current P application practices or as residual P from previous applications, increases the potential for transport of P to surface waters where it can seriously degrade water quality through the stimulation of eutrophication (Isermann, 1990). While it is possible to reduce the surface transport of soil P by measures to reduce overland flow, the control of losses via subsurface pathways will rely largely on reducing P inputs until soil P concentrations fall to levels that are considered to be no longer a risk to local water bodies. The period of time required for the available P status of a given soil to decrease to a target level is directly related to the soil's P-buffering capacity (Holford, 1982; Aquino and Hanson, 1984) or P sorption saturation (Sharpley, 1996), and is influenced by crop uptake. Several workers have conducted greenhouse experiments to study the depletion of available P during repeated cropping (Hooker et al., 1983; Halvorson and Black, 1985; Wagar et al., 1986). Other workers have applied repeated extractions with soil P tests to assess the rate of decrease in plant available soil P (Freese et al., 1995; Lookman et al., 1995; Sharpley, 1996).
Generally, a soil with a high P buffering capacity releases its P to the soil solution slowly, owing to the slowly reversible retention of P by soil colloids during the so-called "slow reaction" (Barrow and Shaw, 1975). Conversely, sandy soils, typically with relatively low P buffering and sorption capacities, can release much of their residual P back into solution when pools of less-strongly held P are exhausted (Ritchie and Weaver, 1993). However, there are scarcely any studies in the literature that critically evaluate the impact of the differential reactions of organic waste and inorganic sources of P in soil on the soil's capacity to retain P against depletion. The aim of this research is twofold; first, to study the short-term changes in P sorption and availability in soils following treatment with different P sources in the form of organic wastes or inorganic P; subsequently, to evaluate the kinetics of P depletion in the treated soils. We hypothesized that the short-term changes in both P sorption and availability and in the rate of P depletion are influenced by P source.
|
MATERIALS AND METHODS
|
|---|
Characteristics of the Soils
Samples were taken from the 0- to 20-cm layer of five agricultural soils in Berkshire, UK. The soils were selected to represent typical, continuously cultivated (for wheat [Triticum aestivum L.] and maize [Zea mays L.]) and limed, loam topsoils with a range of Olsen-extractable (plant available) P values (Olsen et al., 1954). Soils were air dried and sieved (<2 mm). Classification and selected properties of the soils are shown in Table 1 and also presented in Siddique et al. (2000). Soils were analyzed for sand, silt, and clay contents by pipette analysis following dispersion by sodium hexametaphosphate (Day, 1965). Organic matter was estimated as loss-on-ignition at 550°C (Nelson and Sommers, 1982), and pH was measured in CaCl2 
at a soil-to-solution ratio of 1:2.5 (Rowell, 1994). Olsen P was extracted from 1 g soil by 20 mL 0.5 M NaHCO3 (pH 8.5) for 30 min (Olsen et al., 1954). For the determination of labile inorganic P, air-dried soil was extracted with a mixed cation-anion exchange resin in the NaHCO3 form (Saggar et al., 1990). Total P was determined after digestion of oven-dried samples in a nitric acid-perchloric acid mixture (Olsen and Sommers, 1982). A PSI was derived from a single-point P sorption isotherm (P sorbed from a single solution containing 1.5 g P kg–1 soil), following a procedure based on that of Bache and Williams (1971). Duplicate samples (1 g) of air-dried soil were shaken for 18 h with 20 mL 0.01 M CaCl2 solution containing 1.5 mg P plus three drops of toluene. The PSI [mg kg–1/log(mg L–1)] was calculated by the quotient X/log C, where X, mg kg–1 (sorbed P) was calculated as the difference between P added and P in the supernatant (C, mg L–1) at equilibrium.
Characteristics of Organic Wastes
The three organic wastes used in the study were poultry litter, cattle slurry, and urban sewage sludge. They were chosen to represent common alternatives to inorganic P fertilizers in agriculture, while varying widely in their physical and chemical characteristics. The poultry litter was a mixture of manure and wood shavings (bedding material) and was obtained from broiler houses in southeast England. The cattle slurry was sampled from an aboveground storage tank at Reading University farm, southeast England. The slurry was produced from dairy cattle housing. In the storage tank, the slurry had been subjected to regular mixing to maintain aeration and to prevent sedimentation or surface crusting. The sewage sludge was a biological, sludge cake product, obtained from Thames Water Utilities, UK. The sewage sludge had been produced by the activated sludge process followed by mesophilic anaerobic digestion and then processed for the agricultural and horticultural markets by dewatering, centrifugation, and compression. The sludge did not receive any chemical treatment. Reagent grade KH2PO4 was the inorganic P fertilizer source used in this experiment.
The organic waste samples were thoroughly mixed. Subsamples of the poultry litter and sewage sludge were lightly ground to pass through a 2-mm sieve. Cattle slurry subsamples were also passed through a 2-mm sieve to remove any discernible fibrous material. All materials were stored in polythene containers at 4°C. These subsamples were used for the determination of the general properties in duplicate (Table 2). The dry matter content was determined on a 105°C basis. The pH of the sludge and litter was measured in water (pHw) at a solid-to-solution ratio of 1:2.5, after allowing the suspension to equilibrate for 30 min (Ministry of Agriculture, Fisheries, and Food, 1986). The pH of the slurry was determined in a continually stirred, undiluted suspension. The loss-on-ignition of the materials was determined by combustion (Sommers et al., 1976). For determination of water-extractable P, 1 g of fresh material (dry weight) was extracted by end-over-end shaking with 200 mL of distilled deionized water for 1 h, centrifuging, and filtering (0.45 µm). Total P, Ca, and Fe contents were determined after digestion of oven-dried samples in a nitric acid and perchloric acid mixture. All extracts were filtered through a Whatman No. 42 filter paper before analysis for P, Ca, and Fe by inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. The total N content was determined by a semi-micro-Kjeldahl procedure (Bremner and Mulvaney, 1982).
Soil-Phosphorus Source Incubations
Air dried and sieved (<2 mm) samples (100 g) of the Yattendon (Typic Dystrochrept), Swanwick (Aquic Hapludalf), Wickham (Aquic Dystrochrept), Sonning I (Typic Hapludalf), and Sonning II (Typic Hapludalf) soils were mixed thoroughly with poultry litter, cattle slurry, sewage sludge, or KH2PO4 at rates equivalent to 100 mg P kg–1 soil. Incorporation of the P sources into the soil was achieved by mixing for a period of 5 min with a spatula. Distilled water was added to bring the incubation mixtures to the field capacity of the soil. In preliminary studies, the soil field capacity was calculated from the maximum volume of water that a known volume of saturated soil sample could hold following drainage on a bed of sand. The mixtures were incubated in duplicate at this moisture level at 25°C for a period of 100 d.
Phosphorus Sorption and Availability in the Incubated Soils
Phosphorus sorption and availability were determined in the incubation mixtures, in duplicate, at 20 and 100 d. Phosphorus sorption was expressed as the PSI, as described earlier (Bache and Williams, 1971). It is well established that the PSI is a reliable and routine method for ranking soils with respect to P sorption capacity (Mozaffari and Sims, 1994). Several workers have found close relationships between PSI and Langmuir-derived values for P sorption capacity in a range of fertilized and unfertilized soils (Mozaffari and Sims, 1994; Simard et al., 1995; Nair et al., 1998). For measuring P availability, soil samples (1 g air-dry equivalent) were extracted with a mixed cation-anion exchange resin in the NaHCO3 form (Saggar et al., 1990).
Exchangeable Calcium and Ammonium Oxalate-Extractable Iron and Aluminum in the Incubated Soils
Soil exchangeable Ca and ammonium oxalate-extractable Fe (Feox) and Al (Alox) were determined in the incubated soils at 100 d. Exchangeable Ca was determined in extracts obtained by shaking with 0.1 M BaCl2 for 2 h at a soil-to-solution ratio of 1:20 (Hendershot and Duquette, 1986). Determination of Feox and Alox involved shaking the soil with 0.175 M acidified ammonium oxalate (pH 3) in the dark for 2 h at a soil-to-solution ratio of 1:30 (McKeague and Day, 1966; Khalid et al., 1977). The Ca, Fe, and Al in the filtered (Whatman No. 42 filter paper) extracts were measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis.
Sequential Resin Phosphorus Extractions
At 100 d, duplicate soil samples (1 g air-dry equivalent) were taken from the incubation mixtures to evaluate the kinetics of soil P depletion. The samples were shaken end-over-end for 16 h with 30 mL of distilled water and a mixed cation-anion exchange resin in the NaHCO3 form (Saggar et al., 1990). Following recovery of the adsorbed P in HCl, the resin was regenerated in 0.5 M NaHCO3 for reuse. The regenerated resin was replaced in the soil suspension and shaken for a further 16 h. This sequence of resin shaking, P recovery, and resin regeneration was continued until seven sequential P extractions were performed.
In all chemical and resin extracts, and in supernatants from P sorption studies, P was measured in filtered (Whatman No. 42 filter paper) samples as dissolved reactive P by the colorimetric method of Murphy and Riley (1962).
Statistical Analysis
In all cases, the results are presented as means of duplicates. The significance of treatment effects was determined at the 0.05 probability level and was evaluated by single-factor ANOVA and Fisher's LSD. Microsoft Excel was used for all ANOVAs and for correlation and regression analyses.
|
RESULTS AND DISCUSSION
|
|---|
Characteristics of the Soils and Organic Wastes
The wide range in P status among the soils (Table 1) is attributable to different histories of P fertilizer and manure applications and cropping (Siddique, 2000). The organic wastes displayed marked variation in all properties with the exception of pH (Table 2). For example, all wastes differed significantly (P < 0.05) in terms of their contents of dry matter (101–720 g kg–1), water-extractable P (1.7–3.0 g kg–1), and Ca (0.8–42 g kg–1).
Effect of Incubation Period on the Sorption and Availability of Phosphorus
In the vast majority of cases, the addition of the P sources significantly (P < 0.05) decreased the PSI and increased the resin P in the five soils after 20 and 100 d of incubation (Tables 3, 4). The different treatments provided a wide range in soil P sorption and availability. The differential effects of the various P sources on soil P sorption and availability at 20 d incubation has already been discussed in terms of the sources' relative solubilities and Ca contents (Siddique and Robinson, 2003). Briefly, the effects of cattle slurry and KH2PO4 on P sorption and availability were, in most cases, larger than those of the less-soluble poultry litter and sewage sludge. In the poultry litter and sewage sludge treatments, the lower P availability was related to the high Ca (13.5 and 42 g kg–1, respectively) in these sources (Siddique and Robinson, 2003). In all treated soils there was a marked decrease in PSI between 20 and 100 d of incubation; the magnitude of the decreases was dependent on P source (Table 5). Averaged for the five soils, the largest proportional decrease in PSI occurred in the cattle slurry and KH2PO4 treatments. For these treatments, the mean decreases in PSI were 51 and 52%, respectively, compared with 30 and 19% for the litter and sludge treatments, respectively (Table 5). The relatively slow decline in PSI between 20 and 100 d in the soils treated with the sludge and litter may have been because of the low solubility of these amendments combined with the gradual formation of new adsorptive sites for P. It is well known that significant proportions of the P in poultry litter and biological sewage sludge are associated with Ca in the form of sparingly soluble precipitates (Isermann, 1990; Siddique et al., 2000). Sparingly soluble calcium phosphates probably control the solubility of P in the litter and sludge and possibly influence P chemistry in the amended soils through the ability of Ca to contribute to P sorption at soil colloid surfaces. These mechanisms may be considered to contribute to the slow reaction of added P in soils, and are discussed further in the sections that follow, on the availability and desorption kinetics of P.
View this table:
[in this window]
[in a new window]
|
Table 3. Phosphorus sorption index at 20 and 100 d in soils incubated with 100 mg P kg–1 soil, added as sewage sludge, poultry litter, cattle slurry, or KH2PO4.
|
|
View this table:
[in this window]
[in a new window]
|
Table 4. Resin P at 20 and 100 d in soils incubated with 100 mg P kg–1 soil, added as sewage sludge, poultry litter, cattle slurry, or KH2PO4.
|
|
View this table:
[in this window]
[in a new window]
|
Table 5. Mean percentage decreases ±SE in PSI and resin P between 20 and 100 d in soils incubated with 100 mg P kg–1 soil that was added as sewage sludge, poultry litter, cattle slurry, or KH2PO4.
|
|
Averaged for the incubated soils, resin P decreased between 20 and 100 d (Table 5). The decrease in resin P in all treated and control soils may be attributed to time-dependent reactions involving the sorption and precipitation of the added and native P (Barrow, 1983b). It is reported in the literature that the initial retention mechanism of added P is adsorption by both ion and ligand exchange (Sample et al., 1980). A portion of this P can be extracted by mixed cation-anion exchange resins. Subsequently, much slower reactions start to dominate; for example, precipitation, diffusion, and bidentate bonding (Barrow, 1983a). The resin cannot extract these more stable pools of P. In spite of the variable decreases in resin P, the values for resin P in the sludge and litter treatments at 100 d remained consistently lower than those in the slurry and KH2PO4 treatments (Table 4).
Phosphorus Release Characteristics
During the seven successive extractions with mixed cation-anion exchange resin at 100 d, the release of P from all control and treated soils decreased rapidly at first and then declined slowly (Fig. 1). The initial rapid rate of P release from waste-amended soils, followed by slower release, is consistent with the observations made by Lookman et al. (1995); Sharpley (1996), and Toor and Bahl (1999). This initial fast reaction represents the desorption of more labile P, while the latter fractions are rated as less mobile (Kuo and Lotse, 1974; Toor and Bahl, 1999). In most cases, especially during the first extraction, P release appeared to be influenced by P source (Fig. 1). A closer evaluation of the kinetics of P release as a function of P source is provided in the section that follows, on kinetic equations. For all treatments, P release was negligible after the sixth extraction, in spite of the large range in values for initial resin P (Fig. 1).
Kinetic Equations for Phosphorus Release
The release of resin P was described by a simple power equation that can be expressed as
where the constant a represents resin P obtained with a single extraction and the constant b represents the rate of P release per resin extraction. The equation describes the release of resin P very well, with the coefficient for the regression (R2) of resin P and number of successive extractants ranging from 0.96 to 0.99 (P < 0.001).
A similar equation was used by Sharpley (1996) to describe the release of residual P from soils that had been treated for several years with beef feedlot manure, poultry litter, and swine slurry. More recently, Toor and Bahl (1999) studied the kinetics of P desorption in P fertilizer- and poultry manure-amended soils by successive extractions with 0.5 M NaHCO3. They best described P release with the Elovich equation. The values of the kinetic constants of the Elovich equation increased with the increase in the level of fertilizer or poultry manure; however, the experiment did not allow for an evaluation of the kinetic constants as a function of P source.
The values for constant a related well (R2 = 0.96, slope = 1.31, P < 0.001) with the actual values for initial resin P at the 100-d incubation period (Fig. 2). The values for the rate constant b during the seven extractants are shown in Table 6. Values for b ranged from –0.95 (untreated Yattendon soil) to –1.93 (KH2PO4–treated Sonning II soil). A decrease in the constant b indicates an increase in the rate of P release with successive extractions. For all five soils, values for the rate term b in the soils treated with poultry litter, cattle slurry, and KH2PO4 were significantly lower (P < 0.05) than those in the control, implying a faster rate of P desorption in the former (Table 6). With the exception of the Sonning I soil, the values for b in the sewage sludge-treated soils were not significantly different (P > 0.05) from those in the control. For all treated soils, with the exception of Sonning II, values for b increased significantly (P < 0.05) among the P sources in the following order: KH2PO4 and slurry < litter < sludge. With the exception of the Sonning II soil, there was no significant difference (P > 0.05) in the value for b between the slurry and KH2PO4 treatments.
View larger version (17K):
[in this window]
[in a new window]
|
Fig. 2. Relationship (P < 0.001) between the constant a for the equation describing the successive release of resin P and initial resin P for soils incubated with no P addition (circles) or with poultry litter (diamonds), cattle slurry (asterisks), sewage sludge (triangles), or KH2PO4 (squares). The solid line is the linear regression of the constant a on resin P and the broken line represents the 1:1 line.
|
|
Phosphorus desorption can be described simply as an initial fast rate followed by a slower rate (Lookman et al., 1995). In the slurry- and KH2PO4–treated soils, compared with the sludge and litter treatments, there was a higher proportion of bound P in this fast pool after 100 d of incubation. This fast pool accumulates once a certain degree of P saturation has been reached and probably explains the lower b values for the slurry and KH2PO4 treatments.
Among all soils and treatments, the original resin P described 51% (significant at the 0.001 probability level) of the variability in the rate of P release (Fig. 3). However, for each of the five soils analyzed separately, the rate constant b was only weakly related (R2 = 0.30–0.64, P > 0.05) to the initial available (resin) P content following incubation with the various P sources (data not presented). Contrary to this observation, Sharpley (1996) found that, for a given soil, the rate of P release was linearly related (P < 0.05) to initial available (Fe-oxide strip) P content. However, in the study of Sharpley (1996), the soil in question had received its P from the same source (beef feedlot manure); whereas, in the current study, the P was derived from a range of P sources.
View larger version (18K):
[in this window]
[in a new window]
|
Fig. 3. Relationship (P < 0.001) between the constant b for the equation describing the successive release of resin P and initial resin P for soils incubated with no P addition (circles) or with poultry litter (diamonds), cattle slurry (asterisks), sewage sludge (triangles), or KH2PO4 (squares).
|
|
Soil Properties Controlling the Rate of Phosphorus Desorption
The soils incubated with different amendments provided a wide range of values for soil exchangeable Ca and for (Feox + Alox) at 100 d of incubation (Fig. 4, 5). The increases in exchangeable Ca in the poultry litter and sewage sludge-treated soils were attributed to the higher Ca content (13.5 and 42 g kg–1) of these sources compared with the cattle slurry (0.8 g kg–1) and KH2PO4 (0 g kg–1) (Tables 2, 7). The decreases in soil exchangeable Ca in the cattle slurry treatments may have been through the complexing of soil solution Ca by organic acids released from the slurry. Exchangeable Ca may have decreased in the KH2PO4–treated soils because of the formation of sparingly soluble Ca–P compounds in the presence of the high concentrations of solution P associated with the KH2PO4 addition (Table 7).
View larger version (19K):
[in this window]
[in a new window]
|
Fig. 4. Relationship (P < 0.001) between the constant b for the equation describing the successive release of resin P and exchangeable Ca for soils incubated with no P addition (circles) or with poultry litter (diamonds), cattle slurry (asterisks), sewage sludge (triangles), or KH2PO4 (squares).
|
|
View larger version (17K):
[in this window]
[in a new window]
|
Fig. 5. Relationship (P > 0.05) between the constant b for the equation describing the successive release of resin P and the sum of ammonium oxalate-extractable Fe and Al for soils incubated with no P addition (circles) or with poultry litter (diamonds), cattle slurry (asterisks), sewage sludge (triangles), or KH2PO4 (squares).
|
|
View this table:
[in this window]
[in a new window]
|
Table 7. Exchangeable Ca in the five soils following incubation for 100 d with no P addition (control) or with different P sources at rates equivalent to 100 mg P kg–1.
|
|
The values for the rate constant b were linearly related (P < 0.001) to the exchangeable Ca content of the incubated soils at 100 d, indicating that the rate of P desorption decreased with increasing exchangeable Ca (Fig. 4). This observation is consistent with the positive relationship (R2 = 0.64, P < 0.001) between exchangeable Ca and P sorption (PSI) (Fig. 6). It is possible that the increased saturation of aluminosilicate clay minerals with exchangeable Ca in the sludge- and poultry litter-treated soil increased the sorption of P through the formation of a surface complex between P and Ca ions (Helyar et al., 1976). Conversely, the decreased Ca saturation of the clay minerals in the slurry- and KH2PO4–treated soils would have decreased the effective P sorption capacity. Alternatively, Barrow (1972) and Kinniburgh et al. (1975) suggested that the increase in P adsorption with increasing Ca concentration may be because of the specific adsorption of Ca ions by hydrous oxides and an increase in the positive charge on the surfaces. Either of these mechanisms may be responsible for the inverse relationship between P desorption rate and exchangeable Ca content.
View larger version (22K):
[in this window]
[in a new window]
|
Fig. 6. Relationship (P < 0.001) between exchangeable Ca and P sorption index for soils incubated with no P addition (circles) or with poultry litter (diamonds), cattle slurry (asterisks), sewage sludge (triangles), or KH2PO4 (squares).
|
|
Among all treatments, there was a poor relationship (R2 = 0.13, P > 0.05) between the rate constant b and the sum of Feox and Alox (mmol kg–1 soil) at 100 d (Fig. 5). Similarly, for 23 mid-Atlantic Coastal Plain soils, Vadas and Sims (2002) reported that the rate term in a predictive equation of P desorption correlated weakly with Feox (r = 0.13) and with (Feox + Alox) (r = 0.53). However, for the control and for each of the amendments considered separately, with the exception of poultry litter, there was a relatively good relationship (P < 0.05) between b and (Feox + Alox) (data not presented). It is speculated that the rate term b would have correlated more strongly with (Feox + Alox)/organic C than with (Feox + Alox) alone. It is widely reported, particularly for organically amended soils, that it is the increased competition from organic anions (for example, citrate, malate, malonate, oxalate, and tartrate) with P for adsorption sites that can increase the rate at which P is desorbed from the soil (Reddy et al., 1980; Sharpley, 1983; Ogaard, 1996; Toor and Bahl, 1999; Vadas and Sims, 2002). However, the fact that the decrease in PSI for the soils treated with slurry (51%) and KH2PO4 (52%) between 20 and 100 d were very similar (Table 5), as well as there largely being no significant difference (P > 0.05) in the rate of P release between the slurry and KH2PO4 treatments (Table 6), implies that there is no clear evidence in the current study that organic components of the slurry decrease the ability of the soil to retain P against desorption. In future work, a clearer understanding of P reactions should be attained through investigations into the content and composition of organic C both in the amendments and in the amended soils.
|
CONCLUSIONS
|
|---|
The addition of P, either as poultry litter, cattle slurry, sewage sludge, or KH2PO4, provided a wide range of modified values for P sorption and available P in five loam soils. In all cases, the P additions decreased the soil PSI and increased the resin P content. During incubation of the amended soils, both PSI and resin P decreased between 20 and 100 d, and the magnitude of the decreases was dependent on the P source. Generally, the mean percentage decreases in both parameters were greater in the slurry- and KH2PO4–treated soils than in the sludge and litter treatments. The smaller PSI decline in the latter treatments was attributed partly to the lower solubility of the P in the sludge and litter relative to that in the slurry and KH2PO4, and partly to the formation of new adsorption sites for P. In the litter and sludge soils, the formation of new adsorption sites for P may partly explain the relatively small decrease in PSI.
The subsequent release of P in the amended soils was described by repeated extractions with a mixed cation-anion exchange resin and could be expressed by a simple power equation. Analysis of the equations for each P source indicated that the rate factor, averaged among the soils, decreased as follows: KH2PO4 and cattle slurry > poultry litter > sewage sludge. Correlation analyses showed that the rate of P desorption was inversely related to exchangeable Ca. The slower rates of P desorption in the litter- and sludge- than KH2PO4– and cattle slurry-treated soils were attributed to relatively large values for total Ca in the former treatments, which may have increased P sorption strength through the formation of Ca-P complexes at the surface of alumino-silicate clays. The results of this study show that the rate of decline in available soil P following fertilization should consider not only crop uptake but also the differential short-term reactions in soil of manure, sewage sludge, and inorganic sources of P.
Received for publication February 28, 2003.
|
REFERENCES
|
|---|
- Aquino, B.F., and R.G. Hanson. 1984. Soil phosphorus supplying capacity evaluated by plant removal and available phosphorus extraction. Soil Sci. Soc. Am. J. 48:1091–1096.[Abstract/Free Full Text]
- Bache, B.E., and E.G. Williams. 1971. A phosphate sorption index for soils. J. Soil Sci. 22:289–301.
- Barrow, N.J. 1972. Influence of solution concentration of calcium on the adsorption of phosphate, sulphate, and molybdate by soils. Soil Sci. 113:175–180.
- Barrow, N.J. 1983a. On the reversibility of phosphate sorption by soils. J. Soil Sci. 34:751–758.
- Barrow, N.J. 1983b. A mechanistic model for describing the sorption and desorption of phosphate by soil. J. Soil Sci. 34:733–750.
- Barrow, N.J., and T.C. Shaw. 1975. The slow reactions between soil and anions: 2. Effect of time and temperature on the decrease in phosphate concentration in the soil solution. Soil Sci. 119:167–177.
- Bremner, J.M., and C.S. Mulvaney. 1982. Nitrogen—Total. p. 595–624. In A.L. Page et al. (ed.) Methods of soil analysis. Part 2. 2nd ed. Agron. Monogr. 9. ASA and SSSA, Madison, WI.
- Day, P.R. 1965. Particle fractionation and particle size analysis. p. 545–567. In C.A. Black et al. (ed.) Methods of soil analysis. Part 1. Agron. Monogr. no. 9. ASA, Madison, WI.
- Freese, D., R. Lookman, R. Merckx, and W.H. van Riemsdijk. 1995. New method for assessment of long-term phosphate desorption from soils. Soil Sci. Soc. Am. J. 59:1295–1300.[Abstract/Free Full Text]
- Halvorson, A.D., and A.L. Black. 1985. Fertilizer phosphorus recovery after seventeen years of dryland cropping. Soil Sci. Soc. Am. J. 49:933–937.[Abstract/Free Full Text]
- Helyar, K.P., D.N. Munns, and R.G. Bureau. 1976. Adsorption of phosphate by gibbsite: I. Effects of neutral chloride salts of calcium, magnesium, sodium and potassium. J. Soil Sci. 27:307–314.
- Hendershot, W.H., and M. Duquette. 1986. A simple barium chloride method for determining cation exchange capacity and exchangeable cations. Soil Sci. Soc. Am. J. 50:605–608.[Abstract/Free Full Text]
- Holford, I.C.R. 1982. Effects of phosphate sorptivity on long-term plant recovery and effectiveness of fertilizer phosphate in soils. Plant Soil 64:225–236.
- Hooker, M.L., R.E. Gwin, G.M. Herron, and P. Gallagher. 1983. Effects of long-term annual applications of N and P on corn grain yields and soil chemical properties. Agron. J. 75:94–99.[Abstract/Free Full Text]
- Isermann, K. 1990. Share of agriculture in nitrogen and phosphorus emission into the surface waters of Western Europe against their background of eutrophication. Fert. Res. 26:253–269.
- Jarvis, R.A. 1968. Soils of The Reading District. Memoirs of the Soil Survey of Great Britain. Agricultural Research Council, Harpenden, Herts, UK.
- Khalid, R.A., W.H. Patrick, and R.D. DeLaune. 1977. Phosphorus sorption characteristics of flooded soils. Soil Sci. Soc. Am. J. 41:305–310.[Abstract/Free Full Text]
- Kinniburgh, D.G., J.K. Syers, and M.L. Jackson. 1975. Specific adsorption of trace amounts of calcium and strontium by hydrous oxides of iron and aluminium. Soil Sci. Soc. Am. Proc. 39:464–470.
- Kuo, S., and E.G. Lotse. 1974. Kinetics of phosphate adsorption and desorption by lake sediments. Soil Sci. Soc. Am. Proc. 38:50–54.
- Lookman, R., D. Freese, R. Merckx, K. Vlassak, and W.H. Van Riemsdijk. 1995. Long-term kinetics of phosphate release from soil. Environ. Sci. Technol. 29:1569–1575.
- McKeague, J.A., and J.H. Day. 1966. Diothionite and oxalate extractable Fe and Al as aids in differentiating various classes of soils. Can. J. Soil Sci. 46:13–22.
- Ministry of Agriculture, Fisheries, and Food. 1986. The analysis of agricultural material. Ref. Book 427. 3rd ed. MAFF, London.
- Mozaffari, M., and J.T. Sims. 1994. Phosphorus availability and sorption in an Atlantic Coastal Plain watershed dominated by animal-based agriculture. Soil Sci. 157:97–107.
- Murphy, J., and J.P. Riley. 1962. A modified single solution method for the determination of phosphate in natural waters. Anal. Chim. Acta 27:31–36.
- Nair, V.D., D.A. Graetz, and K.R. Reddy. 1998. Dairy manure influences on phosphorus retention capacity of spodosols. J. Environ. Qual. 27:522–527.[Abstract/Free Full Text]
- Nelson, D.W., and L.E. Sommers. 1982. Total carbon, organic carbon, and organic matter. p. 539–579. In A.L. Page et al. (ed.) Methods of soil analysis. Part 2. 2nd ed. Agron. Monogr. 9. ASA and SSSA, Madison, WI.
- Ogaard, A.F. 1996. Effect of fresh and composted cattle manure on phosphate retention in soil. Acta Agric. Scand. Sect. B. 46:98–105.
- Olsen, S.R., C.V. Cole, F.S. Watanabe, and L.A. Dean. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. USDA Circ. No. 939. U.S. Gov. Print. Office, Washington, DC.
- Olsen, S.R., and L.E. Sommers. 1982. Phosphorus. p. 403–430. In A.L. Page et al. (ed.) Methods of soil analysis. Part 2. 2nd ed. Agron. Monogr. 9. ASA and SSSA, Madison, WI.
- Reddy, K.R., M.R. Overcash, R. Khaleel, and P.W. Westerman. 1980. Phosphorus adsorption-desorption characteristics of two soils utilized for disposal of animal wastes. J. Environ. Qual. 9:86–92.[Abstract/Free Full Text]
- Ritchie, G.S.P., and D.M. Weaver. 1993. Phosphorus retention and release from sandy soils of the Peel-Harvey catchment. Fert. Res. 36:115–122.
- Rowell, D.L. 1994. Soil science. Methods and applications. Longman Scientific and Technical, Harlow, Essex, UK.
- Saggar, S., M.J. Hedley, and R.E. White. 1990. A simplified resin membrane technique for extracting phosphorus from soils. Fert. Res. 24:173–180.
- Sample, E.C., R.J. Soper, and G.J. Racz. 1980. Reactions of phosphate fertilizers in soils. p. 263–310. In F.E. Khasawneh et al. (ed.) The role of phosphorus in agriculture. ASA, CSA, and SSSA, Madison, WI.
- Sharpley, A.N. 1983. Effect of soil properties on the kinetics of phosphorus desorption. Soil Sci. Soc. Am. J. 47:462–467.[Abstract/Free Full Text]
- Sharpley, A.N. 1996. Availability of residual phosphorus in manured soils. Soil Sci. Soc. Am. J. 60:1459–1466.[Abstract/Free Full Text]
- Siddique, M.T. 2000. Phosphorus reactions and leaching potential in soils amended with organic wastes. Ph.D. diss. Univ. of Reading, UK (Diss. Abstr. THESIS--R8600).
- Siddique, M.T., and J.S. Robinson. 2003. Phosphorus sorption and availability in soils amended with animal manures and sewage sludge. J. Environ. Qual. 33:1114–1121.
- Siddique, M.T., J.S. Robinson, and B.J. Alloway. 2000. Phosphorus reactions and leaching potential in soils amended with sewage sludge. J. Environ. Qual. 29:1931–1938.[Abstract/Free Full Text]
- Simard, R.R., D. Cluis, G. Gangbazo, and S. Beauchemin. 1995. Phosphorus status of forest and agricultural soils from a watershed of high animal density. J. Environ. Qual. 24:1010–1017.[Abstract/Free Full Text]
- Sommers, L.E., D.W. Nelson, and K.J. Yost. 1976. Variable nature of chemical composition of sewage sludges. J. Environ. Qual. 5:303–306.[Abstract/Free Full Text]
- Toor, G.S., and G.S. Bahl. 1999. Kinetics of phosphate desorption from different soils as influenced by application of poultry manure and fertilizer phosphorus and its uptake by soybean. Bioresour. Technol. 69:117–121.
- Vadas, P.A., and J.T. Sims. 2002. Predicting phosphorus desorption from Mid-Atlantic Coastal Plain soils. Soil Sci. Soc. Am. J. 66:623–631.[Abstract/Free Full Text]
- Wagar, B.I., J.W.B. Stewart, and J.O. Moir. 1986. Changes with time in the form and availability of residual fertilizer phosphorus on chernozemic soils. Can. J. Soil Sci. 66:105–119.
This article has been cited by other articles:
|
|
|
|
 
V. R. Haden, Q. M. Ketterings, and J. E. Kahabka
Factors Affecting Change in Soil Test Phosphorus Following Manure and Fertilizer Application
Soil Sci. Soc. Am. J.,
June 8, 2007;
71(4):
1225 - 1232.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
P. A. Vadas, T. Krogstad, and A. N. Sharpley
Modeling Phosphorus Transfer between Labile and Nonlabile Soil Pools: Updating the EPIC Model
Soil Sci. Soc. Am. J.,
March 29, 2006;
70(3):
736 - 743.
[Abstract]
[Full Text]
[PDF]
|
|
|
TOP
ABSTRACT
INTRODUCTION
