Total Dissolved P Concentrations Research Articles

Phosphorus distribution in the water and sediment of Laizhou Bay and sediment phosphorus release potential

Phosphorus is an integral component of marine biogeochemistry. This research investigated the environmental behavior of P in Laizhou Bay using high-resolution sampling, P fractionation, and isotherm adsorption. The total dissolved P (TDP) concentration ranged from 8.4 to 61.0 μg/L in the bay water, while total P (TP) concentration ranged from 311.6 to 654.5 mg/kg in the sediment. The TDP concentration in the water was high in the estuarine area of the Yellow River and the southwestern bay under the combined effects of riverine inputs, direct wastewater discharge, and limited water exchange ability. High TP concentrations in the sediment were observed near the mouth of the Yellow River and central bay, mainly due to the movement and settlement of fine suspended particles under the influence of ocean currents. The P in the bay sediment was predominantly in the calcium-bound fraction and was associated with small particles such as silt and clay. The equilibrium P concentration (EPC0) ranged from 1.6 to 131.4 μg/L, and P partition coefficient or buffer intensity (Kd) ranged from 104 L/kg to 880 L/kg. The EPC0 decreased from the northeastern to southwestern area, while Kd showed an inverse distribution; therefore, the southwestern bay sediment had high buffer intensity for external P loads. Additionally, ECP0 increased linearly, and Kd decreased with exchangeable P (Exc-P) and Fe-bound P (Fe-P) concentrations in the sediment, demonstrating that P sediment-water exchange in LZB was dominated by contributions from Exc-P and Fe-P. These results can aid the understanding of the P sources and geochemistry of coastal ecosystems, particularly sediment P release potential.

Phosphorus availability and leaching losses in annual and perennial cropping systems in an upper US Midwest landscape

Excessive phosphorus (P) applications to croplands can contribute to eutrophication of surface waters through surface runoff and subsurface (leaching) losses. We analyzed leaching losses of total dissolved P (TDP) from no-till corn, hybrid poplar (Populus nigra X P. maximowiczii), switchgrass (Panicum virgatum), miscanthus (Miscanthus giganteus), native grasses, and restored prairie, all planted in 2008 on former cropland in Michigan, USA. All crops except corn (13 kg P ha−1 year−1) were grown without P fertilization. Biomass was harvested at the end of each growing season except for poplar. Soil water at 1.2 m depth was sampled weekly to biweekly for TDP determination during March–November 2009–2016 using tension lysimeters. Soil test P (0–25 cm depth) was measured every autumn. Soil water TDP concentrations were usually below levels where eutrophication of surface waters is frequently observed (> 0.02 mg L−1) but often higher than in deep groundwater or nearby streams and lakes. Rates of P leaching, estimated from measured concentrations and modeled drainage, did not differ statistically among cropping systems across years; 7-year cropping system means ranged from 0.035 to 0.072 kg P ha−1 year−1 with large interannual variation. Leached P was positively related to STP, which decreased over the 7 years in all systems. These results indicate that both P-fertilized and unfertilized cropping systems may leach legacy P from past cropland management.

Seasonal phosphorus variation in coastal water affected by the land-based sources input in the eutrophic Zhanjiang Bay, China

Phosphorus (P), a significant biogenic element, plays a key role in the primary productivity of estuarine and coastal ecosystems. The study determined that the seasonal dynamics of total dissolved P (TDP)in the coastal area of the Zhanjiang Bay (ZJB) were largely affected by land-based sources. The TDP concentration had significant seasonal variations in the ZJB (P < 0.01), and the annual mean TDP concentration was 3.30 ± 1.12 μmol L−1 in the coastal waters and 30.37 ± 55.07 μmol L−1 in the estuaries and sewage outlets. The spatial distribution of TDP demonstrated a decreasing trend from the top to the mouth of the ZJB. In the TDP composition, dissolved inorganic P (DIP) was the major fraction of the TDP in land-based sources and seawater. Moreover, the ZJB is annually subjected to a load of 3848.07 tons TDP through the land-based input sources, accounting for 10.4%, 37.0% and 52.6% in the dry, normal, and wet seasons, respectively. Most of the monitoring stations in ZJB coastal water did not meet the Grade IV national water quality standard. Both the coastal water and land-based water sources were seriously polluted by P. This study revealed that land-based source inputs played a key role in the P biogeochemistry process in the ZJB. A land-ocean integrated P pollution control strategy should be effectively implemented for water quality improvement and eutrophication mitigation in the ZJB.

Species and potential sources of phosphorus in groundwater in and around Mataram City, Lombok Island, Indonesia

Geochemical evaluation of the species and potential sources of P in groundwater in and around Mataram City, Lombok Island, Indonesia can aid in the initial research on evaluating the fate of P when detailed geological information is unavailable. The results of ion chromatography and inductively coupled plasma-optical emission spectroscopy show that the concentrations of PO43– and total dissolved P (TDP) in groundwater range from approximately 0.1 to 8.5 mg l–1 and from 0.04 to 2.95 mg l–1, respectively. Dissolved inorganic P accounted for 86%, on average, of the TDP concentration, and PO43– represented the predominant P species in this groundwater. The potential sources for most of this dissolved PO43–, according to indices developed based on the PHREEQC software and groundwater quality data, could be the dissolution of hydroxyapatite and/or vivianite minerals. However, the potential sources of dissolved PO43– in groundwater with a TDP concentration of ≥ 1 mg l–1 is likely to be the reduction of Fe(III)–(hydro)oxides, the initial decomposition of organic matter, or the dissolution of carbonate-rich fluorapatite considering the Fe2+, dissolved organic carbon, Ca2+ and F− concentrations measured. In addition, as several groundwater samples had a TDP concentration of ≤ 1 mg l–1 and comparatively high concentration of NO3–, other potential sources of dissolved PO43– in this groundwater could be anthropogenic.

Dolomite and Micronutrient Fertilizer Affect Phosphorus Fate When Growing Crape Myrtle in Pine Bark

Soilless substrates are routinely amended with dolomite and sulfate-based micronutrients to improve fertility, but the effect of these amendments on phosphorous (P) in substrate pore-water during containerized crop production is poorly understood. The objectives of this research were as follows: compare the effects of dolomite and sulfate-based micronutrient amendments on total P (TP), total dissolved P (TDP), orthophosphate P (OP), and particulate P (PP; TP − TDP) concentrations in pour-through extracts; to model saturated solid phases in substrate pore-water using Visual MINTEQ; and to assess the effects of dolomite and micronutrient amendments on growth and subsequent P uptake efficiency (PUE) of Lagerstroemia L. ‘Natchez’ (crape myrtle) potted in pine bark. Containerized crape myrtle were grown in a greenhouse for 93 days in a 100% pine bark substrate containing a polymer-coated 19N–2.6P–10.8K controlled-release fertilizer (CRF) and one of four substrate amendment treatments: no dolomite or micronutrients (control), 2.97 kg·m−3 dolomite (FL); 0.89 kg·m−3 micronutrients (FM); or both dolomite and micronutrients (FLM). Pour-through extracts were collected approximately weekly and fractioned to measure pore-water TP, TDP, and OP and to calculate PP. Particulate P concentrations in pour-through extracts were generally unaffected by amendments. Relative to the control, amending pine bark with FLM reduced water-extractable OP, TDP, and TP concentrations by ≈56%, had no effect on P uptake efficiency, and resulted in 34% higher total dry weight (TDW) of crape myrtle. The FM substrate had effects similar to those of FLM on plant TDW and PUE, and FM reduced pore-water OP, TDP, and TP concentrations by 32% to 36% compared with the control. Crape myrtle grown in FL had 28% lower TDW but pour-through OP, TDP, and TP concentrations were similar to those of the control. Chemical conditions in FLM were favorable for precipitation of manganese hydrogen phosphate (MnHPO4), which may have contributed to lower water-extractable P concentrations in this treatment. This research suggests that amending pine bark substrate with dolomite and a sulfate-based micronutrient fertilizer should be considered a best management practice for nursery crop production.

Impacts of Soil Phosphorus Drawdown on Snowmelt and Rainfall Runoff Water Quality.

Managing P export from agricultural land is critical to address freshwater eutrophication. However, soil P management, and options to draw down soil P have received little attention in snowmelt-dominated regions because of limited interaction between soil and snowmelt. Here, we assessed the impacts of soil P drawdown (reducing fertilizer P inputs combined with harvest removal) on soil Olsen P dynamics, runoff P concentrations, and crop yields from 1997 to 2014 in paired fields in Manitoba, Canada. We observed that Olsen P concentrations in the 0- to 5-cm soil layer were negatively correlated with the cumulative P depletion and declined rapidly at the onset of the drawdown practice (3.1 to 5.4 mg kg yr during 2007-2010). In both snowmelt runoff and rainfall runoff, concentrations of total dissolved P (TDP) were positively correlated with the concentrations of soil Olsen P. Soil P drawdown to low to moderate fertility levels significantly decreased mean annual flow-weighted TDP concentrations in snowmelt runoff from 0.60 to 0.30 mg L in the field with high initial soil P and from 1.17 to 0.42 mg L in the field with very high initial soil P. Declines in TDP concentration in rainfall runoff were greater. Critically, yields of wheat ( spp.) and canola ( L.) were not affected by soil P depletion. In conclusion, we demonstrate that relatively rapid reductions in P loads are achievable at the field scale via managing P inputs and soil P pools, highlighting a management opportunity that can maintain food security while improving water security in cold regions.

A novel approach to evaluating relationships between soil test and runoff P at landscape scales by integrating farmer knowledge on soil drains

Dissolved phosphorus loss pathways are often overlooked relative to erosion P losses but contribute under certain soil land use and management combinations and may be exacerbated by subsurface drainage. Measures of P desorption to water are commonly made in laboratory soil testing and related to an agronomic P test using stronger extractants. We aimed to relate soil drainflow P concentrations as an integrative measure of a range of landscape source and transport processes to soil test P-status and examine other influential soil co-variates. Grassland and cropland sites (n=28)were sampled across Scotland involving farmers to incorporate local knowledge relating drains to influencing soils and gain important management data not often available. Using quality controls (on-site filtration, guidance and pro-forma data collection) farmers took their own samples and posted them on for laboratory analysis. Soils were analysed for CNP parameters, reactive complexes and soil agronomic P status by Modified Morgan’s P (MMorgP). Drain waters were analysed for total dissolved P (TDP), dissolved molybdate reactive (DRP) and unreactive P (DUP). Grasslands (n=11) differed from cropland (n=17) with significantly greater drain concentrations of Total P, DUP, DOC:TDN and soil total C, N and P, oxalate-extractable Fe (Feox) and C:P. Conversely, cropland had greater drain NO3, DRP:TDP, soil pH, Pox and reactive surface P-saturation. Significant relationships were gained between both TDP and DUP with MMorgP across all sites, although relationships showed less scatter for grassland than cropland sites. A group of moderate soil P status soils, mostly cropland, with low organic matter status had proportionally greater DRP losses, with soil N content being a significant inverse predictor of DRP concentrations or DRP:TDP ratios in drain water. The results indicated soil test P (MMorgP) as a main control of TDP concentrations via drainage pathways, but that organic matter quality affected dissolved P speciation, but not concentrations. There was greater risk of DRP losses from cropland soils low in organic matter. The study outcomes benefitted from involving the farming community in terms of coupling soil to drain samples and local management knowledge. Compared to batch laboratory results the additional processes integrated by using field drains as a landscape-scale measure of dissolved P losses will give more realistic relationships for change in P leaching between soils differing in P status spatially, or in time following management.

Risks of phosphorus runoff losses from five Chinese paddy soils under conventional management practices

Abstract Phosphorus (P) runoff from arable land is a major cause for eutrophication of many surface waters. However, relatively little research has been conducted on managing P in rice ( Oryza sativa L.) production systems, where farming practices differ from those of upland cropping systems due to water ponding on the soil surface (field ponding water; FPW). Because FPW is a direct source of surface runoff, identifying the main source of P and the critical period of high P concentrations in the FPW provide important insights to mitigating P runoff losses. In this study, field monitoring and laboratory incubation experiments were combined to evaluate how soil P content and conventional P fertilizer application affected FPW P concentrations in rice–wheat ( Triticum aestivum L.) rotation systems of five Chinese rice producing regions. All soils had Olsen-P concentrations (10.1–20.5 mg kg −1 ) well below the critical levels (30–172 mg kg −1 ) for promoted risks of P loss. However, conventional P application rate significantly elevated FPW P concentrations compared to no P application, and P fertilizer contributed 47–92% of total P (TP) and 59–97% of total dissolved P (TDP) in the FPW. Temporarily, both TP and TDP concentrations peaked one day after P application (0.15–8.90 mg TP L −1 and 0.16–4.49 mg TDP L −1 ), then decreased rapidly and stabilized five days later. We conclude that fertilizer is the major source of P loss in Chinese rice production systems, and that P fertilizer rate should be optimized to reduce P concentrations in the effluent water in the first week following P application.

Atmospheric phosphorus deposition in a near-coastal rural site in the NE Iberian Peninsula and its role in marine productivity

In this study, African red-rains were collected at Montseny (NE Spain) on a weekly basis and analyzed for total particulate phosphorus (TPP), total dissolved P (TDP) and soluble reactive P (SRP) for the period 1996–2008. Wet and dry weekly deposition of TPP was analyzed for all provenances in 2002–2003. In this period, African sources were found to contribute 66% of the 576 μmol m⁻² y⁻¹ of total particulate phosphorus (TPP) deposited in Montseny, split almost evenly between dry and wet deposition. Measurement of this dry deposition further allowed a direct determination of deposition velocity (Vd), which suggested significant depositional differences between African (Vd = 3.1 ± 0.80 cm s⁻¹) and non-African events (Vd = 1.07 ± 0.13 cm s⁻¹). Measurement of TDP concentrations during the African rains suggests a solubility of 11.2% TPP. SRP solubility was lower (2.2%), highlighting the importance of understanding the composition of the atmospherically derived P component. Samples were collected 25 km from the Mediterranean coast and were assumed to represent the atmospheric P input to coastal waters. On an annual basis, atmospheric-derived soluble P contributed <1% of annual new primary production in the western Mediterranean. However, one strong African dust event (22–27 May, 2008) accounted for 24–33 % of the atmospheric P-induced annual new production. These results highlight the potential biogeochemical importance of seasonality, source, and composition of aerosols deposited in the Western Mediterranean Sea.

Crop Residue Effects on Organic Carbon, Nitrogen, and Phosphorus Concentrations and Loads in Runoff Water

Degraded soil surface conditions favor surface runoff, thus enhancing sediment and nutrient losses. This study examined the effect of crop residues on carbon (C), nitrogen (N), total phosphorus (TP), and total dissolved P (TDP) losses by surface runoff in an agricultural loamy soil with degraded structure. Runoff and sediment yield were made over 1‐m2 plots using a rainfall simulator with constant 65 mmh−1 intensity. Four successive rainfall applications were performed, the first three ones 25 mm each and the last one 65 mm. Added corn straw varied between 0 and 4 tha−1 in the five studied treatments. Organic C, N, and TP concentrations in runoff showed a trend to decrease because of the effect of corn straw on soil losses. However, TDP concentration increased with increasing crop residue in the lower two rainfall events. Sedimentary P constituted the major proportion of P in runoff. After 140 mm of cumulative rainfall, nutrient losses were as follows: organic C from 137.7 to 792.7 kgha−1, N from 16.65 to 88.82 kgha−1, TP from 1.72 to 7.87 kgha−1, and TDP 57 to 87 gha−1. Total losses of the studied nutrients were correlated with soil losses.

Impact of flow path length and flow rate on phosphorus loss in simulated overland flow from a humic gleysol grassland soil

In this overland flow simulation experiment, the relationships between flow path length, flow rate and the concentration of different P fractions were investigated. Overland flow was simulated using a 3 mx0.12 m laboratory flume. To remove the impact of rainfall on P lost in overland flow, simulated rainfall was not used during these experiments. Instead overland flow was generated by pumping water into the flume at the surface of the grass sod. The experimental setup allowed for the variation in flow path length and flow rate between and during experimental runs. The results demonstrated that an increase in flow path length caused an increase in Total Dissolved P (TDP), Dissolved Reactive P (DRP) and Total Reactive P (TRP) concentration in overland flow (p<0.01) while an increase in flow rate resulted in a decrease in the concentration of these P fractions in overland flow due to dilution (p<0.01). Total P (TP), Particulate P (PP) and Dissolved Organic P were not affected by the variables tested during this study. When flow path length was increased in conjunction with flow rate, there was an increase in TDP, DRP, and TRP concentrations despite the impact of greater dilution. The results indicate that variations in flow path length during a rainfall event may play a role in determining the concentration of dissolved P fractions in overland flow at field scale.

Measurement and modelling of runoff and phosphate movement from seasonally dry hill‐country pastures

In seasonally dry hill pastures on a Waipawa stony loam (Pallic Soil) in Hawke's Bay, a range of methods was used to measure phosphorus (P) movement and losses in runoff water. Measurements with a rainfall simulator and micro‐plots showed that dissolved reactive P (DRP) and total dissolved P (TDP) concentrations in surface runoff were directly related to soil Olsen P (R2= 0.93 and R2 = 0.90 respectively) status. The distance that surface runoff travelled, as measured by P fertiliser transport, was about 5 m when rainfall in autumn had not occurred for 12–22 days, but decreased sharply in subsequent rainstorms. Over a 12‐month period most natural surface runoff occurred mostly during early summer to late autumn and was inversely related to soil moisture content (R2= ‐0.38 for all data). Most (55–84%) of total P (TP) losses occurred in three of 12 storms measured, with the majority as DRP from low P (60–85%) and high P (70–93%) soils. Continuous flows from twin catchments of 12.6 ha (north, with low soil P status), and 12.8 ha (south, with a moderate to high soil P status) were recorded. For the north catchment, total flow ranged from 18 to 26% of annual rainfall, and for the south catchment from 18 to 21%, over 2000 to 2002. About half of this occurred in July‐August. Over a 7‐month period, surface runoff was equivalent to only about 3% of rainfall. The difference in soil P status of the two catchments provided an approximate index of the difference in TP export. The DRP and TDP concentrations in catchment flow were about 10‐fold less than those recorded in surface runoff from associated pastures. The TOPMODEL runoff simulation model accurately estimated total flow from two catchments (R = 0.89 and 0.87 for north and south catchments respectively), but not the contribution by surface runoff.

A field study of phosphorus mobilisation from commercial fertilisers

Fertilisers contribute to phosphorus (P) exported from agricultural catchments in south-eastern Australia. Phosphorus concentrations were initially measured in overland flow caused by rainfall after broadcasting either single superphosphate [SSP, Ca(H2PO4)2] or diammonium phosphate [DAP, (NH4)2HPO4] blends to pastures. In addition, P concentrations in overland flow were measured at intervals down border irrigation bay before and after fertiliser application. The period between fertiliser application and irrigation varied from 1 to 10 days.For the rainfall-induced overland flow, total dissolved P (TDP) concentrations were higher where DAP rather than SSP had been applied. For the irrigation study, sampling position behind the wetting front, irrigation pre and post fertiliser application, and irrigation number post fertiliser application explained 49.7, 20.5, and 15.2% of the total sum of squares, respectively. TDP concentrations were highest in the wetting front and diminished with distance behind the wetting front. For the irrigation before, and 2 irrigations following, fertiliser application, concentrations in the wetting front were 2.3, 17.6, and 6.5 mg TDP/L, respectively. In general, wetting front concentrations were c. 4 times the mean concentrations for the bays. As most P is exported when the wetting front enters the drainage network, sampling behind the wetting front would appear to underestimate P exports. The TDP concentration decreased as the time between fertiliser application and irrigation increased but the effects were variable between farms and fertilisers. Contrary to the rainfall induced overland flow study, in the irrigation study higher TDP concentrations were measured where SSP rather than DAP had been applied. This finding is explained in terms of differing rates of P mobilisation from the 2 fertiliser blends and an interaction with soil hydrology. The rapidly infiltrating water at the wetting front of irrigation-induced overland flow is likely to carry with it P mobilised at, or near, the soil surface and P infiltration will be proportional to mobilisation rates. It is suggested that higher rates of P mobilisation from DAP than SSP would reduce P exports in border irrigation systems where DAP is applied to the soil.

Phosphorus dynamics in shallow subsurface waters in an uncut and cut subcatchment of a lake on the Boreal Plain

Phosphorus dynamics in shallow subsurface waters (&lt;2.5 m depth) were studied in harvested and unharvested subcatchments of a Boreal Plain lake. The organic soil layer was underlain by discontinuous layers of sand and clay glacial till. Total dissolved P (TDP) concentrations (6-798 µg·L-1) of discrete water samples from mineral layers (0.9-2.5 m deep) generally decreased with depth, were negatively related to Ca (rs &lt; -0.7), and were lower in clay. When the groundwater table rose and saturated the organic layer, TDP concentrations increased in the composite (organic mineral layer) but not in the discrete (mineral layer) water samples, indicating that elevated TDP concentrations originate from the near-surface organic layer. TDP concentrations in composite samples were negatively correlated with water table depth (rs = -0.6) and were positively correlated with transmissivity (rs = 0.7) and dissolved organic C concentration (rs &gt; 0.6). In the riparian buffer zone of the harvested subcatchment, TDP concentrations of composite samples decreased during high runoff, but these values remained higher than concentrations in the unharvested subcatchment. However, surface topography and variable depth to confining clay layers resulted in higher groundwater tables in the harvested subcatchment, especially in the cut area. Mean daily TDP export coefficients were similar between the unharvested (14 µg·m-2) and harvested (12 µg·m-2) subcatchments.

Soil Amendments for Reducing Phosphorus Concentration of Drainage Water from Histosols

AbstractRecently, the Everglades Agricultural Area (EAA) has been scrutinized by groups concerned with the impact of P‐enriched drainage water from organic soils (Histosols) on the ecology of adjoining wetlands. The objective of our research was to evaluate the effectiveness of soil amendments in reducing the P concentration in drainage water from an organic soil. Plastic cylindrical columns were filled with soil collected from a Pahokee muck (euic, hyperthermic Lithic Medisaprist). Three soil amendments were added to the soil columns: (i) a municipal drinking water purification facility waste material (“residual”), which is composed of CaO, Al2(SO4)3, and a starch‐based polymer; (ii) commercial agricultural dolomite [CaMg(CO3)2]; and (iii) commercial agricultural gypsum (CaSO4·2H2O). The amended columns were saturated for 60 d with an aqueous solution containing 5 mg P L−1 and then drained. The columns were then subjected to four P desorption cycles by saturating with distilled water and draining. Leachates were collected and analysed for total dissolved P (TDP). Residual and dolomite amendments reduced soil affinity for P sorption and resulted in a decrease in the quantity of soil P retained after repeated leachings. The net result from gypsum amendment was a small increase in P sorption capacity combined with an increased soil affinity for P. The reduced leachate TDP concentrations resulting from gypsum amendment were long lasting and were dependent on gypsum amendment rate. The effectiveness of gypsum amendments in reducing drainage‐water TDP concentrations needs to be evaluated under commercial agricultural field conditions.

Phosphorus Concentrations in Drainage Water in the Everglades Agricultural Area

AbstractPhosphorus in drainage water leaving the Everglades Agricultural Area (EAA) in southern Florida is alleged to be contributing to the accelerated eutrophication of Lake Okeechobee and the degradation of the Water Conservation Areas and the Everglades National Park ecosystems. Agricultural “best management practices” (BMPs) offer a means for achieving reductions in P in drainage water. Prior to developing and implementing BMPs, it is necessary to establish baseline EAA P concentrations. Baseline total P (TP) and total dissolved P (TDP) concentrations for various crop and field conditions in the EAA were determined. Thirty‐six 0.7‐ha plots were installed at four locations. Average TP and TDP concentrations were derived from 6 to 30 drainage events for each of five conditions between November 1988 and December 1989: sugarcane (Saccharum spp.), radish (Raphanus sativus L.), and cabbage (Brassica oleracea L.) production fields, flooded fallow fields, and drained fallow fields. Baseline TP and TDP concentrations for main farm canals and rainfall were also determined. Average TP concentrations ranged from 0.25 mg L−1 for radishes to 1.03 mg L−1 during the drain‐down of flooded fallow plots. Total dissolved P concentrations ranged from 48 to 80% of TP. Main farm canal TP concentrations averaged 0.16 mg L−1. Total P concentrations in rainfall averaged 0.07 mg L−1 Total P in drainage water during 1989 for sugarcane, cabbage, and drained fallow fields were 0.72, 1.38, and 0.59 kg ha−1, respectively. During the radish season, drainage water TP loading was 0.8 kg ha−1. Flooded fallow fields after radishes yielded a TP loading rate of 3.82 kg ha−1. Total P loading to the fields from rainfall averaged 0.70 kg ha−1. Total dissolved P loading rates ranged from 25 to 60% of TP. Potential areas for BMP development and implementation for P concentration and loading reduction in the EAA include drainage rate, volume, and timing management, fertilizer use reduction, and enhanced crop rotation strategies.