[Immunogenicity, safety and immune persistence of the sequential booster with the recombinant protein-based COVID-19 vaccine (CHO cell) in healthy people aged 18-84 years].

Objective: To evaluate the immunogenicity, safety, and immune persistence of the sequential booster with the recombinant protein-based COVID-19 vaccine (CHO cell) in healthy people aged 18-84 years. Methods: An open-label, multi-center trial was conducted in October 2021. The eligible healthy individuals, aged 18-84 years who had completed primary immunization with the inactivated COVID-19 vaccine 3 to 9 months before, were recruited from Shangyu district of Shaoxing and Kaihua county of Quzhou, Zhejiang province. All participants were divided into three groups based on the differences in prime-boost intervals: Group A (3-4 months), Group B (5-6 months) and Group C (7-9 months), with 320 persons per group. All participants received the recombinant COVID-19 vaccine (CHO cell). Blood samples were collected before the vaccination and after receiving the booster at 14 days, 30 days, and 180 days for analysis of GMTs, antibody positivity rates, and seroconversion rates. All adverse events were collected within one month and serious adverse events were collected within six months. The incidences of adverse reactions were analyzed after the booster. Results: The age of 960 participants was (52.3±11.5) years old, and 47.4% were males (455). The GMTs of Groups B and C were 65.26 (54.51-78.12) and 60.97 (50.61-73.45) at 14 days after the booster, both higher than Group A's 44.79 (36.94-54.30) (P value<0.05). The GMTs of Groups B and C were 23.95 (20.18-28.42) and 27.98 (23.45-33.39) at 30 days after the booster, both higher than Group A's 15.71 (13.24-18.63) (P value <0.05). At 14 days after the booster, the antibody positivity rates in Groups A, B, and C were 91.69% (276/301), 94.38% (302/320), and 93.95% (295/314), respectively. The seroconversion rates in the three groups were 90.37% (272/301), 93.75% (300/320), and 93.31% (293/314), respectively. There was no significant difference among these rates in the three groups (all P values >0.05). At 30 days after the booster, antibody positivity rates in Groups A, B, and C were 79.60% (238/299), 87.74% (279/318), and 90.48% (285/315), respectively. The seroconversion rates in the three groups were 76.92% (230/299), 85.85% (273/318), and 88.25% (278/315), respectively. There was a significant difference among these rates in the three groups (all P values <0.001). During the sequential booster immunization, the incidence of adverse events in 960 participants was 15.31% (147/960), with rates of about 14.38% (46/320), 17.50% (56/320), and 14.06% (45/320) in Groups A, B, and C, respectively. The incidence of adverse reactions was 8.02% (77/960), with rates of about 7.50% (24/320), 6.88% (22/320), and 9.69% (31/320) in Groups A, B, and C, respectively. No serious adverse events related to the booster were reported. Conclusion: Healthy individuals aged 18-84 years, who had completed primary immunization with the inactivated COVID-19 vaccine 3 to 9 months before, have good immunogenicity and safety profiles following the sequential booster with the recombinant COVID-19 vaccine (CHO cell).

Clinical characteristics of 14 pediatric mycoplasma pneumoniae pneumonia associated thrombosis: a retrospective study.

OBJECTIVE: This study aimed to investigate the clinical characteristics and long-term prognosis of mycoplasma pneumoniae pneumonia (MPP)-associated thrombosis and to gain a better understanding of the diagnosis and treatment of the disease. METHODS: The medical records of 14 children with MPP-associated thrombosis between January 2016 and April 2020 were retrospectively reviewed at the Tianjin Children's Hospital. RESULTS: The ages of the patients ranged from 3 to 12 years old. Among the 14 cases, there were five cases of pulmonary embolism, two cases of cerebral infarction, one case of splenic infarction, one case of cardiac embolism, two cases of cardiac embolism with comorbid pulmonary embolism, one case of internal carotid artery and pulmonary embolism, one case of combined internal carotid artery and the cerebral infarction, and one case combined cardiac embolism and lower limb artery embolism. All cases had elevated D-dimer levels. After thrombolysis and anticoagulation therapy, three cases with cerebral embolism still suffered from neurological sequelae. In contrast, the remaining cases did not develop complications. CONCLUSION: MPP-associated thrombosis can occur in any vessel of the body. Thrombosis-associated symptoms may be complex and non-specific. Elevated D-dimer levels in a child with refractory mycoplasma pneumoniae pneumonia should raise suspicion of thrombosis. The long-term prognosis of thrombosis was favorable after the timely administration of anticoagulant therapy.

[Effect factors of collateral blood supply of patients with early trimester cesarean scar pregnancy].

Objective: To investigate the characteristics and effect factors of collateral blood supply of patients with early trimester cesarean scar pregnancy(CSP). Methods: This study was a multicenter case-control study, with 219 inpatients with CSP in First People's Hospital of Zhengzhou, Zhengzhou Central Hospital, Third People's Hospital of Zhengzhou and Henan No3 Provincial People's Hospital from January 1, 2017 to June 30, 2020 who were selected to obtain their clinical data. Double-blind method was performed in digital subtraction angiography imaging analysis. The patients were divided into collateral blood supply group and non-collateral blood supply group, and the incidence of collateral blood supply of patients with early trimester CSP was calculated. Multivariate binary logistic regression analysis was performed to find the independent risk factors of collateral blood supply of patients with early trimester CSP. As well, clinical outcomes after uterine artery embolization (UAE) were compared between the two groups. Results: A total of 219 patients with early trimester CSP have average age of (32.4±5.0) years old and average pregnancy of (51.0±10.6) days. The incidence of collateral blood supply was 12.3% (27 cases), of which16 cases were on the left, 6 on the right and 5 in both sides. A total of 43 collateral vessels were found, with 1.59 vessels per patient on average. Bladder artery was the most common source of collateral blood supply, accounting for 74.4% (32/43), followed by internal pudendal artery for 18.6% (8/43). Multivariate binary logistic regression analysis showed that gestational weeks ≥8 weeks, maximum diameter of gestational sac ≥50 mm and rich blood supply of gestational sac are independent risk factors for collateral blood supply of patients with early trimester CSP, with OR (95%CI) 3.68 (1.06-12.76), 7.00 (1.52-32.19)、9.96 (3.59-27.58), respectively, all P<0.05. The success rates of UAE were 100% in both groups. The reduction in serum ß-Human chorionic gonadotropin (ß-HCG) level at 24 hours after UAE, vaginal bleeding during uterine curettage, hysterectomy and menstrual recovery time were not found to have significant difference between groups (all P>0.05). Conclusions: Early trimester CSP leads to a certain occurrence of collateral blood supply, which may have adverse impact on the efficacy of UAE and patient safety. Gestational weeks, the maximum diameter of gestational sac and the degree of vascularization of gestation sac have certain value in suggesting the collateral blood supply of patients with early trimester CSP, which is helpful for the complete embolization of gestational sac in the process of UAE.

Extranodal natural killer/T cell lymphoma with involvement of the bilateral submandibular lymph node mimicking a rhinoscleroma: a diagnostic challenge.

Extranodal natural killer/T-cell lymphoma, nasal type (ENKL) is a rare and aggressive tumor that can mimic inflammatory conditions and other tumors, and present a diagnostic challenge. We report a 57-year-old Chinese man previously misdiagnosed with rhinoscleroma. The patient had undergone multiple biopsies when the histopathological diagnosis of ENKL was made. Because the diagnosis may be obscured by extensive necrosis, multiple biopsies are necessary to make a certain diagnosis. According to the diagnosis process of this patient, the need to consider a neoplastic cause should be highlighted when faced with an aggressive nasal disease not responsive to maximal treatment.

Characterization of sedimentary phosphorus in Lake Erie and on-site quantification of internal phosphorus loading.

Lake Erie harmful algal blooms and hypoxia are two major environmental problems, and have severe impacts on human health, aquatic ecosystems, and the economy. However, little is known about internal loading of phosphorus (P) from sediments, which pose a challenge for assessing the efficacy of current conservation measures on the improvement of lake water quality. A modified Hedley's extraction procedure was employed to analyze representative sediment samples collected from the Lake Erie basin for assessing sedimentary P stock, potential availability for release into lake water, and internal P loading. Inorganic and organic P in the sediments were characterized by sequential extractions in H2O, 0.5 M NaHCO3, 0.1 M NaOH, and 1.0 M HCl, respectively. In the 0 - 10 cm sediment, total P stock was 172, 191, and 170 metric tons km-2 in the western, central, and eastern basins, respectively. Sedimentary P seems unlikely to contribute to internal P loading in the western basin, while in the eastern basin it can potentially contribute to an internal loading of 359 metric tons P yr-1. In the central basin, 41% of organic P, 15% of non-HCl extractable inorganic P, and 9.7% of residual P in the 0 - 10 cm sediment is potentially available for release into lake water; in the 10 - 20 cm sediment, organic P extracted by NaHCO3 and NaOH is also partially available. The central basin potentially contributes to internal P loading at a total amount of 10,599 metric tons yr-1. Internal P loading may not contribute to HABs in the western basin, but it can cause and maintain hypoxia in the central basin and delay the recovery of lake water quality for a lengthy time period in response to external P reduction measures.

[Change of cervical sagittal alignment after the treatment of growing rods to the early-onset scoliosis].

Objective: To determine the impact of growing rods (GR) technique on cervical alignment in early-onset scoliosis (EOS) through the change of cervical alignment parameters after the GR surgery. Methods: Total of 24 consecutive EOS patients treated in Beijing Chao-Yang Hospital from 2009 to 2018 were retrospectively reviewed (17 males and 7 females). Cervical lordosis, T(1) slope and C(2-7) sagittal vertical axis (C(2-7)SVA), thoracic/lumbar Cobb angle, thoracic kyphosis (TK), global kyphosis Cobb angle, SVA were included in radiographic data in the full spinal standing X-ray before and post operation and at the last follow-up. Based on clinical data, including the upper instrumented vertebra (UIV), proximal junctional kyphosis (PJK) and the number of GR, patients were divided into different groups for statistical analysis. Logistic regression analysis was used to find the independent risk factors of the abnormality of C(2-7)SVA. Results: All patients received at least one time of distraction operation, the mean follow-up was (35±14) months. The C(2-7) Cobb angle increased from 17°±11° to 18°±9° and T(1) slope changed from 28°±13° to 28°±11° and C(2-7)SVA changed from (17±11) mm to (16±10) mm after the operation, but no significant differences were found in those indexes before and after the operation (t=-1.15, 0.14, 0.55, all P>0.05). At the last follow-up after GR technique, the C(2-7) Cobb angle, T(1) slope angle and C(2-7)SVA significantly increased when compared with those before the operation (t=-7.60, -4.08, -2.46, all P<0.05). The △C(2-7) Cobb angle and △T(1) slope angle PJK group was both more significant than those in non-PJK group (t=3.50, 3.25, both P<0.05); while there was no significant difference in the △C(2-7) Cobb angle and △T(1) slope angle when the choice of UIV and the number of GD were taken into account (t=-1.02, -1.61, -0.67, 0.31, all P>0.05). The occurrence of PJK was identified as an independent risk factor for the abnormality of C(2-7)SVA during the GR surgery with logistic regression analysis(OR=11.57, 95%CI: 1.49-91.54, P<0.05). Conclusions: When used for EOS to correct deformity, GR surgery will increase the cervical lordosis and T(1) slope angle of EOS patients. More attention should be paid to the cervical sagittal alignment and cervical sagittal imbalance in EOS patients with PJK.

Modeling the Impacts of Manure on Phosphorus Loss in Surface Runoff and Subsurface Drainage.

Simulation of phosphorus (P) transfer from manured agricultural lands to water bodies via surface runoff and subsurface drainage is potentially of great help in evaluating the risks and effects of eutrophication under a range of best management practice scenarios. However, it remains a challenge since few models are capable of providing a reasonably accurate prediction of P losses under manure treatment. The Environmental Policy Integrated Climate (EPIC) model was applied to simulate the impacts on dissolved reactive P (DRP) losses through surface runoff and subsurface drainage from a solid cattle manure-amended corn ( L.)-soybean [ (L.) Merr.] rotation on a clay loam soil (Vertisol) located in the Lake Erie region. Simulations of DRP loss in surface runoff and tile drainage were satisfactory; however, EPIC did not consider DRP loss directly from manure, weakening its accuracy in the prediction of DRP loss in surface runoff. Having previously drawn on EPIC-predicted surface runoff to initiate SurPhos (Surface Phosphorus and Runoff Model) predictions of DRP losses strictly in surface runoff, no comparison had been made of differences in manure application impacts on EPIC- or SurPhos-predicted DRP losses-accordingly, this was assessed. The SurPhos improved the estimation of DRP loss in surface runoff (Nash-Sutcliffe coefficient, 0.53), especially when large rain events occurred immediately after or within 6 wk of manure application. Generally, EPIC can capture the impacts of manure application on DRP loss in surface runoff and subsurface drainage; however, coupling of the EPIC and SurPhos models increased the accuracy of simulation of runoff DRP losses.

Modeling phosphorus losses from soils amended with cattle manures and chemical fertilizers.

While applied manure/fertilizer is an important source of P loss in surface runoff, few models simulate the direct transfer of phosphorus (P) from soil-surface-applied manure/fertilizer to surface runoff. The SurPhos model was tested with 2008-2010 growing season daily surface runoff data from clay loam experimental plots subject to different manure/fertilizer applications. Model performance was evaluated on the basis of the coefficient of determination (R2), Nash-Sutcliffe efficiency (NSE), percent bias (PBIAS), and the ratio of the root mean square error to the standard deviation of observed values (RSR). The model offered an acceptable performance in simulating soil labile P dynamics (R2 = 0.75, NSE = 0.55, PBIAS = 10.43%, and RSR = 0.67) and dissolved reactive P (DRP) loss in surface runoff (R2 ≥ 0.74 and NSE ≥ 0.69) for both solid and liquid cattle manure, as well as inorganic fertilizer. Simulated direct P loss in surface runoff from solid and liquid cattle manure accounted for 39% and 40% of total growing season DRP losses in surface runoff. To compensate for the unavailability of daily surface runoff observations under snow melt condition, the whole four years' (2008-2011) daily surface runoff predicted by EPIC (Environmental Policy Integrated Climate) was used as SurPhos input. The accuracy of simulated DRP loss in surface runoff under the different manure/fertilizer treatments was acceptable (R2 ≥ 0.55 and NSE ≥ 0.50). For the solid cattle manure treatment, of all annual DRP losses, 19% were derived directly from the manure. Beyond offering a reliable prediction of manure/fertilizer P loss in surface runoff, SurPhos quantified different sources of DRP loss and dynamic labile P in soil, allowing a better critical assessment of different P management measures' effectiveness in mitigating DRP losses.

Environmental Indicator Principium with Case References to Agricultural Soil, Water, and Air Quality and Model-Derived Indicators.

Environmental indicators are powerful tools for tracking environmental changes, measuring environmental performance, and informing policymakers. Many diverse environmental indicators, including agricultural environmental indicators, are currently in use or being developed. This special collection of technical papers expands on the peer-reviewed literature on environmental indicators and their application to important current issues in the following areas: (i) model-derived indicators to indicate phosphorus losses from arable land to surface runoff and subsurface drainage, (ii) glutathione-ascorbate cycle-related antioxidants as early-warning bioindicators of polybrominated diphenyl ether toxicity in mangroves, and (iii) assessing the effectiveness of using organic matrix biobeds to limit herbicide dissipation from agricultural fields, thereby controlling on-farm point-source pollution. This introductory review also provides an overview of environmental indicators, mainly for agriculture, with examples related to the quality of the agricultural soil-water-air continuum and the application of model-derived indicators. Current knowledge gaps and future lines of investigation are also discussed. It appears that environmental indicators, particularly those for agriculture, work efficiently at the field, catchment, and local scales and serve as valuable metrics of system functioning and response; however, these indicators need to be refined or further developed to comprehensively meet community expectations in terms of providing a consistent picture of relevant issues and/or allowing comparisons to be made nationally or internationally.

Solid Cattle Manure Less Prone to Phosphorus Loss in Tile Drainage Water.

Forms (e.g., liquid and solid) of manure influence the risk of P loss after land application. The objective of this study was to investigate the effects of P-based application of various forms of cattle manure (liquid, LCM; or solid, SCM) or inorganic P as triple superphosphate (IP) on soil P losses in tile drainage water. A 4-yr field experiment was conducted in a clay loam soil with a corn ( L.)-soybean [ (L.) Merr.] rotation in the Lake Erie basin. Over the 4 yr, the dissolved reactive P (DRP) flow-weighted mean concentration (FWMC) in tile drainage water was greater under SCM fertilization than under either IP or LCM fertilization. Despite its lower value on an annual basis, DRP FWMC rose dramatically immediately after LCM application. However, the differences in DRP FWMC did not result in detectable differences in DRP loads. Regarding particulate P and total P losses during the 4 yr, they were 68 and 47%, respectively, lower in the soils amended with SCM than in those with IP, whereas both values were similar between IP and LCM treatments. Overall, the P contained in solid cattle manure was less prone to P loss after land application. Accordingly, the present results can provide a basis for manure storage and application of best management practices designed to reduce P losses and improve crop growth.

Modeling Phosphorus Losses through Surface Runoff and Subsurface Drainage Using ICECREAM.

Modeling soil phosphorus (P) losses by surface and subsurface flow pathways is essential in developing successful strategies for P pollution control. We used the ICECREAM model to simultaneously simulate P losses in surface and subsurface flow, as well as to assess effectiveness of field practices in reducing P losses. Monitoring data from a mineral-P-fertilized clay loam field in southwestern Ontario, Canada, were used for calibration and validation. After careful adjustment of model parameters, ICECREAM was shown to satisfactorily simulate all major processes of surface and subsurface P losses. When the calibrated model was used to assess tillage and fertilizer management scenarios, results point to a 10% reduction in total P losses by shifting autumn tillage to spring, and a 25.4% reduction in total P losses by injecting fertilizer rather than broadcasting. Although the ICECREAM model was effective in simulating surface and subsurface P losses when thoroughly calibrated, further testing is needed to confirm these results with manure P application. As illustrated here, successful use of simulation models requires careful verification of model routines and comprehensive calibration to ensure that site-specific processes are accurately represented.

Drainage water management combined with cover crop enhances reduction of soil phosphorus loss.

Integrating multiple practices for mitigation of phosphorus (P) loss from soils may enhance the reduction efficiency, but this has not been studied as much as individual ones. A four-year study was conducted to determine the effects of cover crop (CC) (CC vs. no CC, NCC) and drainage water management (DWM) (controlled drainage with sub-irrigation, CDS, vs. regular free tile drainage, RFD) and their interaction on P loss through both surface runoff (SR) and tile drainage (TD) water in a clay loam soil of the Lake Erie region. Cover crop reduced SR flow volume by 32% relative to NCC, regardless of DWM treatment. In contrast, CC increased TD flow volume by 57 and 9.4% with CDS and RFD, respectively, compared to the corresponding DWM treatment with NCC. The total (SR+TD) field water discharge volumes were comparable amongst all the treatments. Cover crop reduced flow-weighted mean (FWM) concentrations of particulate P (PP) by 26% and total P (TP) by 12% in SR, while it didn't affect the FWM dissolved reactive P (DRP) concentration, regardless of DWM treatments. Compared with RFD, CDS reduced FWM DRP concentration in TD water by 19%, while CC reduced FWM PP and TP concentrations in TD by 21 and 17%, respectively. Total (SR+TD) soil TP loss was the least with CDS-CC followed by RFD-CC, CDS-NCC, and RFD-NCC. Compared with RFD-NCC, currently popular practice in the region, total TP loss was reduced by 23% with CDS-CC. The CDS-CC system can be an effective practice to ultimately mitigate soil P loading to water resource.

Soil phosphorus loss in tile drainage water from long-term conventional- and non-tillage soils of Ontario with and without compost addition.

Recent ascertainment of tile drainage a predominant pathway of soil phosphorus (P) loss, along with the rise in concentration of soluble P in the Lake Erie, has led to a need to re-examine the impacts of agricultural practices. A three-year on-farm study was conducted to assess P loss in tile drainage water under long-term conventional- (CT) and non-tillage (NT) as influenced by yard waste leaf compost (LC) application in a Brookston clay loam soil. The effects of LC addition on soil P loss in tile drainage water varied depending on P forms and tillage systems. Under CT, dissolved reactive P (DRP) loss with LC addition over the study period was 765g P ha-1, 2.9 times higher than CT without LC application, due to both a 50% increase in tile drainage flow volume and a 165% increase in DRP concentration. Under NT, DRP loss in tile drainage water with LC addition was 1447gPha-1, 5.3 times greater than that for NT without LC application; this was solely caused by a 564% increase in DRP concentration. However, particulate P loads in tile drainage water with LC application remained unchanged, relative to non-LC application, regardless of tillage systems. Consequently, LC addition led to an increase in total P loads in tile drainage water by 57 and 69% under CT and NT, respectively. The results indicate that LC application may become an environmental concern due to increased DRP loss, particularly under NT.

[Clinical application of multi-electrode synchronous radiofrequency ablation via switching controller for treating large hepatocellular carcinoma].

Objective: To explore the preliminary clinical efficacy and safety of multi-electrode synchronous radiofrequency ablation via switching controller for treating large hepatocellular carcinoma. Methods: A total of 20 patients with large hepatocellular carcinoma from minimally invasive Interventional department of Sun Yat-sen University Cancer Center were enrolled in this retrospective study from December 2013 to December 2014.The procedures were conducted with multi-electrode synchronous radiofrequency ablation via switching controller under CT guidance.The necrosis rate of tumor was assessed by the following imaging examination.The single factor analysis of variance (ANOVA) was employed to compare the total bilirubin, albumin, renal function, blood coagulation function before and after ablation, to evaluate the safety of treatment. Result: Twenty patients with a total of 31 lesions accepted 23 times ablation procedures using multi-electrode synchronous radiofrequency ablation via switching controller.The recent evaluation after treatment was as followed: complete necrosis rate 51.6% (16/31), nearly complete necrosis rate 22.6% (7/31), partial necrosis rate 9.7% (3/31), treatment effectiveness rate (necrosis rate > 50%) 83.9%.The necrosis rate which was less than half volume of the tumor was only seen in 5 cases with huge hepatocellular carcinoma (16.1%). No dead cases appeared after ablation procedures.The patients' total bilirubin elevated moderately after ablation procedures and reversed to normal level after liver function protection treatment.There were no statistical differences of renal function and blood coagulation function before and after ablation.After ablation procedures, 5 cases (21.7%, 5/23) appeared fever, 6 cases (26.1%) with vomiting, only 3 cases (13.0%, 3/23) with moderately severe pain in 3 days after ablation and remitted after taking oral analgesics in one week. Conclusion: The clinical efficacy of multi-electrode synchronous radiofrequency ablation via switching controller for large hepatocellular carcinoma is satisfactory with guaranteed security, which can be a choice for treating large hepatocellular carcinoma.

Approximating Phosphorus Leaching from Agricultural Organic Soils by Soil Testing.

Phosphorus applied to soils in excess of crop requirement could create situations favorable to P enrichment in subsurface flow that contributes to eutrophication of surface water. This pathway of P loss can be more severe in muck (i.e., organic) soils where agricultural production is intensive. This study evaluated the suitability of various environmental and agronomic soil P tests initially designed for mineral soils to predict dissolved reactive P (DRP) in subsurface flow from organic soils. Intact soil columns were collected from 44 muck soils in Ontario to provide a wide range of soil test P levels. A lysimeter leaching study was conducted by evenly adding water in an amount equivalent to 5 mm of rainfall. The leachate DRP concentration was linearly related to soil water-extractable P and CaCl-extractable P with values of 0.90 and 0.93, respectively, and to Bray-1 P and FeO-impregnated filter paper extractable P in a split-line model with a change point. Mehlich-3 P and Olsen P, a method recommended for agronomic P calibration in Ontario, were not related to leachate DRP concentration. All P sorption index (PSI) based degree of P saturation (DPS) values were closely related to leachate DRP in split-line models, with the DPS indices expressed as Bray-1 P/PSI and FeO-P/PSI having the highest correlation with leachate DRP concentration. Because it is desirable from practical and economic standpoints that the environmental risk assessment shares the same soil test with agronomic P calibration, the two PSI-based DPS indices as presented can be considered as environmental risk indicators of DRP subsurface loss from organic soils.

Impacts of soil conditioners and water table management on phosphorus loss in tile drainage from a clay loam soil.

Adoption of waste-derived soil conditioners and refined water management can improve soil physical quality and crop productivity of fine-textured soils. However, the impacts of these practices on water quality must be assessed to ensure environmental sustainability. We conducted a study to determine phosphorus (P) loss in tile drainage as affected by two types of soil conditioners (yard waste compost and swine manure compost) and water table management (free drainage and controlled drainage with subirrigation) in a clay loam soil under corn-soybean rotation in a 4-yr period from 1999 to 2003. Tile drainage flows were monitored and sampled on a year-round continuous basis using on-site auto-sampling systems. Water samples were analyzed for dissolved reactive P (DRP), particulate P (PP), and total P (TP). Substantially greater concentrations and losses of DRP, PP, and TP occurred with swine manure compost than with control and yard waste compost regardless of water table management. Compared with free drainage, controlled drainage with subirrigation was an effective way to reduce annual and cumulative losses of DRP, PP, and TP in tile drainage through reductions in flow volume and P concentration with control and yard waste compost but not with swine manure compost. Both DRP and TP concentrations in tile drainage were well above the water quality guideline for P, affirming that subsurface loss of P from fine-textured soils can be one critical source for freshwater eutrophication. Swine manure compost applied as a soil conditioner must be optimized by taking water quality impacts into consideration.

Tile drainage phosphorus loss with long-term consistent cropping systems and fertilization.

Phosphorus (P) loss in tile drainage water may vary with agricultural practices, and the impacts are often hard to detect with short-term studies. We evaluated the effects of long-term (≥43 yr) cropping systems (continuous corn [CC], corn-oats-alfalfa-alfalfa rotation [CR], and continuous grass [CS]) and fertilization (fertilization [F] vs. no-fertilization [NF]) on P loss in tile drainage water from a clay loam soil over a 4-yr period. Compared with NF, long-term fertilization increased concentrations and losses of dissolved reactive P (DRP), dissolved unreactive P (DURP), and total P (TP) in tile drainage water, with the increments following the order: CS > CR > CC. Dissolved P (dissolved reactive P [DRP] and dissolved unreactive P [DURP]) was the dominant P form in drainage outflow, accounting for 72% of TP loss under F-CS, whereas particulate P (PP) was the major form of TP loss under F-CC (72%), F-CR (62%), NF-CS (66%), NF-CC (74%), and NF-CR (72%). Dissolved unreactive P played nearly equal roles as DRP in P losses in tile drainage water. Stepwise regression analysis showed that the concentration of P (DRP, DURP, and PP) in tile drainage flow, rather than event flow volume, was the most important factor contributing to P loss in tile drainage water, although event flow volume was more important in PP loss than in dissolved P loss. Continuous grass significantly increased P loss by increasing P concentration and flow volume of tile drainage water, especially under the fertilization treatment. Long-term grasslands may become a significant P source in tile-drained systems when they receive regular P addition.

Reducing nitrate loss in tile drainage water with cover crops and water-table management systems.

Nitrate lost from agricultural soils is an economic cost to producers, an environmental concern when it enters rivers and lakes, and a health risk when it enters wells and aquifers used for drinking water. Planting a winter wheat cover crop (CC) and/or use of controlled tile drainage-subirrigation (CDS) may reduce losses of nitrate (NO) relative to no cover crop (NCC) and/or traditional unrestricted tile drainage (UTD). A 6-yr (1999-2005) corn-soybean study was conducted to determine the effectiveness of CC+CDS, CC+UTD, NCC+CDS, and NCC+UTD treatments for reducing NO loss. Flow volume and NO concentration in surface runoff and tile drainage were measured continuously, and CC reduced the 5-yr flow-weighted mean (FWM) NO concentration in tile drainage water by 21 to 38% and cumulative NO loss by 14 to 16% relative to NCC. Controlled tile drainage-subirrigation reduced FWM NO concentration by 15 to 33% and cumulative NO loss by 38 to 39% relative to UTD. When CC and CDS were combined, 5-yr cumulative FWM NO concentrations and loss in tile drainage were decreased by 47% (from 9.45 to 4.99 mg N L and from 102 to 53.6 kg N ha) relative to NCC+UTD. The reductions in runoff and concomitant increases in tile drainage under CC occurred primarily because of increases in near-surface soil hydraulic conductivity. Cover crops increased corn grain yields by 4 to 7% in 2004 increased 3-yr average soybean yields by 8 to 15%, whereas CDS did not affect corn or soybean yields over the 6 yr. The combined use of a cover crop and water-table management system was highly effective for reducing NO loss from cool, humid agricultural soils.

Accounting for the risks of phosphorus losses through tile drains in a phosphorus index.

Tile drainage systems have been identified as a significant conduit for phosphorus (P) losses to surface water, but P indices do not currently account for this transport pathway in a meaningful way. Several P indices mention tile drains, but most account for either the reduction in surface runoff or the enhanced transport through tiles rather than both simultaneously. A summary of the current state of how tile drains are accounted for within P indices is provided, and the challenges in predicting the risk of P losses through tile drains that are relative to actual losses are discussed. A framework for a component P Index is described, along with a proposal to incorporate predictions of losses through tile drains as a component within this framework. Options for calibrating and testing this component are discussed.

Estimating dissolved reactive phosphorus concentration in surface runoff water from major Ontario soils.

Phosphorus (P) loss from agricultural land in surface runoff can contribute to eutrophication of surface water. This study was conducted to evaluate a range of environmental and agronomic soil P tests as indicators of potential soil surface runoff dissolved reactive P (DRP) losses from Ontario soils. The soil samples (0- to 20-cm depth) were collected from six soil series in Ontario, with 10 sites each to provide a wide range of soil test P (STP) values. Rainfall simulation studies were conducted following the USEPA National P Research Project protocol. The average DRP concentration (DRP30) in runoff water collected over 30 min after the start of runoff increased (p < 0.001) in either a linear or curvilinear manner with increases in levels of various STPs and estimates of degree of soil P saturation (DPS). Among the 16 measurements of STPs and DPSs assessed, DPS(M3) 2 (Mehlich-3 P/[Mehlich-3 Al + Fe]) (r2 = 0.90), DPS(M3)-3 (Mehlich-3 P/Mehlich-3 Al) (r2 = 0.89), and water-extractable P (WEP) (r2 = 0.89) had the strongest overall relationship with runoff DRP30 across all six soil series. The DPS(M3)-2 and DPS(M3)-3 were equally accurate in predicting runoff DRP30 loss. However, DPS(M3)-3 was preferred as its prediction of DRP30 was soil pH insensitive and simpler in analytical procedure, ifa DPS approach is adopted.