Current Best Management Practices Research Articles

Postharvest evaluations of soil erosion, ground cover, and best management practice implementation on integrated biomass and conventional clearcut harvest sites

As demand for wood energy rises, it’s vital to understand the environmental impact of various harvest types, considering different best management practices (BMPs) and site conditions, for sustainable forest management. This study provides a comparative analysis of postharvest site characteristics between biomass and conventional harvest sites located in the Coastal Plain region of the southeastern US. A total of 30 recently harvest sites (15 each for biomass and conventional) were selected from the Coastal regions of Alabama, Georgia, and Florida. Erosion rates were estimated using the USLE-Forest method and ground cover was assessed as a percentage of the area covered by bare soil, litter, light slash, heavy slash, and piles. BMP implementation (%) was based on state-specific BMP surveys. The findings show that stream management zones (SMZs) and harvest areas were less prone to soil erosion, while forest roads, skid trails, and stream crossings were more prone to erosion, regardless of the harvest type. Conventional harvest sites had an overall weighted average erosion rate of 0.35 Mg/ha/year, with an average BMP implementation of 92.70 %, while biomass harvest sites had an overall weighted average erosion rate of 0.22 Mg/ha/year, with an average BMP implementation rate of 97.91 %. Average erosion rate (Mg/ha/year) from the harvest area (biomass=0.11, conventional=0.06) and SMZs (biomass=0.05, conventional=0.02) were not significantly different (p>0.05). Conversely, average erosion rate from roads (biomass=4.17, conventional=6.44), skid trails (biomass=2.15, conventional=3.73), decks (biomass=0.39, conventional=0.72), and stream crossings (biomass=1.53, conventional=5.31) were significantly higher in conventional harvest sites (p<0.05). BMP implementation rates for roads (biomass=98.09 %, conventional=93.71 %), stream crossings (biomass=95 %, conventional=71 %), and timber harvest (biomass=96.44 %, conventional=93.33 %) were significantly higher in biomass harvest sites, while waste management BMP (biomass=89.91 %, conventional=100 %) was significantly higher in conventional harvest sites. Regarding ground cover, conventional harvest sites had significantly larger areas covered by light slash, heavy slash, and piles than biomass harvest sites, while biomass harvest sites had significantly larger areas covered by green growth. Our research shows a significant negative correlation between overall BMP implementation and erosion rates (r=-0.67, p=0.0002), as well as site size (r=-0.38 p=0.0400), indicating that larger sites tend to have lower BMP implementation and increased erosion risk. In conclusion, biomass harvest sites in our study did not yield higher erosion rates in comparison to conventional harvest sites, provided that the current BMP recommendations were implemented properly and in adequate amounts. This study emphasizes the importance of site-specific management strategies to mitigate erosion in all harvest sites, irrespective of harvest type used.

Systematic Review of Best Management Practice Implementation for Agricultural Phosphorus Management in Florida: A 30-Year Overview

Highlights BMPs have been proven to be efficient in managing P loads in Florida. BMP efficiencies vary between 20% and 80%, with few higher than 50%. Integration of modeling strategies and field demonstrations could improve BMP efficiencies. Further implementation of testbeds and pilot studies could improve adoption and enhance our understanding of BMP efficiency. Abstract. In Florida, the implementation of best management practices (BMPs) has significantly reduced phosphorous (P) loads from the Everglades Agricultural Area (EAA) into the Lake Okeechobee watershed over the past two decades. While the removal of over 6,165 metric tons of total phosphorus entering the Everglades Protection Area is a notable achievement, some freshwater sources continue to exceed established limits (Naja et al., 2017), demanding a critical examination of BMP efficiency at managing low P concentrations. In this systematic literature review, we analyzed peer-reviewed journal manuscripts published over the past 30 years, focusing on the intersection of phosphorus management, water, Florida, and the environment. The dataset synthesized from our review provides insights into the efficiency of BMPs in terms of P management over time. Our findings show a predominant focus on stormwater treatment areas (STAs) and constructed wetlands as BMPs with demonstrated good efficiency. However, the variability in reported efficiencies underscores the complexity of phosphorus pollution and its impacts. Treatment trains ranged from 20% to 39% for the lower range of efficiency in phosphorus removal and from 60% to 79% for the higher range of efficiency. Focusing on strategies with higher P load reduction efficiencies could enhance future management strategies in Florida. Field-based pilot studies with well-defined control settings can facilitate long-term evaluations of P management programs that allow the implementation of BMPs. Similarly, the evaluation of new technologies, including materials, precision-smart practices, and the integration of modeling strategies with field-scale studies suggest a promising approach to engaging stakeholders in achieving higher BMP efficiencies. This systematic review highlights current BMP strategies that have demonstrated high P load reduction efficiency. There is a need for continued research that simultaneously assesses strategies to reduce P pollution before it forms and employs a multidimensional approach to P management. This approach should integrate multiple successful BMPs through field and modeling strategies. Keywords: , Agriculture, Best Management Practices (BMP), Florida, Non-point source pollutants, Phosphorus loads.

Increased levels of forestry best management practices reduce sediment delivery from Piedmont and Upper Coastal Plain clearcut harvests and access features, southeastern states, USA

A land use history of intensive agricultural practices, combined with highly erodible soils, have made erosion control and water quality protection essential for forest management in the Piedmont and Upper Coastal Plain of the southeastern U.S. Forestry Best Management Practices (BMPs), which include sustainable harvesting guidelines approved by state forestry agencies, are utilized in these regions to mitigate potential impacts to water quality. In this study, the relationship between three levels of BMP implementation ranging from < 80% (BMP–), 80–90% (BMP-standard) and > 90% (BMP+ ), estimated erosion (Mg ha-1 yr-1) based on the USLE-Forest empirical model, and sediment delivery ratios was explored to better understand impacts to forest water quality. Erosion and sediment delivery estimates by BMP level were multiplied by estimates of area occupied by each operational feature (e.g., decks, harvest areas only, haul roads, skid trails, stream crossings) and annual clearcut timberland (ha-1 yr-1) provided by the U.S. Forest Service FIA Program. The overall goal was to estimate total annual masses of erosion and sediment (Mg yr-1) by BMP level for twelve states with timberland located in either the Piedmont or Upper Coastal Plain. Forty-four clearcut harvest sites were assessed in the region. Over 431,000 ha yr−1 are clearcut in the Piedmont and Upper Coastal Plain, which represents approximately 2% of total forestland area in the regions. The BMP+ (0.5 Mg ha−1 yr−1) and BMP-standard (0.9 Mg ha−1 yr−1) levels of implementation provide considerably more water quality protection than BMP– (2.0 Mg ha−1 yr−1) based on average sedimentation rates for the overall harvest. Overall sediment removal efficiencies at the BMP-standard (54%) and BMP+ (74%) levels indicate that current BMPs are highly effective at mitigating potential sediment delivery from clearcut operations in the regions. The BMP+ level most efficiently limited potential sediment from skid trails (80%), harvest areas (75%), and haul roads (61%), which were also the primary contributors of sediment. Over 93% of clearcut harvests sampled were classified as either BMP-standard or BMP+. These findings indicate that current BMPs are implemented at high levels across the southeastern Piedmont and Upper Coastal Plain, and that BMP effectiveness has improved substantially over time in the regions.

Sedation and paralytic use in open abdomen patients—results from the EAST SLEEP Survey

BackgroundPatients with an open abdomen after trauma or emergency surgery may benefit from reduced sedation and chemical paralysis. We studied the effect of attending surgeon experience on sedation depth and paralytic use, as well as enteral nutrition and time between laparotomies. MethodsWe performed an institutional review board-approved survey (Sedation Level after Emergent ExLap without Primary Fascial Closure) of the senior and active Eastern Association for the Surgery of Trauma membership using Qualtrics (Qualtrics, Inc, Provo, UT). We obtained 393/1,655 responses (23.7%). Spearman’s rho was used for ordinal data, and multivariate logistic regression was used to adjust for trauma center level and presence of trainees in the relationship between surgeon experience and use of deep sedation. ResultsSurgeon experience was associated with deep sedation (Richmond Agitation and Sedation Score ≤–3, P = .001) and chemical paralysis (P = .001). Surgeon experience was associated with less concern about delirium and more concern for evisceration as the reason for sedation depth (P = .001) and for paralysis (P = .001). Using multivariate logistic regression, surgeon experience was associated with deep sedation (odds ratio 3.6 [95% confidence interval 1.3, 10.4], P = .017 for ≥20 years; odds ratio 3.5 [95% confidence interval 1.1, 10.4], P = .025 for 15–20 years). Trauma center level was also significant (odds ratio 7.2 for Richmond Agitation and Sedation Score ≤–3 [95% confidence interval 1.7, 31.0], P = .008 for level III/IV versus level I/II). Increased surgeon experience was associated with delay of commencement of enteral feeds until return of bowel function (P = .013). Few respondents indicated willingness to extubate or mobilize open abdomen patients. Experienced surgeons were likely to wait for a defined time rather than for normalization of resuscitation markers to perform the first takeback laparotomy (P = .047) and waited longer between subsequent laparotomies (P = .004). ConclusionThere were significant variations in practice among respondents based on the length of time since their last residency or fellowship, including variations that deviate from current best practice for management of patients with an open abdomen.

Assessing effectiveness of long-term forestry best management practices on stream water quality at a basin scale-a case study in Southern USA.

Forestry best management practices (BMPs) have proven to be very effective in protecting adjacent stream water quality at the plot scale. However, our knowledge is incomplete about the effectiveness of forestry BMPs in large watersheds where industrial forests are intensively managed. In this study, we compared long-term concentrations and loadings of total suspended solids (TSS), nitrate/nitrite nitrogen (NO3NO2-N), total Kjeldahl nitrogen (TKN), and total phosphorus (TP) before (1978-1988) and after extensive implementation of forestry BMPs (1994-2008) at the outlet of a 5000-km2 riverbasin that is predominately covered by intensively managed pine forests in Central Louisiana, USA. Our study shows that after extensive BMP implementation, both concentrations and loads of TSS in the basin outlet decreased significantly from 34 to 25mgL-1 and from 55,000 to 36,700tyear-1, respectively. However, no significant difference was found in NO3NO2-N, TKN, and TP concentrations between the two periods. The results of nutrient loadings varied, whereby the annual nitrogen loading declined without significant differences (from 1790 to 1600tyear-1 for TKN and from 176 to 158tyear-1 for NO3NO2-N, respectively) but the annual TP loading increased significantly (from 152 to 192tyear-1) after BMP implementation. Theincrease in TP loading is likely due to an increased application of phosphorus fertilizer, which offset BMPs' effects especially during high-flow conditions. These results strongly suggest that current forestry BMPs in this region are effective in reducing sediment loading, but current BMP guidelines for fertilization and nutrient management need to be reviewed and improved.

The effectiveness and resilience of phosphorus management practices in the Lake Simcoe watershed, Ontario, Canada

AbstractUncertainty surrounding future climate makes it difficult to have confidence that current nutrient management strategies will remain effective. This study used monitoring and modeling to assess current effectiveness (% phosphorus reduction) and resilience (defined as continued effectiveness under a changing climate) of best management practices (BMPs) within five catchments of the Lake Simcoe watershed, Ontario. The Integrated Catchment Phosphorus model (INCA‐P) was used, and monitoring data were used to calibrate and validate a series of management scenarios. To assess current BMP effectiveness, models were run over a baseline period 1985–2014 with and without management scenarios. Climate simulations were run (2070–2099), and BMP resilience was calculated as the percent change in effectiveness between the baseline and future period. Results demonstrated that livestock removal from water courses was the most effective BMP, while manure storage adjustments were the least. Effectiveness varied between catchments, influenced by the dominant hydrological and nutrient transport pathways. Resilience of individual BMPs was associated with catchment sensitivity to climate change. BMPs were most resilient in catchments with high soil water storage capacity and small projected changes in frozen‐water availability and in soil moisture deficits. Conversely, BMPs were less resilient in catchments with larger changes in spring melt magnitude and in overland flow proportions. Results indicated that BMPs implemented are not always those most suited to catchment flow pathways, and a more site‐specific approach would enhance prospects for maintaining P reduction targets. Furthermore, BMP resilience to climate change can be predicted from catchment physical properties and present‐day hydrochemical sensitivity to climate forcing.

Current best practice in the management of hypertensive disorders in pregnancy.

Preeclampsia is a potentially serious complication of pregnancy with increasing significance worldwide. Preeclampsia is the cause of 9%–26% of global maternal mortality and a significant proportion of preterm delivery, and maternal and neonatal morbidity. Incidence is increasing in keeping with the increase in obesity, maternal age, and women with medical comorbidities entering pregnancy. Recent developments in the understanding of the pathophysiology of preeclampsia have opened new avenues for prevention, screening, and management of this condition. In addition it is known that preeclampsia is a risk factor for cardiovascular disease in both the mother and the child and presents an opportunity for early preventative measures. New tools for early detection, prevention, and management of preeclampsia have the potential to revolutionize practice in the coming years. This review presents the current best practice in diagnosis and management of preeclampsia and the hypertensive disorders of pregnancy.

Assessment of orchard N losses to groundwater with a vadose zone monitoring network

A 2-year study was conducted to explore the impact of current and alternative best management practices (BMPs) of irrigation and fertigation on nitrate (NO3−) leaching below the root zone. Using a fully randomized complete block design, three fertigation strategies were compared: current BMP with and without accounting for NO3−-N in irrigation-water, and a high frequency fertigation treatment with low-N concentration applications. Temporal changes in water content, pore water NO3− concentrations and soil water potential were monitored within and below the root zone to a soil depth of 3m at eight sites in an almond and a pistachio orchard. NO3− concentrations below the root zone ranged from <1mgL−1 to more than 2400mgL−1 (almond), and up to 11,000 (pistachio) mgL−1, with mean concentrations of 326 and 4631mgL−1, respectively. Within the fertigation cycle, fertilizer injection at the end of an irrigation event generally resulted in lower NO3− losses below the root zone compared with fertilizer injection midway through the irrigation. Pre-bloom and post-harvest flood irrigation in the almond orchard caused deep soil wetting and flushing of NO3− below the root zone, threatening groundwater quality. Statistical analysis using principal component analysis, Chi-squared Automatic Interaction Detector and the Artificial Neural Network showed that most of the deep soil NO3− concentration variability could not be explained by irrigation duration, fertigation timing or local variations in soil physical characteristics. However, mass balance estimates for water and N indicated the annual orchard average N loss could be estimated based on eight monitoring sites in spite of the inherent spatial variations in soil properties and the spatiotemporal variations in water and NO3− applications. The study indicated that reduction of N losses at the orchard scale would require alternative fertigation and irrigation practices, including better control of fertigation amounts and irrigation duration.

Estimating Costs and Effectiveness of Upgrades in Forestry Best Management Practices for Stream Crossings

Forestry Best Management Practices (BMPs) are used for protection of water quality at forest stream crossings, yet effects and costs for gradients of BMPs are not well documented. We evaluated forty-two truck road and skid trail stream crossings using three surrogates of BMP adequacy: (1) potential erosion rates for stream crossing approaches; (2) adequacy of stream crossing BMPs; and (3) overall BMP rating (BMP−, BMP-standard, and BMP+). Subsequently, BMP upgrades were recommended for enhancing BMP− or BMP-standard stream crossings. Costs for BMP upgrades were estimated using an existing road and skid trail cost method. The majority of truck road stream crossings were culverts, while skid trail stream crossings were primarily portable bridges. Potential erosion estimates, BMP audit scores, and BMP ratings all indicated that skid crossings have lower BMP implementation than truck road crossings. BMP improvements commonly identified for skid trail and truck crossings included addition of cover and water control structures. Improved BMPs at skid trail crossings were less expensive than those at truck road crossings. Current BMP guidelines provide economical and effective techniques for reducing erosion, and BMP upgrades have the potential to reduce erosion rates to similar levels found in undisturbed forests.

Suburban watershed nitrogen retention: Estimating the effectiveness of stormwater management structures

Excess nitrogen (N) is a primary driver of freshwater and coastal eutrophication globally, and urban stormwater is a rapidly growing source of N pollution. Stormwater best management practices (BMPs) are used widely to remove excess N from runoff in urban and suburban areas, and are expected to perform under a wide variety of environmental conditions. Yet the capacity of BMPs to retain excess N varies; and both the variation and the drivers thereof are largely unknown, hindering the ability of water resource managers to meet water quality targets in a cost-effective way. Here, we use structured expert judgment (SEJ), a performance-weighted method of expert elicitation, to quantify the uncertainty in BMP performance under a range of site-specific environmental conditions and to estimate the extent to which key environmental factors influence variation in BMP performance. We hypothesized that rain event frequency and magnitude, BMP type and size, and physiographic province would significantly influence the experts’ estimates of N retention by BMPs common to suburban Piedmont and Coastal Plain watersheds of the Chesapeake Bay region. Expert knowledge indicated wide uncertainty in BMP performance, with N removal efficiencies ranging from 40%. Experts believed that the amount of rain was the primary identifiable source of variability in BMP efficiency, which is relevant given climate projections of more frequent heavy rain events in the mid-Atlantic. To assess the extent to which those projected changes might alter N export from suburban BMPs and watersheds, we combined downscaled estimates of rainfall with distributions of N loads for different-sized rain events derived from our elicitation. The model predicted higher and more variable N loads under a projected future climate regime, suggesting that current BMP regulations for reducing nutrients may be inadequate in the future.

Responses of stream benthic macroinvertebrate communities to timber harvesting: Best management practices in a low-gradient watershed in Central Louisiana, USA

AbstractForests are the most dominant land-use type in Louisiana, and timber harvesting is the most economically important of the state’s agricultural commodities. Louisiana has developed voluntary best management practices (BMPs) to minimize negative effects of forest operations on stream water quality, but little is known about how aquatic communities inhabiting low-gradient, headwater streams respond to timber harvesting, and if the current BMPs are effective in protecting community structure and function. In 2005, we initiated a multidisciplinary study in the Flat Creek watershed in central Louisiana to discern the effects of timber harvesting activities, with and without BMP implementation, on benthic aquatic macroinvertebrates. During fall 2007, trees were removed adjacent to two headwater streams in the watershed, and benthic macroinvertebrate samples were subsequently collected at seven stream locations seven times between 2006 and 2009. Our objectives were to describe the community structure of benthic macroinvertebrates in low-order, low-gradient streams, how macroinvertebrate communities responded to timber harvest operations, and whether significant changes in community structure were evident under different levels of BMP implementation. The community structure was predominantly generalist taxa including chironomids, sphaeriid bivalves and asellid isopods. Analyses of variance demonstrated significant increases in bivalve abundance and decreases in the abundance of malacostracan and shredding taxa at most of the sampling sites downstream of BMP-implemented harvest locations in the spring. Additionally, significant increases in bivalves were also found at two sites during late summer. Our results suggest that timber harvesting activities, regardless of BMP implementation, had limited shortterm impacts on resident macroinvertebrates in these lowgradient, subtropical streams. Continued monitoring at the study sites will allow us to better understand the longterm effects of timber harvesting in these stream systems, particularly the resilience of stream biota to harvestingrelated stream conditions.

Best Management Practices for Low-Volume Forest Roads in the Piedmont Region

Forest roads provide important access for forest management activities, yet those roads, skid trails, and stream crossings have repeatedly been reported as major sources of sediment. The passage of the Federal Water Pollution Control Act of 1972 focused considerable research on the development of forestry best management practices (BMPs) for reducing sediment input from forest roads. Recent litigation in the U.S. Supreme Court has reemphasized the importance of enhancing BMPs for forest roads. This paper synthesizes and interprets two decades of applied research on BMPs for low-volume forest roads, with emphasis on research conducted on forest operations in the Virginia Piedmont region. BMP interpretations include (a) current BMP status for forest roads, skid trails, and stream crossings; (b) advantages of preharvest planning; (c) forest road design; (d) forest road closure; (e) recommended BMPs for legacy roads; (f) guidelines for minimizing area of forest roads; (g) deck and skid trail rehabilitation; (h) closure of bladed and overland skid trails; (i) alternative harvest systems; (j) permanent and temporary closure of the stream crossing; (k) selection of stream crossing types; and (l) recommendations for streamside management zones. Major conclusions from this synthesis are that forest roads, skid trails, and stream crossings continue to be ranked as problem sources of sediment, but forestry BMPs can be used to reduce sediment inputs from such areas. Problems with road and skid trails can generally be attributed to poor planning and insufficient quantity or quality of BMPs.

Effects of Timber Harvesting with Best Management Practices on Ecosystem Metabolism of a Low Gradient Stream on the United States Gulf Coastal Plain

Stream metabolism can be used as a measure of freshwater ecosystem health because of its responsiveness to natural and anthropogenic changes. In this study, we used stream metabolic rates to test for the effects of a timber harvest with Louisiana’s current best management practices (BMPs). The study was conducted from 2006 to 2010 in a loblolly pine (Pinus taeda) stand in north-central Louisiana, USA, 45 ha of which was clear cut harvested in the summer of 2007. Dissolved oxygen (DO), water temperature, and stream depth were recorded at a site upstream (serving as a reference) and a site downstream of the harvested area. Using diurnal DO change and an open-system, single-station method at each site, we quantified rates of net ecosystem productivity (NEP), gross primary productivity (GPP), community respiration (CR), and the GPP/CR ratio. The system was predominately heterotrophic, with a GPP/CR ratio of less than one for 82% of the time at the upstream site. No calculated metabolic rate was significantly changed by the timber harvest (two-way ANOVA with interaction; p &lt; 0.001). Overall, the results suggest that timber harvests of similar intensity with Louisiana’s current BMPs may not significantly impact stream biological conditions.

Management of Hyperglycemia in Noncritically Ill Hospitalized Patients

As many as 40% of hospitalized medical and surgical patients have hyperglycemia (defined as blood glucose ≥140 mg/dL), including patients with known diabetes, those with previously undiagnosed diabetes, and those with transient “stress hyperglycemia” resulting from acute illness. In noncritically ill hospitalized patients, hyperglycemia is associated with longer length of hospital stay, higher incidence of infections, more disability after discharge, and mortality. The Endocrine Society in partnership with other organizations (including the Society of Hospital Medicine) has published a new clinical practice guideline that summarizes current best practice for management of hyperglycemia …

Opinions of Forest Managers, Loggers, and Forest Landowners in North Carolina regarding Biomass Harvesting Guidelines

Woody biomass has been identified as an important renewable energy source capable of offsetting fossil fuel use. The potential environmental impacts associated with using woody biomass for energy have spurred development of biomass harvesting guidelines (BHGs) in some states and proposals for BHGs in others. We examined stakeholder opinions about BHGs through 60 semistructured interviews with key participants in the North Carolina, USA, forest business sector—forest managers, loggers, and forest landowners. Respondents generally opposed requirements for new BHGs because guidelines added to best management practices (BMPs). Most respondents believed North Carolina’s current BMPs have been successful and sufficient in protecting forest health; biomass harvesting is only an additional component to harvesting with little or no modification to conventional harvesting operations; and scientific research does not support claims that biomass harvesting negatively impacts soil, water quality, timber productivity, or wildlife habitat. Some respondents recognized possible benefits from the implementation of BHGs, which included reduced site preparation costs and increases in proactive forest management, soil quality, and wildlife habitat. Some scientific literature suggests that biomass harvests may have adverse site impacts that require amelioration. The results suggest BHGs will need to be better justified for practitioners based on the scientific literature or linked to demand from new profitable uses or subsidies to offset stakeholder perceptions that they create unnecessary costs.

Surgical options for reconstruction of the extensor mechanism of the knee after limb-sparing sarcoma surgery: an evidence-based review

Limb-salvage surgery remains current best practice for management of soft tissue and bony sarcomas about the knee, with the range of reconstructive options all providing reassuring levels of long-term survival and function. There is no current consensus as to the best method of reconstruction of the extensor mechanism of the knee (quadriceps-patellar complex), with a wide variety of options proposed. The techniques described in the literature include prosthetic reconstruction, soft tissue reconstruction (comprising reconstruction with pedicled muscle flaps or autogenous tendon grafts), and bony reconstructions (including vascularised fibula flaps). An evidence-based literature review assessing the available reconstructive options has not been undertaken. A thorough literature review was undertaken, evaluating the current evidence regarding the use of surgical techniques for reconstruction of the extensor mechanism of the knee following oncologic resection. The literature identified was critically evaluated based on the current Oxford Centre for Evidence-Based Medicine definitions. There are no randomised trials in the literature in this setting, and thus no level 1 or level 2A studies to support any given technique. As such, there are many favourable techniques for reconstruction that have been well described and have some evidence base to support their use. Overall, there is a trend towards improved outcomes with biological reconstructive options, with lower reported levels of failure, infection and amputation. Despite this, no single technique has adequately proven to be superior. Given the proposed difficulties in randomising patients, good evidence for the optimal reconstructive choices may be hard to establish.

Historical Changes in Water Quality at German Branch in the Choptank River Basin

Many management strategies to improve the health of Chesapeake Bay focus on reducing losses of sediments and nutrients from agricultural land. Plot-scale studies have suggested that Best Management Practices (BMPs) reduce these losses, and natural resource managers have since supported implementation of a variety of BMPs on farms in the Chesapeake Bay watershed over the last two decades. As a test of the efficiency of these BMPs at the watershed scale, all farms within German Branch watershed had BMPs implemented in the early 1990s. Using water quality from two past monitoring programs (i.e., in 1986 and 1991–1995) and current water quality monitoring (i.e., collected 2003–2006), we detected a 28% decrease in baseflow P concentrations a decade after BMP implementation. There were no significant changes in nitrate or total nitrogen concentrations between BMP implementation and the most recent sampling. However, the significant rate of increase (∼0.08 mg N L−1 year−1) from 1986 to the 1990s did not continue to 2003–2006 baseflow conditions, which suggests that BMPs may have suppressed the rate of increase in nitrogen observed earlier in German. These data suggest that other management practices that increase agricultural N losses and natural processes that attenuate N losses at the watershed scale may obscure significant N reductions by current BMPs in the watershed.

Stubborn facts: Still no evidence that the System of Rice Intensification out-yields best management practices (BMPs) beyond Madagascar

For more than a decade, the System of Rice Intensification (SRI) has been vigorously promoted as a method for substantially improving the yield performance of conventional rice agriculture through a set of synergistic management principles that are purported to be accessible to poorer farmers and better for the environment. To evaluate the empirical basis for claims that SRI increases the yield ceiling for rice (i.e. the physiological yield potential), McDonald et al. [McDonald, A.J., Hobbs, P.R., Riha, S.J., 2006. Does the System of Rice Intensification outperform conventional best management? A synopsis of the empirical record. Field Crops Res. 96, 31–36] conducted a retrospective analysis of field experiments that had side-by-side yield comparisons of SRI and current best management practices (BMPs). In addition to studies from Madagascar where SRI was first conceived, 35 site-years of data were compiled from nine different Asian countries. Aside from one set of experiments in Madagascar where SRI more than doubled rice grain productivity with respect to BMPs (140–245% increase), we found no evidence of a yield advantage of this magnitude elsewhere. In 24 of 35 site-years, SRI yields were less than those attained with BMPs and in no case did the SRI yield exceed BMPs by more than 22%. Uphoff et al. [Uphoff, N., Kassam, A., Stoop, W., 2008. A critical assessment of a desk study comparing crop production systems: the example of the ‘system of rice intensification’ vs. ‘best management practice.’ Field Crop Res. 108 (1), 109–114] contest these findings with criticisms of our methodology and, more importantly, contend that key evidence demonstrating yield advantages for SRI over BMPs was not considered in our analysis. The assertion of key evidence that is at odds with our conclusions is false, as we detail in this response. Beyond Madagascar, there is still no empirical evidence that SRI has a unique yield advantage over current BMPs for rice. Then and now, our original article [McDonald, A.J., Hobbs, P.R., Riha, S.J., 2006. Does the System of Rice Intensification outperform conventional best management? A synopsis of the empirical record. Field Crops Res. 96, 31–36] accurately characterizes the global experience with the System of Rice Intensification.

A modeling approach to evaluate the impacts of water quality management plans implemented in a watershed in Texas

Several best management practices (BMPs) have been implemented through Water Quality Management Plans (WQMPs) in the West Fork Watershed of Trinity River Basin in Texas, USA, where nonpoint source pollution is a serious concern. Major sources of pollution are sediment erosion and nutrients. The objective of this study was to evaluate the long-term impact of implementation of WQMPs on nonpoint source pollution at the farm level and watershed level using a modeling approach. The Soil and Water Assessment Tool watershed model was applied to quantify the impacts of implementing WQMPs on sediment and nutrients. A pre-BMP scenario representing conditions of the watershed prior to the implementation of WQMPs, and a post-BMP scenario representing the conditions of the watershed after implementation of WQMPs were simulated to estimate the reductions in nonpoint source pollution due to WQMP implementation. The results are presented as percentage reductions in sediment and nutrient loadings, at the farm level and at two locations within the watershed. The results revealed that (a) the benefits of the WQMPs were greater (up to 99%) at the farm level and (b) the benefits due to WQMPs were 1–2% at the watershed level. Watershed level benefits are tangible as the WQMP implementation area is very small compared to the watershed area. An additional scenario was evaluated to show the possible impacts of expanding the current BMP effort on load reductions. This study showed that a modeling approach can be used to estimate the impacts of water quality management programs in large watersheds.

Enterocolitis complicating Hirschsprung’s disease

Enterocolitis remains a relatively common complication of Hirschsprung's disease with significant morbidity and mortality. The etiology of Hirschsprung's enterocolitis (HEC) is multifactorial and remains poorly understood. Preventative measures and better treatment modalities will evolve out of a better understanding of the underlying pathophysiology. Prompt recognition of HEC allows early intervention and a potential reduction in disease severity and mortality. This review of HEC describes the epidemiology, clinical and pathological features and current best practice in management. Some of the areas of research into etiology and treatment are discussed.