Agricultural Best Management Practices Research Articles

Spatial Variation in Agricultural BMPs and Relationships with Nutrient Yields Across New York State Watersheds

Agricultural nutrients nitrogen and phosphorus can subsequently be transported to waterways and are often managed through the adoption of best management practices (BMPs). However, we have a poor understanding of how the use of BMPs varies spatially and how BMP adoption might be related to nutrient yields in surface waters. To address this, we performed a survey of agricultural landowners across New York State and compared this with estimates of annual incremental nitrogen and phosphorus yields of agricultural origin from the Spatially Referenced Regressions On Watershed attributes (SPARROW) model. Using these socio-behavioral data and SPARROW predictions, we perform colocation analysis to identify areas where watersheds with high nutrient yield from agriculture are collocated with non-use of agricultural BMPs. This colocation analysis offers a novel methodology for identifying areas where monitoring of waterways and promotion of best management practices could be targeted to achieve the greatest benefits.

Experiential Learning And Feedback Of Agricultural Graduates Towards RAWEP And AELP

The basic core of agricultural education institute consists of three intra-curricular components like classroom teaching, experiential learning through supervised experiences and leadership activities to the students to gain knowledge and skill in their academic carrier. Experiential learning is fulfilled through RAWEP and AELP. Agricultural Graduates of B.Sc (Ag.) are exposed to learn the knowledge and skills by staying with contact (host) farmers in the village. Along with RAWEP, students were engaged in running of enterprise and gain self employment and self-confidence by establishing their own enterprise with the principle of learning while doing. Present study taken 90 B.Sc (Ag) graduates from Southern Telangana Zone of the state and reported that helps to improve diagnostic skills (98.88%), understanding various management practices in the farm (91.11%), gain the knowledge and skills by conducting the extension activities (92.22%), developing skills in farm budgeting (96.67%), whereas AELP develops technical competency on various best management practices in agriculture (93.33%).

Quantification of agricultural best management practices impacts on sediment and phosphorous export in a small catchment in southeastern Sweden

Agricultural activities contribute to water pollution through sediments and nutrient export, negatively affecting water quality and aquatic ecosystems. However, implementing best management practices (BMPs) could help control sediments and nutrient losses from agricultural catchments. This study used the Soil Water Assessment Tool (SWAT) model to assess the effectiveness of four BMPs in reducing sediment and phosphorus export in a small agricultural catchment (33 km2) in southeastern Sweden. The SWAT model was first evaluated for its ability to simulate streamflow, sediment load, and total phosphorous load from 2005 to 2020. Then, the calibrated parameters were used to simulate the agricultural BMP scenarios by modifying relevant parameters. The model performed satisfactorily during calibration and validation for streamflow (NSE = 0.80/0.84), sediment load (NSE = 0.67/0.69), and total phosphorous load (NSE = 0.61/0.62), indicating its suitability for this study. The results demonstrate varying effects of BMP implementation on sediment and phosphorus (soluble and total) export, with no significant change in streamflow. Filter strips were highly effective in reducing sediment (−32%), soluble phosphorus (−67%), and total phosphorous (−66%) exports, followed by sedimentation ponds with −35%, −36%, and −50% reductions, respectively. Grassed waterways and no-tillage were less impactful on pollutant reduction, with grassed waterways showing a slight increase (+4%) in soluble phosphorus and no-tillage having a minimal effect on sediment (−1.3%) and total phosphorus (−0.2%) export. These findings contribute to the ongoing efforts to mitigate sediment and nutrient pollution in Swedish agricultural areas, thereby supporting the conservation and restoration of aquatic ecosystems, and enhancing sustainable agricultural practices.

Evaluation of Agricultural BMPs’ Impact on Water Quality and Crop Production Using SWAT+ Model

Subsurface (or tile) drainage improves land productivity by enhancing soil aeration and preventing water-logged conditions. However, the continuous expansion of drained agricultural lands and reliance on synthetic fertilizer in the Midwestern United States have increasingly facilitated nitrate transport from agricultural fields to surface water bodies. Hence, there is a need to implement various agricultural best management practices (BMPs) in order to reduce the adverse water quality impacts resulting from excess nitrate, such as eutrophication and the formation of hypoxic zones. In this study, we used a SWAT+ model to assess the overall impacts on the riverine nitrate load and crop yield in the corn–soybean cropping system based on a combination of different management practices. The corn and soybean yields simulated with the model were found to be in good agreement with the observed yields for both the calibration and validation periods. The long-term simulation over a period of 30 years showed a reduction in the nitrate load of up to 32% without impacting the crop yield. The model results suggest that by reducing the current N application rate by 20% and using a 40:60 split between spring pre-plant and side-dressing N applications combined with cereal rye as a cover crop in corn–soybean rotation, one can potentially reduce nitrate losses without impacting crop yields. This study will help researchers, stakeholders, and farmers to explore and adopt alternative management practices beneficial for offsetting the environmental impacts of agricultural productions on the watershed scale.

Fertilizer management and incorporation of legumes on performance of maize (Zea mays L.) in western hills of Nepal

One of the main obstacles limiting the production of the improved potential crops in Nepal is the low and diminishing productivity of soils. There is a need to take urgent measures to establish good agricultural management practices that check the rate of deterioration and build up soil fertility, In this regard, an experiment was conducted to determine the rotational effect of legumes and nutrient management on performance of maize at Horticulture Research Station (HRS), Dailekh, Nepal during 2018 and 2019. The experiment was laid out in split plot design which consists 4 cropping systems: fallow–maize, lentil-maize, chickpea–maize and field pea–maize as main plot and 4 combinations of manures and fertilizers: control, recommended dose of fertilizer (RDF), Farmyard Manure (FYM), and RDF (50%) + FYM (50%) as sub-plot which were replicated three times. The highest grain yield of 1598 kg ha−1 was obtained from field pea followed by 1388 kg ha−1 in chickpea and 1151 kg/ha in lentil and significantly higher grain yield of 1707 kg ha−1 was obtained from the application of FYM alone. Results obtained showed that yield of maize was increased by 28.8%, 13.5% and 12.7% by use of legumes: chickpea, lentil and field pea, respectively as rotational crop over fallow-maize cropping system. Similarly, the data revealed that significantly higher growth characters of maize were recorded from application of RDF followed by combination of RDF plus FYM. The grain yield of maize was increased by 68.4%, 38.5% and 16.4% from the application of RDF, RDF plus FYM and FYM alone, respectively over control plots. The incorporation of grain legumes like chickpea, lentil and field pea can be effective as rotational crop with maize and application of organic and inorganic fertilizer increase productivity of legumes as well as maize which make viable alternative to agricultural sustainability.

Integrated Agricultural Practices and Engineering Technologies Enhance Synergies of Food-Energy-Water Systems in Corn Belt Watersheds.

Interconnected food, energy, water systems (FEWS) require systems level understanding to design efficient and effective management strategies and policies that address potentially competing challenges of production and environmental quality. Adoption of agricultural best management practices (BMPs) can reduce nonpoint source phosphorus (P) loads, but there are also opportunities to recover P from point sources, which could also reduce demand for mineral P fertilizer derived from declining geologic reserves. Here, we apply the Integrated Technology-Environment-Economics Model to investigate the consequences of watershed-scale portfolios of agricultural BMPs and environmental and biological technologies (EBTs) for co-benefits of FEWS in Corn Belt watersheds. Via a pilot study with a representative agro-industrial watershed with high P and nitrogen discharge, we show achieving the nutrient reduction goals in the watershed; BMP-only portfolios require extensive and costly land-use change (19% of agricultural land) to perennial energy grasses, while portfolios combining BMPs and EBTs can improve water quality while recovering P from corn biorefineries and wastewater streams with only 4% agricultural land-use change. The potential amount of P recovered from EBTs is estimated as 2 times as much as the agronomic P requirement in the watershed, showing the promise of the P circular economy. These findings inform solution development based on the combination of agricultural BMPs and EBTs for the cobenefits of FEWS in Corn Belt watersheds.

Analyzing the impact of agricultural BMPs on stream nutrient load and biotic health in the Susquehanna-Chemung basin of New York

Despite the widespread use of agricultural best management practices (BMPs) to reduce watershed scale nutrient loads, there remain few studies that use directly observed data – instead of models – to evaluate BMP effectiveness at the watershed scale. In this study, we make use of extensive ambient water quality data, stream biotic health data, and BMP implementation data within the New York State portion of the Chesapeake Bay watershed to assess the role of BMPs on reducing nutrient loads and modifying biotic health in major rivers. The specific BMPs considered were riparian buffers and nutrient management planning. A simple mass balance approach was used to evaluate the role of wastewater treatment plant nutrient reductions, agricultural land use changes, and these two agricultural BMPs in matching observed downward trends in nutrient load. In the Eastern nontidal network (NTN) catchment – where BMPs have been more widely reported – the mass balance model suggested a small but discernible contribution of BMPs in matching the observed downward trend in total phosphorus. Contrastingly, BMP implementations did not show clear contributions towards total nitrogen reductions in the Eastern NTN catchment nor for the total nitrogen and phosphorus in the Western NTN catchment, where BMP implementation data are more limited. Assessment of the relationship between stream biotic health and BMP implementation using regression models found limited connection between extent of BMP implementation and biotic health. In this case, however, spatiotemporal mismatches between the datasets and the relatively stable biotic health, typically of moderate to good quality even before BMP implementation, may reflect the need for better monitoring design to assess BMP effects at the subwatershed scale. Additional studies, perhaps using citizen scientists, may be able to provide more suitable data within the existing frameworks of the long-term surveys. Given the preponderance of studies that rely only on modeling to understand nutrient loading reductions achieved by implementation of BMPs, it is essential to continue to collect empirical data to meaningfully evaluate whether there are actual measurable changes due to BMPs.

Impacts of Best Management Practices on Runoff, Soil Loss, and Sediment Yield in the Megech Watershed, Ethiopia

This study evaluated the best management practices on how to manage soil losses from catchment and reduce sediment load into a dam reservoir. This study aimed to evaluate the relationship of runoff, soil loss, and sediment yield with best management practice (BMP) scenarios in the GeoWEPP environment for the selected three micro-watersheds (hot spot areas) in the Megech watershed, upper Blue Nile Basin. The impacts of four agricultural BMP scenarios, including forest five years old, corn, soybean; wheat, alfalfa (4 yr) no till; corn, soybean, wheat, alfalfa (4 yr) conservation till; and winter wheat mulch till, on soil loss, runoff, and sediment yield were quantified. The results revealed that soil loss ranges between 41.45–66.11 t/ha/year and sediment yield rates ranges between 36.5–54.8 t/ha/year with the baseline situation (conventional tillage condition) were found to be higher than the tolerable soil loss (10 t/ha/year) in the region. Implementing BMPs on the crop land of the micro-watersheds has positive impacts on all variables’ runoff, soil loss, and sediment yield reductions. Among the implemented BMPs, forests with a five-year perennial (agroforestry) option showed the highest rate of reduction for all runoff, soil loss, and sediment yield, but no cost benefit analysis was included in this study to choose among the BMPs. This study also identified that agricultural BMPs play a great role in reducing runoff, soil loss, and sediment yield in the Megech watershed to minimize on- and off-site impacts. In general, it is important to consider how cost benefit analysis will change throughout project’s implementation among the selected BMP scenarios at the watershed level in the future.

Innovative extension methods lead to spread of agricultural technologies and socio-economic changes – A successful case in Vizianagaram district of Andhra Pradesh

The transfer of useful knowledge on Good agricultural management practices and technologies to the farmers and influencing the policy decisions in India is evident in agricultural Extension and it improved the production of food grains and other agricultural commodities since long time (Sajesh, VK and A Suresh 2016 ). Number of extension techniques, tools, methods, approaches were used by the extension specialists to achieve this targets. As number of extension methodologies and approaches are available at the desk of an extension agent and a combination of extension methods and Innovative extension approaches are always proven in reaching the farming community. Thus leading to the adoption of the technologies and increasing the farm productivity further to socio economic changes in rural society. In India the state department of agriculture is looking after the job of transfer of technology and during 1974 the ICAR established the KVKs at District level to meet the Extension needs of the Department of agriculture and Farmers. As an innovation, the ANGRAU established the DAATTCs (District Agricultural Advisory and transfer of Technology centre) during 1998 at district head quarters with an objective to test the Minikits and pre released technologies, Diagnosis and immediate solution to the farmers by the Scientists, Capacity building of farmers, rural youth and grass root level Extension functionaries and to work in convergence with line Departments to increase the out reach of Agricultural Technologies.

Efficiency assessment of best management practices in sediment reduction by investigating cost-effective tradeoffs

Efficient best management practices (BMPs) must be both economically and technically feasible; however, designing adequate BMP planning by considering the trade-offs between efficacy and cost-effectiveness is considerably challenging for reducing the environmental impact of soil erosion. To comprehensively evaluate and screen the efficacy and cost-effectiveness of six selected BMPs, we integrated the entropy weight method with the calibrated Soil and Water Assessment Tool (SWAT) model. The results demonstrate that (i) the hybrid use of the SWAT model and the entropy weight method can affordably help refine existing and future BMPs. Watershed management plans should be adjusted according to the wet season and critical source areas (CSAs) because all BMPs show differences in the reduction efficiency of soil erosion under different hydrological seasons and CSAs. (ii) Agricultural BMPs and tree planting can effectively control soil erosion; the reduction rankings in the whole watershed were as follows: > 15° returning farmland to forest (32.16%), residue cover tillage (25.06%), strip tillage (16.43%), > 25° returning farmland to forest (8.96%), contour tillage (8.75%), and no tillage (3.18%). The reduction in soil erosion in the wet season was 17.62 times higher than that in the dry season. Priority and reasonable allocation of BMPs in the wet season can be made according to the timely situation and local conditions of the Yanhe River watershed. (iii) The reduction effects of various BMPs on soil erosion in different CSAs are different. The highest comprehensive evaluation index of both efficacy and cost-effectiveness among the six BMPs was scored by residue cover tillage, which we recommend to be popularized in CSAs of the Yanhe River watershed. In areas with different erosion intensities, strip tillage was also highly efficient, that is, the cost was low, and the reduction effect adequate; hence, it is also suitable for large-scale popularization. Some cultivated lands on the > 15° slope can be selectively returned to forest, supplemented by conservation tillage practices such as strip tillage, residue cover tillage, and contour tillage. The introduced framework can be adapted as a suitable tool for selecting cost-effective conservation practices in different regions by managing efficacy and cost trade-offs.

Efficiencies of best management practices in reducing nitrate pollution of the Sebdou River, a semi‐arid Mediterranean agricultural catchment (North Africa)

AbstractA major problem facing the water sector in Algeria is deteriorating water quality, which is strongly influenced by nutrient inputs to agricultural watersheds. To mitigate the effects of agricultural activities and enhance water quality, this study considered the impact of different best management practices (BMPs) in agriculture. The objective of the research was to evaluate the impacts of various agricultural BMPs on nitrate losses in the Sebdou catchment in north‐west Africa using the Soil and Water Assessment Tool (SWAT) model in order to identify and recommend the most appropriate BMP. The study was carried out in two parts: first, the SWAT model was calibrated and validated to simulate discharge and nitrate losses at the outlet of the catchment, and second, the calibrated model was used to assess the effects of BMPs on nitrate losses. The hydrological modelling fitted well with the observed data for the calibration and validation periods (NSE between 0.63 and 0.65 and R2 between 0.80 and 0.92). Nitrate simulation was also satisfactory (NSE = 0.58 and R2 = 0.58), with the average nitrate exports at the outlet varying between 136 and 149 t N year−1. Agricultural tillage practices were the main N input and plant uptake was the main N output. The simulation results of BMP scenarios (contour farming, strip cropping and terracing) showed a significant decrease in nitrate quantity in soil, nitrate yield in surface run‐off and nitrate exports. The maximum reduction was observed from the use of parallel terraces, which reduced nitrate in soil by 17% (41 kg ha−1) and decreased nitrate flux exportation to below 133 t N year−1 (a reduction of about 11%). This study provided useful information for implementation of the most effective agricultural BMPs in the catchment for stakeholders who are interested in soil and water management.

Macroinvertebrate and diatom indicators of baseline conditions for setting targets in agricultural BMP restoration

AbstractRecovery trajectories from restoration projects are poorly understood, making it difficult to set restoration targets as part of project planning. As part of the Delaware River Watershed Initiative (DRWI), we collected baseline environmental and biological data at 84 sites in watersheds where agricultural Best Management Practices (BMPs) are being implemented and forested land is being preserved. The objective of this study was to understand which diatom and macroinvertebrate community measures best characterize biological integrity along a gradient of land cover, habitat measures, and water chemistry in order to later set targets for recovery. To this end, we ran separate Redundancy Analysis (RDA) ordinations in which environmental variables constrained (1) community metrics and (2) relative abundance (taxonomic composition) for macroinvertebrates and diatoms. To understand where along the environmental gradient the sites were represented differently by the respective biotic community measures (community metrics and taxonomic composition), the two constrained ordinations were then compared using Procrustes distance. For macroinvertebrate communities, we saw the most agreement in site characterization between the ordinations at intermediate % agricultural land, but disagreement at both high and low % agricultural land. For diatom communities, we saw the most agreement between the site characterizations at high to intermediate % agricultural land, with increasing disagreement associated with increasing % forested land cover. Use of baseline data to set targets for ecosystem recovery requires consideration of which data are most relevant for the site conditions and what amount of change is feasible based on project implementation and effectiveness. A key aspect of choosing endpoints is when the loss of information inherent to metrics makes them less useful for accurately evaluating ecological integrity, especially when looking to capture incremental changes. Based on our findings, we suggest the use of some community metrics and some key taxa to set targets of recovery in biotic communities in agricultural streams, and that these targets be adjusted to best fit the ecological conditions at a given site within a larger data set. Accordingly, monitoring must take place in the context of regional conditions and must be designed to inform target‐setting.

Basics of Agricultural BMPs in Northern Florida and Southwestern Georgia

Best management practices (BMPs) are cost-efficient processes that improve daily life, from healthcare to food service. Agricultural BMPs aim to reduce water use and improve water quality and soil on farms and ranches as well as to encourage better forestry practices and lawn care. This fact sheet introduces non-farmers to agricultural BMPs.

A framework for automated and spatially-distributed modeling with the Agricultural Policy Environmental eXtender (APEX) model

Agricultural Best Management Practices (BMPs) are popular approaches to reduce nonpoint source (NPS) pollutant losses. Hydrologic models that can simulate impacts of BMPs at the field-scale can help guide the selection of BMPs. Furthermore, high-performance computing techniques have significant potential for scaling spatial simulations and reducing model runtimes. In this study, a parallel modeling framework for the Agricultural Policy Environmental eXtender (APEX) model was developed for large-scale, high-resolution, spatially-distributed model simulations. It provides a tool for conducting BMP evaluations at field-scale with a distributed architecture and automatic model setup of APEX. Sample results demonstrated the capability of the framework for distributed and semi-distributed modeling and illustrated the performance of parallelization. This framework can help provide guidance for decision makers on agricultural BMPs with large-scale water quality assessments and NPS nutrient loading reductions.

Contribution of Factors Affecting Crop Production in Bangladesh: An Empirical Analysis with Production Function Approach

Bangladesh has achieved a tremendous success in food production in last few decades amidst challenges of land degradation, land use changes and climate effect. In spite of the increasing trend of yields of crops, there still remain some challenges to meet the growing needs due to increase in population and loss of land to development activities. This study aims to identify the rate of contributions or economics of factors of crop production in Bangladesh. Cobb-Douglas production function has been applied in this study of crop production using a number of production factors within the broad terms land, labour and capital. Secondary data, representing factors of production, have been selected based on literature reviews so that they can be appropriate for this study. Data of crop production have been considered as dependent variables, whereas, land area coverage for agricultural production, labour employed in agriculture, agricultural household expenditure, fertilizer applied and irrigation coverage have been considered as independent variables. Land and labour is negatively correlated with crop production, whereas, fertilizer is positively correlated. Crop production which shows decreasing return to scale deserves the adoption of new technology and good agricultural management practices.

Evaluating Hydrological Model Performances on Stream Flow Simulation with Agricultural Management

Two comprehensive agricultural watershed-scale hydrological models: Soil and Water Assessment Tool (SWAT), and Annualized Agricultural Non-Point Source Pollution Model (AnnAGNPS), have been widely used for evaluating agricultural Best Management Practice (BMP). In this study, models were developed for the Big Sunflower River Watershed (BSRW) in Mississippi, USA. Both hydrological models were successfully calibrated and validated for predicting monthly stream flow discharges from three USGS gages (Merigold, Sunflower, and Leland) within the BSRW. The model performances were reasonable with R 2 and NSE values range from 0.45 to 0.84 for SWAT, and from 0.34 to 0.66 for AnnAGNPS. Both models predicted lower stream flow discharge with conservation tillage practice as compare to conventional tillage practice BMP evaluated in this study. Overall, results showed that both SWAT and AnnAGNPS models successfully simulated hydrological conditions of the watershed with agricultural BMP, and these models can be useful for making hydrological decisions related to agricultural watershed managements. Keywords: SWAT, AnnAGNPS, tillage, streamflow, hydrology, BMP DOI: 10.7176/JEP/12-3-03 Publication date: January 31 st 2021

Evaluating Hydrological Model Performances on Stream Flow Simulation with Agricultural Management

Two comprehensive agricultural watershed-scale hydrological models: Soil and Water Assessment Tool (SWAT), and Annualized Agricultural Non-Point Source Pollution Model (AnnAGNPS), have been widely used for evaluating agricultural Best Management Practice (BMP). In this study, models were developed for the Big Sunflower River Watershed (BSRW) in Mississippi, USA. Both hydrological models were successfully calibrated and validated for predicting monthly stream flow discharges from three USGS gages (Merigold, Sunflower, and Leland) within the BSRW. The model performances were reasonable with R 2 and NSE values range from 0.45 to 0.84 for SWAT, and from 0.34 to 0.66 for AnnAGNPS. Both models predicted lower stream flow discharge with conservation tillage practice as compare to conventional tillage practice BMP evaluated in this study. Overall, results showed that both SWAT and AnnAGNPS models successfully simulated hydrological conditions of the watershed with agricultural BMP, and these models can be useful for making hydrological decisions related to agricultural watershed managements. Keywords: SWAT, AnnAGNPS, tillage, streamflow, hydrology, BMP DOI: 10.7176/JEES/11-1-03 Publication date: January 31 st 2021

Unlocking maize crop productivity through improved management practices in northern Tanzania

Addressing the problem of low crop productivity and food insecurity can be accelerated through community-centered implementation of good agricultural management practices. This study was conducted in Babati,Northern Tanzania. The objective of the study was to determine nitrogen (N)and phosphorus (P)application requirements for maize,and demonstrate economically viable best bet yield-improving management technologies under three ecozones namely; ‘low elevation low rainfall’, ‘medium elevation high rainfall’ and ‘medium elevation low rainfall’ ecozone. Two sets of trials were conducted: N (0, 45, 90, 120 and 150 kg ha-1) and P (0, 15, 30, 40 kg ha-1) response trials in 16 representative fields in three seasons of 2013/14, 2014/205 and 2015/16 and; demonstrations trials in 8 farmer-selected fields in 2015/16 season. Combined N and P application increased maize yields by 32 to 62% over single nutrient applications.In the medium elevation low rainfall ecozone, 60-86%yield response to nitrogen was observed.Largely, modest applications of 50 kg N ha-1and 20 kg P ha-1resultedin profitable (marginal rate of return (MRR) of 2.4 to 3.0) yield increases of upto 214% over the farmers practice (unfertilized), varying with variety and ecozone. The source of P (DAP or Minjingu Mazao) had little influence on maize productivity except under low altitude low rainfall where Minjingu Mazao is unprofitable. Farmer rankings and agronomic indices showed new maize hybrids namely Meru H513, Meru H515 and SC627 as priority across the ecozones; Mams H913 is suitable mainly in medium elevation low rainfall ecozone. The conclusion is that use of new maize hybrids and appropriate rates of locally available N and P nutrient sources can bridge existing yield gaps and reduce food insecurity. Technologies from community-driven research in development are easily adopted by a large number of farmers and could result in a quick,yet lasting productivity gains.

Integrating watershed and ecosystem service models to assess best management practice efficiency: guidelines for Lake Erie managers and watershed modellers

Lake Erie is the shallowest and most biologically productive system of the Great Lakes, surrounded by large urban, industrial, and agricultural areas. This combination prompted extensive efforts to promote best management practices (BMPs) to mitigate non-point source pollution in Lake Erie’s watershed. Recent technical and conceptual advancements caution that significant variability exists in the BMP efficiency to reduce the severity of runoff and nutrient concentrations due to differences in implementation, the dependence of operational performance on local soil and climatic conditions, storm events and seasonality, and declining performance over time owing to imperfect maintenance. Given the uncertainty surrounding the design and efficiency of BMPs in abating non-point source pollution, our primary objective is to review the critical strengths and potential weaknesses of nine agricultural BMPs promoted for use in the Lake Erie watershed. We examine the capacity of the current generation of watershed process-based models to recreate possible BMP-mediated changes in the water and nutrient cycles. After reviewing modelling strategies (dynamic, external forcing, and empirical) to recreate non-linear watershed responses and feedback loops to BMP efficiency, our study recommends adopting dynamic representations of the interplay among key mechanisms, like soil moisture, water table, nutrient availability, plant uptake, and subsequent growth. Notwithstanding the increased sophistication of complex mathematical models, their learning capacity is usually compromised by the coarse resolution of environmental data and limited empirical knowledge to accurately parameterize environmental properties and partially understood biogeochemical processes. Moreover, BMPs may differentially affect the provisions of an ecosystem (e.g., a BMP may amplify one ecosystem service while dampening another). In this context, we highlight the expression of the value of ecosystem services in monetary and non-monetary terms as a critical information piece when considering trade-offs among costly and diverse policy decisions. Our study also examines the degree to which different types of valuation methods, socioeconomic models, and data have been operationalized in Lake Erie. Consistent with the Integrated Watershed Management framework, we advocate the adoption of a rigorous mass-balance approach to assess the impact of BMPs on nutrient cycles, as well as the integration of the projected environmental improvements with terrestrial ecosystem services, beneficial use impairments, and aquatic ecosystem services. The proposed strategy has the potential to improve the decision-making process by identifying cost-effective management actions and balancing different goods and services provided by the agroecosystems at different time scales.

Identification of critical areas and evaluation of best management practices using SWAT for sustainable watershed management

Identification of critical erosion-prone areas and selection of best management practices (BMPs) for watersheds are necessary to control their degradation by reducing sediment yields. The current research assesses and proposes a combination of potential BMPs for the Baitarani catchment in India using the Soil and Water Assessment Tool (SWAT). After the successful calibration and validation of the SWAT model developed for this catchment, the model was applied to evaluate the efficacy of eight agricultural and structural management practices and their combinations (three scenarios) for controlling sediment yields at watershed and sub-watershed levels as well as to assess the impacts of combined BMPs on water balance components. A combination of BMPs was found more effective in reducing sediment yields than individual BMPs. Comparative evaluation revealed that structural BMPs (0.66–70%) are better than agricultural BMPs (2–7%) in minimizing sediment yields at watershed level. The costly measures like grade and streambank stabilization structures can reduce the sediment yield up to 70% at the watershed level. The modeling results of the impacts of different combinations of BMPs (three scenarios) indicated that if all the eight BMPs are implemented, the reduction of sediment yields is increased by 76% and 80% at sub-watershed and watershed levels, respectively compared to the Base Scenario. Based on funds availability, a suitable combination of BMPs can be adopted by the concerned decision-makers to effectively reduce sediment yields in the study area. Further, the simulation results of BMPs impacts on water balance components revealed that the annual average surface runoff reduces by 4–14% in the three scenarios, while aquifer recharge (6.8–8.7%), baseflow (8–10.5%), and percolation (1.2–3.9%) increase due to implementation of BMPs. Overall, the findings of this study are very useful for ensuring sustainable management of land and other resources at a catchment scale.