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Guo T, Confesor R, Saleh A, King K. Crop growth, hydrology, and water quality dynamics in agricultural fields across the Western Lake Erie Basin: Multi-site verification of the Nutrient Tracking Tool (NTT). THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 726:138485. [PMID: 32315850 DOI: 10.1016/j.scitotenv.2020.138485] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 03/13/2020] [Accepted: 04/04/2020] [Indexed: 06/11/2023]
Abstract
Agricultural field- and watershed-scale water quality models are used to assess the potential impact of management practices to reduce nutrient and sediment exports. However, observed data are often not available to calibrate and verify these models. Three years of data from the U.S. Department of Agriculture-Agricultural Research Service's 12 paired edge-of-field sites in northwest Ohio were used to calibrate and validate the Nutrient Tracking Tool. The goal of this study was to identify a single optimal parameter set for the Nutrient Tracking Tool in simulating annual crop yields, water balance, and nutrient loads across the Western Lake Erie Basin. A multi-site and multi-objective auto-calibration subroutine was developed in R to perform model calibration across the edge-of-field sites. The statistical metrics and evaluation criteria used in comparing the simulated results with the observed data were: Cohen's D Effect Size (Cohen's D < 0.20) and Percent bias (PBIAS ± 10% for crop yields, subsurface (tile) discharge, and surface runoff and ± 25% for dissolved reactive phosphorus (DRP) and nitrate‑nitrogen (nitrate-N) in tile discharge, and DRP, particulate phosphorus, and nitrate-N in surface runoff). In both calibration and validation, the Cohen's D and PBIAS for annual crop yields, tile discharge, surface runoff, DRP, particulate P, and nitrate-N showed that the average simulated results were similar to the average observed values for each variable. The calibrated model simulated well the annual averages of crop yields, flows, and nutrient losses across fields. The tile drainage and phosphorus transport subroutines in the Nutrient Tracking Tool should be further improved to better simulate the dynamics of discharge and phosphorus transport through subsurface drainage. Stakeholders can use the verified model to evaluate the effectiveness of conservation practices in improving the water quality across the Western Lake Erie Basin.
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Affiliation(s)
- Tian Guo
- National Center for Water Quality Research (NCWQR), Heidelberg University, Tiffin, OH 44883, United States of America.
| | - Remegio Confesor
- National Center for Water Quality Research (NCWQR), Heidelberg University, Tiffin, OH 44883, United States of America.
| | - Ali Saleh
- The Texas Institute for Applied Environmental Research (TIAER), Tarleton State University, Stephenville, TX 76402, United States of America.
| | - Kevin King
- Soil Drainage Research Unit, Agricultural Research Service, U.S. Department of Agriculture, Columbus, OH 43210, United States of America.
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Niraula R, Saleh A, Bhattarai N, Bajgain R, Kannan N, Osei E, Gowda P, Neel J, Xiao X, Basara J. Understanding the effects of pasture type and stocking rate on the hydrology of the Southern Great Plains. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 708:134873. [PMID: 31791796 DOI: 10.1016/j.scitotenv.2019.134873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 09/30/2019] [Accepted: 10/05/2019] [Indexed: 06/10/2023]
Abstract
Grassland is one of the major biomes in the United States (US) and the world. In the US, the majority of grasslands are concentrated in the Great Plains and has undergone through significant interventions or management changes over the last few decades. A key economy-driven intervention in the Southern Great Plains (SGP) include the introduction of new forage species and conversion of native grassland to introduced pasture to increase productivity and its nutritive value for improved cattle production. Since water is one of the fundamental resources needed to sustain grassland productivity, it is important to understand how such pasture conversion and prevailing cattle grazing practices affect water balance and biomass production in a given pasture system. In this study, the Nutrient Tracking Tool (NTT) with its core APEX (Agricultural Policy Environmental eXtender) model was used to assess the hydrological impacts of the pasture introduction, i.e., native pasture (little bluestem, Schizachyrium halapense) vs. introduced pasture (old world bluestem, Bothriochloa caucasica), and the stocking rate in the SGP. Monthly evapotranspiration (ET) and biomass estimates from NTT compared well with observed data at two USDA-ARS experimental pastures (native and introduced) near El Reno, Oklahoma, for the years 2015 and 2016. Simulated long-term average annual hydrologic fluxes (i.e., ET, runoff, and groundwater recharge) from the introduced pasture were slightly lower than the observed data but not significantly different than those from the native pasture under the current management conditions. NTT predicted higher water yield (runoff and recharge) and significantly lower ET for the introduced pasture than the native pasture. Results suggest that grazing has the potential to alter the hydrological balance in the SGP. For example, the increase in stocking rate within the carrying capacity of the farm decreases ET and increases runoff and groundwater recharge for both pastures. Comparison of estimated biomass production between native and introduced pastures indicated that introduced pastures are more efficient in using the available water and thus produce a higher forage biomass per unit of water in the SGP. This study highlighted the potential significance of considering hydrological and other biophysical impacts of new forage introduction and stocking rate changes for the sustainable management of grazing and pasture systems in the SGP.
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Affiliation(s)
- R Niraula
- Texas Institute for Applied Environmental Research (TIAER), Tarleton State University, Stephenville, TX, USA.
| | - A Saleh
- Texas Institute for Applied Environmental Research (TIAER), Tarleton State University, Stephenville, TX, USA
| | - N Bhattarai
- School for Environment and Sustainability, University of Michigan, Ann Arbor, MI, USA
| | - R Bajgain
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - N Kannan
- Texas Institute for Applied Environmental Research (TIAER), Tarleton State University, Stephenville, TX, USA
| | - E Osei
- Agricultural and Consumer Sciences, Tarleton State University, Stephenville, TX, USA
| | - P Gowda
- Forage and Livestock Production Research Unit, USDA-ARS Grazinglands Research Laboratory, El Reno, OK, USA
| | - J Neel
- Forage and Livestock Production Research Unit, USDA-ARS Grazinglands Research Laboratory, El Reno, OK, USA
| | - X Xiao
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - J Basara
- School of Meteorology, University of Oklahoma, Norman, OK, USA; School of Civil Engineering and Environmental Science, University of Oklahoma, Norman, OK, USA
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Bolster CH, Baffaut C, Nelson NO, Osmond DL, Cabrera ML, Ramirez-Avila JJ, Sharpley AN, Veith TL, McFarland AMS, Senaviratne AGMMM, Pierzynski GM, Udawatta RP. Development of PLEAD: A Database Containing Event-based Runoff Phosphorus Loadings from Agricultural Fields. JOURNAL OF ENVIRONMENTAL QUALITY 2019; 48:510-517. [PMID: 30951133 DOI: 10.2134/jeq2018.09.0337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Computer models are commonly used for predicting risks of runoff P loss from agricultural fields by enabling simulation of various management practices and climatic scenarios. For P loss models to be useful tools, however, they must accurately predict P loss for a wide range of climatic, physiographic, and land management conditions. A complicating factor in developing and evaluating P loss models is the relative scarcity of available measured field data that adequately capture P losses before and after implementing management practices in a variety of physiographic settings. Here, we describe the development of the P Loss in runoff Events from Agricultural fields Database (PLEAD)-a compilation of event-based, field-scale dissolved and/or total P loss runoff loadings from agricultural fields collected at various research sites located in the US Heartland and southern United States. The database also includes runoff and erosion rates; soil-test P; tillage practices; planting and harvesting rates and practices; fertilizer application rate, method, and timing; manure application rate, method, and timing; and livestock grazing density and timing. In total, >1800 individual runoff events-ranging in duration from 0.4 to 97 h-have been included in the database. Event runoff P losses ranged from <0.05 to 1.3 and 3.0 kg P ha for dissolved and total P, respectively. The data contained in this database have been used in multiple research studies to address important modeling questions relevant to P management planning. We provide these data to encourage additional studies by other researchers. The PLEAD database is available at .
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Vadas PA, Fiorellino NM, Coale FJ, Kratochvil R, Mulkey AS, McGrath JM. Estimating Legacy Soil Phosphorus Impacts on Phosphorus Loss in the Chesapeake Bay Watershed. JOURNAL OF ENVIRONMENTAL QUALITY 2018; 47:480-486. [PMID: 29864190 DOI: 10.2134/jeq2017.12.0481] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Agricultural nutrient management is an issue due to P loss from fields and water quality degradation. This is especially true in watersheds where a history of P application in excess of crop needs has resulted in elevated soil P (legacy P). As practices and policy are implemented in such watersheds to reduce P loss, information is needed on time required to draw down soil P and how much P loss can be reduced by drawdown. We used the Annual P Loss Estimator (APLE) model to simulate soil P drawdown in Maryland, and to estimate P loss at a statewide scale associated with different combinations of soil P and P transport. Simulated APLE soil P drawdown compared well with measured rates from three field sites, showing that APLE can reliably simulate P dynamics for Maryland soils. Statewide APLE simulations of average annual P loss from cropland (0.84 kg ha) also compared well with estimates from the Chesapeake Bay Model (0.87 kg ha). The APLE results suggest that it is realistic to expect that a concerted effort to reduce high P soils throughout the state can reduce P loss to the Chesapeake Bay by 40%. However, P loss reduction would be achieved gradually over several decades, since soil P drawdown is very slow. Combining soil P drawdown with aggressive conservation efforts to reduce P transport in erosion could achieve a 62% reduction in state-level P loss. This 62% reduction could be considered a maximum amount possible that is still compatible with modern agriculture.
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McLellan EL, Cassman KG, Eagle AJ, Woodbury PB, Sela S, Tonitto C, Marjerison RD, van Es HM. The Nitrogen Balancing Act: Tracking the Environmental Performance of Food Production. Bioscience 2018; 68:194-203. [PMID: 29662247 PMCID: PMC5894078 DOI: 10.1093/biosci/bix164] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Farmers, food supply-chain entities, and policymakers need a simple but robust indicator to demonstrate progress toward reducing nitrogen pollution associated with food production. We show that nitrogen balance—the difference between nitrogen inputs and nitrogen outputs in an agricultural production system—is a robust measure of nitrogen losses that is simple to calculate, easily understood, and based on readily available farm data. Nitrogen balance provides farmers with a means of demonstrating to an increasingly concerned public that they are succeeding in reducing nitrogen losses while also improving the overall sustainability of their farming operation. Likewise, supply-chain companies and policymakers can use nitrogen balance to track progress toward sustainability goals. We describe the value of nitrogen balance in translating environmental targets into actionable goals for farmers and illustrate the potential roles of science, policy, and agricultural support networks in helping farmers achieve them.
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Affiliation(s)
| | - Kenneth G Cassman
- Department of Agronomy and Horticulture, University of Nebraska, Lincoln
| | | | - Peter B Woodbury
- Soil and Crop Sciences Section of the College of Agriculture and Life Sciences at Cornell University, Ithaca, New York
| | - Shai Sela
- Soil and Crop Sciences Section of the College of Agriculture and Life Sciences at Cornell University, Ithaca, New York
| | - Christina Tonitto
- Cornell International Institute for Food, Agriculture, and Development, Ithaca, New York
| | | | - Harold M van Es
- Soil and Crop Sciences Section of the College of Agriculture and Life Sciences at Cornell University, Ithaca, New York
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Sharpley A, Kleinman P, Baffaut C, Beegle D, Bolster C, Collick A, Easton Z, Lory J, Nelson N, Osmond D, Radcliffe D, Veith T, Weld J. Evaluation of Phosphorus Site Assessment Tools: Lessons from the USA. JOURNAL OF ENVIRONMENTAL QUALITY 2017; 46:1250-1256. [PMID: 29293829 DOI: 10.2134/jeq2016.11.0427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Critical source area identification through phosphorus (P) site assessment is a fundamental part of modern nutrient management planning in the United States, yet there has been only sparse testing of the many versions of the P Index that now exist. Each P site assessment tool was developed to be applicable across a range of field conditions found in a given geographic area, making evaluation extremely difficult. In general, evaluation with in-field monitoring data has been limited, focusing primarily on corroborating manure and fertilizer "source" factors. Thus, a multiregional effort (Chesapeake Bay, Heartland, and Southern States) was undertaken to evaluate P Indices using a combination of limited field data, as well as output from simulation models (i.e., Agricultural Policy Environmental eXtender, Annual P Loss Estimator, Soil and Water Assessment Tool [SWAT], and Texas Best Management Practice Evaluation Tool [TBET]) to compare against P Index ratings. These comparisons show promise for advancing the weighting and formulation of qualitative P Index components but require careful vetting of the simulation models. Differences among regional conclusions highlight model strengths and weaknesses. For example, the Southern States region found that, although models could simulate the effects of nutrient management on P runoff, they often more accurately predicted hydrology than total P loads. Furthermore, SWAT and TBET overpredicted particulate P and underpredicted dissolved P, resulting in correct total P predictions but for the wrong reasons. Experience in the United States supports expanded regional approaches to P site assessment, assuming closely coordinated efforts that engage science, policy, and implementation communities, but limited scientific validity exists for uniform national P site assessment tools at the present time.
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Kleinman PJA, Sharpley AN, Buda AR, Easton ZM, Lory JA, Osmond DL, Radcliffe DE, Nelson NO, Veith TL, Doody DG. The Promise, Practice, and State of Planning Tools to Assess Site Vulnerability to Runoff Phosphorus Loss. JOURNAL OF ENVIRONMENTAL QUALITY 2017; 46:1243-1249. [PMID: 29293848 DOI: 10.2134/jeq2017.10.0395] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Over the past 20 yr, there has been a proliferation of phosphorus (P) site assessment tools for nutrient management planning, particularly in the United States. The 19 papers that make up this special section on P site assessment include decision support tools ranging from the P Index to fate-and-transport models to weather-forecast-based risk calculators. All require objective evaluation to ensure that they are effective in achieving intended benefits to protecting water quality. In the United States, efforts have been underway to compare, evaluate, and advance an array of P site assessment tools. Efforts to corroborate their performance using water quality monitoring data confirms previously documented discrepancies between different P site assessment tools but also highlights a surprisingly strong performance of many versions of the P Index as a predictor of water quality. At the same time, fate-and-transport models, often considered to be superior in their prediction of hydrology and water quality due to their complexity, reveal limitations when applied to site assessment. Indeed, one consistent theme from recent experience is the need to calibrate highly parameterized models. As P site assessment evolves, so too do routines representing important aspects of P cycling and transport. New classes of P site assessment tools are an opportunity to move P site assessment from general, strategic goals to web-based tools supporting daily, operational decisions.
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Nelson NO, Baffaut C, Lory JA, Anomaa Senaviratne GMMM, Bhandari AB, Udawatta RP, Sweeney DW, Helmers MJ, Van Liew MW, Mallarino AP, Wortmann CS. Multisite Evaluation of APEX for Water Quality: II. Regional Parameterization. JOURNAL OF ENVIRONMENTAL QUALITY 2017; 46:1349-1356. [PMID: 29293851 DOI: 10.2134/jeq2016.07.0254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Phosphorus (P) Index assessment requires independent estimates of long-term average annual P loss from fields, representing multiple climatic scenarios, management practices, and landscape positions. Because currently available measured data are insufficient to evaluate P Index performance, calibrated and validated process-based models have been proposed as tools to generate the required data. The objectives of this research were to develop a regional parameterization for the Agricultural Policy Environmental eXtender (APEX) model to estimate edge-of-field runoff, sediment, and P losses in restricted-layer soils of Missouri and Kansas and to assess the performance of this parameterization using monitoring data from multiple sites in this region. Five site-specific calibrated models (SSCM) from within the region were used to develop a regionally calibrated model (RCM), which was further calibrated and validated with measured data. Performance of the RCM was similar to that of the SSCMs for runoff simulation and had Nash-Sutcliffe efficiency (NSE) > 0.72 and absolute percent bias (|PBIAS|) < 18% for both calibration and validation. The RCM could not simulate sediment loss (NSE < 0, |PBIAS| > 90%) and was particularly ineffective at simulating sediment loss from locations with small sediment loads. The RCM had acceptable performance for simulation of total P loss (NSE > 0.74, |PBIAS| < 30%) but underperformed the SSCMs. Total P-loss estimates should be used with caution due to poor simulation of sediment loss. Although we did not attain our goal of a robust regional parameterization of APEX for estimating sediment and total P losses, runoff estimates with the RCM were acceptable for P Index evaluation.
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