Analysis of the MANAGE Drain Concentration Database to Evaluate Agricultural Management Effects on Drainage Water Nutrient Concentrations

Abstract

Abstract. Agricultural systems are substantial contributors of nonpoint-source nitrogen (N) and phosphorus (P) pollution, and loss of dissolved forms of these nutrients is exacerbated in subsurface-drained (tile-drained) landscapes. The majority of reviews summarizing drainage nutrient losses have focused on N and P loads, but closer inspection of drainage concentrations is necessary to more directly link cropping management factors with water quality outcomes. More than 1,500 recently compiled site-years of drainage N and P concentration in the Measured Annual loads from AGricultural Environments (MANAGE) Drain Concentration database were used to analyze the impacts of crop selelction, nutrient management, and tillage type on annual drainage nutrient concentrations. The highest annual flow-weighted mean NO3-N concentrations across the database were from corn, corn and soybean (grown within the same plot in the same year), and soybean site-years (14.0, 13.5, and 12.1 mg L-1, respectively). However, crop selection was not a significant predictor for annual average dissolved reactive phosphorus (DRP) concentrations in drainage. Nitrogen application rates below 75 kg ha-1 for corn did not significantly reduce annual NO3-N concentrations compared to rates of 75 to 149 kg ha-1 or 150 to 224 kg ha-1, although the three largest application rate categories (75 to 149 kg ha-1, 150 to 224 kg ha-1, and >224 kg ha-1, respectively) resulted in significantly increasing NO3-N concentrations. The stepwise regression approach was used to reduce and select predictors to model annual NO3-N and DRP concentrations. Regression analysis of NO3-N concentrations had an overall model R2 of 0.59 (n = 254) and indicated that N application rate had the greatest effect on NO3-N concentrations in corn site-years, followed by fertilizer timing and tillage type. Regression analysis of DRP concentrations had an overall R2 of 0.94, and although the model was less robust due to the small sample size (n = 47), fertilizer timing was most closely correlated with annual DRP concentrations. The MANAGE database will continue to evolve and remain a resource for new exploratory efforts to better understand and reduce nutrient losses from agricultural systems. Keywords: Concentration, Drainage, Nitrogen, Phosphorus, Water quality.

Updates to the MANAGE database to facilitate regional analyses of nutrient runoff

“…(2016) and Hertzberger et al. (2019a, 2019b). One particular need is the inclusion of N and P runoff data from urban and industrial land uses.…”

“…The number of site years of annual P runoff load data (dissolved, particulate, and total) in Level II ecoregions in North America As has been done since its development in 2006, we plan to update MANAGE periodically as guided by emerging needs and availability of additional studies. We also encourage other researchers to utilize the MANAGE platform to compile and summarize additional types of nutrient loss studies, as done for drainage by Christianson et al (2016) and Hertzberger et al (2019aHertzberger et al ( , 2019b. One particular need is the inclusion of N and P runoff data from urban and industrial land uses.…”

“…(2016), and Hertzberger et al. (2019a, 2019b) added data from 79 studies of drainage N and P concentrations and loads mainly from the midwestern and eastern United States. In addition, the MANAGE database has been used for meta‐type analyses of management impacts on drainage nutrient losses (Flores et al., 2021; Hertzberger et al., 2019a; Liu et al., 2021; Zhao et al., 2016) and on the impact of agricultural conservation practices on nutrient losses in surface runoff (Nummer et al., 2018; Qian & Harmel, 2016; Reckhow et al., 2009).…”

“…MANAGE presents annual field-scale dissolved, particulate, and total nitrogen (N) and phosphorus (P) runoff data from published studies of agricultural land uses (cultivated and grassland including improved pasture and to include drainage studies. Specifically, Harmel (2015a, 2015b), Christianson et al (2016), and Hertzberger et al (2019aHertzberger et al ( , 2019b added data from 79 studies of drainage N and P concentrations and loads mainly from the midwestern and eastern United States. In addition, the MANAGE database has been used for meta-type analyses of management impacts on drainage nutrient losses (Flores et al, 2021;Hertzberger et al, 2019a;Liu et al, 2021;Zhao et al, 2016) and on the impact of agricultural conservation practices on nutrient losses in surface runoff (Nummer et al, 2018;Qian & Harmel, 2016;Reckhow et al, 2009).…”

“…Specifically, Harmel (2015a, 2015b), Christianson et al (2016), and Hertzberger et al (2019aHertzberger et al ( , 2019b added data from 79 studies of drainage N and P concentrations and loads mainly from the midwestern and eastern United States. In addition, the MANAGE database has been used for meta-type analyses of management impacts on drainage nutrient losses (Flores et al, 2021;Hertzberger et al, 2019a;Liu et al, 2021;Zhao et al, 2016) and on the impact of agricultural conservation practices on nutrient losses in surface runoff (Nummer et al, 2018;Qian & Harmel, 2016;Reckhow et al, 2009). The database has also been used to evaluate modeling tool predictions of best management practices effectiveness, regional water balances, and regional ranges of runoff, sediment, and nutrient loss (e.g., Merriman et al, 2009;White et al, 2010White et al, , 2015aWhite et al, , 2015b.…”