Nitrogen Application Rate Effect on Nitrate-Nitrogen Concentration and Loss in Subsurface Drainage for a Corn-Soybean Rotation

Abstract

Excess precipitation in Midwest agricultural production areas is often removed artificially via subsurface drainage systems that intercept and divert it to surface waters. Nitrogen (N), either applied as fertilizer or manure or derived from soil organic matter, can be carried as nitrate with the excess water in quantities that may have deleterious effects downstream. A field study was initiated in 1989 in Pocahontas County, Iowa, on 0.05 ha plots of glacially derived clay loams. The objective of this three-phase study was to determine the effect of N application rate on NO3-N concentration and loss in a corn-soybean rotation over a wide range of weather conditions. Nitrogen-rate treatment phases with five seasons each (six for phase II) were imposed on subsurface-drained, continuous-flow-monitored plots over a 16-year period. Phase I N rates ranged from 0 to 168 kg N ha-1 in 56 kg N ha-1 increments. Separate plots were used for each crop in phase I, and significant NO3-N concentration differences were not observed between corn or soybean plots; this led to combining both crops in a split-plot configuration for phases II and III to study system effects. Phase II N rates ranged from 45 to 179 kg N ha-1 in 45 kg N ha-1 increments. Phase III was limited to two rates, 168 and 252 kg N ha-1. Average yearly flow-weighted NO3-N concentrations ranged from 3.

Modeling Long-Term Corn Yield Response to Nitrogen Rate and Crop Rotation

“…Variability in EONR and its relationship with spring precipitation in the US Midwest has typically been associated in previous research with an increase in N loss with high spring precipitation but previous studies lacked comprehensive measurements (Meisinger, 1984; Eghball and Varvel, 1997; Kay et al, 2006; Lawlor et al, 2008). The APSIM model analysis explicitly quantified the shape and magnitude of N loss per mm of precipitation and indicated that the shape of the relationship is similar in CC and SC systems ( Figure 5 ).…”

“…Optimal N input needs to be considered when making N recommendations since it has the potential to improve N use efficiency, crop yield, and profitability as well as to reduce environmental impacts (Wang et al, 2003; Lawlor et al, 2008; Kyveryga et al, 2009; Basso et al, 2016). Nitrogen losses by leaching are proportional to the N rate applied and tend to increase rapidly at rates greater than optimal for crop use (Haghiri et al, 1978; Cooper and Cooke, 1984; Andraski et al, 2000; Randall et al, 2000).…”

Corn Nitrogen Fertilization Requirement and Corn-Soybean Productivity with a Rye Cover Crop

“…Successful development of agricultural systems that benefit water quality have to be more inclusive of several agricultural practices, rather than only N rate or timing (Hatfield et al, 2009). Therefore, additional in-field practices are needed to reduce NO 3 losses (Sainju and Singh, 2008).Nitrate losses in tile drainage water from corn production systems can range from 7 to 68 kg N ha -1 yr -1 (Lawlor et al, 2007), and with most values ranging from 29 to 56 kg N ha -1 yr -1 (Sawyer and Randall, 2008). Cover crops have shown potential for uptake of residual N from fertilizers or inorganic N released from degrading soil organic matter (SOM) in the period between annual crops (Strock et al, 2004;Tonitto et al,…”

“…Nitrogen application rate to corn is an important factor in regard to cropping system profitability and NO 3 loss. Applying only the optimal N rate will not stop NO 3 loss, nor necessarily achieve the drinking water standard (Lawlor et al, 2007). Successful development of agricultural systems that benefit water quality have to be more inclusive of several agricultural practices, rather than only N rate or timing (Hatfield et al, 2009).…”

“…Nitrate losses in tile drainage water from corn production systems can range from 7 to 68 kg N ha -1 yr -1 (Lawlor et al, 2007), and with most values ranging from 29 to 56 kg N ha -1 yr -1 (Sawyer and Randall, 2008). Cover crops have shown potential for uptake of residual N from fertilizers or inorganic N released from degrading soil organic matter (SOM) in the period between annual crops (Strock et al, 2004;Tonitto et al, 2006), thus helping reduce NO 3 loss (Staver and Brinsfield, 1998;Qi and Helmers, 2010;Drury et al, 2014;Acuña and Villamil, 2014).…”