Water and nutrient balances in a large tile-drained agricultural catchment: a distributed modeling study

Abstract

Abstract. This paper presents the development and implementation of a distributed model of coupled water nutrient processes, based on the representative elementary watershed (REW) approach, to the Upper Sangamon River Basin, a large, tile-drained agricultural basin located in central Illinois, mid-west of USA. Comparison of model predictions with the observed hydrological and biogeochemical data, as well as regional estimates from literature studies, shows that the model is capable of capturing the dynamics of water, sediment and nutrient cycles reasonably well. The model is then used as a tool to gain insights into the physical and chemical processes underlying the inter-and intra-annual variability of water and nutrient balances. Model predictions show that about 80% of annual runoff is contributed by tile drainage, while the remainder comes from surface runoff (mainly saturation excess flow) and subsurface runoff. It is also found that, at the annual scale nitrogen storage in the soil is depleted during wet years, and is supplemented during dry years. This carryover of nitrogen storage from dry year to wet year is mainly caused by the lateral loading of nitrate. Phosphorus storage, on the other hand, is not affected much by wet/dry conditions simply because the leaching of it is very minor compared to the other mechanisms taking phosphorous out of the basin, such as crop harvest. The analysis then turned to the movement of nitrate with runoff. Model results suggested that nitrate loading from hillslope into the channel is preferentially carried by tile drainage. Once in the stream Correspondence to: H. Li (hli23@illinois.edu) it is then subject to in-stream denitrification, the significant spatio-temporal variability of which can be related to the variation of the hydrologic and hydraulic conditions across the river network.

Simulating cold-region hydrology in an intensively drained agricultural watershed in Manitoba, Canada, using the Cold Regions Hydrological Model

“…The soils, topography, and land use datasets used as model inputs in this study were derived according to the principles described by Liu et al (2013) for prediction in ungauged basins. The sub-basins within the La Salle watershed (Fig.…”

“…Hydrological models have been utilized at varying spatial scales to model the hydrology of agricultural areas of cold-climate countries such as Finland (Grizzetti et al, 2003;Knisel and Turtola, 2000), Russia (Schierhorn et al, 2014a, b), and Canada (Yang et al, 2014(Yang et al, , 2009). Overall, little research addressing specificities of agriculture in cold-region hydrology is available in the literature, although this activity is quite relevant in northern latitude regions such as the northern Great Plains (North America; Desaulniers and Gritzner, 2006;Wishart, 2004;Sharp, 1952;Li et al, 2010), northwestern Europe (Scandinavia; Parry et al, 1988), and northern Asia (Wang et al, 2002;Blanke et al, 2007). Important challenges remain in modelling the hydrology of northern latitude agricultural watersheds, such as integrated modelling of cropping systems and hydrology, representation of processes across spatial scales, and enhanced hydrologic connectivity.…”

Simulating seasonal variations of tile drainage discharge in an agricultural catchment

“…[] or Lam et al . [], were with 1‐D models such as MACRO [ Kuzmanovski et al ., ], DRAIN‐WARMF [ Dayyani et al ., ], and ANSWERS [ Bouraoui et al ., ] or 2‐D models such as SWAT [ Du et al ., ; Koch et al ., ], M‐2D [ Abbaspour et al ., ], MHYDAS‐DRAIN [ Tiemeyer et al ., ], and THREW [ Li et al ., ]. These 1‐D and 2‐D models generally produced good correlation between yearly simulated and observed drainage discharge.…”

Using an inverse modelling approach with equifinality control to investigate the dominant controls on snowmelt nutrient export

“…Some possible explanations may be that the mixing of the soil profile during tillage may have reduced soil stratification and overridden the expected effect of fertilizer input by removing surficial soil NO 3 available for run‐off transport (e.g., Cade‐Menun, Carter, James, & Liu, ; Tiessen et al, ; Abdi, Cade‐Menun, Ziadi, & Parent, ). This may also reflect the dynamic nature of NO 3 , which is highly soluble so run‐off losses may not be not replenished (e.g., Li, Sivapalan, Tian, & Liu, 2010nov, ) and may be subject to leaching below the interaction zone (e.g., Ryan, Kachanoski, & Gillham, ; Kladivko et al, ), rapid uptake by plants, denitrification in anaerobic soils (Dawson & Murphy, ; Groffman & Tiedje, ), and nutrient management practices that minimize excess N inputs. Thus, consideration of the timing and type of nutrient input (mineral or organic) may be essential to predict its impact on run‐off concentrations.…”