Shift of lakeshore cropland to buffer zones greatly reduced nitrogen loss from the soil profile caused by the interaction of lake water and shallow groundwater

2021 ◽  
pp. 150093
Author(s):  
Rongyang Cui ◽  
Dan Zhang ◽  
Gangcai Liu ◽  
Panlei Wang ◽  
Anqiang Chen ◽  
...  
Keyword(s):  
Lake Water ◽  
Soil Profile ◽  
Nitrogen Loss ◽  
Shallow Groundwater ◽  
Buffer Zones ◽  
Reduced Nitrogen

scholarly journals Tracing the Spatial Distribution of Whole-Lake Exchange of Groundwater and Lake Water in Low-Hydraulic Gradient Systems Using δ18O and Electrical Conductivity and Uncertain End-Member Mixing Analysis

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1608
Author(s):  
Peter Engesgaard ◽  
Ingeborg S. Solvang ◽  
Mads Steiness ◽  
Emil Kristensen ◽  
Theis Kragh ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Spatial Distribution ◽  
Lake Water ◽  
Quantitative Estimation ◽  
Shallow Groundwater ◽  
Direct Analysis ◽  
Hydraulic Gradient ◽  
High Precipitation ◽  
End Members ◽  
Lake Systems

δ18O and electrical conductivity (EC) were used successfully to trace the spatial distribution of whole-lake groundwater-lake exchange for a small (four ha) groundwater-fed lake situated in a low relief and low hydraulic gradient area. The method relies on quick sampling of shallow groundwater, direct analysis of EC in the field, and relatively in-expensive analysis of δ18O in the laboratory. Ternary uncertain end-member mixing analysis (precipitation, groundwater, and lake water) quantified the composition of water discharging to and recharging from the lake. The tracer distribution and mixing analysis were in agreement with the interpreted groundwater flow near the lake. The use of only one tracer (either δ18O or EC) gave the same results for the recharge segments, but the discharge segments changed the origin of the water from being groundwater to precipitation controlled. The two tracers complemented each other, especially with different signals in precipitation and groundwater. The uncertain end-members were assessed based on local (groundwater and lake water) and off-site (precipitation) data. The off-site data were found to be useful if it contained representative information on local-site seasonality (uncertainty, variance). Final end-member concentrations could explain the transience of the hydrology at the site (i.e., flooding of the area adjacent to the lake during periods with high precipitation, and variability of the δ18O signal in precipitation). This methodology potentially represents a new option to study groundwater-lake systems. The tracer information collected over only two days is useful by itself for developing the next steps like the quantification of fluxes based on other standard methods (Darcy approach, seepage meters, or temperature). The tracer information can provide quantitative estimation of inputs and outputs by using the mixing analysis.

Influence of the shape of inter-horizon boundary and size of soil tongues on preferential flow under shallow groundwater conditions: A simulation study

2011 ◽  
Vol 91 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Priyantha B. Kulasekera ◽  
Gary W. Parkin
Keyword(s):  
Solute Transport ◽  
Vadose Zone ◽  
Simulation Study ◽  
Soil Profile ◽  
Preferential Flow ◽  
Shallow Groundwater ◽  
Soil Horizon ◽  
Tongue Length ◽  
The Impact ◽  
Water And Solute Transport

Kulasekera, P. B. and Parkin, G. W. 2011. Influence of the shape of inter-horizon boundary and size of soil tongues on preferential flow under shallow groundwater conditions: A simulation study. Can. J. Soil Sci. 91: 211–221. Detailed studies of the impact of soil tongues at soil horizon interfaces are very important in understanding preferential flow processes through layered soils and in improving the accuracy of models predicting water and solute transport through the vadose zone. The implication of having soil tongues of different shapes and sizes created at the soil horizon interface on solute transport through a layered soil horizon was studied by simulating water and solute transport using the VS2DI model. This 2-D simulation study reconfirmed that soil tongues facilitate preferential flow, and the level of activeness of tongues may depend on the number of soil tongues, their spacing and distribution. Also, the size of the soil tongues (length and diameter at the interface between the soil horizons) and their shape influence the rate of preferential flow. Increasing tongue length consistently resulted in an increase in solute velocity across the entire soil profile regardless of the tongue shape; for example, a soil tongue of 0.25 m length increased solute velocity by about 1.5 times over a soil profile without tongues, but this increase might be different for soil types and groundwater conditions other than those considered in this study. Narrowing of tongues increased solute velocity, whereas increasing the number of tongues in a wider soil profile decreased the solute-front's velocity. As tongue length increased, the area containing solutes at prescribed elapsed times decreased. An implication of this study is that soil horizon tongue shape and spacing reduce pollutant residence times, hence inter-horizon boundary morphology should be considered when modelling transport through the vadose zone. As well, since the solute velocity behaviours of a triangular- and a wider rectangular-shaped tongue were nearly identical, simply measuring solute velocity in the field will reveal little information on the shape of a soil tongue.

Sawdust biochar application to rice paddy field: reduced nitrogen loss in floodwater accompanied with increased NH3 volatilization

2018 ◽  
Vol 25 (9) ◽  
pp. 8388-8395 ◽  
Author(s):  
Yanfang Feng ◽  
Haijun Sun ◽  
Lihong Xue ◽  
Yueman Wang ◽  
Linzhang Yang ◽  
...  
Keyword(s):  
Paddy Field ◽  
Nitrogen Loss ◽  
Rice Paddy ◽  
Nh3 Volatilization ◽  
Rice Paddy Field ◽  
Reduced Nitrogen

scholarly journals Minimizing Soil Nitrogen Leaching by Changing Furrow Irrigation into Sprinkler Fertigation in Potato Fields in the Northwestern China Plain

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2229
Author(s):  
Wenzhu Yang ◽  
Yan Jiao ◽  
Mingde Yang ◽  
Huiyang Wen ◽  
Peng Gu ◽  
...  
Keyword(s):  
Soil Profile ◽  
Management Practices ◽  
Root Zone ◽  
Soil Depth ◽  
Irrigation System ◽  
Nitrogen Loss ◽  
Soil Layer ◽  
Furrow Irrigation ◽  
N Leaching ◽  
N Accumulation

Irrigation water is limiting for crop production in arid areas and application rates of fertilizers often exceed crop requirements, resulting in high accumulation of nitrate nitrogen (NO3−-N) in the soil. Management practices play a significant role in the leaching of NO3−-N. This experiment compares the effects of traditional furrow irrigation and sprinkler fertigation on the soil NO3−-N concentration trend throughout the cropping season in potato fields in China. Two irrigation systems that were fertilized, namely by furrow (NF-FI) and sprinkler fertigation (NF-SI), and two controlling without any fertilizer (C-FI and C-SI) were tested in the same experimental site for three consecutive years. Both the NF-FI soils and NF-SI soils with three replications and fertilizer applications of 273 kg N ha−1 exhibited a different trend of NO3−-N accumulation at different depths of soil profile. However, the magnitude of NO3−-N accumulation was low in the NF-SI soil profile. In NF-SI treatments, higher NO3−-N was observed at 20–40 cm soil layer. In the NF-FI, the concentration of the highest nitrate was observed at the 40–120 cm soil layer. The concentrations of NO3−-N in the fertilized soil were higher than those of the control soil for each irrigation system. Residual levels of NO3−-N in the soil depth of 40–120 cm from NF-FI were 1.54, 3.45 and 5.28 times higher than NF-SI after harvesting potatoes from 2015 to 2017. In NF-FI treatments, apparent nitrogen loss was 234.7, 237.5 and 276.7 kg ha−1 after harvesting potatoes in 2015, 2016 and 2017. Meanwhile, apparent nitrogen loss from NF-SI treatments was only 161.9, 132.1 and 148.9 kg ha−1, which was 31.0%, 44.4% and 46.2% lower than that of NF-FI in 2015, 2016 and 2017, respectively. The risk of NO3−-N leaching below the root zone from NF-FI was higher than that from NF-SI. It has been demonstrated that sprinkler fertigation can also be used as a tool for mitigating NO3−-N accumulation and apparent nitrogen loss.

scholarly journals A qualitative description of shallow groundwater effect on surface temperature of bare soil

2009 ◽  
Vol 13 (9) ◽  
pp. 1749-1756 ◽  
Author(s):  
F. Alkhaier ◽  
R. J. Schotting ◽  
Z. Su
Keyword(s):  
Numerical Model ◽  
Soil Temperature ◽  
Skin Temperature ◽  
Soil Profile ◽  
Land Surface ◽  
Shallow Groundwater ◽  
Soil Surface ◽  
Qualitative Description ◽  
Groundwater Depth ◽  
Daily Minimum Temperature

Abstract. Whether or not shallow groundwater affects skin temperature (the temperature of soil surface) is important to detect depth and extent of shallow groundwater by dint of remote sensing and important for land surface modelling studies. Although few studies have been conducted to investigate that effect, they have yielded contradicting conclusions and they stopped in 1982. To determine that shallow groundwater affects skin temperature, we measured soil temperature at two different depths (5 and 10 cm) in seven places with variable water table depths every ten minutes and for six days. After that, we correlated the minimum, maximum and average daily temperatures to average groundwater depth. We also built a simple numerical model using a differential equations solver, Flex PDE, to simulate heat transfer into soil profile and used it to simulate groundwater effect on skin temperature. We found quite high negative correlation between the maximum and average daily soil temperature and groundwater depth. Contrarily, we could hardly find any correlation between the daily minimum temperature and groundwater depth. Numerical simulations, though simple, were useful in showing that groundwater shifted skin temperature curves up in the winter and down in the summer without affecting the shape of the curve. We conclude that shallow groundwater affects skin temperature directly by its distinctive thermal properties in the soil profile and indirectly by affecting soil moisture which in turn has many different and contradictory effects on skin temperature. This study recommends building a comprehensive numerical model that simulates the effect of shallow groundwater on skin temperature and on the different energy fluxes at land surface.

Modeling the Evaporation Line of Lake Water Isotopes in Golmud Drainage Basin, P.R. China

2012 ◽  
Vol 518-523 ◽  
pp. 4186-4193 ◽  
Author(s):  
Hong Yun Ma ◽  
Li He Yin ◽  
Li Guo ◽  
Jun Zhang
Keyword(s):  
Regression Analysis ◽  
Relative Humidity ◽  
Lake Water ◽  
Drainage Basin ◽  
Qaidam Basin ◽  
Isotopic Fractionation ◽  
Shallow Groundwater ◽  
Water Isotopes ◽  
Analysis Method ◽  
Salt Composition

The δD-δ18O line features are very important properties of isotopic characteristics. The δD-δ18O line usually is estimated by regression analysis when samples are sufficient. In thisSuperscript textpaper, the isotopic characteristic of rain water, shallow groundwater and lake water in Golmud drainage area of Qaidam Basin were analyzed, and the isotopic evaporation line of lake water was calculated with Rayleigh fractionation function because the regression analysis method is insufficient in the condition that measured samples of lake water are short. The result shows that the groundwater is the main source of lakes; and the isotopic fractionation of hydrogen and oxygen in lake water controlled by kinetic effect in the process of evaporation. The calculated evaporation line of lake water is δD=3.26δ18O-21.00, which is matched with measured samples. The sensitivity analysis of the slop to the temperature, dissolved salt composition in lake water and relative humidity of air shows that the slop is negative related to the temperature and dissolved composition and is positive related to relative humidity. In typical environmental condition, the slop is increased by 0.0303, 0.1016 and 0.0205, respectively, when temperature decreased 1°C, dissolved NaCl decreased 1mol/L and relative humidity increased by 1%.

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