没有合适的资源?快使用搜索试试~ 我知道了~
利用地下水-农艺耦合模型评价涝渍地区作物-土壤-水动态
0 下载量 145 浏览量
2024-05-23
20:35:12
上传
评论
收藏 6.38MB PDF 举报
温馨提示
![preview](https://dl-preview.csdnimg.cn/89346883/0001-8feac4b5719ca8a5fcfca05d401aeb10_thumbnail.jpeg)
![preview-icon](https://csdnimg.cn/release/downloadcmsfe/public/img/scale.ab9e0183.png)
试读
12页
利用地下水-农艺耦合模型评价涝渍地区作物-土壤-水动态
资源推荐
资源详情
资源评论
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083646.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![doc](https://img-home.csdnimg.cn/images/20210720083327.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083646.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![doc](https://img-home.csdnimg.cn/images/20210720083327.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![rar](https://img-home.csdnimg.cn/images/20210720083606.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![7z](https://img-home.csdnimg.cn/images/20210720083312.png)
![zip](https://img-home.csdnimg.cn/images/20210720083736.png)
![pdf](https://img-home.csdnimg.cn/images/20210720083512.png)
![](https://csdnimg.cn/release/download_crawler_static/89346883/bg1.jpg)
Environmental Modelling and Software 143 (2021) 105130
Available online 13 July 2021
1364-8152/© 2021 Elsevier Ltd. All rights reserved.
Evaluating crop-soil-water dynamics in waterlogged areas using a coupled
groundwater-agronomic model
Chenda Deng
a
,
*
, Yao Zhang
b
, Ryan T. Bailey
a
a
Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO, United States
b
Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, United States
ARTICLE INFO
Keywords:
Groundwater modeling
MODFLOW
DayCent
Message passing interface (MPI)
Waterlogging
Model coupling
ABSTRACT
Waterlogging on croplands has been a known problem for a long time, leading to adverse social, physical,
economic and environmental issues. To better solve the problem, the complicated plant-soil-water dynamics
system needs to be better understood. The challenge is to simulate the interactions between the components in
the systems. There are models that simulate plant-soil-water system but either run the processes independently
leading to inaccuracy or has high invasiveness of using integrated models. This paper presents a tightly coupled
model, DayCent-MODFLOW, that links a 3D ground-water ow (MODFLOW) model and a 1D agroecosystem
model (DayCent). DayCent is responsible for plant-soil-water dynamic in the root zone, whereas MODFLOW
simulates head and groundwater ow in the saturated zone of the aquifer. DayCent passes deep percolation from
the soil prole to the water table and, under conditions of waterlogging in which the water table is within the soil
prole, DayCent soil hydrologic processes are constrained by the presence of the water table simulated by
MODFLOW. The coupling is achieved by adopting a parallel inter-process communication technique MPI
(Message Passing Interface). The model is applied to a waterlogged agricultural area (22 km
2
) in northern
Colorado, USA and tested against groundwater head and rates of evapotranspiration (ET). The model runs in
parallel with multiple processes on the largest AWS Linux server. Groundwater heads match measured heads to a
reasonable degree, and ET rates match reference ET and are highly correlated with crop type. Results show the
strong hydrologic interaction between the two models. Greenhouse gas emissions from soil (N
2
O and CH
4
) were
also estimated by the model under the waterlogged conditions. Although the model can be used to simulate any
plant-soil-aquifer system, no matter the depth of the water table, results from this study show that the model can
be used to assess crop productivity, recharge, ET, and greenhouse gas emissions in areas of shallow groundwater.
1. Introduction
The plant-soil-water system controls the movement of water, nutri-
ents, and greenhouse gases in agricultural landscapes. Understanding
this system under a variety of hydrologic conditions is important for
food production, land management, water management, and nutrient
management. The plant-soil-water system is a complex system consist-
ing of surface water runoff, inltration, soil water dynamics, evapo-
transpiration, recharge and nutrient leaching, carbon (C)-nitrogen (N)
cycling, and consequent hydro-chemical processes such as ow and
nutrient transport in aquifers, stream discharge and nutrient loading,
and greenhouse gas emissions.
The challenge of simulating water transport and nutrient cycling in
such a complex system resides mainly in the interaction between
“zones”, such as water movement between the soil prole and the
saturated zone of the aquifer. As stated by Alley (Alley et al., 2002),
groundwater recharge is the most difcult groundwater budget to
simulate due to factors such as precipitation, irrigation application,
evapotranspiration, land use, crop type, and soil type. A special condi-
tion of plant-soil-water interaction is the presence of saturated condi-
tions in the root zone of crops (i.e. “waterlogging”), which can decrease
crop yield and damage soil health and structure (Cannell et al., 1980;
Cavazza and Pisa, 1988; Collaku & Harrison, n.d.; Houk et al., 2006,
2006, 2006; Kaur et al., 2017). $360 million loss of crop production
every year during 2010–2016 is due to waterlogging and even greater
loss than drought in the United States (Ploschuk et al., 2018). Water-
logging can dramatically change the dynamics of carbon and nitrogen in
soil. The resulting anaerobic condition decreases the rate of organic
* Corresponding author.
E-mail address: cddpeter@rams.colostate.edu (C. Deng).
Contents lists available at ScienceDirect
Environmental Modelling and Software
journal homepage: www.elsevier.com/locate/envsoft
https://doi.org/10.1016/j.envsoft.2021.105130
Accepted 3 July 2021
![](https://csdnimg.cn/release/download_crawler_static/89346883/bg2.jpg)
Environmental Modelling and Software 143 (2021) 105130
2
matter decomposition (Meurant and Riker, 2014), resulting in an
accumulation of soil organic matter that affects nitrogen mineralization
and available nitrogen for crop uptake; and also increases denitrica-
tion, which can increase methane (CH
4
) emission and nitrous oxide
(N
2
O) emission (Bartlett and Harriss, 1993; Parton et al., 2001), both of
which are greenhouse gases.
There are many numerical physically based models that simulate a
range of hydrologic and chemical processes in the plant-water-soil sys-
tem. A subset of these models is agronomic models that simulate hy-
drologic in a one-dimensional domain at the soil prole-scale. These
include SWAP (Kroes et al., 2009), DSSAT (Jones et al., 2003), and
DayCent (Parton et al., 1998; Zhang et al., 2018a,b). They simulate
irrigation, runoff, inltration, and percolation through soil layers, crop
ET, and deep percolation from the bottom of the soil prole. However, as
they do not simulate groundwater ow in the saturated zone of the
underlying aquifer, the uctuation of the water table and its possible
presence in the soil prole and crop root zone is not represented. The
Soil & Water Assessment Tool (SWAT) (Arnold et al., 1998) simulates
hydrological processes and crop yield at the watershed scale, with a
water balance occurring at individual hydrologic response units (HRUs)
across the watershed landscape. The model accounts for groundwater
storage and groundwater discharge to streams but does not simulate
water table uctuation in a physically based manner and hence cannot
account for waterlogging effects on root zone processes and crop yield.
Even the linked SWAT-MODFLOW model (Bailey et al., 2016) does not
account for the condition of shallow groundwater in the root zone –
MODFLOW may simulate a water table at the elevation of an HRU’s soil
prole, but it has no effect on SWAT’s HRU soil prole and root zone
processes. The linked DSSAT-MODFLOW model (Xiang et al., 2020) also
does not account for the effect of shallow groundwater on root zone
processes, as the linkage between the models is performed at the annual
time scale, and day-to-day DSSAT root zone hydrological processes are
not affected by MODFLOW-simulated water table elevation.
Another subset of models simulates vadose zone hydrologic pro-
cesses and water table uctuation, but do not simulate near-surface
hydrology, vegetative growth, root zone processes, and nutrient
cycling. These include the hydrologic and hydrogeologic models MOD-
FLOW (Niswonger et al., 2011), HYDRUS (
ˇ
Simůnek et al., 2012),
MODFLOW-SURFACT (Panday and Huyakorn, 2008), STOMP (White
and Oostrom, 2003), TOUGH2 (Pruess et al., 1999), VS2DI (Healy,
2008), the VSF package (Thoms et al., 2006), and HydroGeoSphere
(Therrien et al., 2010), among many others. There is a general lack of
hydro-agronomic models wherein the simulated water table affects root
zone processes, and root zone processes in turn affect recharge to the
water table.
The objective of this paper is to present a coupled agroecosystem-
groundwater modeling system that can simulate water movement
under waterlogged conditions. The DayCent and MODFLOW are chosen
as the agroecosystem and groundwater models, respectively. DayCent
was selected as it includes carbon and nitrogen dynamics in agro-
ecocystems, and thus is more versatile in applications. MODFLOW is
chosen as it is the most widely used groundwater ow model worldwide
(Langevin et al., 2017). The models are tightly coupled, with system
data passed between them on a daily time step, using a novel Message
Passing Interface (MPI) (Gropp et al., 1996) that avoids code modi-
cation to DayCent and MODFLOW codes and therefore can work with
updated versions of DayCent and MODFLOW. DayCent improves
recharge calculations to MODFLOW, and MODFLOW improves the ac-
curacy of crop yield and nutrient cycling of DayCent in the presence of a
shallow water table. Although the DayCent-MODFLOW linked system
can be applied to any plant-soil-water system, an application to an
irrigated area with shallow groundwater in northern Colorado, USA, will
be shown to demonstrate its capability in waterlogged conditions. The
impact of waterlogged conditions on greenhouse gases will also be
briey described in the model application.
2. Methods
This section provides information about the DayCent and MODFLOW
models and a description of how they are tightly coupled using the MPI
method.
2.1. Introduction to MODFLOW: groundwater ow model
MODFLOW is Fortran-written program (Koelbel et al., 1994) that
numerically solves the three-dimensional ground-water ow equation
by using a nite-difference method (McDonald and Harbaugh, 1988;
Niswonger et al., 2011). MODFLOW is the most widely used ground-
water ow model in the world. Versions include MODFLOW-88
(McDonald and Harbaugh, 1988), MODFLOW-96 (Harbaugh and
McDonald, 1996), MODFLOW-2000 (Harbaugh et al., 2000),
MODFLOW-NWT (Niswonger et al., 2011) and MODFLOW-6 (Langevin
et al., 2017). In this study, MODFLOW-NWT version is used to couple
with DayCent due to its efciency and focus on solving nonlinear
systems.
MODFLOW-NWT simulates groundwater head throughout an aquifer
system by solving the groundwater ow equation for a porous medium.
The ow equation for an unconned aquifer (Bedekar et al., 2012) is:
∂
∂
x
(F
s
K
xx
∂
h
∂
x
) +
∂
∂
y
(F
s
K
yy
∂
h
∂
y
) +
∂
∂
z
(f (F)K
zz
∂
h
∂
z
) + W = ϕ
∂
F
s
∂
t
+ F
s
S
s
∂
h
∂
t
(1)
where x, y, z are the three dimensions; h is groundwater head (L); K is
hydraulic conductivity (L/T). S
s
is specic storage (1/T). ϕis porosity
taken equal to specic yield S
y
; F
s
is the fraction of the cell thickness that
is saturated; and f(F) is a function of F
s
set to 1 for Niswonger et al.
(2011).
MODFLOW also solves the equation for conned aquifers, but this
study is concerned with water table interaction in soil zones, and hence
Equation (1) is presented. The nite difference method is used to solve
Equation (1) by discretizing the groundwater system spatially into a grid
of cells and the simulation time period into time steps. Each cell is
interpreted as a small volume of aquifer material with the same hy-
draulic properties. The equation describes the volumetric water balance
within each of the cell, with groundwater inputs including groundwater
ow from adjacent cells and other groundwater sources (e.g., recharge,
seepage) and groundwater outputs including ow to adjacent cells and
other groundwater sinks (e.g. ET, pumping, discharge). The aquifer
hydraulic properties include hydraulic conductivity K, specic yield S
y
,
and specic storage S
s
. Although the primary variable of solution is
groundwater head h, ow rates using h can be calculated at each time
step.
2.2. Introduction to DayCent: agroecosystem model
The DayCent model (William J. Parton et al., 1998; Zhang et al.,
2018) is a medium complexity agroecosystem model. The major
sub-models of DayCent are plant growth, soil water, soil organic carbon,
soil nitrogen and Greenhouse gas uxes. Major inputs for the model are
daily weather, soil physical properties, plant type, and management
practices. DayCent has been widely used for carbon and nitrogen sim-
ulations in agroecosystems (S. J. Del Grosso et al., 2008; Stephen J. Del
Grosso et al., 2006; Robertson et al., 2018; Zhang et al., 2013). The
model was selected to estimate soil CO
2
and N
2
O emissions/removals for
the US national greenhouse gas inventory (USEPA, 2021) which is
annually submitted to the UN Framework Convention on Climate
Change (United Nations, 1992). The crop growth/production sub-model
has been used in simulations of agroecosystem dynamics not only in the
U.S. but also globally (Cheng et al., 2014; S. J. Del Grosso et al., 2008;
Gautam et al., 2020; Lee et al., 2012; Stehfest et al., 2007; Zhang et al.,
2020). Recently, the DayCent model has been improved in simulations
of crop canopy development, growth, and water use (Zhang et al., 2020;
C. Deng et al.
![](https://csdnimg.cn/release/download_crawler_static/89346883/bg3.jpg)
Environmental Modelling and Software 143 (2021) 105130
3
Zhang et al., 2018; Zhang et al., 2018). This new version of DayCent is
used in this study for coupling with MODFLOW. DayCent is written in
Fortran and C (Kernighan and Ritchie, 2006).
The DayCent modeling code includes the main water balance com-
ponents for a soil prole: inltration of precipitation and irrigation,
surface runoff, deep percolation from the bottom of the soil prole,
evapotranspiration (ET; evaporation and transpiration), and capillary
rise of groundwater:
ΔS
i
= P + I
net
− ET
c
− RO − DP + GW (3)
where ΔS
i
is the net change in soil water at the end of day i and i-1. In this
equation, P, RO, and DP are precipitation, runoff, and deep percolation
on day i, respectively. I
net
is the net irrigation on day i. GW is the ground
water contribution if a shallow water table is present. ET
c
is the actual
evapotranspiration on day i. All units are in cm day-1. The soil prole is
dened by users which is usually less than 3 m in depth. The input soil
parameters include soil texture, bulk density, and eld capacity, wilting
point, and saturated hydraulic conductivity.
Reference ET is simulated using either the standardized Penman-
Monteith method (Allen et al., 1998) or the Hargreave’s method (Har-
greaves and Allen, 2003), with the latter used when only air temperature
is available. The solar radiation, wind speed, and relative humidity are
required to run the Penman-Monteith method. Crop coefcients are used
in conjunction with reference ET to estimate potential ET for each crop
type. The ET is partitioned into potential evaporation and potential
transpiration as a function of the green canopy coverage and residue
coverage. The green canopy coverage (CC) is calculated from Beer’s law
(Monsi and Saeki, 1953; SELLERS, 1985):
CC = 1 − exp( − k × GLAI) (4)
where k (dimensionless) is the light extinction coefcient of the vege-
tation, and GLAI is green leaf area index (m m-1). The GLAI and CC
approach was recently added to DayCent and the detailed description
can be found in Zhang et al. (2018a,b). Water uptake by root is limited
by soil available water. Regarding potential soil evaporation, it can be
reduced by the amount of standing dead biomass and litter on the soil
surface. In DayCent, actual evaporation is also limited by the soil water
potential of the top soil layer and the upward uxes from underlying
layers (Parton et al., 1998).
DayCent simulates 1D water ows using a combined method: a
modied tipping-bucket approach for water ow above eld capacity
and a Richards’ approach (Richards, 1931) for water re-distribution
below eld capacity (Parton et al., 1998). Water table is simply simu-
lated by turning off the drainage of water at the last soil layer for a
user-specied period. When water table is present, the water inltrated
from soil surface starts to saturate soil from the bottom. In the linked
DayCent-MODFLOW, the presence of water table in DayCent simulation
is controlled by the water table elevation in MODFLOW (Section 2.3).
Nitrogen dynamics are simulated in DayCent model using the mass
balance of nitrogen in soil:
ΔN = N
littter
+ N
fert
+ N
deposit
− N
gas
− N
erosion
− N
DP
− N
Root
(5a)
where N
litter
is nitrogen added from plant litter; N
fert
includes both
organic and inorganic fertilizer; N
deposit
is atmospheric nitrogen depo-
sition; N
gas
is gas removed via nitrication and denitrication and in-
cludes N
2
, N
2
O, and NO
x
gases; N
erosion
is the loss due to soil erosion; N
DP
is the removal from the soil prole via deep percolation (both inorganic
and organic forms); and N
Root
is plant root upake.
The emission of CH
4
is produced in soil under anaerobic conditions
by methanogens. In DayCent, the rate is primarily determined by the
availability of carbon substrate (derived from decomposition and root
rhizo-deposition) for methanogens and the impact of environmental
variables including soil texture (redox potential, pH, and soil tempera-
ture), climate, and agricultural practices (Hartmann et al., 2016).
Methane oxidation under aerated conditions is also modeled by DayCent
as a function of soil temperature, soil water content, porosity, and eld
capacity (Grosso et al., 2000) (Del Grosso et al., 2000). DayCent simu-
lates soil N
2
O and NO
x
emissions from nitrication and denitrication
(W. J. Parton et al., 2001). Nitrication is calculated as a function of soil
ammonium (NH
4
) concentration, soil moisture, soil temperature, pH,
and soil texture. Denitrication is a function of soil nitrate concentra-
tion, labile carbon availability, O
2
availability, soil water content, and
soil physical properties that inuence gas diffusivity.
2.3. Description of DayCent-MODFLOW theory
This section describes the basic linkage between DayCent and
MODFLOW, i.e. which information is passed between the two models,
and when. Section 2.4 provides details regarding the Message Passing
Interface (MPI) used to link the models without invasive code modi-
cation to either DayCent or MODFLOW. Section 2.5 describes an
application of DayCent-MODFLOW to a waterlogged site in an agricul-
tural area of northern Colorado, USA.
DayCent-MODFLOW is linked on a daily time step, with results from
each model providing inputs and constraints on the other. Therefore, the
linkage could be termed “tight linkage” or “tight coupling”. The linkage
process through time steps of a simulation is shown in Fig. 1. Each
DayCent model is mapped to one cell of the top layer of the MODFLOW
grid. As DayCent is a 1D eld-scale model, multiple DayCent simulations
are included to represent the collection of cultivated elds overlying the
unconned aquifer. Therefore, multiple DayCent models are linked to a
single MODFLOW model based on the geological locations. The simu-
lation runs according to the following steps, repeated for each time step:
1. MODFLOW passes basic grid cell information to the set of DayCent
models: surface elevation (top of MODFLOW grid cells), bottom
elevation of MODFLOW grid cells, specic yield S
y
of aquifer mate-
rial, and saturated hydraulic conductivity K of top layer (Table 1).
The soil and aquifer properties are shared between DayCent and
MODFLOW. If the time step is the rst of the simulation, MODFLOW
also passes initial groundwater head values for each grid cell.
2. The received values are assigned to corresponding model variables
for each DayCent model.
3. Each DayCent model is run for the time step.
Fig. 1. Flow chart of data passing in the coupled DayCent-MODFLOW model,
showing a single MODFLOW model coupled with a set of eld-based Day-
Cent models.
C. Deng et al.
剩余11页未读,继续阅读
资源评论
![avatar-default](https://csdnimg.cn/release/downloadcmsfe/public/img/lazyLogo2.1882d7f4.png)
![avatar](https://profile-avatar.csdnimg.cn/cb870bbdd7a340338b08a4ccf0175330_weixin_44259522.jpg!1)
___Y1
- 粉丝: 5148
- 资源: 160
上传资源 快速赚钱
我的内容管理 展开
我的资源 快来上传第一个资源
我的收益
登录查看自己的收益我的积分 登录查看自己的积分
我的C币 登录后查看C币余额
我的收藏
我的下载
下载帮助
![voice](https://csdnimg.cn/release/downloadcmsfe/public/img/voice.245cc511.png)
![center-task](https://csdnimg.cn/release/downloadcmsfe/public/img/center-task.c2eda91a.png)
安全验证
文档复制为VIP权益,开通VIP直接复制
![dialog-icon](https://csdnimg.cn/release/downloadcmsfe/public/img/green-success.6a4acb44.png)