Title: Simulation of C and N dynamics in soil and plants
1Simulation of C and N dynamics in soil and plants
- R.A. Poluektov V.V.Terleev
- Agrophysical Research Institute,
- St.-Petersburg, Russia
2Model structure
3Input data
4State variables and output
5Submodels
6Shell structure of AGROTOOL
7Model features
8Model identification consists of 5 steps
9Parameters controlling temp of plant development
10Water stress function
Correction of dry matter accumulation
Argument of water stress function
Stress function
11Calculation of rootshoot ratio
(Two flows model)
12C and N transformation in soil
13Calculation of crs
Distribution of PrimAss
N demand by shoot and root
N uptake by roots
N balance
14 Determination of rootshoot ratio
1- N-dependence of crop, 2 N-uptake by roots
15Dependence of rootshoot ratio on N-doze
1- flowering phase, 2 full ripening phase
16Dynamics of rootshoot ratio by various
N-fertilization
1- variant without N, 2 N45 kg ha-1, 3 N90
kg ha-1
17Model of water retention curve
where volumetric soil moisture, matrix
potential, MH maximum hygroscopy, SP saturation
point, a, b empirical parameters.
18Variants of calculation of hydrological constants
,
,
,
,
r- soil bulk density, rS - solid phase density,
MH maximum hygroscopy, SP - saturation point,
WP wilting point, FC field capacity, LC
lower capillary moisture, UC upper capillary
moisture.
19Calculation of water retention curve for the
soil of Men'kovo experimentation station using
the following experimental data r, rS , MH.
1 water retention curve, 2 specific water
capacity, 3 dependence of UC on yUC, 4 -
dependence of LC on yLC
20Comparison of calculated and experimental data
o experimental points, -.- - interpolated
curve, curve calculated using experimental
data
21Computer system for estimation soil hydraulic
parameters
22Estimation of Badlauchstadt pedotransfer functions
- This program was used for estimation of the
parameters included in pedotransfer functions.
The experimental data for soil texture and
saturated hydraulic conductivity were used for
this purpose. Two additional data, apart from
available MH and SP, were necessary for
estimation of the pF-curve parameters. Such
hydraulic soil parameters as field capacity (FC)
and wilting point (WP) were chosen for this
purpose. The comparison of simulated pF-curves
with experimental data is presented in the
following Figs.
23Comparison between simulated water retention
curves and experimental data sets presented by
Franko et al. (site Badlauchstadt)
24Comparison of simulated and real winter ray grain
yield (Menkovo experimentation station)
25Dependence of spring barley grain yield on
N-dose (Menkovo experimentation station)
26Nitrates leaching (Menkovo experimentation
station)
27Yield and dry mass
28Yield and dry mass
29Yield and dry mass
30Water status
31Water status
32Results of statistical treatment for water content
33Results of statistical treatment for dry mass
34Conclusion
- Generally, there are externally few things in the
World, which we really anything know about. In
the most cases it only seems to us that we know. -
Kharuki Murakami -
Hunting on sheep
35