TSubDevelopmentMaize

1 Introduction

Maize development is regulated by the effective temperature (T_eff) – derived by the positive difference of daily mean temperature and a defined base temperature (T1) of 6°C in agreement with (Pagès and Pellerin, 1994) and Bonhomme et al. (1994)). Furthermore, the development process is separated into five stages further named XStage, following HYBRID-Maize, based on the approach of Yang et al. (2016). The XStages represent the development stages emergence, tassel initiation, silking, effective grain filling and maturity (Figure 1). Development rates between sowing and emergence (DevRateS0), emergence and tassel initiation (DevRateS1), tassel initiation and silking (DevRateS2), silking and grain filling (DevRateS3) are calculated as simple ratio of Teff and the temperature sum (GDD) between the respective XStages (Eq. 1 - Eq. 4 ). Compared to the approach of Yang et al. (2016), an additional GDD is introduced from emergence till silking (GDDsilk) to calculate the development rate from grain filling until maturity (DevRateS4, E5).The GDDs are defined cultivar specific parameters assigned according to the assumptions of Bignon (1990) for a mid-early cultivar at a soil with medium warming dynamics, harvested at the dough stage, which is the harvest date of whole crop silage maize with a typical DM content of 35%.

DevRate_{S0} = \frac{T_{eff}}{{GDD}_{emer}} \tag{1}

DevRateS0: Development rate between sowing and emergence, Teff: effective temperature, GDDemer: corresponding growing degree days

\mathrm{DevRateS1=}\frac{\mathrm{T}_{\mathrm{eff}}}{{\mathrm{GDD}}_{\mathrm{tasini}}} \tag{2}

DevRateS1: Development rate between emergence and tassel initiation, Teff: effective temperature, GDDtasini: growing degree days from emergence till tassel initiation

\mathrm{DevRateS2=\ }\frac{\mathrm{T}_{\mathrm{eff}}}{{\mathrm{GDD}}_{\mathrm{S2}}} \tag{3}

DevRateS2: Development rate between tassel initiation and silking, Teff: effective temperature, GDDS2: growing degree days from tassel initiation till silking

\mathrm{DevRateS3=}\frac{\mathrm{T}_{\mathrm{eff}}}{{\mathrm{GDD}}_{\mathrm{S3}}} \tag{4}

Figure 1: A drawing of an elephant.

x <- seq(1, 100, by = 1)
y <- 0.4+x*2+x^2*3

df <- data.frame(x, y)

p <- ggplot(df, aes(x = x, y = y)) +
  geom_line() +
  labs(title = "Title", x = "X", y = "Y") +
  theme_minimal()
p

Figure 2: Development scheme of maize according to HYBRID-Maize.

1.1 Descendence

The class TPenMonteith is derived from TPlantRelatedSubMod, which is derived from TSubmodel which is derived from TObject or TGraphicControl.

TPenMonteith |____TPlantRelatedSubMod |____TSubmodel

1.2 State variables

The class TSubDevelopent has 10 following state variable(s).

kable(df.state)

State variable	Units	InitialValue	Description
CumPH	[n]	1	number of fully expanded leaves
CumPH_Booting	[n]	0	number of nodes
DS	[-]	0	Development stage for calculating root drymatter (See Hybrid-Maize)
GDD6	[°C*d]	0	Growing degree days from sowing
GDD6_from_emergence	[°C*d]	0	growing degree days from emergence
GDD8	[°C*d]	0	Just for Information, not for calculation.
TLNO	[n]	6	TLNO is the total number of leaves that will eventually appear
TSum_leafLagphase		0
XSTAGE	[-]	0	Phenological stage, non integer values
XSTAGE_till_tassel_emergence	[-]	0

TRUE

1.3 Parameters

The class TSubDevlopemt_Maiz has 12 following parameter(s).

Parameter	Units	Value	Description
GDD6Emergence	[°C*d]	68.34	Temperature sum sowing to emergence
GDD6Silking	[°C*d]	822.60	Temperature sum silking
GDD6Stage2	[°C*d]	510.00	Temperature sum tassel initiation till silking
GDD6Stage3	[°C*d]	202.60	Temperature sum stage 3
GDD6tasini	[°C*d]	320.00	Temperature sum from emergence till tassel initiation
GDD6total	[°C*d]	1534.97	Temperature sum
Phyllochron	[°C*d]	54.05	Phyllochron
Plastochron	[°C*d]	29.18	Plastochron
sen_par	[-]	0.15	en_fact wird als potenz Funktion angenommen, sen_par ist der Krümmungsfaktor dieser
sen_parexp	[-]	2.00	en_fact wird als potenz Funktion angenommen, sen_parexp ist der Exponent dieser
SowingDate	[-]	39191.00	Date of sowing (days from 1.1.1990)
Tbase6	[°C]	6.00	Base temperature

TRUE

References

Pagès, L., Pellerin, S., 1994. Evaluation of parameters describing the root system architecture of field grown maize plants (zea mays l.). Plant and Soil 164, 169–176. https://doi.org/10.1007/BF00010068