Development of a tool to monitor Development of a tool to monitor crop growth and grain yield in crop growth and grain yield in

Córdoba, ArgentinaCórdoba, Argentina

Antonio de la Casa and Gustavo Ovando Antonio de la Casa and Gustavo Ovando

Facultad de Ciencias Agropecuarias – UNCFacultad de Ciencias Agropecuarias – UNC

CREAN CREAN

Córdoba, ArgentinaCórdoba, Argentina

Relevance of the topic selected

FAO model FAO model (Doorembos and Kassam, 1979)(Doorembos and Kassam, 1979)

max1

max1

ET

ETaKy

Y

Yai

Where

Ya/Ymax is the relative yield; (1-Ya/Ymax) the relative yield decrease;

ETa/ETmax the relative evapotranspiration; (1-ETa/ETmax) the water stress or relative evapotranspiration deficit;

Ky is the response of yield to water stress for a given environment.

∑NDVIa: actual NDVI sum for crop cycle

∑NDVImax: maximum NDVI sum for crop cycle

maxNDVI

NDVI1

max1

aKy

Y

Yai

Relative NDVI values substitutesthose of Relative evapotranspiration (Funk and Buddle, 2009)

Conceptual framework

Operative framework

Objective of application

Develop a procedure to estimate corn and soybean yield in Cordoba province, Argentina.

Use different ILWIS routines to calculate FAO Model crop productivity from NDVI MODIS and local (in situ) data.

Flow diagram Flow diagram

❶ ❶ MODIS 250 m NDVI imagesMODIS 250 m NDVI images

❸ ❸ Image Classification

Late soybean:iff(band_1>0.6,iff(band_7<0.3,iff(band_11>0.7,1,0),0),0)

Early soybean: iff(band_1<0.3,iff(band_8>0.7,iff(band_15<0.3,1,0),0),0)

Corniff(band_1<0.3,iff(band_6>0.6,iff(band_15<0.3,1,0),0),0)

iff(band_1<0.3,iff(band_7>0.7,iff(band_15<0.3,1,0),0),0)

soybean:=iff((soybean_1=1 )OR (soybean_2=1),1,0)

corn:=iff((corn_1=1 )OR(corn_2=1),1,0)

Late soybean

Early soybean

Corn

❼ ❼ YMax=∑(YMax=∑(fCov*PAR)*fCov*PAR)*ε*ε*HIHI

Ymax_soybean:=iff(soybean=1,Sum_fCov_Par_01*1.8*0.47*10,?)Ymax_corn:=iff(corn=1,Sum_fCov_Par_01*3.8*0.47*10,?)

❽ ❽ Ya=Ymax-Ymax*Ky*(1-∑NDVI/∑Ya=Ymax-Ymax*Ky*(1-∑NDVI/∑NDVImax)NDVImax)

Ya_soybean:=iff(soybean=1,Ymax_soybean-Ymax_soybean*1.3*(1-ndvi_suma/7.6),?)

Ya_corn:=iff(corn=1,Ymax_corn-Ymax_corn*1.5*(1-ndvi_suma/7.6),?) 

❾ ❾ Image masking Image masking

❿ ❿ Departmental YieldDepartmental Yield

soybean corn

Conclusions

• It was estimated corn and soybean yields in Cordoba, Argentina, using only NDVI and solar radiation data as background information.

• This first prototype, despite its simplified design, produce objective results to contrast with the more qualitative method currently used by the state agency.

• The FAO method for estimating crop productivity structured in GIS is flexible to incorporate modular routines to calculate Ymax, ETmax and ETa using methodologies of more complexity and accuracy derived from remote sensing.

• Improving the procedure at a later stage should take into account satellite imagery to evaluated the different sensitivity to water stress of crops at different phenological stages.