Effects of the spatial variability of soil hydraulic properties on water dynamics

in cranberry production

Gumiere, S.J.; Caron, J.; Périard, Y.; Lafond, J.

NACREW-2013 - QuébecDép. Sols et Génie Agroalimentaire, FSAA, U. Laval.

silvio-jose.gumiere@fsaa.ulaval.ca

• Soil hydraulic properties may present spatial variability and dependence at the scale of watersheds or fields even in man-made structures, such as cranberry fields.

• Water management in cranberry fields should take into account the spatial variability of soil properties.

• First we need to characterize the spatial variability ant its sources.

Introduction

What are the sources of variability in the field?

Variability in crop

productivity

Variability from soil

properties

Variability from root

water uptake

Variability from

irrigation system

Variability from ground

water

We need to characterize these sources in order to understand their effects on crop productivity.

Material and Methods:Field observations: • Irrigation system;• Sat. hydraulic cond. (Ksat);• Soil water retention curves;• Matric potential;• Photosynthesis;• Ground water level;• Crop productivity.

Site A

Site B

Material and Methods:Geostatistics and interpolation• Variographic analyses• Kriging• Thin plate splines (TPS)• Entropy methods …

1( ) ( ( ) ( ))

2h Var X s h X h

Material and Methods:• Variographic analyses• Kriging• Thin plate splines (TPS)• Entropy methods

Find homogeneous zones

Results : Characterization and interpolation

• Saturated hydraulic conductivity;• Spatio-temporal variability of soil matric potential;• Crop productivity;

Saturated hydraulic conductivity of two depths (20 and 40cm)

Site A Site B

Slow zonesFast zones

Very slow zones

Soil Tension at 10 cm (root zone)

kPa

Site A

Before irrigation

After irrigation

T1 + 1 h

Site A

Soil Tension at 10 cm (root zone)

kPa

Before irrigation

After irrigation

T1 + 1 h

Site B

Site A, productivity Site B, productivity

1000 x lbs/acre 1000 x lbs/acre

Conclusion• Spatial patterns of Ksat at both sites.• Matric potential seems to follow the same

patterns.• Crop productivity has high spatial variability.

– Site A, low productivity in fast zones;– Site B, low productivity in very slow zones;

Thank you!Questions???