Relationships between LAI (Leaf Area Index) and Crop-Coefficients

1
Relationships between LAI (Leaf Area Index) and
Crop-Coefficients

• Biogeochemistry Laboratory
• Jung Soo Hyun

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INTRODUCTION

• Evapotranspiration
• evaporation transpiration
• important elements of hydrological model,
  especially, in agricultural or forest area.
• very sensitive to
• physical and chemical conditions soil moisture,
  meteorological conditions and vegetation area.
• physiological factors LAI (Leaf Area Index) and
  root depth

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INTRODUCTION

• Evapotranspiration
• difficult to measure and estimate accurately.
• plant uptakes water from various depth of soil.
• detailed mechanisms of evaporation from soil
  surface are not well known.

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INTRODUCTION

• The evapotranspiration and crop-coefficient
  method
• estimates evapotranspiration directly considering
  effects of vegetation on evapotranspiration.
• evapotranspiration the product of a term
  dependent on the atmospheric conditions
• crop-coefficient the type and status of the land
  cover and vegetation

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INTRODUCTION

• Crop-coefficient (Kc)
• Kc ETc/ETo
• ETc potential crop evapotranspiration
• ETo reference crop evapotranspiration

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INTRODUCTION

• Leaf Area Index (LAI)
• one sided green leaf area per unit ground area in
  broadleaf canopies.
• different along the types of vegetation.
• deciduous trees peaks during the height of
  growing season
• coniferous stands vary far less over the year

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OBJECTIVES

• to investigate
• the relations between physiological
  characteristics of plants (LAI) and Crop
  coefficient.
• the difference of the relations along the plant
  kinds.

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RESULTS

• for sesame(??)
• Kc1.09-0.45exp(-LAI)
• R-0.804, n12, Plt0.001
• range of LAI 08

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RESULTS

• for olive orchard
• linear relationship
• range of LAI 01

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RESULTS

• for winter wheat
• Kc0.40.8466LAI/(0.7887LAI)
• picture
• for maize (???)
• Kc1.100.095LAI
• LAIgt3.0
• Kc0.3823.692LAI/(LAI12.561)
• LAIlt3.0
• picture

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Results

• maize

• white wheat

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CONCLUSIONS

• The relationship between Kc and LAI is different
  along the plant types.
• Considering the range of LAI
• For all kinds of crops, Kc increases linearly
  with LAI until LAI reaches about 1.
• Sesame, white wheat and maize, except for, olive
  orchard have linearity when a LAI reaches about
  3.
• The relationship between Kc and LAI seemed to be
  affected by characteristics of canopy cover
  rather than each physiological characteristics of
  crops.