Irrigation 1/Irrigation 2 Flashcards
Around how much rain does Bordeaux get?
800-900 mm
Why is plant water use important?
Transpiration is the primary means of cooling the plant.
Water provides the pathway for nutrient uptake and the matrix for chemical reactions.
Only 5% of water taken by the roots are directly used to produce the carbohydrates necessary for plant growth.
What is the ratio of CO2 going into a plant compared to water leaving the plant?
1 CO2: 2000 water
Do plants need greater suction to remove water in clay soils?
Yea
Is suction negative or positive pressure?
Negative
What happens to leaf conductance and photosynthesis as the soil dries?
Declines
At what percentage of available water can a plant easily extract water?
60%
What are the reasons for irrigation research?
To save on the cost of irrigation
Safeguard production in dry years
Balance enough water and water stress
Water is a limited resource
Reduce the cost of production while optimizing returns
Grow vines that develop a deep root system
Grow vines that are less reliant on irrigation in times of drought
What is the most important property of water?
The polarity of the water molecule
What is the difference between adhesion and cohesion?
Adhesion (between different molecules) attracts water to a solid surface.
Cohesion (between the same molecules) attracts water molecules together.
Water moves further up through capillary action in what size pores?
Narrow
What are the three main forces acting on water in the soil?
Gravitational, capillary force, osmotic force
Capillary force is more important in clay soils and gravitational force is more important in sandy soils.
What is stronger : capillary force or gravity?
Capillary force
When is field capacity reached?
When all the water has drained out of the macropores
When has a soil reached its wilting point?
When the soil gets dry enough for the plants to wilt
