Irrigation

Question 1

Reasons for the increase in food production.

Answer 1

• Fertelization.
• Irrigation.
• Improved plant varieties.

Question 2

The choice of an irrigation system depends on what? How do we normally make that decision?

Answer 2

The choice of an irrigation system depends on: crop, soil, economics, water quality and water management considerations. Normally, the decision is based on the economics, in a way that we choose the irrigation system that can give more profit to the farmer.

Question 3

Which are the types of irrigation systems? Give one example.

Answer 3

• Surface irrigation: Basin irrigation (Rice)
• Sprinkler irrigation: Pivot irrigation.
• Micro irrigation: Drip irrigation systems.
• Subirrigation: Water table management.

Question 4

What is the soil matric potential?

Answer 4

It’s the force that retains the water in the soil.

Question 5

What is the Soil Water Characteristic Curve?

Answer 5

It’s a curve that describes the relation between soil water content and matric potential. Gives us the quantity of water that we have in a soil when we maintain it to a certain pressure. It’s used to model the waterflow in a porous material. Highly non linear function and very hard to obtain accurately (HYPROP measures). It’s related with the porous medium distribution. We can model it through the Van Genuchten Model and the Brooks and Corey Model.

Question 6

What do you know about Vadose Zone?

Answer 6

The vadose zone is located between the water table and the soil surface. The water content of the soil is less than saturation, many pores are filled with air and the pressure heads are negative.

Question 7

What is the Field Capacity?

Answer 7

Is the equilibrium between capillary forces and gravity. When we achieve this point, we should stop irrigation.

Question 8

What happens if we have a salty water?

Answer 8

If we have a salty water, the concentration of water inside the plant will be lower than outside because the osmotic potential will make more difficult to the plants to get that water since, in order to get it, the plant needs to break some forces. In this case, the electrical forces will be very high so the plants will spend a lot of energy trying to break them.

Question 9

What is the permanent and temporary wilting point?

Answer 9

These points depend from plants to plants and measure the resistance of the plants.
After we pass the permanent wilting point, the plant can not go back, it will die even if we put water after that.
If we pass the temporary wilting point, the plant still has chances to survive, sometimes.