Difference between revisions of "ISY-99i/ISY-26 INSTEON:Evapotranspiration and Irrigation"
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== What is Evapotranspiration == | == What is Evapotranspiration == | ||
| − | + | # ET is an approximation of the amount of water leaving the soil via a combination of evaporation and transpiration (a fancy word for plants drinking it up). | |
| + | # The goal of an ET-aware irrigation system is to approximately (despite all the appearance of precision, we have to remember this) replace this water. | ||
| + | # It does this by tracking the water used/lost from the soil until a threshold is reached (where the plants would starve for water if much more left without replacement). | ||
| + | # In most climates, this will result in watering every few days. | ||
| + | # Rain may offset some of the water use/loss, resulting in less frequent watering. | ||
| + | # Calculations performed once every 24 hours are sufficient for this tracking. | ||
| + | |||
| + | |||
| + | Image | ||
| + | |||
| + | The 3 key concepts here are: | ||
| + | # There's some amount of allowed depletion (based on the plant types, root lengths, etc.). | ||
| + | # This depletion will not typically happen in a single day. | ||
| + | # What is varied is when to water, not how much. | ||
== Irrigation with Evapotranspiration == | == Irrigation with Evapotranspiration == | ||
| − | + | Image | |
| + | |||
| + | # A running balance is used to decide when to irrigate. | ||
| + | # It's not necessary to exactly replace all the water which has left the soil (i.e. zero-out the balance). | ||
| + | |||
Revision as of 23:26, 8 July 2011
What is Evapotranspiration
- ET is an approximation of the amount of water leaving the soil via a combination of evaporation and transpiration (a fancy word for plants drinking it up).
- The goal of an ET-aware irrigation system is to approximately (despite all the appearance of precision, we have to remember this) replace this water.
- It does this by tracking the water used/lost from the soil until a threshold is reached (where the plants would starve for water if much more left without replacement).
- In most climates, this will result in watering every few days.
- Rain may offset some of the water use/loss, resulting in less frequent watering.
- Calculations performed once every 24 hours are sufficient for this tracking.
Image
The 3 key concepts here are:
- There's some amount of allowed depletion (based on the plant types, root lengths, etc.).
- This depletion will not typically happen in a single day.
- What is varied is when to water, not how much.
Irrigation with Evapotranspiration
Image
- A running balance is used to decide when to irrigate.
- It's not necessary to exactly replace all the water which has left the soil (i.e. zero-out the balance).
