[DonovanG44 (OP)]

How would using 1 million Gal. of saltwater as the watering source affect plants/environment in say SE Oregon-Nevada where salt water isn't common?
Could this concept be used continuously if impact is none/minimal or only once in awhile for emergencies?
 
**The purpose for this question is for wild fire control, I've developed a design to aid fighting fires, and would like to utilize salt water instead of fresh for this emergency purpose BUT I don't know the environmental effects.

[alancalverd]

Depends on the plants. If they have evolved in and colonised an area with low salt, they won't like it and may not recover for some time, but

some plants (e.g. marram grass) are very tolerant of sea water and would happily colonise an area, at least temporarily, after a dousing with it, but

some plants (particularly Australian natives) seem to rely on fire to disseminate their seeds and encourage germination!

AFAIK sea water is used to bomb forest fires around the Mediterranean, and the local conifers seem to recover better from the salt than the fire. 

[Arinece]

Like coconut trees, A coconut tree grows well based on salt as we see it around the sea. If we didn't provide fresh water then we have to deliver direct salt to their root.

[evan_au]

wild fire control

If you used salt water for fire-fighting, do it in areas with high rainfall, and good drainage back into the sea, so that rain will wash out the salt quickly - hopefully before the plants are all killed by the salt water.

How would using ...saltwater as the watering source affect plants/environment

Kelp forests grow in seawater - but they don't suffer many fires.
- Mangroves grow in estuaries, where their roots are bathed in salty water twice every day. But they excrete the excess salt via their leaves.
- Perhaps surprisingly, some inland areas with brackish lakes have high salt levels due to evaporation, and some plants can live there. But plants don't grow in dry salt lakes.

Every creature requires a certain concentration of salt in their cells - which is usually:
- Less than the concentration of sea-water today: so creatures living in the sea have mechanisms to pump salt out
- But more than the concentration in fresh water: so creatures living in fresh water have mechanisms to capture and retain salt
- Go outside their tolerance limits, and they sicken & die

Fresh water is a scarce resource, which is affecting human populations and farm production around the world
- There is an incredible number of tons of water needed to deliver a ton of grain or a ton of beef - this invisible water is called "virtual water"
- Much of our farmland is degraded by salt brought to the surface by irrigation; what used to be called "the fertile crescent" in the Middle East (2,000 BCE) is now called "the salt marshes"
- Agriculturalists are trying to breed crops that are more salt-tolerant
- Some scientists are trying to transfer genes from salt-tolerant species into crop species so that they can use poorer water sources
- But dumping salt water on inland areas where crops are watered with fresh water will only kill the crops and degrade the soil.
See: https://en.wikipedia.org/wiki/Virtual_water#Virtual_water_content_of_selected_products