Thread: What is an ideal precipitation level for vegetation?

What is approximately the level of precipitation for vegetation after which it could be regarded as excessive?
Plenty of water is of course good for a plants, but speed of their growth is dictated by other factors such as sun and other nutrients.
Also plants cannot grow indefinitely. Some places with relatively dry climate, for example Canadian Prairies have developed agriculture and produce a lot of wheat. How low should be precipitations that it would become a problem and reduce harvests?

I never seen precipitation as a standard unit.

Please be more precise about what we are precipitating, what kind of soil we are dealing with, (saturation, turbidity, grain size, grain edge, minimum and maximum pore size, dissolved nutriënts, precipitated nutriënts, salts, calcite formation, pH, core temperature, temperature efficiency, density, etc)

I think you catch my drift that i cannot make any statements about a problem, because i don't know what your variable is, or what the normal conditions are.

Originally Posted by Stanley514

What is approximately the level of precipitation for vegetation after which it could be regarded as excessive?
Plenty of water is of course good for a plants, but speed of their growth is dictated by other factors such as sun and other nutrients.
Also plants cannot grow indefinitely. Some places with relatively dry climate, for example Canadian Prairies have developed agriculture and produce a lot of wheat. How low should be precipitations that it would become a problem and reduce harvests?

Are we looking at Chaparral?, savannah?, tiaga?, Norh Pacific bog?, south pacific temperate rainforest?........

The question is much to vague at this point to answer.

Originally Posted by Stanley514

What is approximately the level of precipitation for vegetation after which it could be regarded as excessive?
Plenty of water is of course good for a plants, but speed of their growth is dictated by other factors such as sun and other nutrients.
Also plants cannot grow indefinitely. Some places with relatively dry climate, for example Canadian Prairies have developed agriculture and produce a lot of wheat. How low should be precipitations that it would become a problem and reduce harvests?

FAO - Water Development and Management Unit - Crop Water Information: Wheat

Water Requirements

For high yields water requirements (ETm) are 450 to 650 mm depending on climate and length of growing period. The crop coefficient (kc) relating maximum evapotranspiration (ETm) to reference evapotranspiration (ETo) is: during the initial stage 0.3-0.4 (15 to 20 days), the development stage 0.7-0.8 (25 to 30 days), the mid-season stage 1.05-1.2 (50 to 65 days), the late-season stage 0.65-0.7 (30 to 40 days) and at harvest 0.2-0.25.

The page has much more info including charts and irrigation requirements for different countries and different wheats.

How much rain is needed depends on what you are trying to grow. Wheat does ok on realtively little, radishes need a lot, this year has been too wet for my tomatos.

If some area receives 393 mm precipitations annually,of which 309 mm is a rain, what chances are that this area will develop semi arid or steppe climate? Could forests grow under such precipitations?

Originally Posted by Stanley514

If some area receives 393 mm precipitations annually,of which 309 mm is a rain, what chances are that this area will develop semi arid or steppe climate? Could forests grow under such precipitations?

I'm not sure what you are asking. Will the forest continue to grow if the precipitation changes or will forests grow with that high a volume of precipitation?

Also, what is the seasonal distribution of the precipitation? Stanley, what is behind your question? That might make it easier to give a meaningful answer.