What is the hottest temperate we can grow food at?

[AtomicJoe]

Also:-


http://www.ces.ncsu.edu/depts/hort/consumer/weather/tempeffect-plants.html


Review of Temperature Effects on Plant Growth:
Photosynthesis: Increases with temperature to a point.
Respiration: Rapidly increases with temperature.
Transpiration: Increases with temperature.
Flowering: May be partially triggered by temperature.
Sugar storage: Low temperatures reduce energy use and increase sugar storage.
Dormancy:Warmth, after a period of low temperature, will break dormancy and the plant will resume active growth.

Those statement seem to broadly back up what I have been saying do they not?

 

[Evo]

OK something concrete there.

Now can you then explain why a tobacco farmer in Mississippi can grow two crops in a year whilst one in Canada can only grow one? It seems to me it is because it is hotter in Mississippi, or have I overlooked something?

You've completely overlooked the fact that a more temperate climate has a longer growing season, and may allow more than one planting/harvest. Heat has nothing to do with it.

I didn't post references for something such as two crops in warmer Mississippi because I did not think anyone would dispute
that.

Since you aren't listening to us and insist on pushing the same misconceptions over and over no matter how many times we correct you, you continue your unwillingness to look things up.

I'm going to encourage you to look up valid information on what we've already told you.

You have a 10 day vacation to learn how to look up the information that was given to you here and hopefully you can learn during this period.

Good luck to you.

 

[Ryan_m_b]

Also:-


http://www.ces.ncsu.edu/depts/hort/consumer/weather/tempeffect-plants.html


Review of Temperature Effects on Plant Growth:
Photosynthesis: Increases with temperature to a point.
Respiration: Rapidly increases with temperature.
Transpiration: Increases with temperature.
Flowering: May be partially triggered by temperature.
Sugar storage: Low temperatures reduce energy use and increase sugar storage.
Dormancy:Warmth, after a period of low temperature, will break dormancy and the plant will resume active growth.

Those statement seem to broadly back up what I have been saying do they not?

It is outstanding how you can ignore all the emphasis people have put on optimal conditions. Repeatedly you have claimed that increasing temperature will lead to increased growth without acknowledging the fact that this only applies if you are increasing the temperature towards an optimum. You have not acknowledged the multifactoral nature of plant needs nor that different plants are different. You have not even recognised that plants need temperature changes, not a constant temperature.

Nobody is saying that increasing temperature will never lead to increased growth, they are saying that there are multiple factors that have optimum levels and that all plants are different

From your own link there are are many examples where the authors have stressed that there are optimum levels that change for different plants;

• Chrysanthemums will flower for a longer period of time if daylight temperatures are 50°F. The Christmas cactus forms flowers as a result of short days and low temperatures.
  
  
• Daffodils are forced to flower by putting bulbs in cold storage in October at 35 to 40°F. The cold temperature allows the bulb to mature
  
  
• Plants produce maximum growth when exposed to a day temperature that is about 10 to 15°F higher than the night temperature. This allows the plant to photosynthesize (build up) and respire (break down) during an optimum daytime temperature, and to curtail the rate of respiration during a cooler night.
  
  
• High temperatures cause increased respiration, sometimes above the rate of photosynthesis. This means that the products of photosynthesis are being used more rapidly than they are being produced. For growth to occur, photosynthesis must be greater than respiration.
  
  
• Not all plants grow best in the same temperature range. For example, snapdragons grow best when night time temperatures are 55°F, while the poinsettia grows best at 62°F. Florist cyclamen does well under very cool conditions, while many bedding plants grow best at a higher temperature.
  
  
• Peaches are a prime example; most cultivars require 700 to 1,000 hours below 45°F and above 32°F before they break their rest period and begin growth. This time period varies for different plants.

I realize that you have been sent on a 10 day break but I'm leaving this message here for you when you get back and for others to see.

 

[klimatos]

I don't think there is much point in growing stuff in a desert.

The term "desert" is a climatic term. It usually refers to areas with deficient precipitation. This has nothing to do with the availability of ground water for agricultural purposes.

In point of fact, the world's deserts are amongst it most productive places on a crop value per acre basis. Think of the Imperial Valley in California, the Nile Valley, the Indus Valley, the Gila Valley in Arizona, the list goes on. A very large part of the world's agricultural production is either wholly dependent on irrigation or partially so. I would guess at more than half.

Rainfall is just too unpredictable for successful commercial agriculture.

 

[AtomicJoe]

The term "desert" is a climatic term. It usually refers to areas with deficient precipitation. This has nothing to do with the availability of ground water for agricultural purposes.

In point of fact, the world's deserts are amongst it most productive places on a crop value per acre basis. Think of the Imperial Valley in California, the Nile Valley, the Indus Valley, the Gila Valley in Arizona, the list goes on. A very large part of the world's agricultural production is either wholly dependent on irrigation or partially so. I would guess at more than half.

Rainfall is just too unpredictable for successful commercial agriculture.

Those places sound like places which are warm, they also get a fair bit of sun.

Are there any 'cool' (significantly cooler) which are highly productive?

I guess one problem with colder places is that frost kills many plants so it is hard to produce a lot of food crops there, Antarctica being a prime example, I don't see that area becoming a major food supplier in the near future (unless you now something I don't).I not you quoted me slightly out of context the full test was:

"Well you can assume there is water available I think, I don't think there is much point in growing stuff in a desert."

Hence the 'desert' I refereed to was a place with a lack of water. Thus an irrigated desert would not qualify as a desert
in that respect because although it may technically be a desert, the irrigation makes it far from a desert in effect.
So we are not really in disagreement on that point.

Some people seem to cherry picking worst case scenarios to make their point but I am concerned with the best case scenarios.
I mean the middle of the pacific on the equator is hot, but it is probably not most people's first choice to locate a farm.

 

[DaveC426913]

I guess one problem with colder places is that frost kills many plants so it is hard to produce a lot of food crops there,

Frost only kills plants in frost season.

There's plenty of frost in the Canadian Prairies but they grow lots of wheat.

The point is, plants need sunlight, nutrients, water and a growing season.

While true, hot climes are also common where the above, it's not a cause/effect relationship. Correlation does not mean causation.

Plants will happily grow in greenehouses where they receive lots of sunlight, lots of water but only enough heat to keep them in their preferred range. (Some plants require cool temps, such as strawberries.)

If you did a controlled study that isolated and tested for sunlight, nutrients, water and heat versus growth, you would find that that any test batch deprived of any of the first three would utterly fail to thrive. Whereas any batch provided with the first three but deprived of the fourth would do much better.