What effect heatwave on crops.

[Devil's advocate]

Well 40 degrees in France & much less reported but 44 degrees in Spain & 49 degrees in North Africa.

That is blooming hot, what effect will it have on crops, I presume they plan for hotter/drier than we expect in GB.

We are buying French carrots & they are turning black within hours of purchase.

 

[farmerm]

I wonder if some of the modern wheat varieties have really every been tested by such extreme temperatures at grain fill, even in countries that expect to get such temperatures later in the summer. Optimum temperature for wheat is something like 23C and I did find one research paper that indicated 34C triggers wheat to senesce? Had this heatwave been 2 or 3 weeks earlier its effect on Central European cereal crops may have been dramatic?

 

[Devil's advocate]

I wonder if some of the modern wheat varieties have really every been tested by such extreme temperatures at grain fill, even in countries that expect to get such temperatures later in the summer. Optimum temperature for wheat is something like 23C and I did find one research paper that indicated 34C triggers wheat to senesce? Had this heatwave been 2 or 3 weeks earlier its effect on Central European cereal crops may have been dramatic?

Might even be harvesting wheat in Spain now.

I was more thinking maize, sugar beet, soya, olives, grapes etc.

 

[farmerm]

Might even be harvesting wheat in Spain now.

I was more thinking maize, sugar beet, soya, olives, grapes etc.

Maize being a C4 plant will probably love it?

 

[curlietailz]

https://dl.sciencesocieties.org/publications/aj/pdfs/110/4/1296

Fabulous research paper on heat effects on wheat

 

[Oat]

Barley harvest in Germany may be starting in the next week

 

[Yale]

The heat and humidity is going to be a shock here as summer is really yet to begin proper.

 

[Widgetone]

Good protein wheats, with smaller grains?
Screeny barley?
Lower yield, higher prices . Or maybe the other way round, cant be sure.

Local ( suffolk ) farms are saying how good their crops look

 

[Kidds]

We always found with strawberries that wet winters rotted the roots off, if a wet period followed the roots didn't really recover. If they did recover they never really made a deep well formed system, more immature surface roots.
A sudden hot dry spell was disastrous as the plants could not take up water as quick as it was transpired, even more of a disaster in strawberries as it nearly always fell just as the fruit were swelling putting even more demand on the plant. Usual result in collapsed plants and lost crop. Hot sun exaggerated things as not only did the plants wilt but the wilting exposed the fruit to the sun and they literally cooked.

I would imagine any plant with a compromised root system is going to suffer. Hopefully with the rain we have already had things won't be too bad out there.
It will certainly show up any clubroot you have in your crops.

 

[Wombat]

Barley harvest in Germany may be starting in the next week

talking to a colleague in Germany it will start in the east this week, its not doing any harm at the moment

 

[Exfarmer]

It will so much depend on the availability of the roots to draw water, no water plant will senesce quickly, especially if their is a good wind to aid transpiration.
However all crops will tend to shut down in extreme heat even if copious amounts of water are applied or available to the root.
C4 plants such as maize sorghum etc have developed to cope in this situation, however they must still have water to grow.

 

[DRC]

The heat and humidity is going to be a shock here as summer is really yet to begin proper.

If it gets here. It’s been cold enough today with mizzly rain

 

[Devil's advocate]

We always found with strawberries that wet winters rotted the roots off, if a wet period followed the roots didn't really recover. If they did recover they never really made a deep well formed system, more immature surface roots.
A sudden hot dry spell was disastrous as the plants could not take up water as quick as it was transpired, even more of a disaster in strawberries as it nearly always fell just as the fruit were swelling putting even more demand on the plant. Usual result in collapsed plants and lost crop. Hot sun exaggerated things as not only did the plants wilt but the wilting exposed the fruit to the sun and they literally cooked.

I would imagine any plant with a compromised root system is going to suffer. Hopefully with the rain we have already had things won't be too bad out there.
It will certainly show up any clubroot you have in your crops.

Did they have rain in France & Spain?

Scary with strawberries. Thank goodness tunnels have made the job a bit easier in times of heavy rain.

On light land here & 8 year rotation so very rare to see clubroot here, but yes I know what it can do.

ps Was near you today Kidds at Quantils. Lovely part of the world so much warmer than Barnsley sunny with you, drizzle all day at Barnsley.

 

[Wombat]

Fingers crossed for some 30 degrees this weekend

 

[Yale]

If it gets here. It’s been cold enough today with mizzly rain

Perfect for a day working with sheep putting Clik on the lambs.

 

[Jon Boy]

Maize needs constant regular heat not highs and lows for good growth if it stays in the high 20's 24 hours a day with good access to water you will get optimum growth but when it climbs into the mid 30's growth will slow the same as when the temp drops below 20c.

 

[Devil's advocate]

Does anything grow well at 40 degrees C?

Must be a nightmare for potatoes on the continent. Not just for drought/heat but blight if they irrigate maybe leaf scorch too?

 

[Farmer Roy]

Does anything grow well at 40 degrees C?

Must be a nightmare for potatoes on the continent. Not just for drought/heat but blight if they irrigate maybe leaf scorch too?

No, not really

I've had grain sorghum "cooked in the boot", which literally means the head is steamed while it is still in the stem, when it emerges it is sterile & dead, producing no grain. That happened this year with the extremely hot summer we have just had. 300 ha of Sorghum planted ( with all the necessary management practices common in our environment, zero till, retaining ground cover, plant population, row spacings, soil moisture etc etc ) but was all cooked in the boot & didn't harvest one grain.
Because the plant was so stressed, it also had very high nitrate & prussic Acid levels, so wasn't suitable for hay or grazing, to try & recover anything from it

Cotton will abort squares, flowers & fruit once the heat stresses it too much.

Mid 20's to 30's temps are ideal for these crops, but everything struggles when you hit above 40's

A number of years ago I had a sunflower crop. Planted into a full profile of moisture ( as we always do ), but struck a particularly hot fortnight. The plants were being visibly stressed, my then father in law said "you need some rain", but he was wrong, they had their roots in mud & a full profile underneath - it was heat stress & it was just too much. That period was followed by a few days of cooler cloudy weather ( no rain ) & they just jumped away & started growing again. They had access to moisture, but the temps were too high, too sustained, for them to utilise it

A few degrees difference in temp can have a BIG effect

 

[czechmate]

I largely grow barley as a cereal as it has made the grains before the heat. Including this year, I could be cutting it if I wasn’t finishing off hay. For wheat I switched to soisant (spelling) for its earliness and awns, it was looking very promising but this week is robbing the last bit of yield and it has changed colour dramatically in the last three days. Grass of course dies every summer. Sunflowers are (so far) looking like “bring it on”
The garden is difficult.

 

[Devil's advocate]

No, not really

I've had grain sorghum "cooked in the boot", which literally means the head is steamed while it is still in the stem, when it emerges it is sterile & dead, producing no grain. That happened this year with the extremely hot summer we have just had. 300 ha of Sorghum planted ( with all the necessary management practices common in our environment, zero till, retaining ground cover, plant population, row spacings, soil moisture etc etc ) but was all cooked in the boot & didn't harvest one grain.
Because the plant was so stressed, it also had very high nitrate & prussic Acid levels, so wasn't suitable for hay or grazing, to try & recover anything from it

Cotton will abort squares, flowers & fruit once the heat stresses it too much.

Mid 20's to 30's temps are ideal for these crops, but everything struggles when you hit above 40's

A number of years ago I had a sunflower crop. Planted into a full profile of moisture ( as we always do ), but struck a particularly hot fortnight. The plants were being visibly stressed, my then father in law said "you need some rain", but he was wrong, they had their roots in mud & a full profile underneath - it was heat stress & it was just too much. That period was followed by a few days of cooler cloudy weather ( no rain ) & they just jumped away & started growing again. They had access to moisture, but the temps were too high, too sustained, for them to utilise it

A few degrees difference in temp can have a BIG effect

I liked the detailed explanation, not the situation you are in.

How about Olives & citrus fruit. Maybe walnuts?

On the upside does it make it easy to control couch grass after harvest