permament grass

[Annelie Holzkaemper]

Hi all,

I wonder how a permanent grass cover could be simulated with Daisy. The onyl way I got it to work so far is to re-sow every year (always staring with LAI = 0, which is not what I want).

If I don't re-sow the grass is stuck at DS = 2. It no longer evolves further dynamically. 

Is there a way aroudn this issue?

Thanks in advance and best regards

Annelie

[Per Abrahamsen]

Hi  Annelie.

You need to cut the grass regularly to prevent it from reaching maturity (DS=2).  

Kindly,

Per A.

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[Merete Elisabeth Styczen]

Hi Annelie

It depends somewhat on your purpose of the simulation. If you just want a permanent grass and you are not particularly interested in growth stages and yield, you also have the possibility of using the definition of a permanent grass. It is defined under “vegetation” and is a type of “permanent” vegetation. You can find something called “grass” in “vegetation.dai” under lib in the directory. It mainly takes care of water balance.

 

If you use a grass in rotation where you are interested in yield of grass or seed you will need to check the parameters DSmax and DSnew. If you look in grass.dai, DSnew (defined under harvest) is set to 0.2. It means that when you cut the or harvest the crop, DS goes back to 0.2 and the growth has to start all over. DSmax is the maximum DS-value where the crop survives a cut. It has been set to 3, so you will not run into such a high value, meaning that it can be cut at any stage and re-grow.

 

Hope it helps.

 

Best wishes

Merete Styczen

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