i didn´t understand the question (ed2)

[Richard]

Hey vagabond,
I like some of the images in here. I do have some suggestions though:

about the question                                                                (edit leanne, tiger)                                   

the old lady has alzheimer´s and she said To me, saying the woman has alzheimer's is too on the nose, so I don't think it needs to be mentioned. May be it could be hinted at more so than directly said? Just a thought.
about seventy years ago there was a field -May be consider starting with this line. It sets up the poem just as well as the current first line.
in czechoslovakia, maybe not only there and not only then.
it might have grown wheat in summer
but one late autumn day -I like the use of the seasons here because this poem is somewhat dealing with the idea of time. Would it be possible to work winter in some how? I ask because the woman in the poem is elderly.
the earth produced hands and arms,
digging to reach the sky -I like this image of the bodies in the ground. Your wording here makes the image work for me.
and its air -
then still. -I think this line could work just as well as the ending because the stillness refers back to image of the earth, but could also refer to the woman passing away.
and still she seems waiting for answers. -Another option could be to  replace this last line with something that could hint back to the woman's alzheimer's? May be experiment with her uncertainty of where or when she was seeing such a sight.

about the question

she had alzheimers, but the old lady once said
that about seventy years ago there was a field
in czechoslovakia, maybe not only then and not only there.
it might have produced grain in summer,
but one autumn day it grew a few arms,
digging to reach the sky
and its air -
then still.
and still she seems waiting for answers.
i can´t wait to share her dementia.

  mainly i´d like to know if content is clear enough and if it´s a bad idea to let the subject speak in the last line

Overall, I think you're going in the right direction, and I look forward to seeing where you take this piece from here.

Cheers,
Richard