Exempt income

In which ITR form you want to show ?

I have only agriculture income which is above 5000

agriculture income above 5000 should be shown in ITR 2 in Schedule EI

In you case your income does not exceed basic exemption limit so you shouldn't file any ITR.
Inspite of that you want to file ITR then you can file ITR-1 as nil return and you can show your agricultural income in the exempt income portion there's space given ITR-1 for agricultural income if it doesn't exceed 5000.