Farm land usage query

Do I need to pay any amounts for constructing a small home on farm land which will be used to stay there and continue operations for farming? i have a permission from local Grampanchayat and an assessment was done with yearly amount being paid to them for the constructed house with a receipt. The land in question is 46 guntha with 40% agricultural and rest unusable for agriculture. they call it potkharaba here in Maharasthra. house in concern is small 1 room kitchen types and single storey-ed with no RCC structures and earthern tile roof. the larger room here is 15x10 feet and a small kitchen and bathroom adjoining so this is not a large apartment meant for a large family.. Now the local Talathi demands that there has to be a boja paid for about rupees 12500 for a year which is way to high. This i am informed is to be paid because i have not converted that 0.5 guntha land into NA. I do not pay this large amount for even a 1 bhk of 500 sqfeet in KDMC which is local body for urban area in kalyan. is there some goofup here? as I am already paying revenue for this house to Gram Panchayat and have the said permission for it from them. I read many articles around but nothing concrete. Some say you can construct upto 1600 sq feet in 1 acre and some say it is not required as per some new laws. The house in concern is built on land is because i do not have a home near by to stay and carry out farming and there is nothing like a garden or swimming pool to make it a farm house. we have plantations for banana that show to anyone's eyes on a check that this is indeed used for farming.