Making online accountancy database (first phase)

I want a secured internetplatform, an online accountancy programm for farmers. Each farmer has it's own account where he has to fill in all his costs and incomes of his several crops and animals. Each crop has several cost-categories f.ex. potatoes: seeds, fytocosts, energy, ... the same for sugars beets: seeds, fytocost, ... The farmer must register each cost in the right category. In a next step the programm must calculate the average of each costcategory. The farmer can see only the cost of his own and the average of all the farmers. There's of course a supervision programm needed controlled by me/us, to manage all figures, accounts, ... The programm registers everything of cost and yield of crops, animals, ... Also investmests, loans, ... and lot of other things must be registered. In a first step I would suggest to make a small application to evaluate (see attachment), and then decide to make the hole project.