why can't a farmer sell used produce immediately in the mandi
Answers
I see 3 reasons for it
1. More than 50% farmers are in the clutches of debt. So I doubt if the produce is even theirs to start with.
2. APMC act forces farmer to only sell their products through Mandis established by government. So end users cannot buy their grains directly from farmers.
The mandis created by GOI are restricting farmers instead of ensuring good prices.
3. Finally, A good analysis by Rajiv Tyagi of politics on the issue
We are a strange hypocritical nation. No politician can get the farmer a 'good price' for cauliflower or any other vegetable. He cannot play politics with a farm produce that has such a short shelf life.
But come to grain and we now have a farm produce with a rather large shelf life. This is something he can play politics with. So every politician wants to get the farmer a 'good price' for his grain. Every political party will climb over the other's shoulders, promising the farmer higher prices. Every year, a well publicized exercise announces a minimum support price for grain which the Government purports to be interested in buying. The farmer queues up to sell his wheat. He waits... and waits... and waits... but the Government is not yet ready to pick up the wheat. The farmer does not have enough roofage to protect his entire production. Some of it is stored in bags or just freely in the open. He expects the Government to pick up his wheat. It doesn't. And then it rains. And his entire stock of wheat that was in the open, rots after getting wet. In theory he had become a relatively better-off man. In reality he has sunk further.
With sugarcane, the stakes are even higher! Here is a farm produce which has an industrial process connected with it! Oh goodie! So with sugarcane, every politician has the opportunity to extort or partner with the sugar industrialist, create laws that allow the sugar mills to cheat and ignore the farmer and keep fooling the farmer with 'good prices' for his produce. Then, as a smokescreen, the politicians' Governments will issue periodic threats to jail sundry industrialists and control orders on the price of levy sugar!