දන්න උන් කියපන් රසායනික පෝර නැතුව මුළු රටට ම වවලා කන්න දෙන්න පුළුවන් ද කියල.
You can't. Organic method is OK for small scale production. not suitable for large commercial operations. Not enough yield and cost is higher as well.
In Sri Lanka issue is not the chemical fertiliser, but the farmers. They use too much fertiliser and pesticides even if you actually not need it. Government give them for very cheap price, so they spray as much as they can get.
Government need to stop giving incentives to fertiliser and pesticides. Farmers will eventually use less chemicals.
My father in law used to be Head of agricultural department at one of the largest well established Srilankan company. Above is his personal opinion about the current situation.