The basic reason is lack of proper planning. Most farmers want unexpectedly huge returns but most of the times do not want to invest even a single penny on planning. What would be the result then? Loss....They do not fulfil the criteria for identifying suitable species for their soils.
The another fact is about inexperienced consultants. As I see today in MAP sector majority of consultants are not experts/ qualified in concerned subject and doing consultancy on the basis of their insufficient knowledge and skills about the subject.
For a successful MAP project or any project, it is necessary for farmers to undertake thorough analysis and planning and locate genuine and qualified experts for better planning of their agri projects. For consultants, it is their moral duty to feed the farmers with genuine information and help them for better planning of their projects.
A lot to write on this subject but this is I think enough for now. Please don't mind if there are any mistakes as I made this text in hurry.