Growing spuds In Thailand?

I am an expat living in Thailand and just like I did back home in the UK I want to grow spuds. Despite the locals here saying that spuds wont grow I am now on my second crop of spuds which sadly is producing the same results as the first crop. I have plenty of good haulms above ground but Alla's, no flowers on them and also no spuds below. Thailand is a flat country which bears the hallmarks of once being the sea bed. There are , mussels and other shellfish and the soil is a mixture of sand and clay. whenever the dry season comes which is now there are large areas which have a white covering on the surface which is salt. It never washes away in Thailand. I have Incorporated loads of manure, compost etc and have a good soil. I also have no problems growing any of the local produce here which seems to have adapted to salt conditions, Any Ideas please?