Sodic soil?

Help!

I live near Wexford in the south-east of Ireland.

I have been gardening on a 2/5 of an acre plot on a new bungalow development for 4 years.
Its been one hell of slog as the builder skimmed off all the top soil and sold it, and left me with large areas of compaction, builder's hardcore and rubble. If that weren't bad enough, I have lousy drainage and marl hard pan about 2 foot down.[ I am 3 miles inland from a beach].


Despite all this, I have had some success in both veggies and shrubs; failures or slow growth I put down to what the builder left me. I still felt that there was something wrong given the attention the garden has got....e.g. I've applied a reasonable quantity of rotted local horse manure in the veg garden.
This year I had hoped to make the great leap forward......I constructed, successfully, French drains and remodelled much of my vegetable patch into 14 inch high raised beds after our last 2 lousy summers..

Amongst other things I planted a small selection of 4 varieties of tomato in 8 inch cut tubes over open soil in the greenhouse and British Queen potatoes in one of the large raised beds. Both were doing fine until about 2 weeks ago, when in the space of 4-5 days, the potato leaves went noticeably mottled yellow and partially wilted and at the same the tomatoes [now only 9" high but vigorous, went lemon yellow in the central growing tips. These gradually turned almost white and the plants wilted. The weird thing was that it seemed to happen coterminously, rather than gradually spreading from plant to plant.

I called out an inspector from our Dept of Agriculture who has just sent away lab samples of the tomato plants but her gut reaction was that I have a soil deficiency.

[I have now burned both tomato and potato haulms.

At long last I am now getting to my point. My theory is that my soil, due to location, disposal of topsoil and drainage may be extremely saline. But I suspect I have compounded the problem this year by dumping the extremely poor clay soil from constructing the French drains into the raised beds, thinking that the horse manure would soon put it to rights. Furthermore, whereever I planted, including the tomato'tubes', I mixed sandy soil into peat compost. When I now examine that same spent compost, salt-like particles are clearly evident throughout the mix.

I suspect I have a sodic problem with the whole garden but also believe I have really exacerbated it as described above.

Has this happened to anyone else? Is my theory credible?
Whilst I will look to sending off soil samples to be analysed, I would appreciate hearing the opinions of other gardeners.

Thanks

could the horse manure be contaminated? do the fields the horses use get sprayed to keep weeds down? I think soil salinity will depend on the surrounding geology and how brackish the watertable is, but as you are 3 miles from the coast I think it unlikely that the watertable is affected.

Lovely place, Wexford!