kcchin said:

I have a small garden 30meter square. I dig down and find that the top 40cm
is just plain
sand ,little or no clay or silt. Any crop I plant, the soil is only good for
one crop, next generation
are stunted and will not grow. I assume that I have exhuasted the nutrients
for that crop.
What do I do?
Cart off the top soil (in this case sand, sand) and replace it with a lorry
load of garden soil, or could
I do something else?
I have access to limitless amount of dry leaves throughout the year to use
if I choose to.
Carting off the sand and replace it with garden soil is rather expensive
here in Singapore.

Consider composting some of the leaves and add the compost to the sand.
Chop up the others and use them to mulch the garden. Add used tea leaves or
coffeegrounds to the mulch, if you can get those in quantity.

The first rule of sandy soil is NEVER to dig in it without adding some sort
of organic material -- compost, seaweed, alfalfa pellets (rabbit pellets will
do as a substitute), aged manure, aged mulch -- never EVER!

Any fertilizers will need to be applied in frequent, very light doses or be
either natural slow-release fertilizers (like cottonseed meal or alfalfa meal)
or manufactured to be slow-release (pelletized, resin-encapsulated or chemically
altered to slow its availability/soluability).
--
Pat in Plymouth MI

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)