Once upon a time on usenet Hypatia Nachshon wrote:

I found this:



The most important nutrients
influencing fruit quality are nitrogen,
phosphorus and potassium. However,
when any other nutrient is deficient or
in excess, fruit yield and quality are
negatively altered. Nitrogen (N) in-
creases juice content, TSS per box and
per acre, and acid content. However,
excessive N can induce excess vigor
and promote a vegetative rather than a
flowering tree, and can result in lower
yields with lower TSS per acre. In
contrast, low N levels promote exten-
sive flowering, but fruit set and yields
are poor.
Phosphorus reduces acid content,
which increases soluble solids: acid ra-
tio. Potassium (K) increases fruit pro-
duction, fruit size, green fruit and peel
thickness. Foliar spray of potassium
nitrate or monopotassium phosphate
in the spring often increases fruit size
of tangerine and grapefruit, and fruit
size and total pound solids of Valen-
cia orange. Foliar application (six to
eight weeks before bloom) of urea can
increase flowering and fruit set.

He
http://www.crec.ifas.ufl.edu/extensi...ors_citrus.pdf

Hope it helps.
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)