| dc.description.abstract | The effect of P fertilization on dry matter (DM)
production and eleillen composition and distribution in
sunflower (Helianthusannuus L.) was studied at different
stages of growth. Two varieties (H345 and Issanka) were used
in the study. Phosphorus fertilizer significantly increased DM
production in the leaves but had no significant effect on DM
accumulation in roots, sternsand heads. Phosphorus
fertilizer application affected seed yield and oil concentration
significantly in both varieties. The highest seed yields were
-1
obtained with the application of P at 31.5 and 63.0 kg ha in
Lssanka and H345, respectively , The highest oil content in both
varieties was obtaned with the application:ofP fertilizer at
63.0'kg ha -'.
Calcium concentration in the leaves was increased
significantly by P fertilizer application. S~similarly, P
concentration~ in the stems of'H345 was significantly higher ~n
plots applied with P fertilizer than those with no P fertilizer
application. In other plant parts,P fertilization did not have
significant effect Oil P and Ca concentrations. Nitrogen
concentration in the leaves, stems and heads was significantly
reduced by P fertilizer application but not in the roots. Also, K
concentration in the stems was significantly reduced by P
fertilizer application.
With the exception of seedling stage of growth, the roots had
the highest c;lry. matt·'~rprbdttctibJ1.;allil;.:.,hsa1J:atuhies lowest';'Leaves had
the highest concentrations ·of N, Ca and .Mg during most of the
growing season. The heads had the highst P concentration from
heading to maturity stage. Roots and st e.as had the lowest
concentration from heading to maturity stage. Roots and stems had
the lowest concentrations of N, P, Ca and Mg throughout the
growing season. Seeds had the highest K and Ca
concentrations when compared with other plant parts at maturity.
Nitrogen, P, K, Ca and Mg concentrations in the roots declined
duri.ngthe growing season. Nitrogen concentration an the stems
declined throughout the growing season while P and.K concentrations
did not have a consistent trend during the early stages of plant
growth but declined from floY:'e'rin.gs:.tgae .onward, Calcium
concentration increase~ slightly during t.heearly stages of plant
growth but remained relatively constant from flowering stage to
maturity. Magnesium concentration in the stems remained relatively
constant up to the flowering time, then declineJ. Nitrogen, P,K
and Ca concentrations ~n the heads declined throughout the growing
season but Mg concentration increased slightly up to the flowering
time, then declined. Nitrogen concentration in the leaves declined
throughout the growing season while Ca concentration increased.
Phosphorus andMg concentrations remained relatively constant up
to the flowering time, then declined at maturity ~n both varieties.
Also, in the leaves K concentration increased up to flowering
time ,:·the.nd..ecli.ned-itamaturity. | en |
