A field experiment was carried out in El-Gemmeiza Agric. Res. St., ARC, El-Gharbiya
Governorate, during 2016 and 2017 seasons to study the effect of potassium silicate
mineral or organic and different NPK fertilizer levels on growth and productivity of Egyptian
cotton variety Giza 86 under different sowing dates. The experiment design was a split plot
with four replications. The main plots had two sowing dates; (Early at 8th April and Late at 8th
May) and the sub plots had nine treatments (1- 100% NPK Control, 2- 100% NPK + potassium
silicate mineral, 3- 100% NPK + potassium silicate organic, 4- 125% NPK, 5- 125% NPK +
potassium silicate mineral, 6- 125% NPK + potassium silicate organic, 7- 75% NPK, 8- 75%
NPK + potassium silicate mineral and 9- 75% NPK + potassium silicate organic).
The most important results obtained could be summarized as follows:
1) Sowing date had a significant effect on growth, earliness, seed cotton yield and its components,
where, the early sowing date surpassed the late sowing date.
2) The levels of NPK 125% + foliar with potassium silicate organic sprayed three times at
squaring, initiation of flowering and two weeks after flowering had significant effect on
growth, seed cotton yield/fad and its components.
3) The interaction between sowing dates, NPK fertilizer levels with potassium silicate treatments
had only significant effect on plant high and no. of sympodia/plant.
4) All treatments (sowing dates, levels of NPK 125% + foliar with potassium silicate and the
interaction) wave exhibited any significant effect on all fiber properties.
Generally, from the results obtained revealed that early sowing date in combination with
the NPK fertilizer (125%) and foliar with potassium silicate organic sprayed three times at
squaring, initiation of flowering and two weeks after flowering for obtaining gave the high
productivity of Egyptian cotton variety Giza 86 in clay loam soil.