Two field experiments were carried out at Sakha Agricultural
Research Station at Kafr El-Sheikh Governorate, Egypt, on new hybrid
cotton (Giza 86 X 10229) during 2013 and 2014 seasons to study the
effect of sowing dates (15 April and 15 May) as main plots and five
methods and time of potassium sulphate application as sub plots i.e:
1- Soil application of 24 kg K2O/fed. as potassium sulphate (48% K2O)
after thinning.
2- Soil application of 24 kg K2O/fed. as potassium sulphate (48% K2O) at
two weeks after thinning.
3- Foliar application of 5 kg potassium sulphate (48% K2O)/fed. sprayed
two times at the square and start flowering stages.
4- Foliar application of 5 kg potassium sulphate (48% K2O)/fed. sprayed
two times at the start and peak of flowering stages.
5- Foliar application of 5 kg potassium sulphate (48% K2O)/fed. sprayed
three times at square, start and peak of flowering stages. The most
important results obtained could be summarized as follows:
1) Results obtained revealed that early sowing (15 April) significantly
increased no. of internodes and sympodia on the main stem, no. of
open bolls/plant, boll weight, seed cotton yield/plant and /feddan, dry
weight of vegetative and fruiting organs of plant, days to first flower,
days to first open boll and earliness percentage, while plant height, no.
of more monopodial/plant and first sympodium node were decreased.
2) Results indicated the positive effect of potassium when it was applied
at the proper time as soil application at two weeks after thinning which
resulted in less no. of monopodia and higher no. of sympodia, higher
dry weight of vegetative and fruiting organs, heaviest bolls, and higher
no. of open bolls as well as seed cotton yield/plant and /feddan.
Potassium fertilization showed no effect on no. of main stem
internodes/plant, first sympodium node, days to first flower, days to
first open boll, seed index, earliness percentage and lint percentage.
3) The interaction of planting date by K treatments was not significant for
all traits studied in this investigation.
4) Generally, results obtained revealed that early sowing (15 April) and
the soil application of potassium sulphate (24 kg/feddan) fertilizer at
two weeks after thinning for obtaining high productivity of new hybrid
cotton (Giza 86 x 10229).