Özet:

Aims: This study was performed in 2015-2016 in order to determine how the foliar application of sulfur helped reduce the effects of long-term water stress in Carisma variety cotton plants in different periods of development, namely vegetative growth (VG), flowering and boll development (FB), and boll opening (BO) periods. Methods and Results: The study was set up in randomized complete block with three replications. Development periods (OOO, TTT, TOO, OTT, OTO, TOT) were assigned to main plots and sulfur doses (S0: Control, S1: 150 ml da-1, S2: 250 ml da-1, S3: 350 ml da-1) were assigned to sub-plots. Measurements were made on stomatal conductance, as well as evaporatranspiration and yield to evaluate the physiological effects of water stress. The average amounts of irrigation water used in each full irrigation were 127.5 and 138 mm respectively, for the treatment years. As for the evaporatranspiration values, in the first treatment year it was found between 304 and 1012 mm and in the second year from 256 to 1070 mm. Stomatal conductance values ranged from 269 to 1067 mmol m-2 s-1 in the first year and from 205 to 407 mmol m-2 s-1 in the second year with the highest stomatal conductance value obtained from full irrigation (TTT) during all growth periods in both years. Conclusions: The effects of sulfur dosage on stomatal conductance and yield varied due to exposure to long-term water stress at different developmental periods however, generally speaking, the doses of S1 and S2 cause these values to increase. Significance and Impact of the Study: In the Amik Plain, there was no detailed study to determine how foliar sulfur applications changed the stomatal conductance of cotton when drip-irrigated and subjected to water stress during the different development stages. This research revealed in what dose sulfur should be given to reduce the effects of long-term water stress in Carisma variety cotton plants in Amik plain.

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