EFFECT OF WATER STRESS AND FERTILIZATION ON COTTON PRODUCTIVITY UNDER CALCAREOUS SOIL CONDITIONS

Two field experiments were carried out at the Farm of Nubaria AgriculturalResearch Station, Agricultural Research Center (ARC), Giza, Egypt, representing the newly reclaimeddesert land of North West, Egypt in Nubaria, which located at 46 Km South West of Alexandria city tostudy the effect of irrigation regimes and NPK fertilization, earliness parameters, seed cotton yield, itscomponents of Egyptian cotton (Gossypium barbadense L.) cultivar Giza 94 was used which representlong staple Egyptian cotton category in the two summer growing seasons of 2017 and 2018. Theexperimental design was a split-split plot with four replications, where the irrigation regime treatmentswere allocated to the main plots and the sub-main plots included NPK fertilization, while foliarapplication treatments were taken place in sub-sub plots, where irrigation regimes were irrigation at50% depletion of available soil moisture. (I1), irrigation at 70% depletion of available soil moisture(I2) and irrigation at 90% depletion of available soil moisture (I3). While NPK-fertilizer rates were100% of NPK recommended doses (75 kg N, 31 P2O5 and 48 K2O/fad.), 75% of NPK recommendeddoses (56.3 kg N, 23.3 P2O5 and 36 K2O/fad.) and 50% of NPK recommended doses (37.5 kg N, 15.5P2O5 and 24 K2O/fad.). Foliar application treatments were control (water), potassium silicate (twotimes at the rate of 1 kg/fad., before flowering and two weeks later), extractable mixed of algae, aminoacids and micronutrients (two times at the rate of 1 L/fad., before flowering and two weeks later).Theresults revealed that growth and yield attributes of cotton were affected by water stress under NPKfertilization and foliar application, in this respect the highest value of growth, yield characters wereachieved under irrigation regime (50% depletion of available soil moisture) and recommended dose ofNPK and foliar application of Algal extracts + amino acids + micronutrient) under Nubaria conditions.