Cottonseed, Protein, Oil Yields and Oil Properties as Influenced by Potassium Fertilization and Foliar Application of Zinc and Phosphorus

In maximizing the yield quantity and quality of a crop in terms of the nutritional value of fatty acids and protein, it is necessary to identify the constraints, which operate at a site and to devise methods of overcoming them through the use of inputs or changes in management practices. Field experiments were conducted during two successive seasons at the Agricultural Research Center, Giza, Egypt, on the cotton cultivar "Giza 86" (Gossypium barbadense L.) to study the effects of potassium fertilization (at 0.0 and 57.1 kg of K2O/ha) and foliar application of zinc (at 0.0 and 60 ppm of Zn, two times, 70 and 85 days after planting, "during square initiation and boll setting stage") and phosphorus (at 0.0, 600, 1200 and 1800 ppm of P2O5, two times, 80 and 95 days after planting) on cottonseed. Application of potassium and spraying plants with zinc and phosphorus caused an increase in cottonseed yield/ha, seed index, seed oil content, oil and protein yields/ha, seed oil unsaponifiable matter and total unsaturated fatty acids (oleic and linoleic). However, those treatments resulted in a decrease in oil acid value, saponification value and total saturated fatty acids. The highest P2O5-concentration of 1800 ppm gave the best values of cottonseed yield/ha, seed index and seed oil and protein yields/ha and oil saponifiable matter.