Cottonseed: protein, oil yields, and oil properties as influenced by potassium fertilization and foliar application of zinc and phosphorus

Abstract

In maximizing the quantity and quality of a crop’s nutritional value in terms of fatty acids and protein, it is necessary to identify the constraints which may affect it 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 47.4 kg of K ha–1) and foliar application of zinc (at 0.0 and 57.6 g of Zn ha–1, two times, 70 and 85 days after planting, “during square initiation and boll setting stage”) and phosphorus (at 0.0, 576, 1152 and 1728 g of P ha–1, two times, 80 and 95 days after planting) on cottonseed. The application of potassium along with spraying plants with zinc and phosphorus caused an increase in cottonseed yield ha–1, seed index, seed oil content, oil and protein yields ha–1, 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 P concentration of 1728 g ha–1 gave the best values of cottonseed yield/ha, seed index, and seed oil and protein yields/ha and oil saponifiable matter.

Keywords

• cottonseed
• oil fatty acids
• oil properties
• phosphorus
• potassium
• zinc