RESPONSE OF COTTON CULTIVAR GIZA 90 NPK APPLICATION LEVELS

The present investigation was carried out at Shandaweel Agriculture Research Station during 2005 and 2006 seasons to study the effect of NPK application levels on growth and seed cotton yield as well as its components of the Egyptian cotton cultivar Giza 90 (Gossypium  barb dense L.). A randomized complete blokes design with four replicates was used. Nine treatments were as follows:
NPK₀ : 45 kg N   + 15 kg P₂O­₅       + 0 kg K₂O/ fed
NPK₁ : 45 kg N   + 22.5 kg P₂O­₅  + 24 kg K₂O/ fed
NPK₂ : 45 kg N   + 30 kg P₂O­₅        + 48 kg K₂O/ fed
NPK₃ : 60 kg N   + 15 kg P₂O₅     + 0 kg K₂O/ fed       
NPK₄ : 60 kg N   + 22.5 kg P₂O₅  + 24 kg K₂O/ fed
NPK₅ : 60 kg N   + 30 kg P₂O­₅     + 48 kg K₂O/ fed
NPK₆ : 75 kg N   + 15 kg P₂O­₅     + 0 kg K₂O/ fed
NPK₇ : 75 kg N   + 22.5 kg P₂O­₅  + 24 kg K₂O/ fed
NPK₈ : 75 kg N   + 30 kg P₂O­₅     + 48 kg K₂O/ fed
                The results of  these experiments indicated that plant height at harvest, Number of fruiting branches/ plant, height of fruiting nodes, number of open bolls/ plant, boll weight, seed cotton yield/ plant and feddan were significantly increased by tested treatments in both seasons. The greatest values of these traits were  obtained from the combined fertilization with 75 kg N + 30 kg P₂O₅ + 48 kg K₂O­/fed.