Effect of pre-sowing Application of Nitrogen, Potassium and Sulfur and its relationship on Egyptian Cotton Productivity

Fertilizer use in till systems must be aligned with a correct interpretation of soil chemical attributes and cotton demands. The objectives of this work were evaluate the effect of pre-sowing application of urea, potassium and sulfate on the yield of cotton and soil chemical attributes of till cotton (Gossypium barbadense L.) over two harvesting years. The experiment was arranged in complete randomized block design; the doses of an activation macronutrients were the quarter of recommended dose of them. We were applied the recommended doses of N, P,K on soil. The cotton plants in the experimental plots were manually harvested on October 25, 2015 and October 15, 2016. The soil samples were collected between cotton rows in all plots before sowing on March 27, 2015 and April 1, 2016 at depth of (0-30, 30-60 and 60-90 cm) for soil fertility analyses. -The increasing doses of N,K,S induced a higher values when we addition mixture of urea , potassium and sulfate on plant height, no. of fruiting branches, no. of open bolls before harvest, boll weight, seed cotton yield/ kentar, lint % , micronaire values and pressely values. -On the other hand, % earliness increased by control and reduced by addition the mixture of nutrients. -The mixture (N+k+S) treatment had the highest values of available N and S in the first and second respectively compared with the control treatment. -The addition of potassium Sulphate had gaven a highest values of available K in the first and second seasons respectively compared with the control treatment. -The Mixture treatment had gaven a highest values of N:K which reflected on a Lint% and seed cotton yield/fed at the first and second season , respectively -The control treatment had highest values of N: S ration which affected on seed cotton. It gave a lowest values of seed cotton yield/fed. But the treatment of mixture (N + K + S) gave moderate values of N:S ratio while it was gave a highest values of seed cotton yield / fed. -The highest values of N concentration in fourth leaf (last mature leaf) due to treatment with N (urea) in the first and second seasons. But it had gaven a lowest yield compared with the control treatments. -The highest values of K concentration led to K (potassium sulfate) treatment compared with the control in first and second seasons, respectively -The highest values of N: K ratio was obtained with N ( urea ) treatment. It led to decrease in the seed cotton yield / fed but the highest values of yield / fed was obtained when added all mineral fertilizers as a mixture in soil when N: K was as a compared on control treatments. - The second treatment which caused a highest in yield after mixture treatment was k (potassium sulphate ) , it had gaven ( 9.01 & 9.64 ) yield/fed while N:K was (0.34 & 0.32 ) in the first and second seasons respectively.