Effect of Foliar Application of Potassium Nitrate and Number of Sprays on Growth and Yield of Lettuce Lactuca sativa L.


An experiment was conducted during the winter growing season of 2015 /2016 at Al-Dair, Basrah. The aim was to study the effect of foliar spraying of potassium nitrate and the of spraying on yield and quality of lettuce cv. Local. the experiment included 9 treatments came from the interaction among three potassium nitrate (KNO3) of 0, 0.5 and 1 gm .L-1 and applied with spraying (one, two and three times) at 15-day intervals after 25 days after transplanting. Randomized Complete Block Design was used in a factorial experiment. Treatment means were compared by using Least Significant Differences (L.S.D.) at probability of 0.05 The result showed that spraying of KNO3 at 1gm.L-1 increased yield and improved plant characteristics such as number of total and folded, fresh weight of leaves, plant fresh and dry weight ,leaf area per plant, and leaves dry matter. spraying with three times was the most effective in number of total leaves, leaf area per plant, plant fresh and dry weight and productivity. The interaction of two factors of study had a significant effect in some characteristics. The highest fresh weight of leaves, fresh weight and total productivity came from spray with 1gm. L-1 KNO3 every three times 691 gm, 01gm, 8871 cm2 and 18.7 ton/ donum, respectively.