Effect Of Azotobacter, Compost And Humic Acid On Growth And Mineral Content Of Lettuce (Lactuca Sativa Cv. Alfajr) Grown In Plastic House
Rawnaq H. Rashad, Taha Z. Sarhan
A two-seasonal experiment was conducted in a plastic house at the protected cultivation department in Zakho Technical Institute, Dohuk Polytechnic University, Kurdistan region/ Iraq for autumn seasons (2021-2022) and (2022-2023) to examine the effect of azotobacter, compost and humic acid on growth, and mineral composition of lettuce cv. (Alfajr). The study encompassed azotobacter (with and without), soil addition of compost with three levels (0, 1, and 2) ton.donum-1 and foliar spraying of humic acid at four concentrations (0, 2, 4.and 8) ml.L-1 and their combinations compared to control. The experiment was designed according to randomized complete block design (RCBD) with three replicates. The results displayed that the individual dose and dual interactions of all studied factors significantly improved foliage attributes [head length (cm), leaf area (cm2), chlorophyll content (SPAD)] and leaf mineral content of N, P, and K in both seasons with the superiority for the second season over the first season. The highest ever values of all investigated attributes were measured for plants given azotobacter and compost at (2) ton.donum-1 plus humic acid at concentration (8) ml.L-1 in comparison with control. The azotobacter with compost and humic acid is recommended for organic production of Alfajr cultivar of lettuce.
Keywords: Azotobacter, Compost, Humic acid, Lettuce, Organic productivity