ROLE OF NPK FERTILIZER AND SPRAYING WITH SEAWEED EXTRACT AND NANO IRON ON GROWTH OF GRAPEFRUIT TRANSPLANTS

Abstract

This study was conducted in a lath house, Dept. Of Hort. and Landscape  , College of Agricultural Engineering Sciences, Univ. Baghdad, during 2022 growing season to investigate influence of mineral fertilizers NPK and spraying with seaweed extract and Nano iron on some vegetative growth characteristics and leaf mineral content of two year's old Red blush of grapefruit transplants. Factors of study experiment included addition of three levels of mineral fertilizers NPK (without addition (C0), 2.5 g transplant^-1 (C_2.5), and 5 g transplant^-1 (C₅)), while seaweed extract spray was sprayed with two levels; without spray (S₀)  and spraying at 4 g L^-1 (S₄), As for Nano-iron fertilizer treatments, they were sprayed in three levels (0, 10, and 20 mg L^-1), which are denoted by symbols I₀, I₁₀, and I₂₀, respectively. Treatments were replicated three times (three transplants in experimental unit) at factorial experiment in a RCBD and thus number of transplants used was 162 transplants. The experimental results showed that chemical fertilizers at 5 g L^-1(C₅) significantly increased in leaves number of 47.44 leaf. plant^-1, leaf area of 29.99 cm², leaf phosphor content of 0.400 % and leaf iron content of  175.6 mg kg^-1 . Results also showed that seaweed extract spray, significant superiority in increased in leaves number of 41.30 leaf plant^-1, leaf area of 28.92 cm², leaf phosphor content of 0.339 % and leaf iron content of 173.2 mg kg^-1. Nano- iron spray at 20 mg L^-1 significantly effect in leaves number of 40.45 leaf   plant^-1, leaf area of 28.27 cm²and leaf iron content of 180.6 mg kg^-1. Twice and triple interactions between study factors significantly affected in all studied traits