Environmental Response of Maize to Organic Fertilization and Foliar Silicon Nutrition Under Different Levels of Mineral Fertilization (NPK)

Abstract

A factorial experiment using a randomized complete block design (RCBD) was conducted in the spring of 2024 in a clay loam soil at Ibn Al-Bitar Vocational Preparatory School/Al-Husainiya District, Holy Karbala, to investigate the effects of mineral fertilizers (NPK), organic and foliar silicon application on maize growth and yield. The experiment included three factors: mineral fertilizers (N, P, and K) at three levels: without fertilization, symbolized by M₀, adding 50% of the fertilizer recommendation (150 kg N ha^-1, 50 kg P ha^-1, and 80 kg K ha^-1) and symbolized by M₁, and adding 100% of the fertilizer recommendation (300 kg N ha^-1, 100 kg P ha^-1, and 160 kg K ha^-1) and symbolized by M₂, the second factor was organic fertilization at two levels (0 and 40 kg ha^-1), Symbolizing it sequentially (O_0, and O₁).  and the third factor was foliar feeding with organic silicon at three concentrations (0, 3, and 6 ml L^-1), Symbolizing it sequentially (Si₀, Si_1, and Si₂). The results of the study show that the studied traits, which include plant height, leaf area, chlorophyll index, plant yield, and harvest index, were significantly affected by individual and combined study factors. Level M2 recorded the highest means, reaching (196.503 cm, 63.837 dm plant^-1, 55.662 SPAD, 161.17 g plant^-1, and 48.958%) respectively. Meanwhile, the mean in the organic fertilizer level O₁ was (192.463 cm, 62.598 dm plant^-1, 54.544 SPAD, 157.60 g plant^-1, and 49.003%) respectively. As for the foliar spray with silicon Si₂, it achieved means of (190.184 cm, 61.157 dm plant^-1, 54.234 SPAD, 150.35 g plant^-1, and 48.551%) respectively. Regarding the binary interaction, treatment M₁O₁ recorded the highest means for plant height, leaf area, and chlorophyll index in leaves, with an average of (201.396 cm, 66.217 dm plant^-1, and 51.058%) respectively. Meanwhile, treatment M₂O₁ achieved the highest means in chlorophyll index and plant yield, recording (57.504 SPAD and 176.00 g plant^-1) respectively. The interaction treatment M₂Si₂ recorded the highest means for plant height, leaf area, chlorophyll index, and plant yield, reaching (198.933 cm, 64.568 dm plant^-1, 57.270 SPAD, and 169.75 g plant^-1) respectively. As for treatment M₁Si₂, it achieved the highest mean in harvest index, reaching (50.522%). The interaction treatment O₁Si₂ achieved the highest mean in all mentioned traits (196.672 cm, 63.151 dm plant^-1, 55.922 SPAD, 167.77 g plant^-1, and 50.649%). Finally, the ternary interaction treatment M₁O₁Si₂ gave the highest means for the traits (208.580 cm, 66.922 dm plant^-1, 58.953 SPAD, 186.63 g plant^-1, and 53.473%) respectively, while the control treatment, which did not add fertilizer, had the lowest means for the studied plant traits.