The Effect of Mycorrhizal Inoculation and Different Methods of Applying NPK Chemical Fertilizer on Certain Growth Characteristics of Zea mays L. in Gypsum Soil

With the aim of increasing the efficiency of chemical fertilizer use and reducing nutrient losses in plants, mycorrhizal fungi were used as a safe, readily available, environmentally friendly, and sustainable method. The experiment was conducted in the fields of the College of Agriculture – University of Tikrit, following a completely randomized block design (RCBD), to study the effect of different methods of applying chemical fertilizers and inoculating with mycorrhizal fungi on the growth and yield of yellow corn, as well as certain growth and quality traits. The experiment included two factors: the first was the application of chemical fertilizers using three methods, in addition to a control treatment without fertilizer application, namely: the control treatment (Control) without chemical fertilizer application; application with irrigation water; application in rows parallel to the planting rows at a distance of 5 cm from the seeds; and broadcast application on the soil surface. The second factor consisted of two treatments: inoculation with mycorrhizal fungi and no inoculation. The results showed that the methods of applying chemical fertilizer and inoculation with mycorrhizal fungi had a significant effect on a number of growth characteristics and the nutritional status of yellow corn. The broadcast application method outperformed the others in terms of mycorrhizal infection rate, dry weight, 500-kernel weight, protein content, nitrogen content, phosphorus content, and leaf area, recording values of 80.93%, 12.13 g, 31.10 g, 8.06%, 1.80%, 0.25%, and 718.50 cm², respectively, while the addition of fertilizer to the irrigation water outperformed the other treatments in potassium content, reaching 1.53%, Inoculation with Mycorrhiza fungi also improved a number of traits, with the highest average leaf area reaching 733.08 cm², dry weight 11.28 g, weight of 500 seeds 29.91 g, protein content 8.05%, phosphorus content was 0.23%, and potassium content was 1.53%, while nitrogen content was 1.61%. Interactions were observed between the methods of adding the The phosphorus content was 0.23%, the potassium content was 1.53%, while the nitrogen content was 1.61%. The interactions between fertilizer application methods and mycorrhizae yielded different responses depending on the trait, most notably the superior performance of the mycorrhizae treatment combined with row application for certain traits.