Effect of Different Levels of Urea and the Trichoderma harzianum Biofungicide on Tomato Growth and Resistance to Rhizoctonia solani Root Rot

A field experiment was conducted in the aeroponic beds of the College of Medicinal and Industrial Plants at Kirkuk University during the 2023-2024 season on the tomato crop Lycopersicon esculentum Mill. The experiment aimed to study the effect of adding different levels of urea on tomato growth, yield, and resistance to Rhizoctonia solani (root rot). Urea was applied at levels of 0, 80, 160, and 240 kg ha⁻¹. For comparison, the fungus Trichoderma harzianum was applied at rates of 25 and 50 cm³/L. The soil was prepared for planting. The soil was fertilized with the above urea levels and with both phosphorus and potassium at a level of 80 kg P/ha in the form of superphosphate and 120 kg K/ha, respectively. Then the soil was contaminated with the fungus Rhizoctonia solani, and the tomato seedlings were transplanted on 10/18/2023 The study was conducted using a factorial experiment and a randomized complete block design (RCBD) with three replications. The results showed that the urea level (160 kg/ha) was significantly superior to the other levels in giving the highest plant height, dry weight, chlorophyll content, nitrogen, phosphorus, and potassium concentrations in the tomato plant, among other studied traits. The 240 level negatively affected the studied traits. The results also showed that a concentration of (50) cm3/L of the biopesticide led to a significant increase in all studied growth traits. The interaction between nitrogen fertilization and the addition of the biopesticide T. harzianum significantly affected all studied traits at the combination (160 kg/ha + 50 cm3/L)