Influence of Vermicompost Extract and Spraying with Nano-iron and Nano-boron on the Mineral Content of Papaya Fruit (Carica papaya L.)

Papaya has been introduced to Iraq recently, necessitating the development of integrated fertilization programs tailored to local climatic and soil conditions to ensure optimal growth and high yields. Fertilization management is a key determinant of papaya tree growth and productivity, as the integrated use of organic and mineral fertilizers improves soil properties and increases nutrient absorption efficiency. Therefore, a field trial was conducted on a private papaya farm from the beginning of October 2024 to the end of June 2025 to study the effects of Vermicompost extract and spraying with Nano-iron and boron on papaya tree growth, yield, and mineral content. A three-factor factorial experiment was conducted using a completely randomized block design. The experiment included three factors. The first factor was the addition of Vermicompost extract at two levels (0 and 50) m L⁻¹. The second factor was the spraying of boron nanoparticles at four levels (0, 5, 15, and 10) m L⁻¹. The third factor was the spraying of iron nanoparticles at four levels (0, 2, 4, and 6 m L⁻¹). The results showed that the Vercompost extract (at a concentration of V50) was significantly superior in terms of the highest average content of mineral elements in the fruits (percentage of calcium, magnesium, potassium, sodium, boron, and iron), respectively, compared to the control treatment. Spraying with nano-iron and Nano-boron significantly outperformed the (F6) and (B15) levels respectively, giving the highest average fruit content of the aforementioned mineral elements compared to the control treatment. The two-way interference coefficients (V50×Fe6), (V50×B15), and (Fe6×B15) were significantly superior in the same indices. The triple interaction treatment (V50×Fe6×B15) significantly increased the fruit content of the above mineral elements by (0.193%, 0.362%, 2.534%, 0.340%, 0.143%, 26.033 g.kg⁻¹, 353.64 g.kg⁻¹) respectively, compared to the control treatment.