Efficiency of Using Superabsorbent Polymers in Reducing Mineral Fertilizer Rates Applied in Autumn Royal Vineyards

Superabsorbent polymers (SAPs) addition to soil enhances the properties of soil and increase plant yields. Investigation of the efficacy of SAPs to reduce the rate of mineral fertilizers and produce high-quality grapes was the study's main goal. This investigation was carried out for three seasons (2019, 2020, and 2021) in a private vineyard located in El-Menofia Governorate, Egypt. Autumn Royal grapevines were grafted on Freedom. The vines were seven years old and grown in newly reclaimed sandy soil irrigated by drip irrigation. Several concentrations of polyacrylamide polymer (50, 75, and 100 g/vine/three years) were applied to the examined soil with nitrogen and potassium fertilization rates of 100%, 75%, and 50% of the recommended rate of fertilizer. The data revealed that increasing the amount of applied polymer significantly improved bud burst and fruitful buds percentages; growth parameters; total leaf chlorophyll content; N, P, and K percentages in leaves; and yield. Thus, the most effective method for increasing fruit production was to apply 45 units of N and 75 units of K per feddan, along with 70 kg per feddan of soil conditioner, which is safe for humans and improves the physical and chemical properties of the soil. This treatment considers the impact of SAPs on the preservation of nutrients.