https://doi.org/10.37229/fsa.fjh.2025.10.30

Excessive use of mineral nitrogen fertilizers is a major factor leading to soil nutrient loss and environmental pollution, so reducing nitrogen use and finding sustainable alternatives are essential to improving potato productivity and resource efficiency. Two field experiments were conducted during the 2023 and 2024 seasons (early summer plantation) at Kaha Vegetable Research Farm, Qalyubia Governorate, Egypt, using a randomized complete block design with seven treatments. The study evaluated the effects of different mineral nitrogen levels (100%, 75%, and 50% from the recommended dose) with compensating for the deficiency with alternative organic sources (liquid biogas manure, compost tea, and the biofertilizer Azospirillum brasilenseon) on potato growth, yield, and soil properties. Results indicated that use of liquid biogas manure integration with mineral nitrogen fertilization at 75% of the recommended dose improved vegetative growth parameters, growth, yield and its components. In addition, it improved microbiological properties, enzyme activity and available macronutrient levels in soil in comparison to all treatments in both seasons. It can be concluded that the application of liquid organic fertilizers or biofertilizers are a promising method to reduce mineral nitrogen fertilizers, improve the growth parameters, productivity of potato and increase soil fertility.