EFFECTS OF DIFFERENT FERTILIZERS AND SUBSTRATES ON THE LEAF DEVELOPMENT OF LACTUCA SATIVA IN HYDROPONIC CULTURE

Аннотация

This study investigates the influence of various fertilizers and substrates on the leaf development of Lactuca sativa (lettuce) grown under hydroponic conditions. A comparative analysis was conducted using four substrates (vermiculite, perlite, coco coir, and rockwool) and six fertilizer treatments: mineral salts, humic acid, humic acid + mineral salts, microalgae, microalgae + mineral salts. The results indicate significant variations in leaf number depending on the combination of substrate and fertilizer, with rockwool and microalgae + mineral salts showing the highest efficacy. Annotation This article explores the effects of various fertilizer types and substrates on the leaf development of Lactuca sativa (lettuce) grown in a hydroponic Nutrient Film Technique (NFT) system. The study evaluated four different substrates—vermiculite, perlite, coco coir, and rockwool—combined with six fertilization treatments, including mineral salts, humic acid, and microalgae-based biofertilizers. The results demonstrated that substrate and fertilizer combinations significantly influenced the number of leaves developed by the lettuce plants. The combination of rockwool substrate and microalgae + mineral salts fertilizer yielded the highest leaf production, highlighting the synergistic effect of bio-organic and inorganic nutrient inputs in controlled environment agriculture. The research further supports the environmental and agronomic benefits of integrating biofertilizers into hydroponic systems and emphasizes the potential for sustainable crop production practices in areas with limited arable land. This work contributes valuable insight into resource-efficient and high-yield cultivation strategies relevant to modern soilless agriculture. Keywords: Hydroponics, Lactuca sativa, biofertilizers, substrates, microalgae, mineral salts 1. Introduction Hydroponic systems offer an efficient and sustainable solution to modern agricultural challenges, particularly in regions with limited arable land and changing climatic conditions. Lactuca sativa, commonly known as lettuce, is a popular leafy vegetable suitable for hydroponic cultivation due to its rapid growth cycle and responsiveness to nutrient management. This research aims to evaluate how different substrates and fertilizer combinations affect the number of leaves, an important indicator of plant vigor and productivity. Due to its adaptability and versatility in a variety of dishes, such as salads, stews, vegetable curries, sandwiches, and garnishes, lettuce is a critical component of contemporary diets. Its appeal is not limited to the enhancement of the visual and sensory quality of meals; it also substantially contributes to nutritional intake. Moreover, its capacity to be cultivated in a variety of agroecological zones ensures that it is available and accessible in both local and international markets during the year. In addition to its nutritional value, lettuce is becoming increasingly acknowledged for its therapeutic potential. It is recognised as a substantial source of phytonutrients, which are bioactive compounds that possess disease-preventive, anti-inflammatory, and antioxidant properties. These phytochemicals, in conjunction with 153 essential vitamins and minerals, establish lettuce as a functional food that can offer health benefits that exceed those of fundamental nutrition. The Deep Flow Technique (DFT) and Nutrient Film Technique (NFT) are two of the most common hydroponic systems used for the cultivation of verdant vegetables. Ensures the continuous availability of water and nutrients by replenishing nutrient solutions when water levels decline below a critical threshold in DFT systems. A thin nutrient film that travels over plant roots is the foundation of NFT systems, which are frequently employed in plant factories. For example, NFT is less water-intensive and space-efficient, while DFT guarantees nutrient supply even in the event of pump malfunctions. Each system has its own set of advantages. These systems ensure that the nutrient cycle remains consistent, thereby fostering the optimal conditions for the growth of crops like lettuce. As a modern cultivation system, soilless cultivation offers significant advantages over conventional soil-based agriculture, particularly in enhancing both the yield and quality of horticultural crops. This is achieved by precise regulation of the composition and quantity of nutrient solutions, as well as the properties of the growing media (Nerlich and Dannehl, 2021). At present, rockwool (RC) and coconut coir (CC) are among the most widely used substrates in greenhouse horticulture. Rockwool, in particular, has been utilized for decades due to its optimal physical and chemical characteristics, making it suitable for a wide range of crops. Solid substrate cultivation is extensively employed in greenhouse vegetable production, particularly for fruit-bearing crops such as tomato and cucumber. In Europe, the United States,