Summary of Effects of vegetal protein hydrolysate application method:
Effects of Vegetal Protein Hydrolysate on Hydroponic Lettuce Growth
Hydroponic farming offers a sustainable way to grow crops without soil. Farmers must optimize plant nutrition to achieve high yields and produce quality crops. One effective way to naturally enhance plant growth involves using vegetal-derived protein hydrolysates (PHs), plant-based biostimulants that support crop development. Although researchers have highlighted the benefits of PHs, many studies have relied on a fixed nitrate-to-ammonium (NO₃⁻:NH₄⁺) ratio without exploring how different nitrogen (N) levels and PH application methods impact plant growth. This limitation has led to inconsistent findings across studies.
In this study, researchers investigated how various nitrogen levels (2 or 10 mM), NO₃⁻:NH₄⁺ ratios (100:0, 75:25, 50:50, or 25:75), and PH application methods (foliar spray, root application, or no PH treatment) influenced growth, nutrient absorption, and overall lettuce quality in hydroponic systems.
The study revealed significant impacts of nitrogen levels, NO₃⁻:NH₄⁺ ratios, and PH applications on lettuce development. The NO₃⁻:NH₄⁺ ratio and PH treatments played a crucial role in enhancing shoot growth. Researchers also observed similar trends in chlorophyll content, a key factor for plant photosynthesis and overall health. Additionally, changes in root growth and structure resulted from the combined effects of nitrogen levels, NO₃⁻:NH₄⁺ ratios, and PH treatments.
Among all application methods, root application of PH (PH-R) delivered the best results. It protected lettuce from yield loss caused by low NO₃⁻:NH₄⁺ ratios and prevented a decline in antioxidant compounds triggered by excessive nitrogen levels. PH treatments also boosted nutrient absorption, enabling plants to take in essential minerals for stronger growth. However, PH did not directly alter nitrate concentration in the lettuce.
This research highlights the crucial role of PH interactions with nitrogen levels and NO₃⁻:NH₄⁺ ratios in hydroponic lettuce production. By applying PH through the roots, growers can improve lettuce yield, chlorophyll content, antioxidant levels, and nutrient absorption, reinforcing plant-based biostimulants as a sustainable alternative to synthetic fertilizers in hydroponic farming.
Publication: Journal of the Science of Food and Agriculture
