Pyroligneous Acid Foliar Spray Enhances Tomato Yield and Nutritional Quality
Introduction
Pyroligneous acid (PA), commonly known as wood vinegar, is recognized for its bioactive compounds that enhance plant growth and fruit quality. While its individual effects have been studied, limited research has explored its synergistic interaction with fertilizers. This study investigates the combined impact of foliar PA application and nitrogen-phosphorus-potassium (NPK) fertilizer on the yield and nutritional properties of greenhouse-grown tomato (*Solanum lycopersicum* 'Scotia').
Experimental Design and Application
Greenhouse-grown tomato plants were subjected to foliar PA treatments at concentrations of 0%, 0.25%, 0.5%, 1%, and 2% (v/v in distilled water), applied biweekly. These treatments were applied in conjunction with either a full NPK rate (0.63 g nitrogen, 0.28 g phosphorus, 1.03 g potassium per plant) or a half NPK rate. The NPK fertilizer was applied as a soil drench at 21-day intervals to ensure consistent nutrient availability. The study measured chlorophyll fluorescence, fruit yield, phytochemical properties, and mineral composition to evaluate the biostimulatory effects of PA.
Key Findings
Enhanced Photosynthetic Efficiency
- PA at 0.25% and 0.5% significantly improved maximum quantum efficiency (Fv/Fm) and photosynthetic capacity (Fv/Fo), particularly when combined with full NPK.
- Leaf chlorophyll content increased by 0.60-fold in plants treated with 2% PA alongside full NPK, compared to untreated controls.
Improved Yield and Marketability
The following table documents the yield increases measured in this study.
| PA Concentration | NPK Rate | Fruit Number Increase | Total Fruit Weight Increase |
|---|---|---|---|
| 0% (Control) | Full/Half | Baseline | Baseline |
| 0.25% | Full | 0.15-fold | 0.15-fold |
| 0.5% | Full | 0.30-fold | 0.28-fold |
| 1% | Full | 0.42-fold | 0.37-fold |
| 2% | Full | 0.56-fold | 0.56-fold |
| 2% | Half | 0.22-fold | 0.22-fold |
Increased Nutritional and Phytochemical Composition
- Fruit protein, sugar, and antioxidant activity (DPPH assay) significantly increased with 2% PA and full NPK.
- The 0.5% PA treatment with half NPK enhanced fruit carotenoid and phenolic content, whereas 2% PA plus half NPK increased flavonoid content.
- Overall, PA and NPK fertilizer interaction significantly improved fruit mineral composition, increasing essential nutrients like nitrogen, phosphorus, and potassium.
Implications
This study demonstrates that foliar application of PA, particularly at 2% with full NPK, enhances tomato productivity and quality. The findings suggest that PA acts as a biostimulant, improving nutrient uptake, photosynthetic efficiency, and phytochemical accumulation. Further research is needed to explore the molecular mechanisms underlying these effects, paving the way for more sustainable and efficient agricultural practices.
Article based on: Foliar Application of Pyroligneous Acid Acts Synergistically with Fertilizer to Improve the Productivity and Phytochemical Properties of Greenhouse-Grown Tomato