Whatsapp 
X 
Mail 
Copy link Optimizing Fertigation for Autumn–Spring Tomato Production
Fertigation strategy for soil‑grown greenhouse production
On this page:
In the warm coastal plains of Kumamoto in southern Japan, long‑cycle tomato production, harvested from autumn through spring, is a well‑established greenhouse system. Drip irrigation tubes and tapes are widely used, allowing growers to manage water with precision and to supply nutrients daily through fertigation. The available irrigation water in this region is typically soft, containing very low levels of calcium and magnesium, which makes nutrient management especially important in long‑season soil systems. This article outlines a fertigation approach used by the Japanese grower in the video and designed for these conditions. It is adaptable to similar production environments worldwide.
Understanding Yield Targets and Nitrogen Demand
Before calculating daily nitrogen supply per plant or per hectare, growers should first confirm their target yield level.
- Tomatoes require approximately 2.5 kg of nitrogen per ton of harvested fruit.
- A target yield of 400 t/ha (equivalent to 40 t per 10a) requires roughly 1,000 kg N/ha over the entire cropping period.
- Spread across a 300‑day season, this equals an average of 3.33 kg N/ha/day.
- With a planting density of 24,000 plants/ha, this corresponds to 139 mg N per plant per day.
These values represent average demand. Actual fertigation rates must be adjusted according to the crop’s growth stage.
Fertilization Program by Growth Stage (per hectare)
Using ICL products and adjusting NPK ratios according to crop development, the fertigation program becomes:
| Growth Stage | Target Nitrogen (kg N/ha/day) | Optimal NPK Ratio | Agrolution Special 324 (per ha/day) | Other Products (per ha/day) |
|---|---|---|---|---|
| Transplanting → 1st fruit cluster | 1.0 kg/ha/day | 1 : 1 : 1 | 7.0 kg | or Solinure Polymarine 20‑20‑20 + TE at 5.0 kg |
| 1st fruit cluster → 4th–5th flowering cluster | 2.0 kg/ha/day | 2 : 1 : 3 | 14.0 kg | Option: add Nova SOP 1.75 kg |
| 4th–5th flowering cluster → Harvest | 2.0–3.0 kg/ha/day | 2 : 1 : 4 | 15.0 kg | Add Nova SOP 3.5 kg |
| Harvest → Topping | 2.5–3.0 kg/ha/day | 2 : 1 : 4 | 20.0 kg | Add Nova SOP 3.5 kg |
| Topping → End of harvest | (1.0–) 2.0 kg/ha/day | 1 : 0 : 2 | – | Nutri Liquid N20 (10 L) + Nova Ferti‑K (7.0 kg), or Nutri Liquid N20 (10 L) + Nova SOP (8.0 kg) |
Practical notes for growers:
- Adjust nitrogen supply according to the target yield.
- When calculating per‑plant supply, use your actual planting density.
- Regularly sample soil solution to monitor nitrate levels and fine‑tune fertigation.
Adjusting NPK Ratios with Water‑Soluble Fertilizers
Agrolution Special 324 is formulated specifically for tomato production and can serve as the base fertilizer throughout the season. Its high nitrate‑N content is particularly suitable for autumn–spring crops, when soil temperatures are relatively low and ammonium uptake is reduced.
However, nutrient requirements shift as the crop develops. The most cost‑effective way to adjust NPK ratios is to combine:
- Water‑soluble potassium sulfate (Nova SOP)
- Water‑soluble potassium chloride (Nova Ferti‑K)
- Nitrate‑based liquid nitrogen (Nutri Liquid N20)
In the final stage after topping, fertilizer costs often need to be reduced. At this point, growers may switch from Agrolution Special 324 to combinations of SOP, KCl, and nitrate solution to meet nutrient demand while also rebalancing nutrients accumulated in the soil for the next season.
Immediately after transplanting, Solinure Polymarine 20‑20‑20 + TE (with seaweed extract) can be used to promote rapid establishment, an important factor for achieving high early‑season yields.
| Product | Type | NPK | Notes |
|---|---|---|---|
| Agrolution Special 324 | Water‑soluble compound fertilizer | 14‑8‑22 + 5CaO + 2MgO + TE | Main recommended product |
| Nutri Liquid N20 | Ammonium nitrate solution | 20‑0‑0 | Compatible with Agrolution 324 |
| Nova SOP | Water‑soluble potassium sulfate | 0‑0‑50 | Not tank‑mixable with Agrolution 324; inject separately |
| Nova Ferti‑K | Water‑soluble potassium chloride | 0‑0‑61 | Tank‑mixable when chloride levels in water/soil are low |
| Solinure Polymarine 20‑20‑20 + TE | Water‑soluble compound fertilizer | 20‑20‑20 + TE | Not tank‑mixable with Agrolution 324; contains seaweed extract |
What Are the Foliar Nutrition Options
| Product | Type | NPK | Notes |
|---|---|---|---|
| Nutrivant Plus Tomato | Water‑soluble compound fertilizer | 6‑18‑37 + 2MgO + TE | Prevents leaf‑tip burn; improves root uptake; apply at ≥2‑week intervals |
| BIOZ Moonstone | Amino acid liquid fertilizer | – | Enhances recovery from stress and environmental fluctuations |
Summary
Long‑cycle tomato production requires a fertigation strategy that adapts to changing nutrient demand across the season. By combining Agrolution Special 324 as a base fertilizer with targeted additions of Nova SOP, Nova Ferti‑K, and Nutri Liquid N20, growers can maintain optimal NPK balance, support uniform growth, and manage costs effectively—especially in regions with soft irrigation water.
Related crops
