Nitro-Sulfur Compound Fertilizers: Power Your Crops，Protect Your Soil

I. General Formulations (Suitable for Multiple Crops)
● Balanced Formulation
NPK-S Ratio: 15-15-15 + 10% S
Application: Widely used for leafy vegetables (e.g., spinach, cabbage) and fruiting vegetables (e.g., tomatoes, peppers) requiring balanced nutrients, supporting both vegetative and reproductive growth.
Nitrogen Sources: Nitrate nitrogen accounts for 30%~50% (e.g., ammonium nitrate, calcium nitrate), with the remainder as ammonium nitrogen or urea.
Sulfur Sources: Potassium sulfate (K₂SO₄), magnesium sulfate (MgSO₄), etc.

● High-Nitrogen Formulation
NPK-S Ratio: 25-5-10 + 12% S
Application: Ideal for leafy vegetables (e.g., spinach, lettuce) or crop seedling stages to rapidly promote leaf growth.
Nitrogen Source: Nitrate nitrogen exceeds 50%, ensuring fast-acting effects.

II. Crop-Specific Formulations
● Fruiting Vegetables (Tomatoes, Peppers)
NPK-S Ratio: 18-8-20 + 12% S
Features: High potassium boosts fruit expansion, nitrate nitrogen accelerates nutrient uptake, and sulfur enhances sugar content and disease resistance.
Sulfur Source: Potassium sulfate (provides both potassium and sulfur).

● Tuber/Root Crops (Potatoes, Sweet Potatoes)
NPK-S Ratio: 12-10-20 + 15% S
Features: High potassium promotes starch accumulation, sulfur strengthens protein synthesis, and nitrate nitrogen supports growth during tuber bulking.

● Fruit Trees (Citrus, Apple)
NPK-S Ratio: 16-6-18 + 8% S
Features: Balanced NPK improves fruit flavor and storability, while nitrate nitrogen meets rapid nutrient demands during shoot growth.

● Cereal Crops (Corn, Wheat)
NPK-S Ratio: 22-10-12 + 10% S
Features: High nitrogen supports stem elongation and grain filling, sulfur increases seed plumpness, and nitrate nitrogen adapts to low-temperature absorption needs.

III. Functional Formulations
● Saline-Alkali Soil Formula
NPK-S Ratio: 14-12-14 + 18% S
Features: High sulfur (sulfur or sulfates) alleviates salt damage; nitrate nitrogen avoids soil fixation. Suitable for salt-tolerant crops like sugar beet and sunflower.

● Water-Soluble Fertilizer
NPK-S Ratio: 20-10-20 + 15% S
Features: Fully water-soluble for drip irrigation or foliar spray; nitrate nitrogen enables direct uptake, and sulfur prevents sulfur-deficiency yellowing.

● Low-Temperature Season Formula
NPK-S Ratio: 18-6-12 + 10% S
Features: High nitrate nitrogen (>60%) ensures rapid absorption in cold conditions, ideal for early spring greenhouse crops.

IV. Key Design Principles
Nitrate Nitrogen Proportion: Typically 30%~70% of total nitrogen, favored for fast-acting effects in low temperatures or nitrogen-deficient crops.

Sulfur Sources:
● Potassium Sulfate (K₂SO₄): Provides sulfur and potassium, suitable for chloride-sensitive crops (e.g., tobacco, grapes).
● Ammonium Sulfate ((NH₄)₂SO₄): Contains 24% sulfur and supplements ammonium nitrogen.
● Elemental Sulfur (S): Slow-release sulfur source for long-term soil sulfur deficiency correction.

NPK Ratios: Adjusted based on crop needs, e.g.:
● Leafy Vegetables: High nitrogen (N > 20%), low phosphorus and potassium.
● Fruit Crops: High potassium (K₂O > 15%), balanced nitrogen and phosphorus.

V. Common Raw Material Combinations

VI. Precautions

Avoid Mixing with Alkaline Fertilizers: Nitrate nitrogen reacts with alkaline substances (e.g., wood ash), causing volatilization losses.
Control Chloride Content: Use potassium sulfate instead of KCl for chloride-sensitive crops (e.g., tobacco, potatoes).
Soil Adaptability:
● Acidic Soils: Prefer calcium nitrate to supplement calcium and adjust pH.
● Sulfur-Deficient Soils: Increase sulfur content to >15% or add elemental sulfur powder.

Summary: Nitro-sulfur-based fertilizers offer diverse formulations tailored to crop types, growth stages, and soil conditions. The key lies in optimizing the synergistic effects of nitrate nitrogen and sulfur. Scientific formulations enhance fertilizer efficiency, minimizing nutrient waste and soil salinization.