For those new to agriculture, understanding fertilizers is the first step to successful cultivation. Fertilizers are the “food” for crops, and their proper selection and use directly affect crop yield and quality.
I. Basic Classification of Fertilizers
1. By Source
- Organic fertilizers:Derived from plant/animal residues or excreta (farmyard manure, compost, green manure)
- Inorganic fertilizers (chemical fertilizers):Industrially produced (urea, superphosphate, potassium chloride)
- Biofertilizers:Contain active microorganisms (rhizobium fertilizer, nitrogen-fixing bacteria fertilizer)
2. By Nutrient Composition
- Single-nutrient fertilizers:Contain one primary nutrient (urea – nitrogen, superphosphate – phosphorus)
- Compound fertilizers:Contain two or more primary nutrients (diammonium phosphate – nitrogen & phosphorus)
- Complete fertilizers:Contain all three primary nutrients (N-P-K), e.g., 15-15-15 compound fertilizer
Common Fertilizer Types and Characteristics
| Fertilizer Type | Main Composition | Characteristics | Suitable Crops |
| Urea | N 46% | Fast-acting nitrogen, water-soluble | All crops (base/top dressing) |
| Superphosphate | P₂O₅ 12-18% | Water-soluble phosphorus, contains calcium/sulfur | Phosphorus-demanding crops (legumes) |
| Potassium chloride | K₂O 60% | Fast-acting potassium, contains chlorine | Non-chloride-sensitive crops |
| Organic fertilizer | N+P₂O₅+K₂O≥5% | Improves soil, slow-release | All crops (base fertilizer) |
💡 Did You Know? The numbers on fertilizer packages (e.g., “15-15-15”) indicate the percentage of nitrogen (N) – phosphorus (P₂O₅) – potassium (K₂O), known as the NPK ratio.
II. How Beginners Can Choose Suitable Fertilizers
Step 1: Understand Crop Requirements
Different crops have different nutrient needs:
- Leafy vegetables:Need more nitrogen (spinach, cabbage)
- Fruit vegetables:Need more phosphorus/potassium (tomato, cucumber)
- Root crops:Need more potassium (potato, carrot)
Step 2: Soil Testing
Soil testing reveals:
- Soil pH (acidity/alkalinity)
- Organic matter content
- Primary nutrient levels
- Micronutrient status
Research from China Agricultural University shows precision fertilization based on soil testing can improve fertilizer efficiency by 20-35% [1].
Step 3: Develop Fertilization Plan
Based on crop needs and soil conditions:
- Fertilizer types
- Application rates
- Timing
- Application methods
⚠️ Common Beginner Mistakes
- Using only nitrogen fertilizers
- Over-fertilization causing seedling burn
- Improper fertilizer mixing causing antagonism
- Neglecting organic fertilizers
III. Basic Principles of Fertilizer Use
1. Nutrient Balance Principle
Apply N-P-K balanced according to crop needs, avoiding excess of any single nutrient.
2. Organic-Inorganic Combination Principle
Combine organic and chemical fertilizers to meet crop needs while improving soil.
3. Scientific Application Principle
- Right timing:Follow crop nutrient demand patterns
- Right amount:Determine rates based on target yield
- Right method:Choose appropriate application (base, topdressing, foliar spray)
Recommended Fertilization Plans for Major Crops
| Crop | Base Fertilizer (% of total) | Topdressing Stages | Recommended Fertilizers |
| Rice | 40-50% | Tillering, panicle initiation | Urea + superphosphate + potassium chloride |
| Wheat | 50-60% | Regreening, jointing | Compound fertilizer (15-15-15) |
| Tomato | 30-40% | Flowering, fruiting | Organic fertilizer + high-potassium compound fertilizer |
💡 Practical Tip: Simple Fertilizer Identification
- Urea:White granules, water-soluble, cooling sensation
- Superphosphate:Grayish-white powder, partially water-soluble
- Potassium chloride:White/red crystals, water-soluble
References
[1] College of Resources and Environmental Sciences, China Agricultural University. (2023). Study on Soil Nutrient Status and Fertilizer Use Efficiency in China’s Major Farmlands. [2] Department of Crop Production, Ministry of Agriculture. (2022). Scientific Fertilization Guidelines for Major Crops.Note: Specific fertilization plans should be adjusted according to local soil conditions and crop varieties.
