Soil-Improving Crops for Farmland in South Korea: Classification and Management
1. Green Manure Crops
- Representative Crops: Hairy vetch, crimson clover, Chinese milk vetch, clover varieties, ryegrass, etc.
- Sowing Period:
- Fall sowing (September–October): Hairy vetch, Chinese milk vetch
- Spring sowing (March–April): Crimson clover, clover varieties, ryegrass
- Sowing Method:
- Direct seeding or mixed seeding (with rice, barley, etc.)
- Light tilling after sowing to ensure seed establishment
- Cultivation Management:
- Initial growth management (moisture supply, weed control)
- Incorporate into the soil at the appropriate stage
- Characteristics & Soil Improvement Effects:
- Nitrogen fixation enhances soil fertility
- Root growth improves soil physical properties
- Increases organic matter and promotes microbial activity
2. Leguminous Crops
- Representative Crops: Clover, alfalfa, peanuts, kidney beans, etc.
- Sowing Period:
- Spring sowing (April–May): Kidney beans, peanuts
- Fall sowing (August–September): Alfalfa, clover
- Sowing Method:
- Row planting or spot seeding at proper intervals
- Ensure adequate moisture after sowing
- Cultivation Management:
- Not intended for harvest, so incorporate into the soil after flowering
- Weed control and pest management required
- Characteristics & Soil Improvement Effects:
- Fixes atmospheric nitrogen, enriching the soil
- Root development helps prevent soil erosion
- Increases soil organic matter
3. Gramineous Crops
- Representative Crops: Ryegrass, rye, sorghum, wheat, etc.
- Sowing Period:
- Fall sowing (September–October): Rye, wheat
- Spring sowing (March–April): Ryegrass, sorghum
- Sowing Method:
- Broadcast or row seeding, followed by light covering
- Light rolling after sowing to ensure seed contact with soil
- Cultivation Management:
- Incorporate into the soil before flowering for maximum organic matter return
- If not harvested, till back into the soil when plants reach 30–50 cm
- Characteristics & Soil Improvement Effects:
- Increases soil organic matter and moisture retention
- Suppresses weed growth
- Maintains soil fertility and improves drainage
4. Brassica Crops
- Representative Crops: Rapeseed, mustard, leaf mustard, etc.
- Sowing Period:
- Fall sowing (September–October): Rapeseed
- Spring sowing (March–April): Mustard, leaf mustard
- Sowing Method:
- Spot or row seeding with light covering
- Maintain adequate moisture for germination
- Cultivation Management:
- Incorporate into the soil before flowering
- Weed and pest control required
- Characteristics & Soil Improvement Effects:
- Increases organic matter and provides nitrogen
- Natural pest control (contains organic sulfur compounds)
- Improves soil physical structure
5. Perennial Herbaceous Plants
- Representative Crops: Alfalfa, clover varieties, reeds, silver grass, etc.
- Sowing Period:
- Can be sown in both spring and fall (March–April, September–October)
- Sowing Method:
- Light covering after seeding
- Maintain soil moisture for germination
- Cultivation Management:
- Requires long-term maintenance
- Regular cutting to increase soil organic matter
- Characteristics & Soil Improvement Effects:
- Continuous ground cover prevents erosion
- Deep roots improve soil structure
- Strong nitrogen-fixing ability maintains soil fertility
6. Mixed Green Manure Crops
- Representative Combinations:
- Hairy vetch + rye
- Alfalfa + clover
- Sorghum + beans
- Sowing Period:
- According to the optimal sowing time for each crop
- Sowing Method:
- Select crops with similar growth rates
- Evenly distribute seeds and lightly cover
- Cultivation Management:
- Moisture supply and weed control during early growth
- Incorporate into the soil after flowering
- Characteristics & Soil Improvement Effects:
- Supplies diverse nutrients for enhanced soil fertility
- Improves soil structure and drainage
- Increased pest and disease resistance