Three-stage Mandatory Checklist for Large-scale Planting of Pre-basic & Foundation Seed Potatoes (On-site Execution Version)
This checklist is divided into three stages in planting order: sowing depth control, sprout breakthrough management after intertillage, and navigation adjustment on uneven fields. Each stage includes mandatory tasks and strict prohibitions. A section for responsible person’s confirmation is attached at the end. Please check and confirm each item upon completion.
Stage 1: Sowing Depth Control — Follow Measurements, Not Experience
1.1 Depth Control for Pre-basic Seed (Micro-tubers)
| Soil Type | Permitted Depth | Prohibited Depth |
|---|---|---|
| Sandy soil | 12～15 cm | Over 15 cm |
| Loam | 10～13 cm | Over 15 cm |
| Clay soil | 8～12 cm | Over 15 cm |
Must-do
- Adjust each row of the seeder before sowing, and measure the vertical distance from tuber top to ridge surface with a ruler.
- Randomly dig and measure 3 sampling points every 200 meters during sowing, and keep records.
- Adopt the lower limit (8～10 cm) for clay soil or overly wet soil.
Strict Prohibitions
❌ Do not use the same sowing depth for pre-basic seed and foundation seed.
❌ Do not bury micro-tubers deeper than 16 cm for drought resistance.
1.2 Depth Control for Foundation Seed
| Soil Type | Permitted Depth | Prohibited Depth |
|---|---|---|
| Sandy soil | 18～20 cm | Over 20 cm |
| Loam | 16～18 cm | Over 20 cm |
| Clay soil | 13～15 cm | Over 20 cm |
Must-do
- Check after sowing: The soil cover above tubers shall not exceed 20 cm (use a 20 cm stick for vertical measurement).
- Keep the depth deviation within ±2 cm across the whole field.
Strict Prohibitions
❌ Do not bury tubers deeper than 20 cm.
❌ Do not apply the depth standard for sandy soil to clay soil.
Stage 2: Identification & Remedies for Sprout Emergence after Intertillage and Ridging — Targeted Solutions for Different Seed Tubers
Inspect ridge surfaces daily for 3 to 10 days after intertillage. Foundation seed and micro-tubers show distinct emergence symptoms and require different treatments.
2.1 Three Typical Symptoms of Stunted Sprouts for Foundation Seed
| No. | Manifestation | Judgment |
|---|---|---|
| ① Ridge cracking | 0.5–2 cm wide cracks on ridge tops with dry edges | Sprouts are under compression due to hard soil |
| ② Bent sprouts | Sprouts emerge sideways with L-shaped bases | Failed vertical penetration, growing toward weak soil areas |
| ③ Uneven seedling height | Height gap over 5 cm between seedlings on the same ridge | Excess soil cover or soil compaction in local areas |
Treatment Procedures for Foundation Seed (Follow in order)
- Loosen soil along cracks and check moisture by hand.
- If dry: Apply furrow irrigation slowly. Do not let water overflow ridge tops; only moisten the soil around tubers.
- If moist but compacted: Rake ridge surfaces lightly to a depth of 1–2 cm to break hard soil crusts.
Prohibition: Do not re-ridge, which will make sprout penetration harder.
2.2 Sole Symptom & Mandatory Remedy for Micro-tubers (Pre-basic Seed)
Symptom: Fine cracks appear on ridges. White sprouts break through soil but stop growing for 48 hours. Tips turn dark and hook-shaped.
Only remedy: Irrigate immediately without delay.
Irrigation Guidelines
- Water supply: Drip irrigation, micro-sprinklers or slow furrow irrigation. Avoid strong water flow over ridges.
- Water volume: 8–12 cubic meters per mu. Only moisten the 5 cm soil layer around tubers.
- Time limit: Finish irrigation within 4 hours after spotting symptoms.
- Post-inspection: Cracks shall close and sprouts grow 1–2 cm within 24 hours. Apply half-volume supplementary irrigation the next day if no improvement.
Strict Prohibitions ❌ Do not postpone treatment
❌ Do not add extra soil cover
❌ Do not compact ridges with rollers
❌ Do not use flood irrigation (causes tuber rot)
❌ Do not add extra soil cover
❌ Do not compact ridges with rollers
❌ Do not use flood irrigation (causes tuber rot)
Stage 3: Uneven Fields — Auto-navigation Is Unreliable, Manual Intervention Is Mandatory
When the field elevation difference exceeds 5 cm (about half a hoe depth), GPS auto-navigation fails to detect terrain changes, resulting in uneven sowing depth. The following three rules must be strictly enforced.
3.1 Terrain Inspection Before Sowing & Intertillage
Drive the tractor across the field to mark all areas with an elevation difference over 5 cm, including old ditches, depressions, slope toes and height gaps at field edges. Number these areas on the field map and insert red warning flags.
3.2 On-site Navigator System During Operation
Assign at least one dedicated navigator for each seeder or intertiller. Stand behind and beside the machine to monitor the working depth of furrow openers and ridgers. Follow the standard gesture instructions below:
| Gesture | Meaning | Operator’s Action |
|---|---|---|
| Raise palm | Excessive working depth, lift the machine | Raise the three-point hitch manually |
| Lower palm | Insufficient working depth, lower the machine | Lower the machine manually |
| Clench fist | Stop immediately | Brake and check for problems |
| Circle forward with fingers | Normal condition, keep working | Maintain current settings |
Special Requirements
- For pre-basic seed plots: Navigators must stay alongside the machine at all times. Micro-tubers only tolerate a depth error of ±2 cm, which auto-navigation cannot guarantee.
- For foundation seed plots: Switch to manual mode when passing flagged areas, and revert to auto-navigation afterwards.
3.3 Secondary Remediation After Operation
- Exposed tubers (insufficient soil cover): Cover lightly with 1–2 cm of moist soil taken from furrows. Dry soil or large soil clods are not allowed.
- Overly buried tubers (pre-basic seed >15 cm, foundation seed >20 cm): Gently scrape off excess topsoil with a flat shovel before seedling emergence. Do not let sprouts break through the soil on their own.