Detailed Explanation of Key Production Techniques for Grade AA Potatoes

I. Production Site Conditions

1. Environmental conditions: The atmosphere, soil and other conditions of the green food production base shall be monitored by an environmental monitoring agency designated by the provincial green food management department and meet the environmental standards for green food production sites.

2. Soil conditions: Choose light loam or slightly sandy soil with deep soil layers, loose structure and good drainage, with a pH value of 5.6-7.0. Flat land or gentle slopes are suitable, and low-lying plots must be avoided. For the previous crop, choose wheat or soybean stubble with autumn plowing, and pay special attention to avoiding plots where long-residual pesticides were used the previous year. Continuous cropping or rotation with solanaceous fruit crops is not suitable.

3. Growing conditions: Potatoes require a frost-free period of 85-105 days, an annual temperature of >=10°C, and annual precipitation of 450-550 mm.

II. Variety Selection

According to ecological and environmental conditions, select approved and promoted potato varieties that meet production, processing and market needs, are specialized, high-quality and strongly stress-resistant. In Heilongjiang Province, mainly choose starch-processing-specific varieties, such as: Neishu No. 7 and Kexin No. 12, etc. Seed purity is required to be above 95%, with no diseased tubers.

III. Seed Potato Treatment

1. Sprouting and sunning: Take the tubers out of the cellar about 20 days before sowing and place them under scattered light at 15-20°C for sprouting. When most tubers have sprouted, place them in sunlight to sun the seeds until the young sprouts turn green or dark purple, which is suitable. Remove diseased, rotten and frozen tubers.

2. Cutting: Cut into wedge-shaped pieces weighing about 20-25 grams. During cutting, discard diseased and rotten tuber pieces. If blackleg-diseased tubers are found, dip the knife in 5% Lysol, then rinse it clean with water before further use.

IV. Land Preparation, Sowing and Fertilization

1. Land preparation: Autumn plowing to a depth of 18-22 cm. After plowing, harrow with a heavy harrow or light harrow followed by a strip drag harrow, and level and finely harrow the land. If conditions permit, form ridges in autumn or spring.

2. Sowing: (1) Sowing date: When the local temperature stably passes 10°C. Generally in early to mid-May; (2) Sowing method: Ridge sowing, manual dibbling or mechanical sowing, with a sowing depth of 5-8 cm. During sowing, deep planting with shallow covering should be adopted, with a soil covering thickness of about 5 cm; (3) Sowing density: 60,000 plants per hectare for early-maturing varieties, 50,000-55,000 plants per hectare for mid-maturing varieties, and 45,000-50,000 plants per hectare for late-maturing varieties. High-starch varieties are generally late-maturing varieties. Ridge spacing 65-70 cm, plant spacing 22-26 cm.

3. Fertilization: Apply biological potassium fertilizer recommended for green food production at 1-1.5 kg/mu, and special organic compound fertilizer at 20 kg/mu. The use of chemically synthesized fertilizers is prohibited.

V. Field Management

1. Harrowing: After sowing, harrow once the weeds germinate, to achieve the effect of weed control and temperature increase.

2. Hoeing and ridging: Carry out three hoeings and three ridgings. After the flowering period, pull out large weeds in the field. During the growth period, promptly remove degenerated plants and diseased plants.

3. Topdressing: At the bud stage and flowering stage, spray Sunflower foliar fertilizer biological preparation twice, at 150 grams per hectare, mixed with 50 jin of water, and spray uniformly. Spray once more after 15 days.

4. Disease prevention: Control late blight at the bud stage. Central diseased plants should be removed promptly, and sprayed with Baidefu 70% wettable powder at 500-700 times dilution, once every 7-10 days. The last application should end 20 days before harvest.

5. Pest control: During the seedling stage, control the 28-spotted ladybird with high-efficiency BT insecticide at 25-30 grams/mu mixed with 50 kg of water, sprayed at 2000 times dilution.

VI. Harvest

1. Harvest time: Early to mid-September, choose clear and fine weather for harvesting.

2. Harvest method: Mechanical harvesting or manual harvesting. Grade AA green food potatoes must be harvested separately, stored separately and processed separately.

3. The seed of Grade AA green food potatoes must be harvested separately and stored separately, and must not be mixed.

VII. Storage

1. The storage cellar should be dug to a depth of about 8 chi, deeper than the freezing layer.

2. The cellar temperature should be controlled at 1-4°C, and the humidity should be controlled between 85-95%.

3. Frequently check the cellar temperature and humidity. Ventilate by opening and closing the cellar door, and use methods such as ground heating channels to regulate the temperature inside the cellar, maintaining the normal metabolic activity of the seed potatoes.