Detailed Explanation of GAP Standardized Planting Operation Procedures for Asarum heterotropoides

I. Site Selection and Land Preparation

1. Site Selection Select a natural forest cutover site that meets the Grade II standards of GB5618-1995, with an irrigation water source, and water quality that complies with the "Farmland Irrigation Water Quality Standard GB15084-92," far from main traffic roads, surrounded by natural forest and planted forest on all sides, where a dust-proof forest belt may be established, with no pollution sources nearby.

2. Land Preparation Clear debris from the field, plow twice with a tractor to a depth not exceeding 30 cm, then harrow 5 times, leveling and pulverizing the soil. Make raised beds by hand; seedbeds 1.2 m wide, 25 cm to 30 cm high, 25 m long, with paths 1.2 m wide, neat and uniform.

II. Seed Selection and Sowing

1. Seed Selection Select seeds from disease-free plots and plants, and place them in a cool, ventilated place for 2 to 3 days. After quarantine, rub and wash them; after draining, soak the seeds in a 1500-fold solution of Procymidone for 2 hours, mix evenly with 3 times their volume of fine sand, add water, and place in a cool, ventilated place. One to two days before sowing, put them in a fine-mesh bag and bury them in the sowing plot until sowing.

2. Sowing The sowing period is mid-July. Use the more effective drill sowing method, with a row spacing of 10 cm and sowing depth of 2 cm, at a sowing rate of 25 g per sq m. After sowing, cover with 1 cm of soil, gently level with a small rake, cover with a layer of straw matting, water thoroughly, and keep the bed soil moist.

3. Transplanting Transplanting can be done from after the soil thaws until before it freezes. Use 2-year-old or 3-year-old seedlings; before transplanting, soak for 4 hours in a 200-fold solution of 10% carbendazim plus an 800-fold solution of 50% zineb, then plant. Plant spacing 5 cm x 6 cm. Hole planting may also be used, with 3 to 5 plants per hole. When planting seedlings, straighten the fibrous roots; position the buds at a uniform height, plant into moist soil, and cover with soil to a uniform depth. Plant large and small seedlings separately by category. Drench the roots with Dexon. If propagating by division, select rhizomes that are long and have many buds, cut them into segments at intervals of 1 to 2 buds, each with 5 to 10 fibrous roots, and plant.

III. Field Management

1. Weeding Weed after the seedlings emerge, ensuring early, small, and complete weeding. Weeds between rows can be removed with a small hoe, which also loosens the soil; weeds among the seedlings should be pulled by hand without damaging the seedlings. Weed 3 to 4 times per year, striving to keep the beds and paths free of weeds.

2. Irrigation Asarum heterotropoides has a high water requirement, and soil moisture should be maintained at around 40%. Irrigate promptly during drought; especially since the seedlings' roots are shallow, water promptly when drought is detected to maintain seedbed moisture.

3. Fertilization Apply farmyard manure, commercial organic fertilizer, humic acid fertilizers, microbial fertilizers, etc. Apply 7 to 10 kg of decomposed pig manure or 0.3 to 0.4 g of superphosphate per sq m.

4. Light Regulation Asarum heterotropoides is sensitive to light; weak light causes excessive vegetative growth and affects tillering; too strong light easily scorches and withers the leaves, causing reduced yield. Shade nets can be set up to regulate light; the shade net is 1 m high and 1.5 m wide. Install the shade net as soon as the seedlings emerge, with a light transmittance of 40%. Vine plants may also be planted on both sides to form a trellis for shade, but the shading degree must be ensured.

IV. Pest and Disease Control

Adopt biological control methods, apply little or no pesticide, and when necessary use the minimum effective dose, or choose high-efficiency, low-toxicity, low-residue pesticides.

1. Disease Control The main disease is sclerotinia, which can occur from early spring sprouting to late June. On affected plants, many irregularly shaped black sclerotial particles adhere around the roots, and brown streaky lesions appear on the petioles, gradually expanding until the aboveground parts wilt, lodge and die, and the entire root rots, leaving only an empty skin; this is called the "cancer" of Asarum heterotropoides. Control should focus on prevention. After seedling emergence each year and before the plants wither in autumn, spray with a 500-fold solution of Tian'an, or a 1000-fold solution of 50% carbendazim, or a 1000-fold solution of thiophanate-methyl, or a mixture of a 200-fold solution of 10% carbendazim plus an 8000-fold solution of 50% zineb, once every 10 days for 2 to 3 consecutive times. In severe cases, pour a 500-fold solution of 50% carbendazim onto the roots. If a single plant is found diseased, dig out the diseased plant promptly, remove the soil from the diseased hole, disinfect with quicklime or a 160-fold solution of 10% carbendazim, or replace with new soil, and loosen the soil frequently to improve soil aeration. If the shading degree is too great, regulate the light and increase light transmittance. Drain well during the rainy season, and water lightly before harvest.

2. Insect Pest Control The main pests are cutworms and black hairy caterpillars. Cutworms bite the buds and sever the petioles and rhizomes, causing missing seedlings. Zinc phoxim poisoned soil may be spread in the field for control, or poisoned bait may be used to lure and eliminate them, or they may be caught by hand. When larvae are doing damage, they must be eliminated before the 3rd instar to reduce losses. Black hairy caterpillars can be controlled by spraying the leaf surface with a 500-fold to 1000-fold solution of 90% trichlorfon.

V. Harvesting and Processing

Direct-seeded plants can be harvested after 4 years; if seed is to be collected, this can be extended to 6 years. For transplanted Asarum heterotropoides, if 2-year-old seedlings are planted, harvest 3 to 4 years after planting; if 3-year-old seedlings are planted, harvest 2 to 3 years after planting. The harvest period for cultivated Asarum heterotropoides should be August to September; harvesting during this period gives good quality and high yield.

When digging, use a flat hoe or spade, starting from one end of the bed and turning the soil to pick them out. After digging, large rhizomes can be cut in half with a knife, and the soil on the rhizomes quickly rinsed off with running water. This method can reduce damage to the fibrous roots and increase yield. However, do not wash the stems and leaves above the roots, to prevent the leaves from turning black. After sun-drying, immediately place in a cool, ventilated place to dry in the shade, avoiding sunlight as much as possible to prevent the leaves from turning yellow. When drying in the shade, avoid wetting by dew. When dried to half-dry, tie into small bundles, and sell after fully dry. The whole plant with washed roots may also be dried in a dryer to half-dry, tied into small bundles, and then further dried for sale.