Techniques of pollution-free cultivation of Houttuynia cordata Thunb

Houttuynia cordata Thunb, scientific name, belongs to perennial herb of Saururus family. It tastes slightly pungent and cool. It enters lung meridian. It has obvious inhibitory effect on influenza virus and pneumococcus. It has the effects of clearing heat, detoxifying, diuretic, analgesic, cough, expelling wind, regulating qi and strengthening stomach. Its tender stem, tender leaves cold or boiled soup taste delicious, often eat can prevent influenza, pneumonia, eczema and other diseases, is a kind of health vegetables for both medicine and food. Huize County has a long history of cultivation and edible Houttuynia cordata, with a perennial cultivation area of about 200 hectares and a total output value of 7.5 million yuan. The products are sold to all parts of the country through wholesale markets in Kunming and other places, enjoying a high reputation. The pollution-free cultivation techniques are summarized as follows for reference.

1. Land selection and preparation

1. Lot selection. Select the plot with flat terrain, sufficient water source, convenient irrigation, deep tillage layer, suitable soil structure, good physical and chemical properties, moderate fertility, meeting the requirements of GB/T18407.1--2001, and loam or sandy loam soil.

2. Fine soil preparation. After selecting the plot, thoroughly remove weeds, gravel, deep ploughing and sunning. Before planting, ploughing and harrowing shall be carried out, and sufficient base fertilizer shall be applied to make the plot loose, fertile and flat.

3. Apply enough base fertilizer. Before planting, 4000- 5000kg of fully decomposed farm manure and 150- 200kg of plant ash (or 15kg of potassium sulfate) shall be evenly spread every 667 square meters, and ploughed once, 25- 30cm deep, so as to fully mix fertilizer with soil.

4. Scientific bedding. According to local conditions, low-lying land and cold-soaked land are made into open beds, and highlands are made into flat beds with a width of 1.5--2m.

2. Cultivation techniques 1. Planting time. It is usually planted after the end of the late frost in spring.

2. reproduction methods. Generally, underground stems are used for asexual reproduction.

3. Planting methods. Choose fat seed stems, cut them into 5- 10cm long with sterilized knives, and ensure that each section has 3- 4 sections. A planting ditch with width of 15cm and depth of 20cm is opened on the ridge surface, and the seed stems are laid flat in the ditch according to the plant spacing of 5 cm, and covered with fine soil with thickness of 6- 7 cm. Wet soil does not need watering, soil dry when irrigation, 15--20 days can germinate.

III. Field management

1. Water and fertilizer management. Proper irrigation and drainage throughout the growth period to keep the soil moist and the bed surface free of ponding. No topdressing is needed in the early stage, and urea 10--15 kg is applied every 667 square meters in time in the peak growth period of stems and leaves. During the whole growth period, it is forbidden to irrigate polluted water, prohibit the application of garbage, sludge, human (animal) feces and urine without harmless treatment, nitrate nitrogen (ammonium nitrate, etc.) and compound (mixed) fertilizer with nitrate nitrogen as raw material, and prohibit the application of any fertilizer within 30 days before harvest.

2. Pest control. Houttuynia rarely occurs pests and diseases, generally do not need chemical control.

IV. Timely harvest

The tender stems and leaves can be harvested from April to October and can be harvested many times. The underground stem products can be harvested from summer to winter according to market demand. After harvest, wash and tie the market. During storage and transportation, water properly for preservation. During processing, storage and transportation, the products must be kept clean and hygienic to ensure that they meet the requirements of GB18406.1--2001 and the national food hygiene standards.