Detailed Explanation of Pollution-Free Cultivation Techniques for Houttuynia cordata
Houttuynia cordata, scientific name Houttuynia cordata Thunb., also known as ceyergen, is a perennial herbaceous plant of the family Saururaceae. Its taste is slightly pungent, its nature is cool, and it enters the lung meridian. It has a marked inhibitory effect on influenza virus and pneumococcus, and has the effects of clearing heat, detoxifying, promoting urination, relieving pain, stopping cough, dispelling wind, regulating qi, and strengthening the stomach. Its tender stems and tender leaves are delicious when served cold or boiled in soup. Regular consumption can help prevent influenza, pneumonia, eczema, and many other diseases. It is a health vegetable that serves as both food and medicine. Huize County has a long history of cultivating and eating Houttuynia cordata, with a year-round cultivation area of about 200 hectares and a total output value of 7.5 million yuan. The products are sold through wholesale markets in Kunming and other places to all parts of the country and enjoy a very high reputation. The pollution-free cultivation techniques are summarized below for reference.
I. Land Selection and Soil Preparation
1. Plot selection. Choose a plot with flat terrain, sufficient water sources, convenient drainage and irrigation, deep plough layer, suitable soil structure, good physical and chemical properties, moderate fertility, compliance with the requirements of GB/T 18407.1-2001, and loam or sandy loam soil.
2. Fine soil preparation. After selecting the plot, thoroughly remove weeds and crushed stones, and deep plough and sun the soil. Before planting, plough and harrow level, apply sufficient base fertilizer, and make the plot loose, fertile, and level.
3. Apply sufficient base fertilizer. Before planting, evenly broadcast 4000-5000 kg of fully decomposed farmyard manure and 150-200 kg of plant ash (or 15 kg of potassium sulfate) per 667 sq m, then plough once to a depth of 25-30 cm so that the fertilizer and soil are fully mixed.
4. Scientifically make beds. Make beds according to local conditions. Make sunny beds in low-lying land and cold soaked land, and make flat beds on high land, with a bed width of 1.5-2 m.
II. Cultivation Techniques 1. Planting time. Generally plant after the late frost ends in spring.
2. Propagation method. Generally use underground stems for asexual propagation.
3. Planting method. Select plump seed stems and cut them with sterilized tools into 5-10 cm lengths, ensuring each segment has 3-4 nodes. Open planting furrows 15 cm wide and 20 cm deep on the bed surface, place the seed stems flat in the furrows at a plant spacing of 5 cm, and cover with 6-7 cm of fine soil. If the soil is moist, no watering is needed; if the soil is dry, irrigate in a timely manner. They will sprout and emerge in 15-20 d.
III. Field Management
1. Water and fertilizer management. During the entire growth period, drain and irrigate in a timely manner, keeping the soil moist without water accumulating on the bed surface. No topdressing is needed in the early stage. During the vigorous growth period of stems and leaves, apply 10-15 kg of urea per 667 sq m in a timely manner. During the entire growth period, it is forbidden to irrigate with polluted dirty water, and forbidden to apply garbage, sludge, untreated human (livestock) manure and urine, nitrate nitrogen (such as ammonium nitrate), and compound (mixed) fertilizers using nitrate nitrogen as a raw material. No fertilizer of any kind may be applied within 30 d before harvest.
2. Pest and disease control. Houttuynia cordata rarely suffers from pests and diseases, and generally no chemical control is needed.
IV. Timely Harvest
For harvesting tender stems and leaves for food, harvest can be done from April to October, and multiple harvests are possible. For products based on underground stems, harvest can be carried out successively from summer to winter according to market demand. After harvest, wash clean and tie into bundles for market. During storage and transportation, water appropriately to keep fresh. During processing, storage, and transportation, the products must be kept clean and hygienic, ensuring compliance with the requirements of GB 18406.1-2001 and the national food hygiene standards.