Key Points of High-Yield Cultivation Techniques for Intercropping and Relay Cropping of Medicinal Tree Peony

Tree peony is a precious Chinese medicinal herb with a long growth cycle, high yield and stable and considerable economic benefits. In recent years, market demand has been increasing. In order to improve economic benefits, the Bozhou Municipal Institute of Rare Medicinal Herb Cultivation has, through years of trial planting, successfully developed a new technique for intercropping and relay cropping of tree peony with crops, which is now being promoted nationwide. The methods are as follows.

1. Seedling raising methods

Tree peony is usually raised from seed and then transplanted. The seedling raising period is best from August to December. Tree peony is generally sown in drills. On a prepared seedbed, open furrows 3--4 cm deep with a row spacing of 10--15 cm and a plant spacing of 5--7 cm, sow the seeds in the furrows, then cover with a layer of moist fine soil, rake it level and press it down lightly, then cover with a 5--10 cm thick layer of wheat straw to help preserve soil moisture. Use 50--60 kg of seed per 667 sq m. After the soil thaws the following year, remove the covering straw between “Yushui” (Rain Water) and “Jingzhe” (Awakening of Insects). When about 80% of the seedlings have emerged, spray the stems and leaf tops of the seedlings with Bordeaux mixture diluted 1:200 to disinfect the seedbed and promote root growth, in preparation for autumn transplanting.

2. Transplanting methods

Tree peony is generally transplanted from September to November. In a prepared field, dig holes with a row spacing of 45--55 cm and a plant spacing of 35 cm. To increase yield, 2 plants can be planted per hole. The method is: hold two seedlings in one hand and separate them slightly, while filling soil into the hole with the other hand. When the hole is full of soil, lift the seedlings slightly upward so that the roots are straight but the terminal buds should not rise above the ground surface, then fill the soil around the seedlings to the top, firm it down and cover with 10 cm of soil for overwintering.

3. Intercropping and relay cropping

Tree peony grows slowly in the first 3 years. In order to make full use of the land and increase income, intercropping and relay cropping are used, and the economic benefits are very considerable. In the first 2 years, cotton can be intercropped. Plant one row of cotton in each furrow between tree peony rows, with a cotton plant spacing of 40 cm, and leave one working path every two rows of tree peony to make it easier to spray and prune the cotton. The intercropped cotton has the same yield as cotton grown in specialized cultivation. Soybeans, corn, vegetables and other medicinal herbs are intercropped in the same way as cotton. The dormancy period of tree peony is from early July to mid-February, so double-row intercropping does not affect either crop. Intercropping can also be done in the second year, at half the density of the first year. The third year is the full flowering period of tree peony, which can produce 130--160 kg of seed. In the fourth year, seed production can reach more than 200 kg, and at the same time the roots and stems can be harvested as medicinal material, with a yield of 550--650 kg of dried tree peony per 667 sq m.

4. Disease and pest control

Tree peony basically has no diseases or pests throughout its growth period. If leaf spot disease or root rot is found, control methods for fruit trees can be used as a reference.

5. Harvesting and processing

Generally 3--4 years after transplanting, tree peony is dug up from August to October. Dig out the roots, clean off the soil and place them indoors. After a few days, the roots and stems become soft, making it easier to remove the core. The tree peony after core removal is sun-dried for medicinal use and is commonly called “black Danpi”. Some people scrape off the outer skin of the roots with a piece of glass, then remove the core and sun-dry it, which makes powder Danpi (scraped Danpi). The best quality has thick flesh, thick and long strips with no woody core, a white powdery broken surface and a strong aroma.