Technical points for achieving early high yield through close planting of honeysuckle

Honeysuckle (Lonicera japonica) is a perennial semi-evergreen woody vine, also known as erhua or shuanghua, and is a traditional valuable Chinese medicinal herb. The roots, stems, leaves and flowers of honeysuckle can all be used medicinally, but the main medicinal part is the dried flower buds, which have the effects of clearing heat and detoxifying, eliminating chronic inflammation and improving human immunity.

In recent years, with the intensification of honeysuckle development and the broadening of application fields, market demand has grown ever larger. Improving cultivation techniques to increase the early-stage yield of honeysuckle and maintain the duration of the full-yield period has become a major problem urgently needing solution in production.

In recent years, based on the characteristics of honeysuckle cutting seedlings - a short purely vegetative growth period and simultaneous vegetative and reproductive growth - we have adopted measures such as increasing the initial planting density and gradually thinning after one year according to growth conditions and available space. This has not only greatly increased the early-stage yield of honeysuckle, advancing entry into the full-yield period by 2 to 3 years, but also ensured that after entering the full-yield period, plant growth is basically unaffected. Space utilization remains relatively rational, making full use of land, space and climatic resources, greatly improving comprehensive benefits, and overcoming the shortcomings of purely dense planting orchards, which have high early-stage yield but declining later yield, and of sparse planting orchards, which enter the full-yield period late and have low early-stage yield. The technical points are introduced below.

I. Planting time

Honeysuckle can be planted in all four seasons. The survival rate is relatively high when planted from mid-September to mid-March of the following year. South of North China, autumn planting is preferable. Although air temperature drops noticeably during this period, soil temperature remains within the range suitable for root growth. Before the soil freezes, the wounded roots of newly planted honeysuckle can heal and produce a large number of new roots, resulting in a high survival rate, vigorous growth the following spring, a short recovery period and high flower yield. Honeysuckle planted after the New Year can survive, but germination and root healing and growth proceed simultaneously, creating a prominent conflict between the aboveground and underground parts competing for nutrients and water, resulting in a long recovery period, poor early-stage growth and low flower yield in the current year. In areas with severe winter cold, drought and water shortage, spring planting can be used to prevent desiccation.

II. Planting patterns

1. Equal-row equal-plant pattern

In this pattern, after entering the full-yield period, both row spacing and plant spacing are 1.5 to 2 m, with 167 to 296 plants per 667 sq m. The initial planting density (667 to 1184 plants/667 sq m) is 4 times the full-bloom density. After one year, alternate rows are thinned, retaining 333 to 592 plants. After 2 to 3 years, alternate plants are thinned, retaining 167 to 296 permanent plants. With this pattern, vegetables such as garlic, onion and spinach can be intercropped in the first year. The advantage of this pattern is that it ensures honeysuckle growth is unaffected by crops, with high early-stage yield: in the first year, the yield per 667 sq m can reach 10 to 20 kg, in the second year 30 to 40 kg, and the full-yield period can be reached in 3 to 4 years.

2. Wide-row dense-plant pattern

In this pattern, after entering the full-yield period, row spacing is 1.8 to 2 m and plant spacing is 1.6 to 2 m, with a density of 185 to 231 plants/667 sq m. The initial planting density (740 to 924 plants/667 sq m) is 4 times the full-bloom density. After one year, alternate plants are thinned, retaining 370 to 462 plants per 667 sq m. After 2 to 3 years, a second alternate-plant thinning is carried out, retaining permanent plants. With this pattern, in the first year, in addition to intercropping vegetables between rows, low-stalk crops such as @#@245@#@ and barley can also be intercropped, but the sowing width should not exceed 1 m so as not to affect honeysuckle growth. The advantage of this pattern is convenient field management, but honeysuckle growth is slightly affected by crops.

3. Direct-cutting orchard establishment pattern

Use vigorous branches with a diameter of more than 0.8 cm and a length of 35 to 40 cm as cuttings to replace seedlings for orchard establishment. The planting density and thinning steps are the same as patterns 1 and 2. The burial depth of the branches is 1/2 to 2/3 of the branch length. After burial, firm the soil and water thoroughly. Water 2 to 3 times in total before overwintering, and before overwintering cover with soil to prevent freezing and preserve moisture. When establishing an orchard by this method, the issue of replanting missing plants must be considered, so plants can be partially densified between plants or two plants per hole. The advantages of this pattern are: it can solve the problem of insufficient seedling sources. The disadvantages are: frequent watering, poor coordination with intercrop management, and a survival rate slightly lower than when using seedlings.

III. Main technical measures

1. Variety selection

There are many honeysuckle varieties. The main superior varieties cultivated in production are Fengqiu Damaohua and Shandong Jizhuahua. Fengqiu Damaohua is a nationally protected variety of origin. It has an upright tree habit and thick, sturdy branches, making shaping and pruning easy. The flower buds are 4 to 6 cm long, with a chlorogenic acid content of 5.6% to 6.7%. Its medicinal components are well balanced, it is resistant to pests and diseases, and it has strong adaptability. It can bear flowers in the same year after planting, and after entering the full-yield period it can produce 100 to 150 kg per 667 sq m. It is the preferred variety in production.

2. Orchard site selection

Honeysuckle is drought-tolerant, cold-tolerant, waterlogging-tolerant and tolerant of poor soil. It is not demanding regarding soil and can grow and flower normally in both slightly acidic and alkaline soils. However, to meet the requirements of high yield, high quality and pollution-free cultivation, the orchard site should be selected as loose, fertile land with convenient drainage and irrigation. It should also be far from cities, industrial and mining enterprises and major traffic routes, and the air, soil and irrigation water should be tested and meet national standards.

3. Fine land preparation

Before planting a close-planted honeysuckle orchard, the land must be leveled and sufficient basal fertilizer applied. Apply 4 to 5 cubic meters of high-quality decomposed organic fertilizer, 50 kg of superphosphate, 50 kg of ammonium bicarbonate, 10 kg of potassium sulfate and 1 kg of zinc sulfate per 667 sq m. To eliminate underground pests, 1 kg of phoxim per 667 sq m can be mixed with 20 kg of fine sandy soil and broadcast before plowing for soil treatment. The plowing depth is 25 cm. Harrow immediately after plowing, then form beds 2 to 4 m wide with ridges.

4. Use vigorous seedlings

Vigorous seedlings are the foundation for improving the survival rate, advancing flower bud formation and achieving early high yield. At present, the standard for vigorous seedlings used in Fengqiu honeysuckle production is: thick sturdy stems, short internodes, small hollow core, seedling height above 50 cm, old stump diameter above 0.8 cm, old stump length above 15 cm, new branch base diameter above 0.5 cm, new branch length above 30 cm, and more than 3 lateral roots above 15 cm. Using vigorous seedlings, a large number of flower buds can form in the same year, and the full-yield period can be reached 2 to 3 years earlier.

5. Scientific planting

First plan the planting points according to the determined row and plant spacing, then dig planting holes 50 cm square at the planting points, placing raw soil and topsoil separately. Apply 5 to 10 kg of decomposed organic fertilizer and 0.3 to 0.5 kg of superphosphate per hole. Mix the fertilizer evenly with topsoil and fill it into the hole. Plant 1 plant per hole. The planting depth should be slightly deeper than the seedling's depth in the nursery. After planting, firm the soil and water thoroughly with the planting water. After the water dries, cover with soil slightly higher than the ground. To improve the survival rate and promote rapid recovery, generally water once more 2 to 3 weeks after planting, and thereafter water as needed.