Key Technical Points for Cultivating Leafy Goji (Vegetable Goji)
Goji (Lycium) is a perennial small shrub of the genus Lycium in the nightshade family (Solanaceae), distributed throughout the country. The plant is light-loving, cold- and heat-tolerant, drought-tolerant and intolerant of wet conditions. Its suitable growing temperature is 15-20°C; growth is slow at 10°C, and poor above 25°C. At present, in northern regions of China such as Ningxia, Gansu, Shaanxi and Shandong, the main purpose is fruit harvesting, while in southern regions of China such as Guangdong and Shanghai, the purpose is mainly vegetable use.
Vegetable goji has a sweet-bitter taste and a distinctive flavor; it is not only rich in nutrients but also has fairly high medicinal value. Every 100 g of goji greens contains 5.8 g protein, 1 g fat, 61 g sugar, 3.9 mg carotene, 3 mg Ve, 155 mg calcium, 67 mg phosphorus and 3.4 mg iron. When soil fertility and moisture are sufficient, the stems and leaves of goji are tender and fresh, with little fiber and good taste.
Vegetable goji mainly has two cultivated varieties: large-leaf goji and fine-leaf goji. Large-leaf goji has broad, ovate leaves, a delicate fragrance, a mild sweet-bitter taste and a distinctive flavor, and is nearly thornless; fine-leaf goji has lanceolate leaves, a stronger fragrance and bitter taste, and thorns in the leaf axils. Most goji varieties planted in the Shanghai area are large-leaf goji, mostly grown as annual crops under protected cultivation, with a small amount grown in the open field in a perennial cultivation model; it can also be used as a hedge or for soil stabilization along riverbanks.
1 Propagation Methods
Goji propagation methods include seed propagation, cuttings propagation, division propagation, layering propagation and tissue culture propagation. Among these, seed propagation and cuttings propagation have the advantages of fast speed and high survival rate, and are highly practical in production.
1.1 Seed propagation Soak the seeds, mix them evenly with moist fine sand, keep them moist to promote germination, and sow once half of the seeds have sprouted white. The sowing time is preferably March-April, and under protected cultivation it can be advanced to February. Before sowing, deep-plow the seedbed and apply sufficient base fertilizer; after building the beds, open shallow furrows about 40 cm apart for drilling. When sowing, evenly scatter the mixed seeds and fine sand into the furrows, cover with soil and press firm, then water and cover with plastic film to retain moisture. About 1 week after sowing, the goji seedlings emerge one after another. After emergence, the film should be removed, and water should be sprayed to retain moisture. When the seedlings are about 5 cm tall, thinning can be carried out at a spacing of 3-6 cm. During thinning, care should be taken to pull out inferior seedlings, and weeds should be removed promptly, with watering and fertilizing.
1.2 Cuttings propagation In spring and autumn, select 1-2 year old lignified thick branches from superior individual plants, cut them into cuttings about 10 cm long with 2-3 buds, soak their ends in 300 mg/L IBA solution for 20 min, and then insert them for cuttings. The insertion depth is about 1/3-1/2 of the cutting, and the cutting medium is a 2:1 mixture of garden soil and vermiculite. Before cutting, it is best to disinfect the medium first. Whether using container seedling raising or seedbed seedling raising, the medium thickness should be more than 10 cm to facilitate rooting and budding of the cuttings. After cutting, water thoroughly and cover tightly with nylon film; after 2 weeks, the cuttings begin to root and sprout. Trials found that cuttings treated with rooting agent can reach a rooting rate of 100%. About 3 weeks after cutting, the roots and new shoots of goji have grown well, and they can be transplanted.
2 Cultivation Techniques
2.1 Planting In general, both seedling-grown and cuttings-grown goji can be planted in the same year they are raised. Seedling propagation takes slightly longer, and early growth is slower than that of cuttings-grown plants, so in production the seedlings can also be planted in the spring of the second year. Vegetable goji is suitable for wide-row, dense planting in spring or autumn, with a row spacing of 30 cm and a plant spacing of 10-15 cm. Before transplanting, fertilizer should be applied well, and old leaves and dead branches should be removed. When transplanting, transplant with soil whenever possible and damage the roots as little as possible to help the seedlings survive. Under general conditions, goji seedlings with well-developed root systems can reach a transplanting survival rate of 100%. About 1 month after planting, cuttings-grown goji can be harvested for tender leaves and tender shoots.
2.2 Fertilizer and Water Management The yield and quality of vegetable goji are greatly affected by fertilizer and water. In production, fertilizer and water management should be strengthened according to the growth characteristics of goji to increase its yield and tenderness. This plant requires much fertilizer during the growing period and needs continuous supplementation of nitrogen, phosphorus and potassium fertilizer. After goji seedlings develop new roots and new shoots, light topdressing should be applied in time. In addition to manure water, foliar spraying of 0.2% urea plus 0.3% potassium dihydrogen phosphate can also be used, sprayed once every 15 d. In seasons with little rain, attention should be paid to irrigation to keep the soil moist.
2.3 Pruning and Training During the growth of goji seedlings, attention should be paid to timely pest and disease prevention and weeding. In the Shanghai area, goji has relatively few pests and diseases; the main pest is aphids. If aphids occur severely, 40% dimethoate 1000-fold solution or 50% pirimicarb 2000-fold solution can be used for control. Weeds found in the goji field should be pulled out promptly to avoid competing with goji for nutrients. In the later stage of goji growth, the plants should be heavily pruned, maintaining a height of about 50 cm. By pruning the plants, lateral buds and latent buds can be forced to sprout, forming clump-like, multi-headed dwarfed plants, so that the tender tips are concentrated on one horizontal plane, making harvesting convenient, and the tender stems are thick and the tender leaves large, with good quality.
3 Development and Utilization Value
3.1 Alleviating off-season vegetable supply and enriching variety choices Vegetable goji can clear heat and detoxify, brighten the eyes and clear the liver, and also has anti-aging effects; it is a very good health-type vegetable. The production and supply of vegetable goji can ease the contradiction between market supply and demand and has a positive effect. In the process of adjusting the planting industry structure in suburban areas, developing and utilizing vegetable goji with a natural flavor is of great significance for increasing farmers' income and promoting the sustainable development of agriculture and forestry.
3.2 Vegetable goji has strong stress resistance and is pollution-free Goji was originally a wild vegetable, tolerant of barren soil and with strong stress resistance, and it suffers relatively little pest and disease damage during growth. Vegetable goji has a special delicate fragrance and strong resistance to stress, pests and diseases, and less pesticide is applied in production, which has a positive effect on producing pollution-free vegetables and green food and safeguarding the public's vegetable food safety.
3.3 Low planting cost and high output value Goji is simple to cultivate and manage artificially, and can be planted in front of and behind farmers' houses, by riversides or as fences; without special cultivation, it can be harvested for a long time. If grown under protected cultivation, production and harvesting can be carried out year-round, obtaining a higher output value.
3.4 Greening courtyards and beautifying the environment Perennially cultivated goji, in addition to being used as a vegetable, also has a certain ornamental value. Goji has a relatively long ornamental period of green leaves, white flowers and red fruits each year, and has the effect of greening courtyards and beautifying the environment. In the past, people often planted goji in front of and behind their houses to green their courtyards; in recent years, some residents have also grown goji as bonsai on balconies, so it can be used both as a vegetable and for viewing, achieving two goals at once.