A detailed guide to high-yield jicama (yam bean) cultivation techniques: grow this way for higher yields
Jicama, also known as yam bean, Mexican turnip, sinking root, and so on, is an annual or perennial twining herbaceous vine in the genus Pachyrhizus of the legume family Fabaceae that forms tuberous roots. It originated in tropical America and is now widely distributed across tropical regions of the Eastern Hemisphere. It is commonly cultivated in the provinces of southwestern China, where its underground tuberous roots are harvested for eating raw or cooked. Its cultivation economic value is somewhat low, but its nutritional value is considerable. Let us take a look at high-yield jicama cultivation techniques below!
Jicama's growth habits
Jicama is a vegetable that likes warmth and light, and its growing period requires relatively high temperature conditions. The germination stage requires a temperature of 30°C, and the suitable temperature for the aboveground parts and the flowering and pod-setting stage is 25-30°C. The growth and development of the tuberous roots has a relatively broad adaptability to temperature and can swell and grow under relatively low temperature conditions. However, when the temperature is below 15°C, growth and development are inhibited. Its soil requirements are relatively strict, and suitable soil conditions are necessary to obtain high yield and good quality. It requires deep, loose, well-drained loam or sandy loam, and is not suitable for planting in clayey soil with poor aeration and permeability.
Jicama seed selection, land selection, and land preparation
The edible part of jicama is the underground tuberous root, so it is best to choose sandy loam with deep soil, good drainage, medium fertility, and strong water and fertilizer retention. After the previous crop is harvested, carry out land preparation. The shape of the jicama tuberous root is related to variety, soil, and cultivation. If flat-round varieties are cultivated too deep, the fleshy roots will grow downward, forming long roots, with increased fiber leading to reduced quality. Generally, plowing to 17-20 cm is appropriate, while for sandy loam only 13-17 cm is needed, and for spindle-hammer shaped types it can be slightly deeper. Apply 500 kg of plant ash and 2000-3000 kg of decomposed barnyard manure per mu. Fifteen days before sowing, break up the soil clods and rake them level, making high beds 1.2-1.3 m wide, with bed furrows about 25 cm deep to facilitate drainage.
Jicama cultivars
1. Early-maturing varieties: The plants have medium vigor, the leaves are relatively small, the tuberous roots swell earlier, and the growing period is shorter. The tuberous roots are flat-round or spindle-shaped, with thin skin and few fibers, and a single root weighs 0.4-1 kg. They are eaten fresh or stir-fried. Varieties include Guizhou Huangping jicama, Sichuan Suining jicama, Chengdu Muma Mountain jicama, Taiwan Malay variety, Guangdong Shunde yam bean, and so on.
2. Late-maturing varieties: The plants have strong vigor, a long growing period, and the tuberous roots mature relatively late. The tuberous roots are flat spindle-shaped or conical, with relatively thick skin, more fibers, high starch content, and less water. A single root weighs 1-1.5 kg, and large ones can reach more than 5 kg. They are suitable for processing into starch. Commonly used varieties include Guangdong Zhanjiang large yam bean, Guangzhou suburban late yam bean, Taiwan conical variety, and so on.
Jicama sowing methods
1. Sprouting: Jicama seeds are hard, and sowing dry seeds results in slow and uneven germination, so sprouting before sowing is mostly used in production. Before sprouting, the seeds should be carefully selected, choosing old, plump, and fresh ones as seed. For sprouting, first soak the seeds for 10-12 hours, and after they absorb water and swell, place them in a 25-28°C incubator to sprout. Take them out and rinse them once a day. After 4-5 days, select the seeds that have already sprouted and sow them, finishing sowing in 2-3 batches.
2. Sowing: Jicama is generally direct-sown, and the sowing methods can be divided into ground-creeping cultivation and trellis cultivation. Ground-creeping cultivation generally uses a row spacing of 50 cm, plant spacing of 33 cm, and 1-2 seeds per hole, with 3000 plants per mu, and a seeding rate of about 2 kg. Trellis cultivation uses deep furrows and high beds, with a bed height of 20-25 cm, furrow width of 50 cm, and bed surface of 90 cm. Two rows are planted per bed, with a row spacing of 50 cm and plant spacing of 33 cm, 3-4 seeds per hole, and a seeding rate of 2.5-3.0 kg per mu. After sowing, cover with 2-3 cm of soil, and seedlings will emerge 15 days after sowing.
Field management of jicama
1. Thinning and replanting: Fifteen days after sowing, the jicama seedlings emerge. After the first pair of basal leaves appears, carry out thinning and replanting, leaving 1-2 seedlings per hole, and finally establishing 1 plant per hole. Replanting should be done promptly, and on cloudy days seedlings should be transplanted with a soil ball.
2. Cultivation and weeding: For jicama, from when the seedlings are 7 cm tall until the side vines spread over the ground, promptly carry out cultivation and weeding. Cultivation should be shallow, and it is important not to damage the roots. During cultivation, earth can be hilled up 4-7 cm to prevent the fleshy roots from being exposed outside the soil, turning green in color, and deteriorating in quality, but it is also important not to hill up too deeply, as the tuberous roots easily become elongated.
3. Water and fertilizer management: During the jicama seedling stage, loosen the soil and apply topdressing in time. Each time the soil is loosened, water with human excrement and urine once to promote early development. In early to mid-June, when the tuberous roots swell, apply a heavy topdressing once. If drought occurs, pay attention to watering. If heavy rain occurs, drain water in time. If waterlogging appears in the field, it can easily cause the jicama skin color to turn brown or the tuberous roots to rot, affecting yield and quality.
4. Flower removal and pinching: Jicama begins to produce inflorescences at the 5th-6th node, and afterward, as the vine extends, inflorescences are produced at almost every node. If allowed to bloom freely, pods will form in abundance and waste nutrients, and the roots will not easily thicken. Therefore, except for those intended for seed production, as soon as inflorescences appear, they should be cut off immediately, while retaining the leaves for photosynthesis, roughly in 2-3 rounds. When the main vine has 18-24 leaves, pinch the growing tip; after pinching, the vine stops growing.
5. Pruning and trellising: When the jicama seedlings grow to 30 cm tall, insert 1 small bamboo or cotton stalk per hole, build a human-shaped trellis, and tie adjacent jicama seedlings together to let the vines climb onto the trellis.
6. Harvesting and seed saving: Generally, after 5-6 months from sowing, the fleshy roots of jicama can be harvested. In the Yangtze River Basin, early and medium-maturing varieties are harvested in September, and medium-late-maturing varieties are harvested from late October to early November. Tuberous roots for raw eating should be harvested early; the roots are crisp and tender, juicy, and sweet, but not suitable for storage. For medium-late-maturing varieties, the yam bean skin is thin and not tolerant of frost, so they should be harvested before frost. Generally, the yield per mu can reach more than 3000 kg.
Jicama pest and disease control
1. Sclerotinia rot
[Damage] It harms the base of the stems of jicama seedlings and adult plants. The base of the seedling stem becomes water-soaked and rots, which can cause damping-off. In adult plants, water-soaked light brown lesions often appear on the stem near the ground, petioles, and leaves, with indistinct edges, often causing rot of the leaves or stem base.
[Control] In the early stage of the disease, spray for control with 30% huihuishaxing wettable powder at 800-1000 times dilution, 20% iprodione · carbendazim suspension concentrate at 1500-2000 times dilution, or 40% junhenjing wettable powder at 1000 times dilution.
2. Viral disease
[Damage] It harms the leaves of jicama. Diseased leaves turn yellow, and in severe cases all the upper leaves of the plant turn yellow, forming a pattern of yellow on top and green below, with plant dwarfing and obvious leaf drop.
[Control] Spray for control with 20% moroxydine acetate copper wettable powder at 800-1000 times dilution, 1.6% diethyl aminoethyl hexanoate aqueous solution at 2000 times dilution, or 1.45% bingdubike at 500 times dilution.
3. Aboveground pests
[Damage] The aboveground pests of jicama include tobacco cutworm, cabbage moth, diamondback moth, bean leaf roller, and so on, mainly harming the leaves of jicama.
[Control] In the young larval stage, spray to kill with 20% chlorantraniliprole suspension concentrate at 3000-5000 times dilution or chlorfenapyr at 1500 times dilution.
4. Underground pests
[Damage] The underground pests of jicama include white grubs, cutworms, mole crickets, earthworms, and so on, mainly harming the tuberous roots of jicama.
[Control] After pinching the main vine and at the early stage of tuberous root swelling, drench the roots twice with 50% phoxim emulsifiable concentrate at 500 times dilution or 40% chlorpyrifos emulsifiable concentrate at 800-1000 times dilution.