Detailed guide to high-yield cultivation techniques for kudzu root: master the key points for easy, abundant harvests

Kudzu root, also called fen ge or gegen, is a commonly used traditional Chinese medicinal herb, and demand for it is increasing year by year. Its key high-yield cultivation techniques are described below.

Using root heads as planting material

At each annual kudzu harvest, select thick, pest- and disease-free, undamaged, intact root heads as planting material. Cut off the tuberous roots and spread them in a dry, cool indoor spot to air for 1-2 days before planting. If dug up in winter, they need sand storage: first spread a 10 cm thick layer of river sand on the indoor floor, then place a layer of root heads on the sand, cover them with a 15 cm thick layer of river sand, and surround the sides with bricks. During sand storage, keep the river sand slightly moist and check frequently; if rot is found, remove it immediately. They can be taken out for planting the following year. In areas with no frost or only brief frost, they can be left in place as seed stock and dug up only when planting the following year, placing 1 root head per hole at planting time.

Choosing the plot

Kudzu tuberous roots grow thick and large and penetrate deep into the soil, so it is best to choose a sunny gentle slope, flat land, or field edge corner with deep, loose, fertile, well-drained sandy loam soil. Before planting, deep plow more than 30 cm, then dig holes 40 cm deep and 40 cm wide at a row spacing of 60 cm and a plant spacing of 50 cm, applying 10 kg of mixed fertilizer such as barnyard manure, grass turf ash, and compost per hole. Mix the surface soil with the fertilizer evenly, then plant. After planting, cover the hole surface with grass to keep the soil in the hole loose and moist, which favors plant growth.

Rational fertilization

Kudzu root is a fertilizer-tolerant plant. Applying sufficient base fertilizer and topdressing rationally are important measures for increasing tuberous root yield. Topdressing usually needs to be done multiple times. The first is in March to April, when the seedlings are 30 cm tall, applying 3-5 kg of human and livestock manure water per hole; afterward do it once a month, with the same fertilizer type and amount as the first. The 4th and 5th applications are done 45 days apart, applying 10 kg of barnyard manure and grass turf ash, 100 g of superphosphate, and 100 g of potassium sulfate per hole. Mix the above fertilizers and apply them in a ring ditch or hole beside the plant, then earth up after application to promote tuberous root growth.

Thinning seedlings and building supports

Kudzu has strong sprouting ability, and planted kudzu heads often grow multiple stems and vines. Too many stems and vines will affect the formation or growth of the underground tuberous roots. Therefore, when the seedlings grow to 15-20 cm, keep only 1-2 robust seedlings per hole and remove the rest. Kudzu is also a twining herbaceous vine with long vines and many nodes, and its nodes easily grow adventitious roots when they touch the soil. Therefore, when the seedlings grow to 30 cm, build supports with bamboo strips or wooden strips. The supports can be made into a fence or a triangular crossing shape, and the seedlings should be guided onto the supports to grow twining around them. This makes management easier, benefits photosynthesis and ventilation and light penetration, and can also prevent the stems and vines from touching the soil and growing adventitious roots that consume nutrients. Supports should not be built too late; if too late, the vines become tangled with each other, making management inconvenient.

Pinching the top and removing flower clusters

When the kudzu stems and vines grow to 200 cm, the terminal buds should be pinched off to encourage more branching and more leaves, enhancing photosynthesis. However, too many branches will cause excessive leaves that shade each other, affecting photosynthesis and also causing stems and leaves to consume too many nutrients, which is unfavorable for tuberous root growth. Therefore, excessive and overly dense branches and leaves should also be appropriately removed. From May to July each year, except for plants kept for seed, the flower clusters that appear should be removed in stages and batches in good time to prevent excessive nutrient consumption during flowering, thereby helping the accumulation of nutrients in the tuberous roots and increasing yield.

Root pruning

If the plant grows too many tuberous roots, nutrient accumulation is often not concentrated, so the tuberous roots do not grow large, affecting yield and quality. Therefore, after the tuberous roots have formed and grown to 2-3 cm in diameter, the soil around the plant should be scraped open, and 2-3 thicker tubers should be selected and kept while the others are removed, so that nutrients are concentrated in 2-3 tuberous roots to increase yield.