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Pueraria lobata (Willd.) Ohwi

Fabaceae
Kudzu, Japanese arrowroot

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors

Uses

Kudzu is primarily, grown for pasture, hay, and silage. It is palatable to all types of livestock. Kudzu is nearly equal to alfalfa in nutritive value. Leaves, shoots and roots are eaten by some humans. Useful fiber is obtained from stems, and starch is obtained from the tuberous root (roots up to 35 kg each). In China and Japan Ko-fen flour, made from the roots, is used in soups. Said to be cultivated for its tuber in the uplands of New Guinea and New Caledonia. Used for erosion control and soil improvement on banks, slopes and gullies where a permanent planting is desired. It is used as shade, planted around buildings.

Folk Medicine

Chinese reportedly use the plants as a diaphoretic and febrifuge, the root decoction for colds, dysentery and fever. The root starch is official in the Japanese pharmacopoeia. Shoots are used as a lactagogue.

Chemistry

Raw roots (per 100 g edible portion) contain 113 calories, 68.6 percent moisture, 2.1 g protein, 0.1 g fat, 27.8 total carbohydrate, 0.7 g fiber, 1.4 g ash, 15 mg Ca, 18 mg P, and 0.6 mg Fe. Starch of roots contains (per 100 g) 340 calories, 16.5 percent moisture, 0.2 g protein, 0.1 g fat, 83.1 g total carbohydrate, 0.1 g ash, 35 mg Ca, 18 mg P, 2.0 mg Fe, and 2 mg, Na. Cooked leaves contain (per 100 g) 36 calories, 89.0 percent moisture, 0.4 g protein, 0.1 g fat, 9.7 g total carbohydrate. 7.7 g fiber, 0.8 fat, 34 mg Ca, 20 mg P, 4.9 mg Fe, 0.03 mg thiamin, 0.91 mg riboflavin, 0.8 mg niacin. Feeding trials on goats indicated that kudzu hay (protein, 10.3; total dig. nutrients, 28.7; and starch equivalent, 16.1 kg 100 kg) compared well with cowpea bay, berseem hay and wheat bran in digestible protein value, but was inferior to legume hays in starch equivalent.

Description

Perennial coarse herbs with woody base; stems elongated, up to 20 m long, twining or prostrate, whitish-puberulent with coarse spreading or reflexed brown hispid hairs; stipules lanceolate, subacute, medifixed,l 15–20 m long, green; leaves trifoliolate, the leaflets green, loosely appressed, hirsute on upper surface, densely whitish-puberulent beneath., terminal lobe rhombic-orbicular, 10–15 cm long and as wide, abruptly acuminate, sometimes 3-lobed, lateral lobes often bifid; racemes densely many-flowered, nearly sessile or short-peduncled, 10–20 cm long; flowers reddish-purple, rarely almost white, 18–20 m long, fragrant, bracts linear, 8–10 mm long, 0.2–0.3 mm wide, long-pilose, caducous, bracteoles caducous, narrowly ovate or broadly lanceolate, acute; lowest calyx-lobe 1.5–2 times as long as the tube; pods flat, densely, dark brown, spreading-hispid, linear, 6–8 cm long, 8–10 mm wide. Fl. July–Sep.; seed maturing before frost, rarely setting seed northward. Seed small, about 100,000/kg.

Germplasm

Few cvs have been developed, and 'Kudze 23' is the only cv developed which produces more crowns than comon; its finer leaves and stems make it especially valuable as forage. Most strains grow 35 m or more in a single season. Assigned to the Indochina-Indonesia and China-Japan Centers of Diversity, kudzu or cvs thereof is reported to exhibit tolerance to drought, frost, grazing, heavy soil, slope, vines and weeds. (2n = 24)

Distribution

Native to Japan and the Orient, areas of Eastern Asia; rarely cultivated in Java. More widely cultivated in southeastern United States, being best adapted south of Virginia and Kentucky, west to Oklahoma and Texas although it will grow as far north as New York and Lincoln, Nebraska.

Ecology

A warm weather plant, growing from early spring until late fall. Above-ground parts killed by frost. Deep-freezing kills the entire plant. Grows on a wide range of soil types, but does not make good growth on very light poor sand or on poorly drained heavy clay. Cannot stand waterlogging on any soil. Grows best on well-drained loam soil of good fertility. On soils of low fertility, liberal use of manure and light application of superphosphate when plant is first cut is beneficial. Sometimes soil needs a complete fertilizer, other times lack of boron is a limiting factor (Use borax at rate of 30 kg/ha). Kudzu is deep-rooted, therefore drought-resistant. However, it does not do well in the tropics and dies out very quickly. Ranging from Warm Temperate Moist through Subtropical Moist Forest Life Zone., kudzu is reported to tolerate annual precipitation of 9.7 to 21.4 dm (mean of 15 cases = 13.5), annual mean temperature of 12.2 to 26.7°C (mean of 15 cases = 18.1°C), and pH of 5.0 to 7.1 (mean of 13 cases = 6.1).

Cultivation

Kudzu is propagated from seed, cuttings or crowns. Plants are usually started by rooting runners at the nodes, and transplanting 2-year old plants. Plants can be started from both softwood and hardwood cuttings, but need special conditions and care, (greenhouse misting; this method rarely used). The very hard seed coats should be scarified with acid or by mechanical means before planting to insure higher germination; even then, 70 percent germination is considered excellent. Seed sown very thick when planting. Usually not much seed is set, and then, only on parts of the plant that have climbed up on a support. If allowed, kudzu will climb up and over trees eventually smothering them out. Seed planted in a nursery in well-drained soil of good structure, in rows 1 m apart, planting 15–25 seed/20 cm of row, 0.6–1.3 cm deep when soil is warm, depending on the locality, in early or late spring. Seedlings require about 4 months to develop 4–6 true leaves and one or more roots 1.3 cm in diameter and 15 cm long. At this stage they are ready to transplant to field about the time of first fall frost. Where seed is plentiful, it may be direct-seeded in the field., allowing 1 kg/ha, with 10–12 seeds per 30 cm in rows 2 m apart. Fertilizer is applied at planting time. New stands must be cultivated and kept free of weeds the first year. Kudzu in the cotyledonous stage will withstand temperatures down to -7°C. It loses this tolerance to cold as the third and fourth leaves develop. Plants should be inoculated with the right strain of bacteria to insure maximum production. Important to protect plants from drying during planting and to tamp moist, well-propared soil about them to prevent drying after planting. Holes should be deep enough for roots to be spread out to full length. Crown buds should be level with ground surface and very lightly covered with soil. Short-cuts in planting usually result in poor stands. On ordinary good land, kudzu will grow enough in one year to extend 14 m. When field is to be used for hay or grazing, spacing is not as important, as when the field is to be regularly planted or rotated to another crop. Spacing varies from 3–10 m between rows and 1.3–3.3 m apart in rows, usually requiring about 1,250 plants per hectare. Established stands used for grazing or hay should receive 400–600 kg/ha superphosphate every second or third year, or 10 tons of good stable manure or mixture of smaller amounts of manure and a mineral fertilizer.

Harvesting

Harvested in several ways, depending on usuage. Kudzu gives in 2–3 years a good ground cover which is long-lived if not overgrazed or mowed too often. Hay: Makes a good coarse hay, retaining its leaves after cutting, does not shed an appreciable amount of leaves during growing season, is palatable to all kinds of livestock, and can be fed with very little waste. Kudzu with its heavy viny growth is difficult to cut, particularly the first time, because the vines catch on the divider board of an ordinary mower; modified mowers have been developed. Hay should be harvested when vines and ground are dry. Leave hay in swath for several hours before windrowing. Following morning when dew is off, cut plants should be put in small stacks or the windrow turned, and in the afternoon it should be put in the barn or baled. Stacks are capped with a waterproof cover, e.g. canvas. Pasture: Kudzu makes good pasture, steers gaining more than 1/2 kg/day, averaging 107.5 kg season. Kudzu can be pastured from late spring until frost or even later. It is especially valuable as a reserve feed for periods of drought. Do not graze plants until third year. If growth is vigorous, it may be grazed lightly the second year. For maximum production, pasture should be divided into 2 or more plots and grazed alternately or in rotation. In fall, rye, oats, or a winter legume (crimson clover, burclover, or vetch) should be seeded in the kudzu pasture to prevent loss of plant food by leaching and to supply pasture before kudzu growth starts in spring. Livestock should be taken from pasture before growth starts in spring. If pastured continuously, plants should not be grazed closer than 30–45 cm. If alternate or rotation grazing is practiced, plants can be grazed to 15–25 cm. Good silage can be made of kudzu by mixing it with grass, the mixture containing about 60 percent moisture. Total moisture content of kudzu at time of cutting is about 75%, so kudzu must be handled rapidly to prevent drying out too much. Cattle readily eat good silage.

Yields and Economics

Forage yield of 5 MT/ha are expected from good stands on fertile soils. About 25,000 plants or crowns can be harvested from an ordinary well-established plantation of 1 hectare. Under ideal conditions, twice that number. Planting stock should be left in the field until needed. However, if large numbers of plants are being handled for commercial sale, and it is necessary to dig them before the planting season, they should be stored in a cool well-ventilated place, and should be heeled-in in moist sphagnum moss or in soil with ample but not too much moisture.

Energy

Several have suggested that the best way to get rid of a weed is to eat it, or use it in some other destructive fashion. The biomass of the kudzu could be converted into ethanol or beef and manure by patient entrepreneurs. Planted in empty oil barrels, the kudzu (like the grape vine) has been suggested as an energy-saving cooler, the canopy of leaves of kudzu lowering temperatures of shaded areas by 10deg. or more. The tropical species, producing year round, yields 0–20 MT/ha/yr with yields as low as 1 MT reported in Australia and Colombia, 7 in Taiwan, and 20 in Cuba.

Biotic Factors

Velvetbean caterpillars (Anticarsia germatilis) eats the leaves and root-knot nematodes (Meloidogyne sp.) attack the roots. Kudzu is said to be cross pollinated and bees are the reported pollinators. Kudzu is attacked by several fungi: Alternaria sp. (leaf-spot), Colletotrichum lindemuthianum (anthracnose), Fusarium sp. (stem rot), Macrophomina phaseoli (charcoal rot), Mycosphaerella puericola (angular leaf-spot), Pellicularia solani (damping-off). It is also attacked by the bacteria Pseudomonas phaseolicola and Ps. syringae (bacterial blight and halo blight).

Complete list of references for Duke, Handbook of Energy Crops

Last update Thursday, January 8, 1998 by aw