How to Grow Rhubarb for High Yield? Detailed Explanation of Cultivation Techniques

Rhubarb, also known as Dajiangjun, Xiangdahuang, Matihuang, Nandahuang, etc. It is a perennial herbaceous plant of the Polygonaceae family. Its underground rhizome is used medicinally and has effects such as purging heat and causing purgation, promoting blood circulation and resolving accumulations, and antibacterial and anti-inflammatory actions. It is mainly used to treat excess-heat constipation, delirium and mania, food stagnation with abdominal distension, damp-heat jaundice, and blood stasis amenorrhea. It has significant therapeutic effects on constipation, acute appendicitis, intestinal obstruction, purulent skin diseases, burns and scalds, viral infections, hepatitis, and vasculitis. It is mainly produced in Qinghai, Gansu, Shaanxi, Sichuan and other provinces. It is now introduced and cultivated in various places.

Morphological Characteristics 1. Palmate-leaf rhubarb (Rheum palmatum): A perennial tall herb, about 2 m tall. The rhizome and roots are thick and yellowish-brown. The stem is erect, smooth, hairless, and hollow. The basal leaves have thick, fleshy, long petioles, about as long as the leaf blade; the leaf blade is broadly ovate or nearly circular, up to 40 cm in diameter, palmately semi-lobed, with 5 (7) lobes, each lobe sometimes further pinnately lobed or coarsely toothed, slightly cordate at the base, hairless or sparsely covered with nipple-like small protrusions above, and pubescent beneath; stem leaves are smaller, alternate, with short petioles; the stipules are sheath-like, membranous, densely covered with short soft hairs. The panicle is large, terminal; flowers are small, several clustered, purplish-red or reddish-purple; pedicels are slender, with a joint in the middle-lower part; tepals are small, in 2 whorls, the inner whorl slightly larger, elliptical; stamens 9, anthers slightly large and exserted; styles 3, stigmas capitate. Fruiting branches are mostly clustered; the achene has 3 angles, with wings along the angles, slightly concave at the apex, slightly cordate at the base, brown.

2. Zhaogute rhubarb: A perennial tall herb, about 2 m tall. It resembles palmate-leaf rhubarb, but the leaf blade of this species is palmately deeply lobed, with 3-7 lobes; the lobes are further pinnately deeply lobed, and the small lobes are narrow and long, linear-lanceolate.

3. Medicinal rhubarb: Similar to palmate-leaf rhubarb, but the leaves of this species are shallowly lobed, with large teeth or broadly triangular; the flowers are also larger, yellowish-white, and the flower buds are elliptical. The fruiting branches are spreading.

I. Growth Habits Rhubarb prefers a cold, humid, and cool climate; it fears high temperatures and avoids continuous cropping. Soil requirements: deep, loose, fertile sandy loam rich in organic matter is best.

II. Land Preparation and Fertilization Choose a field with high terrain and good drainage, and plow deeply and harrow finely. In combination with land preparation, apply sufficient base fertilizer: 3000 kg of farmyard manure, 20 kg of urea, and 50 kg of phosphorus-potassium fertilizer per mu. Then make beds and wait for sowing.

III. Sowing Rhubarb is propagated by seed. It is carried out in two steps: raising seedlings and transplanting. The sowing period is divided into spring sowing and autumn sowing. Spring sowing is around Qingming; autumn sowing is around Liqiu. Seeds are collected and sown as they mature. Before sowing, first use a drill to open shallow furrows on the prepared bed surface, then evenly scatter the seeds into the furrows. Cover the seeds with soil and water to preserve moisture so as to facilitate emergence. The sowing rate is 5 kg per mu. After sowing, seedlings can emerge in about one week at a suitable temperature. After the rhubarb seedlings are fully established, strengthen management, and they can be transplanted after one year of growth. During transplanting, set the rhubarb seedlings on the prepared bed surface at a row spacing of 70×50 cm. Water to preserve moisture so as to facilitate survival.

IV. Field Management After the rhubarb seedlings are fully established, attention should be paid to intertillage and weeding to ensure no weeds on the bed surface. For large-scale planting, soil treatment with a medicinal-field herbicide should be carried out before seedling emergence, which can effectively control various weeds. Water promptly in dry weather, and pay attention to drainage in rainy weather. Topdressing should be applied once around Liqiu: 20 kg of urea and 10 kg of potassium dihydrogen phosphate per mu. In the 2—3 years after transplanting, rhubarb is prone to bolting and flowering; except for plants retained for seed production, flower stalks should be removed as early as possible to prevent nutrient consumption.

V. Pest and Disease Control The main disease of rhubarb is root rot, which can be controlled with 1:1:100 Bordeaux mixture before onset. Or use 65% mancozeb in the early stage of the disease. For downy mildew, use phosethyl-Al or carbendazim in the early stage of the disease. The main pests include aphids, which can be controlled with pirimicarb. For underground pests, use zinc phosphide mixed with poison bait for control.

VI. Harvesting and Processing Rhubarb is generally harvested in autumn after 3—4 years of planting, when the seeds mature. When harvesting, first cut off the aboveground stems and leaves, then dig out the underground rhizome. Remove the soil completely and dry it in the sun before selling it for medicinal use. The yield per mu is 500 kg.