Detailed Explanation of High-Yield Cultivation Measures for Mustard Greens in Winter

Mustard greens (Brassica juncea) are annual or biennial herbaceous plants of the genus Brassica in the Cruciferae family. They are a famous specialty vegetable of China, originally from China, and a commonly cultivated vegetable throughout the country, mostly distributed in the provinces south of the Yangtze River. The main and lateral roots of mustard greens are distributed within about 30 cm of the soil layer. The stem is a shortened stem, and the leaves are borne on the shortened stem. They come in shapes such as elliptical, ovate, obovate and lanceolate, with leaf colors of green, dark green, light green, yellow-green, green with stripes, or purplish red. They are rarely cultivated in European and American countries, and originated in Asia. Li Shizhen's "Compendium of Materia Medica" recorded the medicinal value of mustard greens.

Morphological Characteristics of Mustard Greens

Mustard greens (the original variety) are annual herbs, 30-150 cm tall, usually hairless, sometimes with bristles on young stems and leaves, covered with a bluish-white bloom, and pungent in taste; the stem is upright and branched. The basal leaves are broadly ovate to obovate, 15-35 cm long, with a rounded-obtuse apex, a cuneate base, lyrately pinnatifid with 2-3 pairs of lobes, or undivided, with incised teeth or teeth on the margins, and a petiole 3-9 cm long bearing small lobes; the lower stem leaves are smaller, with incised teeth or teeth on the margins, sometimes with rounded-obtuse serrations, and do not clasp the stem; the upper stem leaves are narrowly lanceolate, 2.5-5 cm long and 4-9 mm wide, with indistinct sparse teeth or entire margins. The raceme is terminal and elongates after flowering; the flowers are yellow, 7-10 mm in diameter; the pedicels are 4-9 mm long; the sepals are pale yellow, oblong-elliptical, 4-5 mm long, upright and spreading; the petals are obovate, 8-10 mm long and 4-5 mm wide. The silique is linear, 3-5.5 cm long and 2-3.5 mm wide, with the valves having 1 prominent midvein; the beak is 6-12 mm long; the fruiting pedicel is 5-15 mm long. The seeds are spherical, about 1 mm in diameter, and purplish brown. The flowering period is March-May, and the fruiting period is May-June. 

High-Yield Cultivation Measures for Mustard Greens in Winter

I. Variety Selection Leaf mustard greens prefer cool and humid climate conditions. The optimum growth temperature is 15-20°C. Excellent varieties suitable for local winter planting include Guangdong Chaozhou mustard greens, Taiwan Nongyou Da Jie Wang, Thailand Chia Tai wrapped-heart mustard greens, Fujian large-leaf mustard greens, Guangxi Guangji greens, Guangdong Nanfeng mustard greens, etc.

II. Seedling Management

1. Seedbed Selection

Choose land with high, dry terrain and fertile soil. Apply 1500 kg of human manure and urine plus 50 kg of superphosphate per 667 sq m as base fertilizer. First plow and sun-dry, then place rice straw on the soil and burn it to disinfect the soil. Then mix with ash and carefully make the beds. Sow 50 g of seeds per 66.7 sq m of land, which can provide seedlings for 1334 sq m of land. After sowing, cover with 0.5 cm of fine soil.

2. Sowing Time

The best sowing period in Nan'an City is around National Day (that is, from the 15th to the 20th day of the eighth lunar month). Plant in early to mid-November, when the temperature is still relatively high, which is beneficial to the early growth of the plants. From the end of November to mid-December, during the Minor Snow and Major Snow solar terms, the temperature is lower, and soft rot and downy mildew occur less, which can reduce the amount of pesticides applied during the vigorous growth period of mustard greens and lower the pesticide residues in the vegetable.

3. Thinning and Final Spacing

Carry out the first thinning when the seedlings produce their first true leaf, removing leggy seedlings and variant seedlings. Carry out the second thinning when they have 2 true leaves, and finally maintain a seedling spacing of 5 cm square. Transplant when they have 5-6 true leaves. During the growth period, if the growth is poor, apply a topdressing of thin, decomposed pig manure liquid with a little urea. During the seedling period, prevent damage from aphids, flea beetles and underground pests. III. Field Management

1. Field Plot Preparation

Choose farmland with neutral soil, relatively high fertility, convenient drainage and irrigation, and good water source quality for planting. After the late rice is harvested, directly broadcast the base fertilizer on the rice field stubble. Then plow deep furrows, build the beds with the furrow soil (mainly on both sides), position according to plant and row spacing, break up the soil, make planting holes, and transplant. This saves labor and effort and gains the initiative of the season.

2. Reasonable Close Planting

Generally, transplant in early to mid-November, choosing a time at the end of a cold spell and the beginning of a warm one. Use deep furrows and high beds, with a bed width of 1.0 m, a row spacing of 50 cm and a plant spacing of 50 cm. Open planting holes in a triangular arrangement, and plant about 2600 plants per 667 sq m. After placing the seedlings into the holes, mix 15 kg of ternary compound fertilizer plus burned soil per 667 sq m and cover the roots with it, then cover with soil and press firmly as appropriate.

3. Intertillage and Weeding

Before the rows close, loosen the surface soil, eliminate weeds, and aerate the soil. Be careful not to bury the heart of the vegetable with soil. The furrow soil should be cleared evenly. This facilitates drainage and irrigation. 4. Fertilizer and Water Management

(1) Water Management

After transplanting, water once, and water again the next evening. Depending on weather conditions, irrigate once every 6-7 days thereafter. In the early stage, mainly use light irrigation, and drain as soon as the soil is kept moist. In the middle and late stages, gradually use large furrow irrigation, but it is best not to let the water exceed the bed surface. Stop irrigation one week before harvest. This facilitates storage, transportation and processing.

(2) Reasonable Fertilization

After transplanting and survival, apply a light dressing of human manure and urine water once. The second topdressing is combined with irrigation, applying 7.5 kg of compound fertilizer plus 2.5 kg of urea per 667 sq m. The third topdressing is carried out 20 d after the plants have become established, applying 10 kg of compound fertilizer plus 5 kg of urea per 667 sq m. The last application is along with large furrow irrigation, applying 20 kg of urea per 667 sq m, plus 12.5 kg of compound fertilizer and 7.5 kg of potassium chloride. In the late growth stage, combined with pesticide spraying, add 1 small packet of the organic fertilizer Fuwanjia plus 1 small packet of nutritional nucleotides per sprayer tank for foliar spraying.

5. Pest and Disease Control

The main diseases of mustard greens include soft rot, downy mildew and anthracnose. For soft rot, in the early stage of the disease, drench the roots with 2000-fold agricultural streptomycin solution or spray with 500-fold Keshade; for downy mildew, use Redomil or metalaxyl; for anthracnose, use 800-1000-fold Shibaogong.

The main pests include aphids, striped flea beetles and cabbage caterpillars. For aphids and striped flea beetles, use 3000-fold 10% Dagongchen or 1500-fold Anlübao; for cabbage caterpillars, the early larval stage is the best time to control this pest, and 2500-fold 5% Regent, 1500-fold Yitaibao or 1500-fold Abamectin can be used. IV. Timely Harvest

For high-yield cultivation, the harvest period is February-March of the following year. Mustard greens are generally harvested before the beginning of flowering, as the quality deteriorates if harvested after flowering.