Cultivation and management techniques of lettuce in autumn

Lettuce (scientific name: Lactuca sativa L.var. AngustanaIrish.) Also known as lettuce, Asteraceae lettuce species can form a variety of fleshy tender stems, herbaceous plants in 2012. Alias stem lettuce, lettuce bamboo shoots, green shoots, lettuce. Delivery period: from January to April. It is native to Central or North China. The aboveground stem is edible, the stem skin is white-green, the stem is crisp and tender, the young stem is emerald green, and turns white-green after maturity. Mainly edible fleshy tender stems, which can be eaten raw, salad, fried, dried or pickled, and tender leaves can also be eaten. Stems and leaves contain lettuce and lettuce. It tastes bitter and has analgesic effect. Lettuce has strong adaptability and can be cultivated in spring and autumn or overwintering, mainly in spring and harvested in summer.

Morphological characteristics of lettuce

Lettuce is an annual or biennial herb, 25-100 cm tall. The root extends vertically. Stem erect, solitary, distal panicle branched, all stem branches white. Basal leaves and lower stems large, undivided, oblanceolate, elliptic or elliptic-oblanceolate, 6-15 cm long and 1.5-6.5 cm wide, apex acute, shortly acuminate or rounded, sessile, base cordate or arrowhead-shaped semi-clasping, margin undulate or serrulate, acuminate upward, homomorphic or lanceolate to basal leaves and lower stems, leaves on lower branches of panicles and leaves on panicles very small. Ovate-cordate, sessile, base cordate or arrowhead-clasping, margin entire, all leaves glabrous on both surfaces. Inflorescences numerous or extremely numerous, arranged in panicles at the top of stem branches.

Involucral bracts ovoid, 1.1 cm long, 6 mm wide; involucral bracts 5-layered, outermost layer broadly triangular, ca. 1 mm long, ca. 2 mm wide, outer triangular or lanceolate, 5-7 mm long, ca. 2 mm wide, middle layer lanceolate to ovate-lanceolate, ca. 9 mm long, 2-3 mm wide, inner layer linear-elliptic, 1 cm long, ca. 2 mm wide, apex acute of all involucral bracts, glabrous outside. There are about 15 ligulate florets. Achenes oblanceolate, 4 mm long and 1.3 mm wide, compressed, light brown, with 6-7 veinlets on each side, apex acute into a fine beak, beak filiform, ca. 4 mm, as long as achenes. Crown hairs 2-layered, slender, scaberulous. The flowering and fruiting period is from February to September.

Lettuce is a straight root system, most of the lateral roots occur after transplantation, shallow and dense, mainly distributed in 20-30 cm soil layer. The stem is shortened. Leaves alternate, lanceolate or oval, etc., light green, green, dark green or purplish red, leaves spreading or wrinkled, entire or notched. The shortened stem gradually elongated and thickened with the plant growth. after the stem tip differentiated into flower buds, the stem grew thicker while the flower stem elongated, forming a rod-shaped fleshy tender stem. The flesh is light green, emerald green or yellowish green. Panicle with yellowish flowers, each inflorescence with about 20 flowers, self-pollination and sometimes cross-pollination. Achenes, black-brown or silver-white, with crown hairs.

Cultivation and management techniques of lettuce in autumn

I. Seedling and transplanting

1. Seed treatment

Before sowing, the seeds should be treated at low temperature. First, use low temperature to promote germination, 100g seeds with 1 kg of water, then soak 4 drops of Aishou 1 kg water drop for 8 hours, then rinse with clean water and filter dry, wrap the dried seeds with a wet cloth, then wrap the cloth with a semi-dry wet towel and refrigerate it in the freezer (below 16 ℃) for 23 days.

2. Seedling raising and seedbed preparation

First level the seedbed, soak the seedbed with 10 grams of dimethazone per square meter with water, then sow the seeds on the side of the box, sow 5 grams per square meter, keep moisture, build an arch shed, the height of the arch shed is 1 meter to 1.2 meters, and then cover the film on the arch frame, the film is 6 inches from the ground, not to the ground, in order to facilitate ventilation, cover the sunshade on top of the film.

3. Management of seedling bed

In the management, the key point is to prevent and cure the blight, and irrigate the root with the liquid of 500 times of Dixong 1Ru. The seedling bed is often kept moist. When sprinkling with water, it is best when the day is cool and the ground is cool.

4. Cultivation and management

① mu applies base fertilizer, 10, 000 jin of pig manure per mu, or 5000 jin of fermented chicken and duck manure, then 50 kg of compound fertilizer with 45% content, and 50 kg of lime all over the field. After deep turning, it is flat and less fine, open the box to hit the nest (the row spacing is 1.5 feet × the nest spacing is 1.2 feet), plant 3500 hm 4000 nests per mu, and immediately drench 10% of the light dung water after planting.

② seedling fertilizer was applied immediately 5-7 days after planting, and 5kg urea was added to pig manure water per mu.

③ applied open plate fertilizer, and when the seedlings grew to 5mu, 1.5kg urea was added to pig manure per mu for topdressing.

5. Pest control

There are mainly soft rot, downy mildew, brown spot and Sclerotinia sclerotiorum in bamboo shoots. the method is as follows: a bucket of water (30 jin) is sprayed every 10 days with 15 grams of lienomycin, 20 grams of chlorothalonil and 20 grams of Dupangke dew. When sealing the box, spray once every 10 days for 3 times. Pay special attention to: boron fertilizer should be sprayed on the leaf surface. When the seedlings grow to 6 inches high, use boron fertilizer to add 15 grams per bucket of water (do not overuse) for foliar spraying, and apply it again when sealing the box.

Second, sowing

1. Seed treatment (same as seedling transplanting)

2. Re-apply base fertilizer, keep the soil moist, and pay attention to cooling, drought resistance and seedling protection.

3. The amount of seed used per mu is 0.75 kg.

4. 25-30 days from budding to harvesting small plants. (cultivation management, pest control and seedling transplanting are the same)

III. Field management

Suitable age can be planted when the seedling age reaches 25 days. Transplanting should be carried out after 5 p.m. in sunny days or in cloudy days. The row spacing of transplanting lettuce plants is 35-35 cm, watering enough water at the time of planting, and watering live trees again the next morning until they are alive. Early topdressing and watering seedlings after living plants, applying 1000 kg of clear water manure per mu, 20-30 kg of urea per mu at rosette stage, and 25 kg of urea per mu when closing rows. The seedlings were watered slowly once after living plants, combined with dung to achieve drought resistance and nutrition; enough water was watered in the rosette stage, if there was a lack of water, it was easy to bolt; if it was closed, it was irrigated in time in case of drought, the border surface was moist and drained, and the ditch was soaked in time in case of overcast and rainy weather, so that the rain stopped the field and stopped watering a week before harvest.

The diseases of early control Cordyceps lettuce include aphids, downy mildew, gray mildew and so on. Control of aphids with 1000 times of dimethoate or trichlorfon; control of downy mildew with 600,800 times of Ruidu or 1000 times of ethyl aluminum; and control of gray mildew with 1000 times solution of 50% Sukeling or 50% prohydantoin, sprayed every 7 days for a total of 2 times. The first intertillage was shallow, light and uniform; the second intertillage was slightly deeper and cultivated soil around the plant; the third intertillage was carried out before closing the row, combined with topdressing and soil cultivation to form a semi-high ridge, which was beneficial to root absorption. Early harvest early autumn lettuce on the market; when autumn is light, as long as the lettuce is close to the harvest standard, the lettuce can be harvested and listed in batches, and the standard is that the heart leaf is equal to the outer leaf. If it is not harvested in time, lettuce is easy to pick moss, and the growth point and flower buds can be removed in sunny days to control the top growth, increase the nutrient reflux of stem, promote the hypertrophy of tender moss and achieve high quality on the market.