A Detailed Guide to Flax Cultivation Techniques and Management Methods

Flax (scientific name: Linum usitatissimum L.): an annual herbaceous plant, which can be divided into three types: fiber flax, oil flax and dual-purpose oil-fiber flax. The stem is erect, can reach 1.2 m in height, the upper part is slender and soft, with a waxy coating; the leaves are alternate, lanceolate, 20-40 mm long, 3 mm wide, with a white bloom on the surface; the flower has 5 petals, 15-25 mm in diameter, blue or white; the fruit is a capsule, the seeds are flat and ovate, and it prefers a cool and humid climate.

Flax Cultivation Techniques

1. Site selection and previous crop selection

Site selection: The flax root system is poorly developed, has weak fertilizer uptake, the seedlings grow slowly, and are easily harmed by weeds. Therefore, when planting flax, choose a plot with deep soil, loose texture, good water and fertilizer retention, good aeration, flat terrain and few weeds. Flax is suitable for neutral and slightly acidic soil, pH 6.5-7.5, and the goal of high yield can be achieved under conditions of soil organic matter content of 27-53 mg/kg.

Previous crop selection: Practice has proved that flax planted after corn and soybean has the highest yield, followed by wheat, and flax planted after millet and sorghum has the lowest yield. Our county mostly chooses corn stubble for planting flax, but attention must be paid to the herbicides applied to the previous crop. If long-residual pesticides such as doucaote have been applied, flax must absolutely not be planted. Flax cannot be planted in continuous cropping or after a crop of the same type, otherwise damping-off is likely to occur at the seedling stage, causing reduced yield. Continuous cropping of flax also easily makes anthracnose more severe.

2. Plowing and land preparation

Lanxi County has a cold-temperate continental monsoon climate. In spring, drought occurs in nine out of ten years, and there are often strong winds. Flax seeds are small, the soil covering is shallow, and seed germination requires a lot of water, so improving sowing quality and preserving soil moisture are the keys to ensuring a full stand from a single sowing of flax. Harrowing stubble on the original ridge is the main land preparation method adopted in our county. The procedure is: one harrowing and half rolling, with harrowing, leveling and rolling carried out in continuous operations. Stubble harrowing land preparation not only creates a level and loose topsoil layer, but also reduces the massive loss of moisture from the plow layer below 10 cm, with an obvious moisture-conserving effect.

3. Fertilization

Rational application of chemical fertilizers: Applying appropriate chemical fertilizers while applying organic fertilizer has a good yield-increasing effect. Chemical fertilizers can be applied into the soil by machine before sowing or at sowing. The application rate should be determined according to soil type, fertility, pH, soil texture, planting density and yield target. For slightly alkaline soil, use a nitrogen-phosphorus-potassium ratio of 1:3:1; for black soil, use a nitrogen-phosphorus-potassium ratio of 2:1:1. Where conditions permit, adding trace fertilizers such as zinc fertilizer and copper fertilizer also has an obvious yield-increasing effect.

4. Sowing

(1) Seed selection: A superior variety is the internal factor for high flax yield. Our county selects varieties such as Heiya No. 10 and Shuangya No. 7. (2) Seed treatment: Before sowing, the seeds must be carefully selected, thoroughly removing dodder, grass seeds and male flax, as well as shriveled seeds and soil particles and other impurities, so that the seed purity reaches above 95% and the germination rate reaches above 90%. To prevent flax seedling-stage diseases, seed treatment must be carried out before sowing. Sun the seeds for 4-5 d before sowing. Use carbendazim-thiram for seed dressing, with a dosage of 0.3% of the seed amount, for control. (3) Determination of sowing period and sowing rate: Sow when the soil temperature at sowing depth stabilizes at 7-7.5°C and the soil moisture content is not lower than 20%. Our county generally sows from late April to early May. The sowing rate should be determined according to soil fertility conditions and the target number of retained seedlings. For plots with high soil fertility, retain 15-18 million seedlings per hectare, with a sowing rate of 105-112.5 kg/ha. For plots with general fertility, retain 13.5-15 million seedlings per hectare, with a sowing rate of 97.5-105 kg/ha. For plots with poor fertility, retain 12-13.5 million seedlings per hectare, with a sowing rate of 90-97.5 kg/ha.

5. Field management

1. Chemical weeding: Chemical weeding occupies an important position in the integrated control of weeds in flax fields and is an important means of weed control at the flax seedling stage. Spray on stems and leaves when flax seedlings are 10-15 cm tall and weeds have 3-4 true leaves. Quizalofop-p-ethyl 3000 g/ha + MCPA 750 g/ha has a good effect on grass weeds; MCPA 750 g/ha + quizalofop-p-ethyl 600 ml/ha has a good effect on broadleaf weeds.

2. Manual weeding: Manual weeding is an indispensable part of integrated weed control. Most often, when flax seedlings are 6-10 cm tall, manually pull weeds 1-2 times, or use a hoe to loosen the soil and resist drought while weeding.

3. Pest and disease control: The main diseases of flax include damping-off and anthracnose, and integrated control measures should be adopted. Select disease-resistant varieties, carry out rational crop rotation, rational close planting, and rational fertilization to enhance the disease resistance of flax. Promptly and thoroughly remove diseased plants found in the field. Also always pay attention to insect pests. When pests such as armyworms and meadow moths are found, promptly spray 80% dichlorvos emulsifiable concentrate at 800 times dilution for control.

6. Harvest

Timely harvesting of flax is the key to ensuring a bumper harvest and improving flax fiber quality. Flax should be harvested at the yellow-ripe stage.

Pest and disease protection:

Flax has pests and diseases throughout its entire growth period. It is necessary to adhere to "prevention first, integrated control" and, on the basis of selecting disease-resistant varieties, practicing crop rotation, and strengthening fertilizer and water management, promptly carry out control according to the types of pests and diseases that occur, so as to ensure the healthy growth of flax seedlings and reduce losses.  
  The main pests and diseases of flax are: damping-off, fusarium wilt, powdery mildew, rust, armyworm, aphid, and black cutworm. If damping-off or fusarium wilt occurs, use 100 g of carbendazim wettable powder per mu or 80 g of 80% chlorothalonil wettable powder mixed with 50-60 kg of water for spray control; for powdery mildew and rust, use 30-40 ml of triadimefon emulsifiable concentrate per mu mixed with 50-60 kg of water for spraying; for armyworm and aphid, use 16 ml of 25% lambda-cyhalothrin emulsifiable concentrate per mu mixed with 50 kg of water or deltamethrin at 1000-1500 times dilution for spray control; for black cutworm, pyrethroid or organophosphorus insecticides can be selected for spray control at the young larval stage, or carbofuran can be selected for poisonous soil broadcasting.  
  Flax field weeding methods include manual weeding and chemical control. In fields with few weeds, manual weeding can be used; if the terrain is low-lying, the groundwater level is high, and the weed damage is severe, the corresponding herbicide can be selected according to the weed species. To control grass weeds, use 80-100 ml of 0.9% "Weiba" emulsifiable concentrate per mu mixed with 50 kg of water for spraying; to control dicotyledonous weeds, use 100-150 g of MCPA per mu mixed with 50-60 kg of water for spraying. After the flowering period, in fields with severe rodent damage, poisons such as bromadiolone and sodium diphacinone can be selected to prepare poisoned bait for control.