Industrial hemp is particularly sensitive to soil fertility. No matter which soil or previous crop is used to cultivate hemp, attention should be paid to soil cultivation measures and a large amount of organic fertilizers to achieve high and stable yields. Industrial hemp requires a soil pH of at least 6 and above, and the vigor cycle of most seeds is 1-2 years. Hemp seeds are no exception, and must be planted in the best vigor cycle of the seeds.
Mineral nutrients that need to be obtained from the soil: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, etc.;
Need to obtain non-mineral elements from air and moisture: carbon, hydrogen, oxygen, etc.;
Growing Conditions for Industrial Hemp
Industrial hemp does not have high temperature requirements. It can germinate when the soil temperature is above 1°C, but the seedlings must emerge neatly. Generally, it should be sown when the soil temperature is 8-10°C. Seeds can tolerate low temperatures of 3-5°C or lower for 10-15 days after germination; at -5°C, their growth will be delayed a little. However, if sufficient water and nutrients can be supplied, low temperature at the seedling stage has little effect on subsequent development and yield. Industrial hemp for seeds likes cold, and the large temperature difference between day and night is conducive to improving the yield and quality of hemp seeds.
Cannabis is a light-loving crop. In seed cultivation, strong light is conducive to the germination of axillary buds and inflorescence development of hemp plants, thereby increasing seed yield. In fiber cultivation, weak light can inhibit the germination of axillary buds, reduce branching and promote apical growth, which is beneficial to improve fiber yield and quality.
Hemp is a short-day crop, shortening the sunshine can promote flowering, but the plant is short, the fiber yield is low, and the grain matures early; prolonging the sunshine can delay flowering, which will lead to prolonged vegetative growth, taller plant growth, and high fiber yield.
Industrial hemp for fiber requires a lot of water. The whole growth period needs 500-700mm of precipitation. During the rapid growth period (the plant height increases by 4-6cm/day), the soil humidity should be high, and the soil moisture should be 70% of the soil field water capacity- 80%, the growth and development is the best, which is beneficial to improve the fiber production. However, industrial hemp is resistant to drought and barrenness at the same time. When the seeds are used, drought has a greater impact on the vegetative growth of industrial hemp, and the plants are short and have less impact on the grain yield. Industrial hemp has a particularly strong growth potential, and it will not stop producing even in very barren land, but the yield is low, so industrial hemp for seeds can be grown in severely barren areas.
Industrial hemp for fiber has high requirements for nitrogen, phosphorus and potassium. Nitrogen is the most, potassium is the second, and phosphorus is the least. The combination of nitrogen, phosphorus and potassium has a significant effect of increasing production. Potassium fertilizer has the effect of improving fiber yield and quality. Industrial hemp for seeds has lower nutrient requirements, and farmyard manure is better. For chemical fertilizers, an appropriate amount of nitrogen fertilizer is used, and phosphorus and potassium fertilizers are increased. High nitrogen fertilizer will cause plants to grow leggy and waste nutrients; increasing phosphorus fertilizer can increase grain yield; potassium fertilizer can increase grain oil content.
The following is a brief description of the specific steps of industrial hemp cultivation
Land selection: deep soil layer, strong water retention and fertility, soft and fertile soil, sandy loam with good drainage, and pH 6-6.5 slightly acidic.
Crop rotation: Rotation with crops such as rice, vegetables and jute can reduce pests and improve oxygen storage capacity.
Fertilization: 3/4 of the nutrients of cannabis must be absorbed in the early stage of growth, but the root system in the seedling stage grows slowly and the absorption capacity is weak, so enough base fertilizer should be applied, generally 1500-2500 kg of manure, soil manure or green manure, and 40-50 kg of plant ash.
Sowing: Choose pure and full, full and complete, free from pests and diseases, uniform in size, fresh in color, high germination rate, the thousand-grain weight of small and large seeds should be more than 20 grams and 25 grams respectively, the germination rate is more than 95%, and the impurity rate is not much. at 5%. Rinse the seeds with clean water before sowing, then soak them in water for 2-3 days, take them out and expose them to the sun for 1 day before sowing.
April-July is the hemp cultivation period, and the specific steps are thinning, fixing seedlings, cultivating seedlings, fertilizing, cultivating soil, irrigating and draining. During this period, attention should be paid to the prevention of wind disasters, pest control and other work.
Note: During the growth period of cannabis, it is vulnerable to wind damage due to its tall stems. To this end, measures such as fine soil preparation, cultivating strong seedlings, late irrigation of head water, light irrigation and frequent irrigation, appropriate nitrogen topdressing, and increased phosphorus and potassium fertilizer should be taken.
Harvest: Hemp for fiber is harvested around July-August; hemp for seed is harvested around September.
Receipt standard: the middle and lower leaves of the hemp plant fall off, the stems and leaves are yellow-white, and the upper stems and leaves are yellow-green or when the male flowers are in full bloom and the female flowers have small fruits.