Marijuana is particularly sensitive to soil fertility. No matter what kind of soil or previous crop is used to cultivate marijuana, we should pay attention to soil tillage measures and apply a large amount of organic fertilizer in order to achieve high and stable yield. Here is an introduction to the cultivation and fertilization technology of marijuana.
Deep sowing and multiple harrowing
The soil for planting cannabis should be deeply cultivated, deepen the active soil layer, and evenly cultivated, improve the physical and chemical properties of the soil, enhance the ability of soil water and fertilizer conservation, so as to facilitate the development of cannabis root system, promote the increase of plant height and stem diameter, and improve the yield. The cultivation of hemp field varies according to rotation, which is described as follows:
(1) Continuous cultivation of hemp fields with one crop a year. Most of the hemp areas in northern China are continuous cropping with one crop a year. After the hemp harvest in the last season, shallow tillage and stubble elimination shall be carried out immediately.
10-15 days after stubble removal, carry out early autumn tillage with a depth of 20-25cm to meet the requirements of narrow tillage width and deep, uniform and fine soil turning. After ploughing, set up a ridge to dry the soil, rake the soil to store moisture in case of rain, and then plough again after ploughing. Plough and rake for 3-4 times continuously until the soil is more raked to preserve moisture and survive the winter before freezing. The next spring, the top of the ridge is raked and increased, combined with the application of base fertilizer, and then shallow tillage and fine raking to mix the dung and soil, and then fine raking and leveling.
(2) Cultivation of hemp fields sown in spring. More than one year cropping system is implemented in the Huang Huai plain and the southern hemp area. After the harvest of the previous crop, i.e. shallow tillage and stubble elimination, followed by deep tillage in autumn (or winter). After tillage, rake the land to protect the pit for overwintering. In some areas, there are also those who do not rake the soil after autumn tillage. In the second year, apply base fertilizer, shallow tillage, rake flat and fine, waiting for spring sowing. Some hemp areas have the habit of planting flax in the border. The direction of border making is consistent with the direction of water flow. The length and width of hemp border are determined according to the size of hemp field, terrain and convenient field operation. Tai'an hemp area in Shandong Province pays special attention to the soil moisture and water at the bottom of the hemp border. Irrigation should be carried out first before sowing, so as to promote the emergence of hemp seedlings in a neat, complete and strong manner.
(3) Cultivation of summer sown hemp fields with more than one year of maturity. In the central and southern hemp areas of China, hemp can be planted with wheat stubble, especially when it is planted in summer. Most of the pre summer hemp crops are winter crops such as barley, wheat, rape, broad beans and peas. After the former crops are harvested, it is generally too late to plough deeply. After the former crops are made of residual roots, the land is raked. After raking, the furrow is opened for fertilization, and the furrow sowing is carried out. In the case of machine cultivated areas, the round rake can be used to rake the land, and the depth of the rake can reach 10 cm. The base fertilizer can be applied before the rake, and the seeds can be sown after the rake.
Fertilization technology of marijuana
(1) Effects of various nutritional elements on the yield and quality of hemp fiber. Cannabis is a crop that needs more fertilizer. The requirements for the three elements of N, P and K are: more N, less K and less P. N fertilizer plays a major role in increasing the yield of cannabis. The combined application of NP or NK fertilizer is better than that of N fertilizer alone, and the combined application of N, P and K is better.
Proper application of trace elements also promoted the yield and quality of cannabis. Applying boron fertilizer, manganese fertilizer + zinc fertilizer or boron + manganese + zinc fertilizer on peat soil and black soil can increase seed and stem fiber. The application of copper fertilizer on peat soil can improve the rate of long fiber, and the application of boron fertilizer + copper can significantly increase the yield of fiber. Sodium can partly replace potassium, which plays a good role in improving fiber yield and quality.
(2) Increase the application of base fertilizer and early topdressing. Most hemp farmers in China use organic fertilizer as base fertilizer, generally 30-40t / hm2 organic fertilizer, combined with deep ploughing in autumn, or shallow ploughing in spring. Hemp base fertilizer generally accounts for 70% - 80% of the total fertilization. There is also the habit of applying bean cake, hemp residue, human and animal manure or chemical fertilizer on the surface of the soil before sowing, so that the fertility of the whole cultivated layer of the soil is sufficient. The combination of delayed effect fertilizer and fertilizer can not only meet the needs of nutrients in the seedling stage, but also better ensure the nutrient supply in the rapid growth period.
All kinds of fine fertilizers, including cake fertilizer and chemical fertilizer, have different effects on hemp yield. According to the experimental study, on the basis of applying 60 t / hm2 of circle fertilizer and 1500 kg / hm2 of cake fertilizer, the fiber yield is 1477 kg / hm2; The fiber yield was 1380 kg / hm2 by applying 20 t / hm2 of ring fertilizer and 225 kg / hm2 of ammonium sulfate; Applying 502.5 kg / hm2 ammonium sulfate, 136.5 kg / hm2 calcium superphosphate and 67 kg / hm2 potassium sulfate, the fiber yield was 1328 kg / hm2. The yield of cake fertilizer increased by 6.1% - 10.1% compared with other fertilizers, and the hemp yield of cake fertilizer was also higher. The yield increasing effects of various organic fertilizers are also different. According to the experimental research, the application of farm manure is 25 t / hm2: the fiber yield of fire manure soil is 1532 kg / hm2, that of chicken manure is 1460 kg / hm2, that of pig manure is 1279 kg / hm2, that of horse manure is 1137 kg / hm2, and that of big manure soil and chicken manure is better.
Different types of chemical fertilizers have different yield increasing effects. According to the experiment, on the basis of applying 60 t / hm2 of ring fertilizer as base fertilizer, applying 60 kg / hm2 of pure nitrogen, in which the fiber yield of urea is 1467 kg / hm2, ammonium sulfate and ammonium bicarbonate are applied, and the fiber content is 1406 kg / hm2 and 1357 kg / hm2 respectively, and only 1072.5 kg / hm2 without topdressing. The yield increase effect of urea.
Marijuana topdressing is generally early. When the seedling height is 25-30cm and will enter the rapid growth period, combined with irrigation head water topdressing is suitable. At this time, the top dressing will increase the yield by 5% - 15% when the plant height is 1m. The amount of topdressing chemical fertilizer is generally 112.5-150kg urea per hectare. When some hemp areas are still irrigated with second and third water, the weak seedlings are treated with fertilizer. In addition, some hemp areas emphasize the application of more base fertilizer rather than topdressing. The reason is to avoid the small amount of chemical fertilizer and uneven application, which will cause the field hemp plants to compete with each other, resulting in uneven growth, the increase of small hemp and the decrease of hemp yield. Therefore, topdressing should suit measures to local conditions and strive for practical results.