What are the technical points of rice dry raising seedling bed fattening?

The main advantages of dry raising rice seedlings are short seedling age, strong seedling and convenient management. Can be inserted by machine and manual, with high efficiency and good quality. It is suitable for different production systems. What are the technical points of rice dry raising seedling bed fattening?

According to the experimental research and production practice, the three-stage (three-stage) fertilization method is widely used in various places, that is, fertilization in autumn (or before winter), fertilization in spring and fertilization before sowing, which can improve the physical and chemical properties of bed soil. especially the improvement of soil physical properties is ideal.

The main results are as follows: (1) fertilization in autumn: mainly applying organic fertilizer, fertilizing the whole layer and mixing evenly, combined with the application of available nitrogen, plus mulch, heat preservation and moisture preservation to promote decay. In production practice, the full-layer fertilizer application method of dry ploughing, dry finishing and dry application is generally required to apply 2 kg of organic fertilizer per 1 m 2, plus an appropriate amount of available phosphorus and potassium fertilizer. Organic fertilizer should be applied in layers, quick-acting chemical fertilizer should be applied early and in different stages, and the tillage depth should be from deep to shallow. The working procedure is to pour organic fertilizer and soil fertilizer into 0cm 20 cm soil in three stages to accelerate decay.

(2) fertilizing in spring: mature organic fertilizer must be applied on the principle that it can rot fully before sowing. In the application, it is still appropriate to sooner rather than later, the sooner the better, but also adhere to the thin pieces of mulch into the soil and bed soil to mix evenly. When turning over the bed soil, when you find a large mass of unripe organic fertilizer, it should be removed immediately.

(3) fertilizing before sowing: it is mainly the application of available nitrogen, phosphorus and potassium to rapidly increase the intensity of fertilizer supply. three points must be paid attention to: first, the time of fertilizer cultivation must be more than 15 days before sowing, this is because different parts of seedlings have different ability to absorb and assimilate different forms of nitrogen. The root system can not assimilate ammonium nitrogen, when the root system absorbs too much ammonium nitrogen and accumulates in the root system, it is easy to form ammonia poisoning, resulting in fertilizer damage, burning roots and dead seedlings.

Therefore, ammonium nitrogen must be converted to nitrate nitrogen before sowing. Urea and other ammonium nitrogen applied in the seedbed must be gradually transformed into nitrate nitrogen under the action of oxygen and nitrifying bacteria, which has a process and takes a certain amount of time. In addition, the phosphate fertilizer sold on the market often contains some impurities harmful to the growth and development of seedlings, so phosphorus and potassium fertilizer had better be applied together with nitrogen fertilizer in advance. Second, it is suitable to increase the amount of phosphorus and potassium fertilizer, which can promote root growth and improve the stress resistance of seedlings, and pay attention to the balanced application of nitrogen, phosphorus and potassium. Third, fertilizing 1 meter before sowing is generally applied with urea 30g 50g, calcium superphosphate 100g 150g, potassium chloride 40g 50g, mixed and spread to bed seedlings in three times. After each application, the fertilizer must be fully raked so that the fertilizer is evenly mixed in the 0-10 cm soil layer. Finally, the contents of available nitrogen, phosphorus and potassium in bed soil reached the fertility level of 150 mg / kg, 20 mg / kg and 120 mg / kg respectively. At present, special nutrient agents for strengthening seedlings are selected in many places before sowing, which can omit many operation links, labor-saving, safe and reliable, and good effect. It is worth popularizing and applying.