What are the key points of topdressing techniques for dry rice seedlings at seedling stage? With the method of increasing production

The seedbed of dry rice seedlings is carefully and strictly fattened. The total amount of fertilizer supply can fully meet the amount of fertilizer needed for the growth of dry seedlings, and the nutrients are comprehensive and the content of available fertilizer is high. However, because the seedbed soil is relatively dry or semi-arid, the mobility of nutrients is poor, resulting in insufficient root fertilizer absorption and lack of fertilizer in disguised form; secondly, due to less free water and weak transpiration in dry seedlings, poor transportation and distribution of fertilizer nutrients in the body can also lead to fertilizer deficiency in a disguised form.

With the increase of leaf age after four leaves of dry rice seedlings, the growth of aboveground stems, leaves and tillers continues to increase, the daily increment of nutrient elements is also increasing, and the supply of fertilizer is relatively insufficient, so the contradiction of lack of nutrition is exposed. When cultivating middle or large seedlings, there are often symptoms of yellowing of dry seedlings, so it is necessary to apply fertilizer timely and appropriately.

The main results are as follows: 1. The leaf color of dry seedlings is generally dark green, and it is difficult to detect at the initial stage of fertilizer deficiency. When the leaves turn yellow, it shows that the degree of fertilizer deficiency is heavier than that of wet seedlings with the same leaf color.

2. The type of fertilizer used for dry seedlings should take into account the characteristics of seedling bed drying, and high quality urea should be selected as the best choice, and other volatile fertilizers should not be applied directly. At the same time, it should not be directly applied, but should be sprayed with water to prevent leaves or seedlings from being burned due to high fertilizer concentration. If chemical fertilizer is used directly, it must be sprayed and leached immediately after application.

3. The lack of fertilizer in dry seedlings is caused by the lack of water, so when topdressing, one should not use too much fertilizer at one time, and 1%-2% urea should be sprayed to avoid burning seedlings and improve fertilizer efficiency. However, like watering, the time of topdressing should be controlled in the evening, which should be carried out at the same time as water replenishment; the amount of fertilizer and water consumption should be strictly controlled so as not to weaken the physiological effects of drought-raised seedlings.

In order to give full play to the yield-increasing advantage of dry-raised seedlings, shallow planting and sparse planting must be achieved. The following work should be done when transplanting:

1. Fertilize and prepare the soil.

After transplanting, 1500-2000 kg per mu of organic fertilizer was applied as base fertilizer, and 15-20 kg of middle fertilizer, 10 kg of potash fertilizer and 10-15 kg of urea were applied per mu. Zinc sulfate was increased by 0.5-1 kg in zinc deficiency field. Wheat field, thin field appropriate more application, broad bean field, fertilizer field appropriate less application, soil preparation first dry plough dry Harrow, and finally into the horizontal field, so that the field flat soil fine. After Tian Ping is well settled for 1-2 days, it is advantageous to transplant seedlings shallowly without lodging.

2. Skillfully pull out dry seedlings.

The new root of dry raising seedling is short, the old root is brittle, and it is easy to pull seedling. Do not water or irrigate 2-3 days before pulling seedlings, otherwise it will weaken the "outbreak effect" of dry seedlings after transplanting, and the seedlings will still be inverted or replaced after transplanting. Pour water thoroughly the night before pulling seedlings, you can use a shovel or rake to dig the seedling field, and then pull seedlings, seedling roots with a small amount of soil transplanting is better.

3. Transplanting rice seedlings in shallow water. When planting seedlings, the field water layer can not exceed 2 cm, transplanting seedlings do not fall seedlings do not float seedlings, generally transplanting depth 2 cm. If the planting is too deep, the heart leaves of the seedlings will be soaked in water for a long time. It is easy to lead to dead seedlings, low mud temperature around the root system, slow tillering and high tillering nodes, so it is difficult to form large panicles and large grains.

4. Reasonable sparse planting. The sparse planting of dry seedlings should be comprehensively considered according to the biological characteristics of varieties, soil fertility, climatic conditions, yield level and other factors. In order to achieve high quality and high yield. Because of the dense planting, the large tillers are not strong and the small tillers are continuous at the tillering stage, resulting in excessive population in the field, poor ventilation and light transmission, and serious disease. It is not conducive to the prevention of "shade harm" weather and "low temperature at heading and flowering stage", and the seed setting rate is low. According to the different sparse planting experiments of Dali Agricultural Technology Department and Municipal Meteorological Bureau, it is concluded that the row spacing of hybrid rice in Dali is (45.5) inches, 30,000 clumps per mu and 30,000 seedlings per mu. It is suitable for japonica rice with 40, 000 clumps and 40-70, 000 seedlings per mu. Areas with high fertilizer and good heat conditions can be sparse, while areas with cold soaked fields and poor heat conditions can be denser appropriately.