1. Characteristics of rice seedling throwing
(1) saves labor and reduces labor intensity. Compared with conventional transplanting methods, ordinary seedling throwing can save labor by 22.5-37.5 pieces /hm2, improve work efficiency by 5-8 times, advance transplanting season and shorten transplanting time.
(2) Stable and high yield. Throwing seedlings to cultivate rice can shorten the turning green period, promote early growth and rapid growth, especially increase low tillering and early maturity, which is conducive to high and stable yield.
(3) Saving seeds and special fields is beneficial to intensive seedling raising. The ratio of seedling-throwing cultivation to Honda is generally 1∶30-50, and the seedling rate is high, which can save 7.5kg/hm2 of hybrid rice and 90% of paddy fields in early and late rice provinces.
2. Technical points
(1) Preparation before seedling raising. ① Prepare enough seedling trays. Choose 56 1 hole 525-600 seedling tray /hm2. ② Paddy field preparation. Paddy field should be sheltered from the wind and sunny, with fertile soil, good structure, convenient irrigation and drainage, sticky loam or loam, dry land and vegetable garden. The ratio of paddy field to field is 1∶40. Paddy fields should be fully fertilized, raked, leveled and made into compartments. ③ Preparation of nutrient soil. At present, nutrient soil is mainly prepared by seedling strengthening agent. Where there is no seedling strengthening agent, nutrient soil can also be prepared with compound fertilizer or urea.
(2) seed treatment. The seeds are pre-soaked in clear water for about 6 hours, then soaked in 500 times of concentrated chlorine solution for about 35 hours, and then washed with clear water after being taken out.
(3) Soil preparation. Honda should reach the standard of "flat, shallow, rotten and clean", that is, the site should be flat and the height should not exceed one inch; Shallow water is better than fresh mud; The soil should be firm and loose, with moderate hardness and no sundries on the field surface. If it is clay land, it should be stored for 2-3 days after ploughing, drained, cleaned and planted; If it's sand, throw it with a plow.
(4) sowing. Sow the seeds evenly on the seedling tray, and sow them with a seeder where conditions permit. Arrange the seedling tray beside the seedbed after sowing, and pay attention to press the bottom of the seedling tray into the seedbed to ensure that all parts are in full contact with the seedbed. Spread 1 layer of nutrient soil on the seedbed, and the nutrient soil should just cover the seeds.
(5) throwing and planting. Lift the tray with your left hand, grab the seedling 8- 10 with your right hand, gently shake it, and throw it up for 2-3m to let it fall freely. According to the area and density of the field, the number of seedling trays is determined, roughly 2/3 is thrown first, and the rest 1/3 is thinned. After throwing, pick up a sidewalk every 3 meters with a width of 30cm. Then use bamboo poles to make up the sparse, so that the whole field is roughly uniform.
(6) Seedling management. Mainly focused on fertilization at seedling stage and pest control. When the seedlings are 1.5 leaves, spray 300g/ha of urea on the water surface of 30kg/ha; 3.5 foliar spraying 600g/ha urea and 30kg/ha water. The main disease at seedling stage is Rhizoctonia solani. When two leaves 1, spray 45kg/hm2 of Kukesong 800- 1 000 times solution.
(7) On-site management. In the early stage of watering, the principle of "establishing seedlings in shallow water, promoting tillering with thin water and controlling tillering with sunshine" should be followed. When raising seedlings in shallow water, the seedlings will not enter the water for 2-3 days, which is beneficial to the rooting of the seedlings; Thin water promotes tillering, that is, irrigating 2-3cm water layer to promote effective tillering; Tillering control in the field is to dry the field when the number of seedlings is enough to control ineffective tillering. In the later stage, water management follows the principle of "deep water booting stage, shallow water filling stage and waterless yellow ripening stage", that is, maintain 5- 10cm water layer at booting stage, maintain 5cm water layer at filling stage, and stop water until the seeds are mature and full at yellow ripening stage.
Generally, the fertilization method of "one-step cleaning" of base fertilizer is not used to throw seedlings. Because of too much base fertilizer, the early growth was vigorous, the population was too large, and the ear formation rate decreased, and the late fertilizer removal was not conducive to the formation of large ears. Generally, N 150- 180kg/hm2, P2O5 75-90 kg/hm2, K2O 120- 150kg/hm2 were applied. Fertilization mode is "promoting before controlling", that is, 60%-70% of base fertilizer, 20%-25% of tiller fertilizer and 0/0%-/0/5% of ear fertilizer.
Second, matters needing attention in rice seedling throwing cultivation
Six points should be paid attention to in the popularization of rice seedling throwing technology: (1) bud burning prevention. Mainly pay attention to the excessive dosage of seedling raising agent (including chemical fertilizer), and the nutrient soil should be mixed and applied, and then planted after the paste settles; The seedling strengthening agent must be "layered fertilization, half up and down, layered tray and interlayer sowing". (2) Anti-crosstalk. The main measure is to clean up the soil on the seedling surface after sowing, so that the seedling field can not be irrigated. (3) Prevent seedlings from growing in vain. The main method is to raise seedlings with seedling strengthening agent, or soak seeds with uniconazole and spray paclobutrazol in time. (4) Prevent seedlings from drifting. The main measures are to stick to throwing seedlings with flower mud (covered with mud) water, and not throwing seedlings in strong winds and heavy rains and deep water. (5) Prevent unevenness. The method is to adhere to the three-step seedling throwing method, the first step is to throw 70%, the second step is to connect with the work line, and the third step is to throw the remaining 30%. (6) Prevention of herbicide injury. Mainly adhere to the use of butyl benzyl, Ching Tien, throwing seedlings and other herbicides, do not use herbicides containing acetochlor and metsulfuron-methyl, and pay attention to the dosage and use of herbicides. Third, pest control.
1. Control of Sheath Blight
(1) agricultural control: select disease-resistant varieties, resistant to waterlogging sclerotia, reduce bacterial sources, and salvage large areas out of the field and bury them deeply every season. Strengthen cultivation management, apply sufficient base fertilizer and topdressing early. In order to achieve shallow tillering, sufficient seedlings to open fields, dry fields to promote roots, heavy drought and fertile fields, light drought and thin fields, moist long ears, early water cut-off and prevention of premature aging, we must master the principle of "shallow before middle and moist after".
(2) Pesticide control measures include: grasping the appropriate control period and applying pesticides at the end of tillering when the incidence reaches 15%. It is better to spray 500- 1000 times of clomazone solution or 1500 ml of 5% jinggangmycin 750 kg water or pour 6000 kg water per hectare. You can also choose 600 times solution or 25% triadimefon wettable powder (65,438+500 g/ha) for Lvbang 98 rice, and control water (65,438+0,654,38+0 kg) for 65,438+0 times at the beginning and end of booting stage respectively. The prevention and treatment effect on the disease spot rate, disease plant rate and disease severity of functional leaf sheaths is remarkable, and the function is effectively protected. 25% diluted EC can also be used at the booting stage of rice, which can effectively control rice sheath blight, leaf sheath rot, false smut and false smut. It can cure many diseases in the middle and late stage of rice. In addition, the application of rare earth pure nutrients is advocated.
2. Control of trunk borers
Control of rice leaf roller in the peak period of egg incubation. For light occurrence, use 1.8% avermectin 50mL or 2.0% avermectin 45mL per mu, add water 15-30kg (depending on rice growth and insect situation), and spray again every 15d: for heavy occurrence (reproduction), use/kloc per mu.