Rice No-tillage Throwing Technique

(1) requirements for the selection of demonstration rice fields and rice varieties 1. For the selection of no-tillage rice fields, rabbit ploughing and seedling throwing should be carried out in paddy fields with sufficient water source, convenient drainage and irrigation, flat land, deep ploughing layer and good ability of water and fertilizer conservation. Easy dry fields, shallow thin fields, leaking paddy fields and sandy fields are not suitable for no-tillage and seedling throwing. If the previous stubble is rice, the stubble height should be as low as possible, generally no more than 10 cm, so as not to throw the seedlings on the grass and affect the survival. Before chemical weeding, low-lying fields, mountain pits and cold-soaked fields should be opened well to drain water. 2. Variety (combination) selection no-tillage seedling throwing cultivation generally has no special requirements for variety (combination). According to the characteristics of no-tillage throwing seedlings, rice varieties (combinations) with strong tillering ability, developed root system, strong stem, lodging resistance and stress resistance should be selected. Like the conventional ploughing and throwing seedlings, the varieties (combinations) with moderate or early growth period should be selected, and the maturing period should be matched well to ensure the safe heading in the second night. (2) Weed control and field management before seedling throwing 1. Selection of chemical herbicides before no-tillage seedling throwing chemical herbicides should be selected to kill herbicides. The herbicides had better have the advantages of safety, speed, high efficiency, low toxicity, short residual period, strong rain resistance and so on. At present, there are two types of no-tillage herbicides used in rice fields: one is internally absorbed herbicides, such as domestic glyphosate, Roundup, farmer le 747, etc., and the other is contact herbicides, such as paraquat, gram no-trace and so on. The effect of internal inhalation herbicide was good, but the weeding speed was slow. After spraying, the root system was poisoned and died first, and the leaves began to turn yellow after 7 days, and the roots, stems and leaves all died about 15 days after spraying. The weeding speed of contact-killing herbicide was fast, the stems and leaves of weeds began to wither 2 hours after spraying in sunny days, and most of the weeds and rice stump died after 3 days, but the underground rhizomes, stolons and some dicotyledonous aquatic weeds could not be removed. These two kinds of herbicides are safe and efficient herbicides and can be used alone or in combination. 2. Weed control and field management before seedling throwing, fertilization (1) Management before herbicide spraying, maintain a thin water layer or moist one week before spraying to facilitate weed germination and soil softening, and discharge water 2 days before application. (2) spraying herbicides as far as possible, spraying herbicides on sunny days, generally 9-15 days before seedling throwing for early rice, and late rice in the evening or the next morning on the day of early rice harvest. The reserved period of green manure field and glyphosate chemical weeding should be longer, while that of gram-free chemical weeding in ordinary field can be shorter. For paddy fields with malignant weeds such as Wuba root grass, wandering grass, water peanut and so on, gram can be used to control weeds without trace. the method is as follows: 20% gram per mu, 200 ml per mu, plus 250 ml of hydrogen carbonate or potassium chloride 2.5 kg, 50 ml of water, 60 kg of water, evenly sprayed on weed stems and leaves, rice stump, rice straw and green manure. For the rice fields with winter fallow and many malignant weeds in the previous crop, glyphosate should be used to control weeds. The method is to use 1000 ml of glyphosate per mu, spray 30-50 kg of water, and soak in water for 2-5 days after 7 days. Attention should be paid to the application of herbicides: ① sprayer requires a better degree of atomization, the higher the degree of atomization, the better the effect, and it is strictly forbidden to use Qing water canister spraying; ② early rice no-tillage field can choose gram traceless or glyphosate herbicides, late rice no-tillage field is best to use gram without trace; no matter what kind of herbicides ③ uses, the field water must be drained before application to ensure that there is no water on the field, otherwise the effect of sterilization can not be achieved. ④ herbicides must be dispensed with clear water, not sewage or mud water, otherwise the efficacy will be reduced; ⑤ chooses glyphosate herbicides, it rains within 4 hours after spraying, the effect will be affected and needs to be re-sprayed; ⑤ spraying should be uniform and thoughtful and can not be missed. 3. Management and fertilization after herbicide application (1) soak the paddy field with backwater in time. The no-tillage early rice field was soaked in backwater for 7 days after spraying for 7 days, and the late rice field was soaked in backwater for 2-4 days after spraying. The suitable water depth was to submerge the crop stubble, and then let the water layer dry naturally (shallow). (2) fertilization. For the no-tillage field of early rice with green manure in the previous crop, a few days after spraying herbicide, an appropriate amount of lime (30 kg per 1000 kg of green manure) can be applied to speed up the decay. In the no-tillage field, the straw can be returned to the field before returning water, and the amount of straw returned to the field can reach half of that of the previous rice straw, which requires that there is basically no mature rice residue on the straw, and the straw returned to the field should be evenly put into the row of the rice pile and stick to the mud on the ground. can not be casually scattered to cause overhead on the rice pile, otherwise remedial measures should be taken to put the straw on the ground. In order to speed up the maturity of straw returning to the field, 2kg of "rotten stalk Ling" can be applied per mu. The application of basic fertilizer was carried out in the bubble field 2-4 days before seedling throwing. According to the growth characteristics of no-tillage paddy field, such as enrichment of nutrients in topsoil, less nutrients in the lower layer, slower seedling setting, shallow root distribution, late tillering, slow tillering speed, delayed seedling time and low seedling peak, the principle of light application of base fertilizer and heavy application of returning green fertilizer and tillering fertilizer was carried out. Base fertilizer to compound fertilizer, phosphate fertilizer, less ammonium bicarbonate, do not apply the last mature manure. The amount of nitrogen applied by base fertilizer accounts for 25% of the total amount of nitrogen applied during the whole growth period. Generally apply gram traceless weeding fields, combined with soaking fields, you can apply rotten organic fertilizer and calcium superphosphate 25 kg per mu, ammonium bicarbonate 25 kg or compound fertilizer 25 kg or compound fertilizer 25 kg / mu as base fertilizer, which can accelerate the decay of rice piles, straw and weeds; fields with glyphosate weeding should be discharged to soak the water with medicine, and change shallow water and base fertilizer before throwing seedlings. (3) less tillage and compensatory elimination of malignant weeds. Contact-killing herbicides such as gram without trace have poor control effect on some weeds, and if a small amount of malignant weeds are not removed before seedling throwing, they can be pulled out manually; for rice fields where the soil surface is not softened enough and rice fields with a certain number of malignant weeds such as root grass, wandering grass, water peanuts and seedlings sprouting and growing seedlings, iron-toothed rakes are used for 1-2 times. (3) the method of sowing and raising seedlings by no-tillage and throwing seedlings is basically the same as that by ploughing and throwing seedlings, but it requires higher seedling quality, using 353-hole or 434-hole seedling plates with large pore diameter, using seedling-strengthening agent to raise seedlings, or using special fertilizer and paclobutrazol to improve the quality of seedlings, take root early after throwing, and stand early to turn green. (4) throwing seedlings 1. Seedling age and seedling throwing period. According to the temperature and seedling age, "late sowing and early throwing" is advocated in the suitable temperature range. Proper seedling throwing is beneficial to early rooting, rapid seedling setting, early tillering, prolonging effective tillering stage and increasing effective panicle number. The suitable leaf age of throwing seedlings is 2.5 ~ 3.5 leaves, and the leaves of early rice and late rice should not exceed 4.0 and 4.5 leaves, respectively. Early rice seedling throwing should be carried out directly in sunny days, and seedling throwing should be avoided in windy and rainy days, and seedlings should be thrown in cloudy days or sunny days after 4 p.m., so as to facilitate seedling survival. 2. Planting density. No-tillage throwing planting density should be determined according to variety characteristics, seedling quality, soil fertility, fertilization level, seedling throwing period and yield level. Compared with ploughing and throwing seedlings, it is generally appropriate to increase by about 10%, with early rice throwing 2.2-24000 grain per mu and two nights throwing about 22000 rice per mu. 3. Moisture requirement. For the no-tillage rice field in which the straw is returned to the field, keep the water layer immersing the rice straw instead of floating during seedling throwing, so that the rice straw is in a moist state, which not only ensures the water supply of the seedlings, but also is beneficial to the decay and decomposition of the rice straw. For ordinary no-tillage paddy fields, the paddy soil should be in a moist state or retain only a shallow water layer when throwing seedlings. (5) Field management 1. Control of weeds after seedling throwing. Weeds cannot be cultivated manually after seedling throwing. Herbicides that can control all weeds in the rice field at one time and are safe to the seedlings, such as butyl benzyl and Nongde, etc., should not be used for a long time as far as possible, and the dosage should not be increased at will. It is forbidden to use herbicides containing Acetochlor and metsulfuron, such as Acetochlor, metsulfuron, etc. For new herbicides, they should be tested first and then demonstrated. Chemical weeding should be carried out 5-7 days after seedling throwing for early rice and 4-5 days after seedling throwing for late rice. Herbicides should not be used before seedling and should not be used late after seedling. Suitable herbicides and application methods for rice seedling throwing are as follows: 30% butyrobenzyl 100ml 120g per mu, or 35% benzyquine (also known as Tianqing, Qiuyaojing) 20mu 30g, or 53% phenylethyl benzyl 35m 40g, or 50% quick-killing barnyard wettable powder 20ml 25g plus 10% nongde wettable powder 15g, sprinkle weeds after mixing fine soil or urea, or spray water. The paddy field should have a water layer of 3-5cm when applying the pesticide. After taking the medicine, the water was preserved for 5 times for 7 days. 2. Scientific water management, no-tillage and seedling throwing are sensitive to water requirements, and the principles of frequent irrigation, shallow irrigation, more exposure and light drying should be grasped in water management. Stand seedlings and tiller in shallow water after seedling throwing (avoid deep water before tillering); maintain water layer for several days after applying herbicide (before bud), replenish water when lack of water; open field and dry field when 75% of seedlings are sufficient; keep moist after young panicle differentiation stage, and irrigate shallow water layer during heading and flowering stage; keep soil moist during grain filling period to prevent water loss too early, so as to improve seed setting rate and 1000-grain weight. 3. Scientific topdressing: the amount of nitrogen applied in the green period accounted for 20% of the total nitrogen application in the whole growth period, and the early rice was left behind for 5 days. Late rice was applied for 4 days after 3 min. The amount of nitrogen applied at the tillering stage accounted for 25% of the total nitrogen application during the whole growth period, and it was applied 10-12 days after early rice and 7 Mel days after late rice. When the seedling stage is 20-23 days after throwing early rice, 18 days after late rice throwing, or when the number of hybrid rice seedlings reaches 130000 seedlings per mu and conventional rice reaches 220000 seedlings, a small amount of supplementary fertilization can be applied if the rice seedlings are yellow and weak. In the early stage of young panicle differentiation, we should grasp the exposed and sun-dried fields, make the leaf color fade, and apply panicle fertilizer in time before irrigation at the tip of the second leaf. The amount of nitrogen application accounts for 15% of the nitrogen application during the whole growth period. If the leaf color fade is not obvious or the light condition is poor, the application should be postponed or reduced step by step. The appropriate supplementary application of strong seed fertilizer in the later stage can be applied at the full heading stage, and the amount of nitrogen applied is 5% of the total amount of nitrogen to prevent premature senility. After the full heading stage, the extra-root topdressing was carried out once. 4. Prevention and control of diseases and insect pests: in order to reduce the insect source of rice straw returning to no-tillage rice field, we should timely apply sterilizing herbicide to kill stubble, soak the field in time to kill borer pupae, and reduce insect sources. the control of other major diseases and pests, such as rice planthopper, rice longitudinal leaf roll, sheath blight, rice blast, bacterial leaf blight and bacterial stripe disease, are more or less the same as ploughing and throwing seedlings, but field observation and prediction should be made to control diseases and insect pests in time.