When planting rice, why should water be released in the paddy field at the right time?

When planting rice, why should water be released in the paddy field at the right time? Rice is an aquatic plant, and it can grow well with water. Especially at tillering stage, rice needs a lot of water to grow well. Under the condition of water, the effect of fertilization and application can be ensured, so as to achieve high yield. If China rice is planted, one seed can only produce one or two small ears of rice. Under suitable water conditions, a seed can produce 4-6 big panicles of rice, which can fertilize water and even produce more than 20 big panicles of rice. It is conceivable that the yield of rice can be planted with water or without water.

How many days is the planting time of rice? Different varieties of rice have different planting cycles.

Generally, the growth cycle of early rice is about 90 days, and that of late rice is about 1 10 days.

The growth cycle of rice is different in different planting places.

Rice planting: Why is rice not suitable for deep transplanting? The transplanting depth of rice has a great influence on the greening, tillering and seedling protection of seedlings.

When the transplanting depth of rice is more than 3 cm, the seedling will be inhibited from turning green and tillering, especially the tillering in the lower node will be obviously inhibited, the tillering will increase in the late stage of the upper node, the tillering will be delayed, the tillering quality will be poor, and the weak seedling will become stiff when it is deeply transplanted. So it is not suitable for deep transplanting.

Generally, when the transplanting depth is 0.5 cm, the seedlings are easy to be scattered, and there are many seedlings falling and drifting. When the mechanical transplanting depth of rice is about 2 cm, there is no seedling falling and floating, and the plant has many roots, strong growth and strong tillering. Therefore, it is appropriate to control the depth of rice mechanical transplanting at about 2 cm. The artificial transplanting depth is1~1.5 cm; The bowl surface of bowl cultivation and pendulum planting is flush with the mud surface; It is appropriate to throw the seedlings into the soil for 2/3 (seedlings in mud-throwing state).

Rice planting time in Jining, Shandong Province has started in many places, and some places with less land may have been planted!

I checked the literature on rice cultivation and didn't see such a report.

Theoretically, there will be no difference, because the same conditions belong to the same underground water system, that is to say, well water and river water come from the same circulating water system. The source is the same, so there must be no difference between rice irrigated with this water.

God, this question is quite ...

It's hard to say ~

Hehe, it is usually for transplanting to calculate how long the seedling period is. Moreover, early rice and late rice transplanting have different requirements for seedlings.

For a few leaves of millet, we seldom count them.

Morphological characteristics, diagnostic indexes and seedling management of rice at different growth stages

(1) seedling stage 1. Suitable seedling age, neat leaf age, robust seedlings, beautiful Ye Ting, developed root system and strong resistance to phytotoxicity after transplanting. 2. Diagnostic index (1) full seedlings: the leaf area coefficient per mu of rice field is about 3.0-3.5 when transplanting; The total number of seedlings per mu for big seedlings is100-10.2 million, for medium seedlings,150-20 thousand, for small seedlings, 25-30 thousand, and for single-season hybrid rice, it is about 501750 thousand. The leaf age is even, the leaf age of middle seedling is 6. 1-7.0, that of big seedling is 8. 1-9.0, that of young seedling is 4. 1-5.0, and that of soilless seedling is 3.0. (2) Strong rooting ability, developed root system per plant and more white roots. Living trees will turn green 2 14 days after planting, and the standard of living trees is that the heart leaves will spit water in the morning. (3) Strong plant injury resistance, blue-green leaves of middle seedlings, no drooping leaves, and C/N ratio of 10- 13, which is called strong seedlings; When the big seedlings are light green, the leaves are hard and straight, and the ratio of carbon to nitrogen is above 15, they are called old and strong seedlings, while the small seedlings are light green and the leaves are slightly curved, which is called tender and strong seedlings. (4) The seedling base is thick, with the thickness of 0.5-0.7 cm; The tillering rate of large seedlings is over 95%, that of medium seedlings is about 50%, and that of small seedlings is about 30%. 3. The seeds selected according to the nursery stock management chart (1) should be mature and full, pure, large and full, with high germination rate and strong germination potential. (2) Soaking seeds to accelerate germination can meet the temperature, moisture and air required for seed germination, so that the seeds can germinate quickly and orderly, the roots and buds are strong, and they can take root quickly after sowing and cultivate strong seedlings. (3) Seeding seedlings in the open field at the right time is too early, which is prone to low temperature hazards, slow growth, and seedlings rot and die. (4) The sowing amount is suitable for over-dense sowing, with poor rooting and insufficient illumination, and the seedlings are slender, yellow and thin; Sowing is suitable and the seedlings are strong. (5) Wet the flat ditch water after rooting and sowing, keep the seedling board moist, take root quickly, grow seedlings early, root buds grow vigorously, and the seedling rate is high. After sowing, only long buds take root in deep water, which is easy to cause inverted buds and floating seedlings. If the temperature is low, it will also cause rotten seedlings and dead seedlings. Drain and dry. (6) At the early stage of weaning and fertilization, all nutrients in endosperm have been exhausted, and its growth depends on its own roots to absorb water and nutrients, make organic matter and live independently. Topdressing should be carried out as early as possible, usually starting when a leaf is combined. (7) The stress resistance is the weakest when the seedlings are prevented from dying in the three-leaf stage. When the temperature is 5-7℃, indica rice will suffer from chilling injury. In the 2-3 leaf stage, due to the invasion of bacteria, bacterial wilt or verticillium wilt seedlings often appear on sunny days when the temperature changes from low temperature and rainy to high temperature. (2) Tillering stage: 65,438+0. After transplanting, the living trees grow green for 3-5 days, and the leaves gradually turn pale green, and tillering begins at 7-65 days and 438+00 days. The leaves are not drooping, and the plants are loose and solid. 2. Diagnostic index (1) Tillering: Tillering begins about 7 days after planting (that is, n leaves are transplanted, and coextensive points occur when N+2 leaves are exposed), and at the end of effective tillering (that is, when the leaf age is equal to the total leaf age minus the number of elongation internodes above ground), the total number of tillers reaches the number of ears per mu (generally, it should exceed about 10% of the number of ears, and should not be less. When tillering reaches the peak, the total tiller number per mu is generally 1.5 times or more than the suitable number of spikes per mu (1/3). (2) Leaf area coefficient: 2.0 at early tillering stage, 3-3.5 at peak tillering stage and 3.5-4.0 at peak tillering stage. (3) Leaf color: After turning green, the color of functional leaves (top 3 leaves) is darker than that of leaf sheath, and the top 4 leaves are darker than the top 3 leaves. The leaves are curved, the leaf length and panicle spacing gradually increase, the tillers are bifurcated, the angle is large, the plant type is loose, the ineffective tillering period ends at the end of tillering, the leaf color changes from green to light green, and the top 4 leaves and the top 3 leaves are colored with sheath color. (4) Roots: The roots are developed, white and hairy, and orange without black roots. 5. Schematic diagram of seedling management (1) Strong seedlings in tillering stage (2) Effects of different planting methods of shallow and deep seedlings on green trees (3) Weak seedlings in tillering stage (3) Long panicle stage (1). 4-5 leaves with high yield, green leaves, Ye Ting uncovered, thick and short internodes, elastic and fresh base. 2. Diagnostic index (1) tillering: When young panicles are differentiated, the total tiller number per mu is stable at about 1.5 times of the suitable panicle number; At booting stage, the total number of tillers per mu was slightly larger than the appropriate number of ears. (2) Leaf area coefficient: young panicle differentiation period is about 4, when two leaves are inverted, it is about 6, and booting period is 7 (dwarf, Ye Ting; It can be bigger when the weather is sunny and the humidity is small, and smaller when it is not sunny. (3) Leaf color: light green before and after jointing stage, light green in the whole field, turquoise recently, turquoise at booting stage (meiosis stage), and slightly faded before heading; The number of green leaves in early rice is more than 4, and that in middle and late rice is 5. The length of flag leaves gradually decreases from long to short, and it is thick and straight. (4) Roots: the root tip is white, with many branches, strong elasticity, no black roots or few roots, well-developed superficial roots (floating roots) and deep roots. 3. Because of the seedling management chart (1), strong seedlings at jointing stage (4) and strong seedlings at fruiting stage (1), the high yield looks neat and consistent, with many green leaves, slow leaf aging, yellow stems and few empty grains. 2. Diagnostic index (1) Leaf area coefficient: the leaf area coefficient from heading to filling stage is about 3-3.5. (2) Leaf color and number of green leaves: it turned slightly green after heading, but the leaf color was lighter than that at booting stage, and the leaf faded slowly. When heading, the number of green leaves per mu of early rice is 4, and that of middle and late rice is 4- 15; Heading 15-20 days mature, with more than 3 early rice grains and more than 4 middle and late rice grains; There are 1.5 green leaves at the maturity of early rice and 2.5 green leaves at the maturity of middle and late rice. (3) Roots: The root tip is white, with few black roots and rotten roots, and a few branched roots still grow to wax maturity. (4) The maturity standard is that the grain glume is 90-95% yellow (90% for early rice and 95% for middle and late rice). 3. Because of the seedling management chart (1), shallow water irrigation should be used during heading and flowering construction to prevent plant diseases and insect pests. Adjust the sowing date to control the late rice at full heading before the daily average temperature is above 22℃; At this time, if there is a lack of fertilizer, drought or the temperature is too low and too high, it will cause heading difficulties, poor pollination, increased infertility rate and increased empty chaff rate. (2) Normal mature rice is properly managed in the early and middle stages, properly fertilized in the later stage, with neat heading, fast filling speed and high seed setting rate. At maturity, intermittent irrigation, root protection and leaf protection will increase grain weight and yield. (3) Premature senescence and branch degeneration caused by lack of fertilizer or high temperature and drought lead to premature senescence, serious degradation of spikelets, smaller panicle type or short filling time, insufficient grouting materials, more green husk grains, lower grain weight and lower yield. (4) Improper application of panicle fertilizer, too long basal internodes or long-term deep-water irrigation, and micrococcus sclerotiorum in the early stage of grain filling can also cause lodging; Or soil rot, long-term waterlogging, improper baking in the field, poor root development, easy to lodging in the late filling stage. Apply panicle fertilizer correctly, control the imaginary length of internodes and upper leaves, and make the stems strong and lodging-resistant; Bake the field at the right time, dry and wet, promote the roots and strengthen the stalks and ears.

The rice planting time in Changde, Hunan Province is from March 23rd to 30th, and the live broadcast time is from March 28th to April 5th. The planting time of one-season rice is April1August-30, and the direct broadcast time is April 25-May 25. The planting time of double-cropping late rice is June1May-28.

The similarities and differences between rice planting in China and India are the same: in terms of climate, they are located in tropical and subtropical monsoon climate with the same rain and heat, with light, heat and water conditions; Topographically, they are located in alluvial plains and wide valleys in the middle and lower reaches of rivers. The soil is deep and fertile, which is convenient for water diversion and irrigation and the water source is guaranteed. From the social and economic conditions: they all have a long history of planting and rich traditional experience, and they are intensively cultivated; Dense population and abundant labor force; Rice is the staple food of local people, and the market demand is large. China and India can be self-sufficient or basically self-sufficient, and export slightly in good years.

Difference: The yield per unit area of Indian rice production is lower than that of China, and the growth is very slow.

How long does it take to grow rice? Take Wuxi, Jiangsu as an example:

Paddy fields were flooded in May 15, rice was sown on May 22nd, rice was transplanted in June 18, and rice was harvested after1October 25th.

Rice planting technology Rice is one of the main food crops in Daguan County. It occupies an important position in the county's grain production, and improving rice yield and total output is an important way to ensure food security. Therefore, the popularization and application of rice high-yield cultivation techniques is an important measure to improve rice yield.

1. Select excellent varieties with high yield, high quality and strong insect resistance according to local conditions.

According to local ecological conditions, production conditions, economic conditions, cultivation level and occurrence of diseases and insect pests, select high-quality and high-yield varieties (such as Xiangyi 725, QYou 6, Yiyou 1988) with strong resistance to diseases and insect pests, lodging resistance, strong tillering ability, high panicle formation rate and high seed setting rate, among which Xiangyi 725 is suitable for local cultivation.

2. Cultivate strong seedlings

Cultivating strong seedlings is one of the key technical measures to increase rice production. Production practice has proved that the cultivation of strong seedlings should be based on enriching soil and protecting seedlings with soil. In rice seedling raising, dry land seedling raising technology should be popularized and applied. Seedling raising in dry land has the characteristics of early growth, rapid development, no obvious turning green period, high effective tillering rate, strong stress resistance and high seed setting rate. More decomposed farmyard manure should be applied to the dry seedbed.

2. 1 strong seedling standard

Roots: The root system is developed, thick and short, white, without black roots. Seedling: the base is thick and flat, the leaves of the seedling are green and the leaves do not come loose. Vigorous growth, neat and consistent population, small individual differences, elastic seedlings, wide and healthy leaves, short leaf sheaths, thick and flat pseudostems, reaching more than three tillers by 30 days of seedling age. Dark green leaves, many green leaves, few yellow leaves and dead leaves, moderate seedling height, no pests and diseases.

2.2 sowing

2.2. 1 seed preparation

Select and purchase high-quality and high-yield seeds that have been approved, tested and demonstrated, are suitable for local planting, resistant to pests and diseases, lodging resistance, strong tillering ability, large panicle and high seed setting rate.

Seedbed preparation

Choose the mature dry land or vegetable garden with flat terrain, sunny lee and deep soil layer as the dry seedbed. Carefully prepare the soil in advance, so that there are no large clods in the soil subdivision, and the soil moisture is adjusted according to 1.5-1.6 m, with a ditch depth of 30 cm and a compartment height of15 cm; Apply 65,438+0,500-2,000 kilograms of fully decomposed high-quality farmyard manure, 50 kilograms of calcium superphosphate and 5 -8 kilograms of potassium fertilizer as base fertilizers per mu of seedbed, fully mix farmyard manure and calcium superphosphate for composting about 20 days in advance, level the soil surface after fertilization, and wait for sowing.

2.2.3 soaking seeds to accelerate germination

Before soaking the seeds, spread them out in the sun for 1-2 days, then soak them in 3% carbendazim solution for 12 hours, and then wash them with clear water until the water becomes clear. Generally, it should be soaked for 3 days, and washed with clear water 3-4 times a day. After 3 days, clean the seeds, preheat the seeds with 50 -60℃ water, wrap the seeds with wet sacks, keep the temperature at 30 -35℃, and push out the rice buds after 24 hours. After the rice buds are exposed, the temperature is gradually reduced to about 20℃, the seeds are spread out and sown under natural conditions 1 day.

sow seeds

Sowing date: According to the local climatic conditions, we can sow when the temperature is stable above 10℃, and the sowing date in our county is the first ten days of April.

Sowing: Rice seeds should be sparse and uniform, and it is appropriate to sow10-12kg per mu of seedbed. After sowing, build a shed and cover with plastic film, keep warm and moisturize, prevent low temperature from causing rotten buds and seedlings, and reduce production losses.

Seedbed management

Weeding: When weeds appear in the seedbed after rice sowing, weeds should be weeded in time and gently pulled out manually to prevent damage to rice seedlings.

Water and fertilizer management: keep the seedbed soil moist until the second leaf stage, and control water and reduce moisture after the second leaf stage to prevent diseases. When the seedbed soil turns white, or there is no water drop at the seedling tip in the morning and evening, or when the seedlings begin to roll leaves, the film is uncovered for irrigation in the morning and evening, and the film is uncovered for ventilation and cooling in the high temperature weather at noon to prevent the seedlings from being burned at high temperature. 2. Apply 5 kg urea per mu as weaning fertilizer at leaf stage to promote growth and health; 4. Apply 7-8kg of urea and 2-3kg of potassium fertilizer per mu in leaf stage to promote tillering; 4.5-5 seedling hardening in leaf stage, ready for transplanting, and applying urea1.5-2kg per mu as wedding fertilizer 3-4 days before transplanting.

Pest control: according to the occurrence of pests and diseases in seedling stage, select appropriate pesticides to control pests and diseases in seedling stage to prevent pests and diseases from being introduced into the field and reduce the occurrence of pests and diseases in the field.

transplant

3. 1 Thickness of whole field and individual fertilization

After rice harvest, plough and bury the stubble in time, and then plough and rake before sowing. Refine the whole field, make the surface smooth, and achieve "green irrigation, no water accumulation in the drainage field". The base fertilizer is mainly organic fertilizer, and nitrogen, phosphorus and potassium are applied together. Before planting, 65,438+0,500-2,000 kg of organic fertilizer was applied with paddy field ploughing, 40-50 kg of calcium superphosphate and 8-65,438+00 kg of potassium fertilizer were applied with paddy field harrowing.

3.2 Timely hardening of seedlings and proper early installation.

Dry-raised seedlings should be planted early, and small and medium-sized seedlings should be planted early. The seedlings are about 30 days old, and it is appropriate to transplant when they grow to 5-6 leaves. Because the roots of dry seedlings are developed and the seedlings are too big, it is easy to cause root damage when raised.

3.3 Reasonable close planting

According to the fertility of rice field, the transplanting density is determined, and according to the tillering situation of seedlings, 1-2 seedlings with tillers are planted in each hole.

Double row strip planting: large row 0.9- 1.0 feet, small row 0.4-0.5 feet, nest spacing 0.4-0.5 feet. 1998- 1999, in Huatacun Formation and Jinping Village of Cuihua Town, a comparative experiment of double-row strip planting and conventional transplanting was carried out for two consecutive years. Compared with conventional transplanting, the yield of double row strip planting increased by 76.4 kg and 88.5 kg respectively, and increased by 1 1.2% and 13.3% respectively.

Box-type strip planting: unpacking according to 5 feet, ditch depth 0.8- 1.0 feet, planting 5-6 rows per box, and nest spacing 0.4-0.5 feet. From 1998 to 2000, the comparative experiment of box planting and conventional transplanting was carried out in Huatacun Formation of Jinping Village for three consecutive years. Compared with conventional transplanting, box belt planting increased yield by 63.2-76.8kg, and increased yield by10.6-12.1%.

Seedling throwing: throwing seedlings per mu 1.5- 1.8 million plants, with thin and even throwing seedlings. During the period of 1998-2000, the comparative experiment of seedling throwing and conventional transplanting was carried out in Su Yu village of Xiongkui village for three consecutive years. The yield of seedling throwing was 72.1-79.3kg, an increase of 9.8-1.1%.

4. Tian Tuan management

4. 1 topdressing

Topdressing urea 10- 15 kg, calcium superphosphate 15-20 kg, potassium fertilizer 4-5 kg and zinc sulfate 1.5 kg per mu. Topdressing seedling fertilizer about 10 day after transplanting to promote effective tillering, accounting for 30-35% of the total topdressing; Topdressing at booting stage accounts for 65-70% of the total topdressing amount, so as to improve the seed setting rate and promote grain fullness.

4.2 Reasonable irrigation

In order to promote good root growth, enhance absorption capacity, and promote rice growth and health during rice growth. In water management, the purpose is to increase the root activity, focusing on aerobic ventilation, root maintenance and living roots. Appropriate deep-water irrigation is beneficial to the greening period, shallow water irrigation is maintained at booting stage, heading stage to full heading stage, and the rest irrigation conditions are mainly kept moist.

The tillering stage requires shallow water to promote tillering, and tillering should be properly controlled in the late tillering stage to reduce ineffective tillering, increase permeability, and promote rice growth and health. It is not advisable to re-bask in the sun when tillering is controlled. Irrigation should be used in dry season to prevent dehydration from affecting the appearance quality and cooking and eating quality of rice; In the mature stage of grouting, seeds should be wet and dry; Drainage and drying in the sun during the yellow ripening period to promote ripening; When harvesting, make sure there is no water in the field, so as not to affect the quality of rice by soaking it in water.

5. Pest control

5. 1 Main pests and diseases

The main rice diseases in our county are: rice blast, bacterial leaf blight, sheath blight, false smut and so on. The main pests are: rice planthopper, rice stem borer, armyworm, rice mud worm and so on.

5.2 Preventive and control measures

In the prevention and control of rice diseases and insect pests, we must adhere to the principle of "prevention first, comprehensive control". Comprehensive control measures are mainly to plant insect-resistant varieties, based on suitable cultivation, supplemented by chemical protection.

5.2. 1 Agricultural prevention and control: select insect-resistant varieties, cultivate strong seedlings, rationally plant in close density, rationally fertilize and scientifically irrigate; Remove plants damaged by pests and diseases in time to reduce the base of pests and diseases in the field; After rice harvest, the paddy field should be plowed in time, weeds in the field and surrounding areas should be cleared in winter, the wintering places of pests and diseases should be destroyed, and the base of pests and diseases and the incidence of pests and diseases in the coming year should be reduced.

5.2.2 Chemical control: strengthen field investigation and grasp the occurrence of pests and diseases in time; During the growth of rice, pesticides with high efficiency, low toxicity and no residue are selected to control pests and diseases, and the water layer of 3-6 cm in the field is kept for 3-5 days after application.

Soak seeds with 20% tricyclazole wettable powder 500-700 times, and accelerate germination after washing; Spraying 30g of 75% tricyclazole wettable powder or150-200g of 40% kewensan emulsifiable concentrate with 50-60kg of water per mu to control rice blast.

Soak the seeds for 48 hours with 500 times of 10% high chlorine solution, 500-600 times of 20% thiabendazole wettable powder solution and 500-800 times of 45% mancozeb aqueous solution. Spraying 500 times solution of 1 times 10% diclofenac at the three-leaf stage of rice and five days before transplanting, using 28-35g of 35% chlorhexidine wettable powder, 20-25g of 15% diclofenac wettable powder or 23g of 45% amobam aqueous solution with 50-60% water per mu.

Spraying 50-76 ml of 20% triadimefon EC or 50% carbendazim wettable powder 100 g, 50-75 g of 30% zolam wettable powder and 0/00kg of water 100 kg per mu, or mixing 25kg of fine soil to control rice sheath blight.

5 ~ 10 days before heading, 150 ml of 5% jinggangmycin aqueous solution or 75 ml of 20% fenxiuning EC or 12.5% Mucor aqueous solution 150 ml and 50 ~ 60 kg of water were mixed and sprayed twice to prevent and control false smut.

Use 10% imidacloprid wettable powder, or 25% Youle wettable powder 2000-2500 times solution, or 5% Regent gel suspension 1200- 1500 times solution to control rice planthoppers.

Before sowing or transplanting, mix 2.5-3kg of 3% carbofuran granules with15-20kg of fine soil per mu; When transplanting, soak the seedlings in water with 90% trichlorfon crystal 0.5 for 400-500 kg 10 minute; Spraying 50% chlorpyrifos EC or 50% Bataan aqueous solution 800- 1000 times in the field to control rice borers.

Spraying 800- 1000 times of Baichong or 50% acetamiprid EC, 500 times of 25% chlordimeform or 25% dimehypo, 20% fenpropathrin or 2.5% dimehypo EC for 4000-5000 times to control rice armyworm.

25% trichlorfon powder 3-4 kg per mu; Or 4 kilograms of tobacco powder mixed with 25 kilograms of hydrated lime, applied when the morning dew is not dry; 50% cartap 800 times solution; Or 90% crystal trichlorfon 1000 times liquid spray to control rice negative mud worm.