What are the specific requirements for meteorological conditions in the critical period of rice growth? Thank you, the more detailed the better!

The days from sowing to maturity of rice are called the whole growth period, and from transplanting to maturity is called the field (Honda) growth period. The growth period of rice will change with the temperature and sunshine hours in its growing season. The growth period of the same variety in the same area is relatively stable under the conditions of timely sowing and timely transplanting, which is the inherent genetic characteristic of this variety.

Mi's life (Wang Weijin, 1998.8)

Seedling stage: seedling stage

Tillering stage of seedlings: effective tillering stage and ineffective tillering stage in greening stage.

Young spike development stage: the completion stage of differentiation stage formation stage.

Flowering and fruiting period: milk mature period, wax mature period and complete mature period.

The life of rice goes through two stages: vegetative growth and reproductive growth, in which the vegetative growth stage mainly includes seedling stage and tillering stage. Seedling stage refers to the period from seed germination to seedling drawing; Tillering stage refers to the period from transplanting to turning green to jointing. After transplanting, the root system of seedlings is damaged, and it takes 5-7 days for the overground part to resume growth, and the root system germinates new roots. This period is called the green transition period. After turning green, rice began to tiller until the jointing stage stopped, and some tillers had a certain number of roots, which were called effective tillers after heading and fruiting. A part of tillers born in the future can't head and bear fruit or die gradually, which is called invalid tiller. Effective tillering occurs in the early tillering stage, which is called effective tillering stage, and ineffective tillering occurs in the late tillering stage, which is called ineffective tillering stage.

The main growth characteristics of rice in vegetative growth period are root growth, tillering and leaf increase. The establishment of some vegetative organs provides reliable material guarantee for the growth and development of panicle in the future. At this stage, the high-yield seedling frame is mainly built through fertilizer and water management, which requires high quality of the population and should prevent the nutrition from growing too fast. Otherwise, it is not only easy to cause pests and diseases, but also easy to cause difficulties in later growth control, which has a great impact on the formation of rice yield.

The reproductive growth period of rice includes jointing and booting stage, heading and flowering stage and filling and fruiting stage. The jointing and booting stage refers to the period from the differentiation of young panicles to the growth of panicles, which usually takes about one month; Heading and flowering period refers to the time from the extraction of rice ear from the top stem sheath to the complete flowering of rice ear, usually 5-7 days; Filling and fruiting period refers to the period from rice ear flowering to grain maturity, which can be divided into milk maturity, wax maturity and complete maturity. The growth characteristics of rice in reproductive growth period are long stems and long spikes, flowering and fruiting, grain formation and enrichment, which is the main stage to win high yield. In cultivation, special attention should be paid to the coordination of fertilizer, water and gas, to prolong the functional period of roots and leaves, to improve the conversion rate of material accumulation, and to achieve sufficient panicle number, large panicle type, high 1000-grain weight and high seed setting rate.

Rice is a warm crop. The biological zero of japonica rice is 65438 00℃, and that of indica rice is 65438 02℃. Before the third stage of early rice, the average daily temperature was lower than 12℃ for more than three days, and it was easy to be infected with cotton rot, resulting in rotten and dead seedlings. When the temperature is higher than 40℃, the late-season rice seedlings are easy to be burned. When the daily average temperature is below 15 ~ 17℃, tillering stops, resulting in stiff seedlings. During the meiosis of pollen mother cells (microspore stage and meiosis fine line stage), the lowest temperature is lower than 15 ~ 17℃, which will cause spikelet degeneration, no grain increase and delayed heading. The suitable temperature for heading and flowering is 25 ~ 32℃ (25 ~ 30℃ for hybrid rice). When the average temperature is lower than 20℃ for three consecutive days (japonica rice) or lower than 22℃ for two to three consecutive days (indica rice), empty shells and shriveled grains are easy to form, but when the temperature is higher than 35 ~ 37℃ (hybrid rice is higher than 32℃), the seed setting rate will decrease. During the grouting period, the daily average temperature is required to be between 23℃ and 28℃. When the temperature is low, the movement of matter slows down, and when the temperature is high, the respiratory consumption increases. When the temperature is lower than 13 ~ 15℃, the grouting is quite slow. Japonica rice is more adaptable to low temperature than indica rice,

Because the photorespiration of rice is enhanced at high temperature. The suitable temperature range of photosynthesis is wide, which is 25 ~ 35℃ for indica rice and 18 ~ 33℃ for japonica rice. When the temperature of indica rice is lower than 20℃ or higher than 40℃, and that of japonica rice is lower than 15℃ or higher than 38℃, the photosynthesis will be sharply weakened. When the temperature rises to 32℃, the root respiration of rice increases rapidly, then slowly, reaches the maximum at 38℃, and then slows down, while the leaf respiration of rice increases linearly with the temperature rising from 20℃ to 44℃. Under low temperature (especially frost), the photosynthetic efficiency is inhibited, and the water absorption of rice roots is reduced, which leads to the closure of stomata and the withering of leaves. Root respiration is more sensitive to high temperature than leaves.

The water requirement of wet rice in the whole growing season is generally between 700 ~ 1200mm, and the field transpiration coefficient is between 250 ~ 600. The total transpiration of rice varies with light, temperature, moisture, wind, fertilization, photosynthetic efficiency of varieties, growth period and maturity. Transpiration of single-season mid-late rice is the highest at booting stage, double-season early rice is the highest at flowering stage and double-season late rice is the highest at jointing booting stage. When the soil moisture is lower than 57% of the field capacity, the photosynthetic efficiency of rice begins to decline; When the air relative humidity is 50 ~ 60%, the photosynthesis of rice leaves is the strongest. With the increase of humidity, photosynthesis gradually weakened. Rice needs water layer irrigation to improve root activity and transpiration intensity, and promote the accumulation of sucrose and starch in leaves and the movement of substances. The suitable depth of flooding irrigation is 5 ~ 10 cm, but in order to remove toxic reducing substances in soil and improve soil permeability and root activity, different degrees of open field and sun exposure should be carried out. Shallow water irrigation should be used in rice seedling stage, which is beneficial to rooting; In the tillering stage, in order to promote tree division, water was used to adjust the temperature, and the water layer was kept at about 2 ~ 3 cm. Drainage at late tillering stage promotes root development. The jointing and booting stage is the most water-demanding stage for rice, which is suitable for deep-water irrigation (6 ~10 cm). According to the weather and soil conditions, it can be slightly dehydrated or maintain a certain water layer at the heading and flowering stage, and the air relative humidity of 70 ~ 80% is beneficial to fertilization; Shallow water should be used in the field during filling stage, and it should be dry, wet and dry in the late stage of milk ripening, which is beneficial to improve root activity and material distribution and operation. The yield reduction of rice is the most serious in the turning green stage, meiosis stage and flowering and filling stage, and the lack of water in the turning green stage affects the survival and tillering of seedlings. Lack of water during meiosis leads to a large number of spikelets degeneration, delayed heading and decreased seed setting rate. Drought at heading stage affects heading and seriously reduces yield. During irrigation, the grain weight decreased due to drought, which affected the yield. Rice is most sensitive to flooding at the turning green stage, meiosis stage and flowering stage. Long-term flooding will lead to the death of seedlings, the rot of young ears and the decline of seed setting rate.

Illuminated rice is a sunny crop and needs high light conditions. The saturated light intensity of a single leaf of rice is generally around 30,000 ~ 50,000 lux, and the light saturation point of the population increases with the increase of area index, with the highest tillering stage being about 60,000 lux and booting stage reaching over 80,000 lux, but its photosynthesis is not obvious with the increase of light intensity like C4 crop corn. According to the statistics of IRRI1976, the photosynthetic rate of 50 rice varieties is 34.5 ~ 62. 1 mg decimeter -2 hours-1 (the average is about 44.6 mg decimeter -2 hours-1). Under the condition of light saturation, the photosynthetic rate and light saturation point of the upper first and second leaves of rice are significantly higher than those of the third and fourth leaves (see figure). The light saturation point of rice ear is 1 ~ 30000 lux, and the maximum homogenization is 2 mg decimeter -2 hours-1. The light saturation point of leaf sheath is 20000 ~ 40000 lux, and the maximum homogenization amount is 3 mg decimeter -2 hours-1.

It is observed that when heading rice, if the leaf area index is 7. 1, 90% of the spreading leaves are intercepted by the sunshine leaves 30 cm below the canopy top, while only 50% of the erect leaves are intercepted. Therefore, in theory, the net photosynthetic rate of erect leaf rice population is greater than that of horizontal leaf rice population. However, when the leaf area index is quite small, the horizontal leaf rice population shows higher photosynthesis. In addition, when the sunlight is direct, only one side of the leaves of the rice population receives strong illumination; When sunlight is scattered, the lower leaves of this group receive more light than the leaves in direct sunlight. When the leaf area index of the population is greater than 3, the reflected radiation is about 20% of the solar radiation, and the solar radiation absorbed by the population is the highest at booting stage and gradually decreases after full heading. Most of the energy is consumed by conduction and transpiration. The net photosynthetic intensity of rice does not exceed 5% ~ 6% of the total absorbed energy at most, in which the net energy conversion rate is about 5% at booting stage and 7% at heading stage, and then decreases rapidly. Rice is a short-day crop, and different varieties have different responses to the length of sunshine. In Guangzhou, the light length of 465,438+0 varieties was artificially controlled, and their responses are shown in Table 2. It can be seen that early rice and middle rice have no certain critical light length for heading, and they can heading normally in short or long days, belonging to short-day insensitivity type; Most late rice varieties promoted heading under short sunshine, delayed heading under long sunshine, and the critical light length of heading was strict, which was sensitive to short sunshine.

The photosynthetic rate of CO2 and O2 on rice leaves increased with the increase of CO2 concentration. When the CO2 concentration is 100 μ L/L, the growth rate of rice seedlings is more than 2.5 times that of 300μl/L/L. The variation of CO2 concentration in paddy field can reach 60μl/L/L in one day, and the maximum difference of CO2 values at different levels in paddy field can reach 40μ l/L at noon. The CO2 flux in paddy field can be expressed by the following formula: P=D 1-2(C 1-C2), p is CO2 flux, and C 1 and C2 are Z 65438 respectively. When the wind speed in rice field is greater than 0.3 ~ 0.9 m/s, it is enough to further enhance the transport of CO2 needed for photosynthesis. The absorption of CO2 by rice is greatly influenced by O2 content. When the O2 concentration is as low as 3%, the photosynthesis and material production of rice will be obviously enhanced. However, it will directly destroy the fertilization process of rice and produce serious infertility.

The growth period change of rice varieties with light-temperature response is determined by the comprehensive action of three factors: photosensitivity, temperature sensitivity and basic nutritional growth period. The growth period of basic nutrition reflects the growth period of rice varieties under high temperature and short sunshine; Photosensitivity reflects the response characteristics of rice varieties to different day lengths, and the growth period of rice varieties with strong photosensitivity is obviously shortened in a short day. Temperature sensitivity is the response characteristic of rice varieties to temperature during their growth. When the temperature is high, the growth period of varieties with strong temperature sensitivity will be obviously shortened. The characteristics of temperature sensitivity, photosensitivity and basic vegetative growth period are shown in Table 3.

Production and meteorology

The relationship between the number of days at heading stage of rice varieties in China and latitude, altitude and longitude shows that from south to north, with the latitude increasing by 65438 0 degrees, the annual average temperature decreases by 0.8℃, the average temperature in rice growing season decreases by 0.3℃, and the average length from summer to day increases by 5.4 minutes (not equal to the difference), and the heading stage of rice varieties is delayed by 2 ~ 2.5 days. From west to east, the average temperature and daily length of rice growing season changed little every 5 degrees to the east, and the days of heading were similar. Therefore, when rice is introduced from south to north, the plain moves to the plateau, the growth period is prolonged and the heading is slow, so it is appropriate to introduce early-maturing varieties; The northern rice moved south, the plateau moved to the plain, and the growth period was shortened, which was suitable for introducing late-maturing varieties. Things are introduced into each other, and there is little change in the growth period, which is easy to succeed. In addition, in low latitudes (south of 26 N), early, middle and late indica and japonica rice can be introduced to each other locally. Early and middle rice, early and late indica rice and japonica rice can be introduced in mid-latitude areas in the south (26 ~ 32 N), and early and middle japonica rice can be introduced in mid-latitude areas in the north (32 ~ 40 N). Only early japonica rice can be introduced in high latitudes (40 ~ 53 N).

Early japonica rice suitable for sowing date should be sown when the temperature is stable above 10℃ (about 8℃ for plastic film seedling) and planted above 15℃; Early indica rice was sown above 65438 02℃ and planted above 65438 07℃. In order to ensure that the full-heading flowering period of rice is basically not harmed by low temperature, the daily average temperature in the safe full-heading period of japonica rice should be kept above 20℃, and the low temperature below 20℃ should not occur for more than 3 consecutive days, and the low temperature below 22 ~ 23℃ should not occur for indica rice (including hybrid rice) for 2 ~ 3 consecutive days. Early japonica rice in the north and early indica rice in the south should also avoid chilling injury at booting stage (the minimum temperature is not lower than 15℃ for japonica rice and 17℃ for indica rice). It is necessary to make the heading and filling stage of rice suitable for light, water and temperature, and try to avoid the occurrence period of diseases and pests in order to obtain higher photosynthetic yield and grain yield.

Reasonable population structure, leaf area index of heading and filling of rice has a great relationship with yield. The optimum leaf area is mainly determined by the amount of solar radiation. The optimum leaf area index of rice at full heading stage in China is 6.0 ~ 8.0. The suitable population of rice in the early and middle stages should be mastered according to the temperature and seasonal conditions. The early and middle rice season is short, which requires the leaf area to increase quickly, and the late rice requires the leaf area to increase slowly, but it is generally required to harvest in the middle stage (10 ~ 15 days after jointing stage), which is beneficial to strong stalks and big ears.

Hybrid rice seed production and meteorology ① determine the effective accumulated temperature difference (X) between parents' sowing dates: X = a-(B/ kloc-0/0b/), where A and B are the effective accumulated temperature values from parents' sowing to the beginning of heading, respectively (see Table 4), and b/is the effective accumulated temperature needed to ensure that parents meet at full flowering and heading stages 2-3 days earlier than their parents. The flowering characteristics of parents are very different. The male parent's flowering period is relatively concentrated (5 ~ 7 days); The flowering period of the female parent is scattered (about 15 days), and the male parent sows in two stages, and the female parent starts heading 2 ~ 3 days earlier than the first male parent. ② Determine the meeting time of flowering time according to the flowering weather conditions. In normal weather, the male parent of hybrid rice (taking IR24 as an example) starts to blossom at 9 ~ 1 1 in the morning, and closes the glume around 1 in the afternoon, with the peak at10 ~1. The female parent (such as Zhenshan 97) began to blossom at 7 ~ 10 in the morning and closed the glume at 2 ~ 3 in the afternoon, with no obvious peak period. It rained all day without flowers; The start time of flowering on cloudy days is delayed and concentrated; It is sunny and rainy, and the rain is concentrated. The ear temperature in autumn seed production is below 27℃ (30℃ in spring), and the higher relative humidity is as follows.

Conducive to flowering.