? Abstract: What is the story of Lichuan's past? Two-headed rice, two seizures in three years? This fully shows that rice production in Lichuan is frequently attacked by disasters. The natural climate of rice production in Lichuan city is enough to represent the situation of mountainous areas in southwest Hubei and Wuling. By analyzing the chilling injury of 20 10 rice production in Lichuan city, the natural risk of rice production in the future can be avoided and reduced.

Paper Keywords: rice production; Low temperature chilling injury; preventive measure

Rice is one of the three major food crops in Lichuan City, with an annual output of about 654.38+0.3 billion kilograms. In 20 10, rice production in Lichuan city was attacked by many natural disasters, such as chilling injury, especially the obstacle chilling injury in late August, which led to the failure of some late-maturing combinations (varieties) and the sharp decline of rice production in the city. In order to find out the disaster situation and draw lessons from rice production, we organized a special class to investigate, evaluate and analyze the rice disaster situation in Lichuan City.

One is the loss of rice yield caused by chilling injury.

In 20 10, the rice planting area in Lichuan City was 334,500 mu, the total output was116.29 million Jin, and the yield per mu was 347.7 Jin/mu, which was 53.3 Jin lower than that in the previous year (statistics), with a decrease of 13.29.

The disaster-stricken areas are mainly the alpine rice areas in Er at an altitude of 800- 1200m, followed by the alpine rice areas above 1200m, and the low rice areas below 800m are basically unaffected.

According to the investigation and statistics, in 20 10, there were 14 towns and 395 villages in Lichuan city, and 125600 households suffered from low temperature damage to varying degrees. The affected area is 203,000 mu, including 1.6 million mu, involving 258 1.5 households, with an average yield of only 650 mu. The severely affected area is 68,000 mu, involving 59 1 household 7 1 household, with an average yield of 276 kg per mu, which is 3 1% lower than that of the previous year, and the total output is reduced by 8.5 million kg. The light disaster area is105,000 mu, involving 406 14 households, with an average output of 309.9 kg, a decrease of 68.5 kg or 23% compared with the average output of the previous year, with a total output of 7192,500 kg. The unaffected area1315000mu, with an average output of 486.2kg and a total output of 63,935,300kg.

Second, the influence process of low temperature chilling injury on rice production

(a) Effect of delayed chilling injury on rice production

According to the data of Meteorological Bureau, the highest temperature in April of 20 10 was 26.8℃ (29th), the lowest temperature was 14℃( 14), and the average temperature was1.9℃, which was lower than the average temperature/kloc-0. The highest temperature in May was 30.0℃ (24th), the lowest temperature was10.2℃ (20th), and the average temperature was 16.8℃, which was 0.3℃ lower than the historical average temperature of 17. 1℃. The highest temperature in June was 3 1.8℃( 18), the lowest temperature was 12. 1℃(9), and the average temperature was 19.6℃, which was 0.7℃ lower than the historical average temperature of 20.3℃. This delayed chilling injury led to the slow growth of seedlings and delayed the transplanting period by more than 10 days. Over the years, the initial transplanting period was in early May, the peak transplanting period was in mid-May, and the ending period was around May 25th. At the beginning of this year, the transplanting period was around May 10, the transplanting peak was in late May, and the ending period was in early June. After June 10, some fields are still transplanting rice. More seriously, delayed chilling injury delayed the growth of rice by about 15 days. Over the years, the peak of rice tillering appeared in mid-June, from June 20 to 25, and the field was full of seedlings. Heading began around August 5, and August 15 was basically full. After the seedlings entered the field this year, the tillering peak appeared in late June, the whole seedling stage was around July 5, and the heading stage was around August 10. 40% of rice heads before August 20th, 50% before August 25th, and 10% is in the first heading or heading stage, and the maturity period is the whole year.

Effect of barrier chilling injury on rice production

It rained continuously from August 23rd to 26th, and the temperature dropped sharply. On 23rd, the highest temperature was 24.0℃, the lowest temperature was 20.4℃, the average temperature was 2 1.6℃, and the rainfall was1.7mm.: On 24th, the highest temperature was 24℃, the lowest temperature was 19.6℃, the average temperature was 20.9℃, and the rainfall was 34.8 mm: on 25th, the highest temperature was 2 1.2℃, the lowest temperature was 19.0℃, and the average temperature was 19.8℃, and the rainfall was 34.8 mm. ; On 26th, the highest temperature 19.4℃, the lowest temperature 17.0℃, the average temperature 18℃, and the rainfall was 26.0 mm: from 23rd to 26th August, 50% of the rice in the second alpine rice region of Lichuan City was in full heading stage, and the average temperature was lower than 22℃ for four consecutive days.

(3) Interaction between obstacle factors and chilling injury in rice fields.

The investigation found that the late heading was mostly in Yinshan field with insufficient light, cold-soaked mud field with low water-cooled mud temperature, and high-fat field with rice greedy for green and late maturity. These fields with obstacles interact with low temperature and chilling injury, resulting in reduced production or even no harvest.

(d) cultivation factors

Because of the high price of seeds, farmers reduced the original field application variety of 1 kg-1.5 kg to 0.5 kg -0.75 kg in order to save costs. In this way, too few basic seedlings enter the field, which prolongs the tillering stage of rice and leads to a long time from heading to heading, so the heading stage is late, while the heading stage of late-maturing varieties coincides with Ershan 2065 and 438.

Third, technical measures to solve the chilling injury in rice production

(1) Spraying 920

Spraying 2 grams of 920 with 30 -60 kilograms of water (30 kilograms of motorized sprayer and 60 kilograms of manual sprayer) on the leaves of rice at heading stage can solve the problem of neck covering, improve the ear layer, reduce the humidity of the ear layer, reduce the incidence of ear neck blast and improve the seed setting rate.

(2) foliar fertilization

Spraying 0.25 kg of potassium dihydrogen phosphate and 30 kg -60 kg of water (30 kg of motorized sprayer and 60 kg of manual sprayer) on the leaves of rice during grain filling stage to supplement phosphorus and potassium nutrition, increase grain weight and improve seed setting rate.

(3) Drainage and heating

In paddy field, from rest period to heading period, excess water is removed, mud temperature is increased, and heading is achieved early.

(d) Strengthening pest control.

It is suitable for controlling rice blast, sheath blight, rice leaf roller, rice planthopper and false smut.

Four. suggestion

The climate characteristics of Lichuan City are: low temperature and little sunshine in late spring and early autumn, and the effective accumulated temperature is relatively insufficient. Therefore, the following suggestions are put forward for rice production:

(a) according to? Good morning.

As far as the market situation is concerned, it can be said? Good morning. It is one of the key technical measures to prevent and avoid disasters in rice production, and it is necessary to sow early, that is, from late March to April 5; Early transplanting refers to transplanting rice in early May and ending before May 25th. Topdressing tiller fertilizer early, under the premise of applying sole fertilizer, topdressing tiller fertilizer 5 -7 days after planting, so as to achieve the goal of full sowing in the field before June 20 -25 and full heading before August 15, and avoid the harm of low temperature autumn wind.

(2) Select suitable varieties (combinations)

Second, early-maturing hybrid rice combinations should be selected in alpine rice areas, and varieties with low temperature tolerance and shade tolerance should be selected in shady mountain fields and cold-soaked mud fields; Early maturing and fertilizer-tolerant varieties should be selected in natural high-fertilizer fields.

(3) Rational cultivation

Due to the low temperature of water-cooled mud in Yinshan field and cold-soaked mud field, it is necessary to adopt sparse sowing, dry seedling raising, appropriate extension of seedling age, cultivation of strong seedlings with multiple tillers and appropriate increase of transplanted basic seedlings; Transplanting early in natural high-fertilizer fields, properly controlling basic seedlings, controlling nitrogen fertilizer, and applying more phosphorus and potassium to enhance stress resistance.

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2. Tanaka; Wu. Physiological ecology of rice [M]. Shanghai Science Press, 1980.

Third, Wang Yutong. Diagnosis of rice [M]. Henan Science Press, 1982.

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