Reasonable remediation of early rice after waterlogging

Reasonable remediation of early rice after waterlogging

6 Mel July is the rainy season in the southern region, some rainstorms or torrential rains may cause flooding, and the seedling fields of early rice, medium rice and late rice may all be destroyed. The root system of rice plant in flooded paddy field was damaged, and even a large number of dead seedlings appeared. Corresponding remedial measures should be taken according to the flooded degree and growth of early rice.

1. Characteristics of flooded early rice

The waterlogging tolerance of early rice was different in different growth stages, and the symptoms were also different after waterlogging, and the degree of loss was mild and severe. After waterlogging at seedling stage and tillering stage, thin seedlings are often caused, and the basal leaves are yellowish brown, and the phenomenon of leaf collapse occurs after water withdrawal, but it can generally restore growth. The elongation of internodes of early rice was often affected by waterlogging at jointing stage. after retrogression, the internodes of early rice were shorter than normal, the plants showed dwarfism, thin and curved, and the number of rotten leaves and black roots increased. The early rice was waterlogged at booting stage, the empty grain rate increased and the mature stage was delayed, and the spikelet and branches were degraded seriously, resulting in the death of young panicle, the appearance of white panicle and the serious reduction of yield. During the milking stage, waterlogging caused most leaves to wither, grains blackened, some grains germinated and 1000-grain weight decreased, which had a great effect on yield. The effect of flooding is that the root system is seriously damaged. The number of black root and yellow root of flooded rice increased. It was observed that conventional indica rice and japonica rice were submerged for 4 days, hybrid rice was submerged for 6 days, and the proportion of black root and yellow root reached 100%. After 10-14 days, the proportion of black root alone reached 90%, and some of the roots died. Second, leaves, tillers, main stems and tiller nodes died one after another. The first death of waterlogged rice is the submerged leaves, the affected heart leaves will also die, and then the tillers, main stems and tiller nodes die one after another, resulting in lack of rice, and the total number of seedlings decreased seriously. Third, the number of high tillers increased. The surviving rice plants grow tillers along with the heart leaves, and some even grow tillers on the elongated stem nodes. Fourth, the growth period is postponed and the heading stage is elongated. The growth period of rice was delayed after flooding, and the more flooded days were, the more obvious the delay was, the full heading stage and mature stage of rice fields flooded for 3-5 days and nights were delayed by 1-2 days, and those submerged for 7 days and nights were delayed by 2-3 days, and the serious ones could reach more than 5 days. Fifth, the output has declined. The number of rice fields affected by waterlogging is insufficient, the tillers born after the disaster are higher, the panicle shape becomes smaller, the 1000-grain weight decreases, the yield decreases, and the serious loss reaches more than 80%.

2. Remedial measures

The main measures are: ① quickly remove stagnant water. Immediately after the occurrence of flood, we should organize forces to rush and drain, so that the seedlings of early rice can come out of the water as soon as possible, so as to minimize the time of flooding. In the process of drainage, the high shore fields should be discharged first, and the low-lying fields should be discharged later. The field can be drained at once on cloudy and rainy days. If there are few leaves in the field, the growth of grain seedlings is strong, and there is more floating mud in the field, it can be combined with drainage to prevent the lodging of grain seedlings. If the drainage meets sunny weather, the drainage speed should be slowed down when the temperature is high, and the shallow water layer should be properly preserved in the field. If drained once, it is easy to cause green and withered seedlings and cause greater losses. ② removes sediment in time. After flooding, the stems and leaves of early rice are often covered with sediment, resulting in foliage or lodging. In order to restore the growth of the seedlings as soon as possible, we should organize forces to pick up the accumulated sediment in the field as soon as possible and remove the floating matter, so as to reduce the degree of crushing injury of the seedlings, and sweep the bamboo pole back and forth to sweep the sediment off the stems and leaves. When the tip of the seedling is exposed, rinse the seedling with clean water. After receding water, straighten the seedlings and remove rotten leaves and yellow leaves. ③ opens ditches to control water at the right time. When the stagnant water in the paddy field recedes, the water in the field is still saturated, so it is necessary to open a ditch to drain the water from the soil in the field, reduce the water content in the field as soon as possible, and make the floating mud formed by flooding gradually settle down, so as to promote the growth of new roots. Adhering to the dry and wet irrigation method can not only ensure the need of water for rice plants, but also ensure the ventilation of the soil, and promote the occurrence of a large number of roots in the upper nodes and strong vitality. If you encounter low temperature at heading stage, we should adopt deep irrigation, late filling and fruiting stage, and pay attention to avoid cutting off water prematurely. ④ increased the application of available fertilizer. During the flooded period of early rice, the vegetative organs of rice plants were damaged to varying degrees, and the growth of roots, leaves and tillers resumed after water, which required a lot of mineral nutrition, and there was a large amount of fertilizer loss in the original paddy field. at this time, the combination of root topdressing and foliar topdressing should be adopted to apply available fertilizer. Topdressing should be fast and sufficient to promote the growth of rice plants as soon as possible. After drainage, per mu (1 mu = 667 square meters, the same below) early rice fields were mixed with urea and potassium chloride of 5 kg and 6 kg respectively. It can also be used with a concentration of 0. 3% potassium dihydrogen phosphate solution of 50 kg, foliar spraying for 1 to 2 times to meet the nutrient needs of rice plants, improve leaf photosynthetic function and promote the growth of grain seedlings as soon as possible. ⑤ strengthened the control of diseases and insect pests in flooded early rice. . after early rice is flooded, due to the decrease of plant disease resistance and the formation of a microclimate environment with high temperature and humidity in the field, it is conducive to the occurrence and spread of diseases and insect pests, and is most likely to cause the occurrence and prevalence of bacterial diseases such as bacterial brown streak and bacterial blight. Therefore, it is necessary to adhere to the rational use of fertilizer and irrigation, strive to separate drainage and irrigation, prevent early rice field series irrigation, and achieve shallow water irrigation. Control the application of nitrogen fertilizer and properly increase the application of phosphorus and potassium fertilizer to enhance the disease resistance of the plant. Chemical control should be carried out in time for old disease areas and flooded rice fields with bacterial leaf blight and bacterial brown stripe disease. For the diseased mound, 20% Yeqing double wettable powder can be sprayed with 100 ~ 150 g per mu, 50 kg of water, or 100 g of 97% strong chlorine wettable powder and 50 kg of water per mu. Spray should be uniform and comprehensive, and spray enough liquid to control the spread of bacterial diseases in time. In addition, the leaves and tillers born after the restoration of growth in flooded early paddy fields are relatively green and vulnerable to the harm of Chilo suppressalis medinalis, especially after the restoration of early rice growth, the leaves are bright green and the growth period is often delayed, which is most likely to encounter the explosive harm of the second generation of rice leaf rollers, resulting in a large number of white leaves, which has a great impact on the production of early rice. The available effective agents are avermectin, methyl avermectin benzoate, tetrachloroacetamide, chlorobenzamide, indenyl and so on. In addition, the delay of growth and development increases the chance of human invasion of rice planthopper and rice stem borer, so it is necessary to grasp the pest situation in time to control it. In the later growth stage of flooded early rice, if there are many overcast and rainy days, we should pay close attention to the occurrence and control of rice cancer, especially the occurrence and control of panicle and neck blast. The effective pesticides that can be selected are: Bacillus subtilis, polyantimycin, spring leimycin and other biological pesticides. And tricyclazole, prothiazole and other chemical pesticides.