First, adverse effects. It is mainly due to lack of illumination and temperature drop, which is not conducive to the growth of vegetables. The second is the high humidity in the air and the increase in the incidence of vegetables. In addition to these two obvious hazards, there is also a lot of pollutants in the air during haze. These pollutants, through wind-breaking and other agricultural activities, fall on the blades and block the pores, affecting the photosynthesis of the leaves of the vegetables and Respiration, thus affecting the growth of crops.
Second, management measures.
1. Be prepared to prevent it in advance. One must have the habit of listening to the weather forecast, do a good job of watering and fertilizing before the haze days, cultivate strong seedlings, build up strong, accumulate nutrition, and increase plant resistance. Second, we must increase the level of hardware facilities, such as the use of anti-fog film, install the fill light.
2, lighting management. During the day, the insulation (grass weeds) should be uncovered as much as possible so that the vegetables will be exposed to scattered light, and artificial lighting measures such as light irradiation and installation of plant fill light can be used to minimize the influence of haze weather on facilities vegetables. . After the temperature in the greenhouse rises, the air is properly ventilated, air is exchanged, and the humidity in the greenhouse is reduced.
3, fertilizer and water management. Fertilizer management. In foggy weather, do not water or top-dressing as much as possible to avoid lowering the ground temperature and increase the humidity in the shed. If it is really necessary to water, it should be irrigated with small amount of water and put out in a timely manner. In addition, vegetable growers are advised not to apply water and water as little as possible in December and January. Watering will reduce the temperature and increase the humidity. This will cause the slow growth of vegetables and increase the incidence of vegetable diseases. It is recommended to concentrate water once in late November to chase big fertilizer.
4. Pest control. Fog and haze will easily lead to the occurrence of bacterial diseases such as gray mold, leaf mold and epidemic diseases, and bacterial diseases such as keratopathies in the vegetables. It is necessary to take active measures to prevent diseases, combine prevention and control, and control pests and diseases. Chemical control should give priority to the choice of smoke agent; if you need to spray control, you should choose the symptomatic sensitive agent, such as powdery mildew first select the sulfur preparations, the combination of triadimefon and thiophanate-methyl agent is penetrated once, there must be flow from the leaf Drops of feeling, once cured 80-90%; downy mildew, disease first copper preparations. It is necessary to drain moisture in time and reduce the humidity in the shed. During the day when the fog is high, the humidity in the air is high, and the moisture in the leaves is not easy to evaporate, resulting in non-absorbent roots. At this time, the nutrient elements transported by the water to the leaves do not go up, and it is easy to cause nutrient deficiencies in the roots and leaves, and yellow leaves appear. Or yellowing on the edge of the leaf. In this case, if the application of the fertilizer in the soil is not very large, despite the fact that there are many fertilizers in the soil but the root system does not absorb, this time the problem of lack of nutrition on the ground should be supplemented by foliar dressing. Foliar dressing should pay attention to the reasonable ratio of NPK and trace elements, and it is recommended to spray brassin, potassium dihydrogen phosphate, with high utilization rate.
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