The reason is as follows: The weight of soil pathogens caused by the successive years of heavy earthworms is high, and the nutrient content is not balanced. It is easy to induce crop root rot and other diseases.
Second reason: Due to the recent good prices of cucumbers, vegetable farmers have a large number of fertilizers in order to increase production, but this will lead to a large accumulation of soil salinity. In addition, vegetable farmers do not understand the characteristics of fertilizers needed for crops, and the ratio of nitrogen, phosphorus, and potassium in the fertilized materials is extremely uncoordinated, which also causes the accumulation of salt in the soil. Therefore, stem base contraction caused by excessive salt accumulation in soil is also an important factor causing dead trees. The dead trees caused by salt damage showed that the roots of the crops were disease-free, but the part that was close to the soil was dry and shrinking, resulting in poor nutrition and death of plants in the aboveground parts.
Reason 3: Root rot:
1 Cucumber (Fusarium solani) root rot: This is a common root rot. Mainly invading the main roots and stems, the first was water immersed, after the rot, the rot of the disease Department vascular bundle brown, was filamentous vascular bundles, early noon wilting leaves, sooner or later still recover, severe wilting withered.
2 Grafted cucumber Pseudomonas spp. Root rot: The disease is a common type of grafted cucumber. Normal seedling development is normal, after the onset of fruiting period began, the initial leaf loss of vitality, sunny noon wilts, cloudy days or sooner or later restore the status quo, repeated wilting after a few days died. It was observed that the base of the black squash stalk was mainly atrophic and soft and decayed, but it did not rot. The vascular bundles in the roots did not change color, and were different from the root rot and blight of Fusarium rot. Both of the above two root diseases are soil-borne diseases. The bacteria resides in the soil or in the sick and remains with the water. It invades the roots and wounds. High humidity facilitates the onset of disease. Continuous cropping, low-lying land, clay land, and wet ground are common. .
Reason 4: According to the test, the lower soil pH is also a cause of dead cucumbers. For example, in some areas, the soil pH is only about 5.8. The main causes of soil acidification are:
1 Excessive consumption of potassium and trace elements in the soil will cause the soil to develop toward acidification.
2 Long-term excessive use of chemical fertilizers. For example ammonium sulfate [(NH4)2SO4], its nutrient part is in the nitrogen (N) ammonium cation (NH4+), so the plant will absorb a large amount of ammonium ions without absorbing sulfate ions (SO4)2- without nutrients. A large amount of hydrogen ions (H+) are discharged during the absorbed ion exchange process, resulting in acidification of the soil. Acidification of soil can damage soil structure and make soil compact. At the same time, under acidic conditions, the solubility of aluminum and manganese increases, the effectiveness increases, and it is easy to produce toxic effects on vegetables.
Reason 5: Nematode damage. Root knot nematodes cause the roots to form nodules and cause dead trees.
Understand the cause of serious death of cucumber in Liaocheng area, you can treat it symptomatically.
First, to avoid double weighting: Continuous cropping with non-guad crops.
Second, increase the organic fertilizer: Apply a large number of decomposed organic fertilizer, not only can increase the shed soil organic matter content, improve the buffer capacity of the soil acidification, so that the soil PH value increased, but also in the shed organic fertilizer high decomposition rate , It can increase soil effective nutrients, improve soil structure, and promote the development of soil beneficial microorganisms, inhibit the occurrence of vegetable diseases.
Third, change the fertilization method: If the plant growth is weak but the results are high when the use of high-nitrogen compound fertilizer, when the plant growth and good results should use high-potassium compound fertilizer. At the same time pay attention to the input of trace elements, vigorously promote the use of organic-inorganic compound fertilizers and inhibit the acidification tendency of the soil. The use of acidic compound fertilizers with the same proportion of nitrogen, phosphorus and potassium, and application of chlorinated fertilizers should be minimized.
Fourth, the root rot control can be used to irrigate the root pharmaceutical: Xiangnong 4, carbendazim, colamine ammonia water agent, Kwong Ling, carbendazim plus Fumei double. Mixed rooting agents, such as root-strength seedlings, Fengshouyi, and Chifeng, can also be used to spray the rhizosphere with 300 times of a mixture of 77% donin and 50% acetaminophen in a 1:1 ratio. Irrigation liquid half a catty.
5. Use solar energy for high-temperature soil disinfection in summer free time: Use lime nitrogen (calcium ammonia cyanide), add straw (wheat straw, rice husk, etc.), and chicken manure, duck dung, etc., turn into the soil and plow the soil and mix it. Ridge, cover film, irrigation, closed greenhouse, the use of solar energy, straw brewing heat, chemical heat generated by calcium cyanamide kill all kinds of fungi in the soil, bacteria and root knot nematodes.
According to a farmer dealer in Jixian County, Liaocheng City, many local vegetable growers quit the boring shed because of the complexity of the summer boring and the high investment, which eventually led to serious plant diseases, insect pests, and dead trees in the crop. It is suggested here that the majority of vegetable farmers should not cause greater losses in the future because of immediate interest.
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