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Due to the long-term continuous cropping of greenhouses, pathogens and insect eggs accumulate; excessive application of physiological acidic fertilizers and excessive application of nitrogen fertilizers makes a large amount of nitrate nitrogen accumulate, while the application of decomposed farm manure or organic fertilizer is small, and the soil buffer is poor, so that the soil acidification, when the crop will appear dead seedlings, growth point necrosis and other phenomena; the fertilization type is single and excessive, resulting in a rise in soil salt and aggravation of salt damage. Then how to regulate continuous crop disorders, symptomatic prevention and treatment is particularly important.
First, the type of soil obstruction of continuous cropping
1, greenhouse continuous cropping obstacles Due to the long-term application of acidic and physiological acidic fertilizers such as calcium phosphate and potassium chloride, excessive application of nitrogen fertilizers, so that a large amount of nitrate nitrogen accumulates, the amount of organic fertilizer is small, the soil buffer is poor and other factors, resulting in serious soil acidification, and plants are prone to dead seedlings, missing plants, growth point necrosis and other phenomena.
2, salt accumulation and poison greenhouse facilities cultivation, both due to unreasonable fertilization, but also the lack of rainwater leaching, resulting in a large amount of salt in the fertilization process in the tillage layer. According to the measurement, when the total salt concentration of the soil reaches 0.30%-0.50%, it is difficult for the crop to absorb water and is prone to withering because it is higher than the concentration of plant cell solution.
3, nitrogen dioxide and ammonia excess poisoning in greenhouse fertilization often focus on nitrogen fertilizer, ignoring the case of too much nitrogen fertilizer, ammonium nitrogen is easy to convert into NO2 gasification of nitrite, resulting in crop leaves, leaf backs to produce white spots and yellow spots and other fertilizer symptoms, while the plant free ammonia is too much, diseases and insect pests are very easy to infect.
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4. Nutrient imbalance causes physiological deficiency disorders, and unreasonable fertilization causes nutrient imbalance (1) Imbalance between chemical fertilizer and farm fertilizer and organic fertilizer application. Often the amount of chemical fertilizer is large, farm manure, organic fertilizer is affected by fertilizer sources, stubble, field tillage management, the amount of application is insufficient, affecting the natural quality of agricultural products. (2) Imbalance in the application of nitrogen, phosphorus and potassium. Often nitrogen fertilizer is excessive, potassium fertilizer is lacking, resulting in a decline in nitrogen fertilizer utilization rate, increased fertilization costs, and increased fertilizer damage. (3) The application of a large number of element fertilizers and medium and trace element fertilizers is unbalanced. Due to the antagonism between some elements, too much nitrogen and phosphorus fertilizer, reducing the effectiveness of calcium, boron, zinc and other nutrients, continuous cropping is easy to find early and late tomato blight and umbilical rot caused by calcium, and boron deficiency causes radish and celery stem fissure, making the leaves twisted, thickened and brittle.
Second, the stubble soil obstacle control countermeasures
1, increase the application of farm manure Farm manure nutrient content is comprehensive, the soil pH, salinity, tillability, buffer and other physical and chemical traits have a regulatory effect, the general crop stubble, each stubble per 667m2 application of decomposed farm manure 2500-5000kg is appropriate, in order to promote early emergence of seedlings at the seedling stage. The second is the use of straw mulching or deep turning grass technology, which can play a role in soil modification, heat preservation, moisture preservation, and grass pressing.
2, balanced fertilization Chemical fertilizer application is unreasonable, especially excessive nitrogen fertilizer application is the leading factor of soil obstruction of stubble. Therefore, balanced fertilization is a key measure for crop production with high yield, high quality and high efficiency. First, the rational application of nitrogen, phosphorus and potassium, the general principle is to control nitrogen, stabilize phosphorus, and increase potassium. Base fertilizer should be applied in full layer, fully mixed with the soil, topdressing should be drizzled root irrigation or drip irrigation, avoid surface dry application, it is best to choose a reasonable organic nutrition package, per mu drip irrigation or Chong Shi Jiamei dividend 1 bag + Jiamei Hailibao 2-3 kg or Jiamei dividend 1 bag + Jiamei profit to 4-5 kg is more ideal. The second is to apply medium and micro fertilizers and biological fertilizers in an appropriate amount. In view of the fact that the production of crop stubble is prone to boron, calcium, zinc and other deficiency symptoms, you can choose to apply high-efficiency instant boron fertilizer, Jiamei brain platinum, etc., and at the same time select fulvic acid, high potassium and high calcium package nutrition Jiamei dividend, Jiamei profit to reduce soil-borne diseases, improve crop quality, improve yield.
3. Regulate soil pH Soil acidification is a more common and serious obstacle factor. The hydrogen ion content of stubble soil is often tens of times higher than that of normal soil, which seriously affects crop growth. First, increase the application of organic fertilizer and organic activation nutrition Jiamei dividend, control the amount of nitrogen fertilizer, reduce the content of nitrate ions and nitrogen, try not to apply acidic and physiological acidic fertilizers such as calcium superphosphate, and switch to calcium, magnesium, phosphorus fertilizer, potassium sulfate and other fertilizers, which can not only adjust soil acidity, but also supplement magnesium, calcium, sulfur and other elements to improve the quality of vegetable crops; the second is to apply lime to neutralize acidity. For soil with a pH of ≤5.5, 50-60 kg of lime is applied per 667 m2 during ploughing, which is fully mixed with the soil, which can improve the pH value and have a killing effect on soil pathogens.
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4. Reasonable rotation
(1) Match varieties according to soil fertility. The planting of legumes can increase the content of soil organic matter and improve soil fertility, while the long-term planting of fast-growing leafy vegetables with more nitrogen will cause imbalance of nutrients in the soil and reduce fertility, resulting in nutritional poverty in some crops. Therefore, it is necessary to rationally match and plant crops with long growth period and short growth period, and those that require more fertilizer and less fertilizer.
(2) Rotation is carried out according to the depth of crop roots. It is recommended that you arrange for deep-rooted root vegetables, nightshade fruits, legumes, melons (with the exception of bitter melon) and shallow root leafy vegetables, onions and garlic to rotate crops, so that different levels of fertilizer in the soil can be effectively used.
(3) Rotation according to the nutrient needs of different crops. Different crops have different nutrient absorption, such as rapeseed, cabbage and other leafy vegetables need more nitrogen fertilizer, melon, tomato, pepper and other fruits and vegetables need more phosphorus, potassium fertilizer, the above should be implemented rotation. Generally, the stubble of leafy vegetables with more nitrogen is generally arranged for eggplant fruits that require more phosphorus and potassium, and the bitter melon, celery and cabbage stubble that absorbs fertilizer quickly are generally planted with tomatoes, eggplants, peppers, etc. that absorb organic fertilizers better the following year.
(4) Rotation is carried out according to the soil pH. Planting potatoes, kale, etc. will increase soil acidity, while planting corn, pumpkin, etc. will reduce soil alkalinity. Therefore, planting corn and pumpkin and then planting alkaline-sensitive onions and garlic can achieve high yields, while planting potatoes and kale and planting alkalinity-sensitive onions and garlic will lead to reduced yields.
(5) Rotation is carried out according to the degree of occurrence of pests and diseases. Such as cucumber blight, aphids, etc., can also infect other melon crops, if you change to non-cucurbitaceae vegetable Owen, will receive the effect of reducing or eliminating diseases and insects. Another example is the planting of Chinese cabbage after the harvest of green onions and garlic, which can significantly reduce the soft rot of Chinese cabbage. In addition, the implementation of grain and vegetable rotation and water and drought rotation can also effectively control soil infectious diseases.
(6) Use varieties with large coverage to suppress weeds. Some crops that grow rapidly or have high cultivation density, long growth period and large leaf cover to the ground, such as melons, kale, potatoes, etc., have obvious inhibitory effects on weeds.
This article was written by cathay pacific's technical team
bibliography:
"Greenhouse Vegetable Continuous Cropping Soil Obstruction and Countermeasures" Xu Fuzhi Gaotai County Laneway Township Agricultural Technology Station
"Heavy stubble, continuous work obstacles are serious!" Here's a trick! 》Tianbao Agricultural Technology Service Platform
"Soil Continuous Cropping Obstacles in Vegetable Greenhouses and Their Prevention and Control", Agricultural Technology Extension Station, Dongliang Town, Fuxin Mongol Autonomous County, Liaoning Province