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In the process of transforming from conventional agriculture to organic agriculture , the first question is how to replace conventional fertilizers and pesticides? In the practice of organic agriculture, the use of organic fertilizer, manure, and cake fertilizer can basically meet the nutritional needs of crops. Fertilizers are not the most headache for organic farmers ; the prevention and control of diseases and insect pests are not the same. Due to modern agriculture for many years, farmers have already They are accustomed to using various chemical pesticides. At the same time, chemical pesticides are inexpensive and convenient to use. Farmers rarely spend time and experience trying methods to control pests without chemical pesticides. In this case, in the early stage of the transformation of organic agriculture, it is often helpless to face sudden insects. Therefore, the control of organic agricultural diseases and insect pests has become an obstacle to the healthy development of organic agriculture.
In conventional agriculture, the strategy for pest control is to focus on prevention rather than prevention. Emphasis is on the right medicine and rational use of the drug. It focuses on the relationship between crops and pests, especially the impact of pests and diseases on crops. The management strategy of the means; and the prevention and control of organic agricultural diseases and insect pests is mainly prevention, so that under the conditions of natural growth, the crops rely on the natural resistance of the crops to the external environment to improve their ability to resist diseases and insects. Cultivate healthy plants and create a good environment (roots, canopies, and surrounding environmental conditions), take measures to regulate rather than eliminate pests, and drugs allowed in organic agriculture can only be used under emergency conditions that have to be used. Not for routine prevention.
When the species and number of herbivorous insects reach a certain level, they are called pests. This is because fungi, bacteria, viruses, spider mites and insects are everywhere in nature. Under natural ecological conditions, due to the large number of natural enemies, these organisms generally cannot reproduce in large numbers. Therefore, as long as they do not affect our crop yield and quality, they are not pests. Once these organisms multiply in large quantities and bring harm to crops, it just shows that we have made mistakes in agricultural production . In other words, outbreaks of pests and diseases are often a sign of incomplete organic agriculture systems.
And it has been found that under natural ecological conditions, the most vulnerable plants are often the weak plants. Just as people's illness is related to diet, stress, climate and other factors, the outbreak of pests and diseases is often closely related to soil, natural enemies, farming measures and even human activities. Therefore, if an outbreak of a pest or disease occurs, first find out what caused it.
The basic principle of promoting crop health is to simulate natural ecosystems and increase the diversity of cultivated crops. Diversified planting is the use of changes in crop cultivation methods to increase the diversity of plants in the ecosystem. Through the interdependence of plants and the change in the amount of natural enemy food, provide alternative food for natural enemies, increase the types and number of natural enemies, and strengthen natural enemies against pests. Natural control ability; this is because single planting provides highly concentrated resources and unified ecological conditions, which promotes the rapid development of pests suitable for the environment, and because of a single environmental factor, it cannot provide abundant food and reproduction for natural enemies to choose from And habitats, so that natural enemies are reduced.
Two hypotheses are currently available to explain the reduction in pests caused by diversification.
The first hypothesis is the "natural enemy hypothesis", which believes that diversified planting can provide better living conditions for natural enemies, more pollen, nectar and prey, attract natural enemies and enhance their reproductive ability; increase the diversity of plant-eating insects, So that when the main pest is reduced, it can be used as an alternative food source for natural natural enemies to keep it in the crop system so that the system has more pest predators and parasites.
The second is the "resource density hypothesis". It is believed that diversified planting includes both host and non-host crops, so that the host crops are not as densely distributed as single crops, and multiple crops have different colors, smells, and heights. It is difficult for pests to land, stay and breed offspring on host crops, reducing obligate parasitic pests.
Crop diversification is not only beneficial for the prevention and control of organic agricultural diseases and insect pests, but also has a great effect on the control of crop diseases and weeds. It is also conducive to improving the nutritional level of plants, using the depth of the root system and the degree of demand for different nutrients, and making full use of the soil. In nutrition.
Diversified cultivation of organic agriculture can also cut off the food chain and nutritional supply of pathogenic bacteria, avoiding excessive accumulation of pathogenic bacteria and causing diseases and insect pests in the roots of crops. Diversified cultivation of organic agriculture includes: crop rotation, mixed cropping, intercropping, setting up field isolation zones, and non-crop cultivation. Diversified cropping includes both time and space. Time mainly refers to reasonable rotation, sowing, and harvesting time. Varying choices, for the complex planting of multiple crops and different varieties in space, consciously setting up insect habitats in the field.
June 19, 2017
Chengdu Xinxin Electronic Technology Co., Ltd. Editorial Department
Editor: Little Devil in Gourd