When the cultivars of the crops are relatively single, the occurrence of pests and diseases is particularly serious in the case of continuous cropping, which will directly harm the growth and development of the crops, resulting in a decrease in yield and quality, an increase in input-output ratio, and a significant reduction in economic benefits. Continuous cropping obstacles are not only difficult to control, but also cause excessive use of pesticides. The data show that China's current annual chemical pesticide use is more than 1 million tons, a large number of pesticide residues reduce crop quality, affecting environmental safety and human health.
Continuous cropping obstacles means that when the same species or the same crops are continuously planted on the same soil, even under normal cultivation and management conditions, there will be varying degrees of slow growth, poor development, weakening of growth, and reduced yield and quality. Severe diseases and insect pests. Japan calls such problems a bogey phenomenon, and European and American countries call it replantation.
Then, why is it difficult to prevent and treat continuous cropping obstacles? The first is the hidden path of transmission. The pathogens overwinter or over the summer on the soil residues, directly infest the crop under suitable conditions, and it is difficult to effectively kill the pathogens by pouring or fumigation with chemical pesticides.
Secondly, the incubation period is long and concealed. After the pathogen is successfully infected, it is latent in the plant. At this stage, the host's nutrients are used for growth and reproduction. When the pathogen accumulates to a certain threshold and the environmental conditions are favorable for the onset, the disease is concentrated and erupted in a short period of time. Finally, the pathogens are colonized in the crop body, and the disease site is special, and it is difficult for chemical agents to achieve better control effects.
At present, the commonly used methods for controlling continuous cropping obstacles include soil sterilization, application of soil amendments, rational application of organic fertilizers and microbial fertilizers, soilless cultivation, implementation of rotation or intercropping.
Studies have shown that the application of organic fertilizer under continuous cropping and rotation conditions, the yield increase is 133% and 81%. This also shows that organic fertilizer has a certain effect on alleviating the obstacles of continuous cropping, and it is one of the effective measures to alleviate the obstacles of continuous cropping. Long-term and appropriate application of organic fertilizer in a timely manner helps to increase the content of effective trace elements and organic matter in the soil, which is beneficial to improve the resistance of plants.
At present, with the increasing planting intensity, many regions have been planting the same crop for several years on the same plot, resulting in a decline in both yield and quality, and frequent cropping obstacles. The prevention and control of continuous cropping should start from the soil, the soil is healthy, and the concept of scientific fertilization is established. Other problems can be solved.
The specific manifestation of continuous cropping obstacles is that the soil-borne diseases are increasing year by year. The greenhouse crops have been growing well, and there are many symptoms in three or five days or even half a month. Inexplicably, they die slowly. The insect pests that could have been controlled very simply have become medicine-free because of years of continuous cropping; Grass damage is also one of the obstacles to continuous cropping.
More importantly, due to continuous cropping, the distribution of beneficial elements and essential elements in cultivated soil is uneven, and the effective element content is greatly reduced, resulting in a lower and lower level of nutrient supply of the whole soil. At the same time, the acidification, salinization and compaction of cultivated soils pose a threat to soil health.
The causes of continuous cropping obstacles are nothing more than changes in soil physical and chemical properties, soil microbial changes, such as soil microbial population and fauna changes, physiological group changes, biomass and fauna changes, and increased number of pathogenic microorganisms. The changes of soil physical and chemical properties are closely related to soil microbial changes. Finally, the original microbial balance of the soil is destroyed and the crops are caused.
How to prevent continuous cropping obstacles? I think we should start with the soil, the soil is healthy, and other problems will be solved. In addition to soil disinfection and pH adjustment, the addition of beneficial microorganisms and trace elements is also a very important tool. Many farmers do not pay attention to the application of trace elements in the application, and believe that it is optional. In fact, the lack or misuse of trace elements can lead to various physiological diseases such as crop deficiency. (Agricultural Resources Guide, Sheng Jianwei Ma Gaosheng)
This article URL: How to prevent crop continuous cropping obstacles? Prevention and control of continuous cropping obstacles from the soil
