Why do soil-borne diseases and insect pests in newly developed soils rarely break out? And the soil for growing the same crop for many years in a row is getting worse? These two issues are worth considering.
The root cause lies in the soil microorganisms. The microorganisms in the newly developed soil are rich and diverse, including fungi, bacteria, actinomycetes, and protozoa, both can help decompose root secretions, decompose organic matter, decompose harmful substances, There are beneficial microorganisms that release soil fertility, secrete proteases, secrete antibiotics, etc. At the same time, there are also harmful microorganisms that like to grow under stress (anaerobic, high temperature, high humidity, drought, etc.) and use crops as nutrients and food sources.
The good soil environment breeds a large number of rich beneficial microorganisms. On the contrary, the living environment of harmful microorganisms is relatively harsh, both from the restrictions of the soil environment, and from natural enemies or competitors-the vigorous microorganisms Suppressed, there is very little living space, and most choose to sleep.
And with our artificial interference and destruction, such as continuous cropping, unreasonable application of fertilizers and pesticides, and unreasonable irrigation, it has caused a series of problems such as soil acidification, salinization, compaction, reduced aeration, heavy metal pollution, and reduced organic matter. It greatly limits the reproduction of beneficial microorganisms. On the contrary, even as the reproduction of harmful microorganisms provides rich nutrients (root secretions) and hosts, the soil microbial lineage gradually reverses, harmful microorganisms gradually occupy the upper hand, and the ecological balance of soil microbes in the root zone, As a result, soil-borne diseases and insect pests began to break out. This is the fundamental source of soil-borne diseases and insect pests.
2. A new method to prevent soil-borne diseases and insect pests
1. Organic fertilizer + inorganic fertilizer + microbial inoculant combined with basic application to increase the number of beneficial microorganisms.
(1) Match organic fertilizer with microbial inoculants
The combination of organic fertilizer and microbial inoculum needs to consider two factors, as follows:
On the one hand, organic matter is a food source for the survival and reproduction of microorganisms. When there is sufficient organic matter in the soil, the microorganisms multiply rapidly. In poor soil, simply supplementing the microbial inoculants, beneficial microorganisms are difficult to multiply in the soil, and the effect is limited.
On the other hand, organic matter is food for beneficial microorganisms, but also food for harmful microorganisms. Simply supplementing the soil with organic fertilizers, although it can play a role in improving the physical and chemical properties of the soil, there are also risks. In soils where soil-borne diseases and pests are more serious Harmful microorganisms have the upper hand, and organic fertilizer applied to the field may become a source of food for the growth and reproduction of harmful microorganisms. Therefore, it is necessary to add an appropriate amount of microbial bacterial fertilizer to the organic fertilizer to increase the number of beneficial microorganisms in the organic fertilizer and make it dominant. The more severe the soil-borne diseases and insect pests, the higher the corresponding microbial bacterial fertilizer addition.
(2) Pay attention to the carbon to nitrogen ratio (C/N)
When the organic carbon-to-nitrogen ratio (C/N) is 25, microorganisms are most easily decomposed and utilized, and at the same time, organic matter decomposition is also the most thorough. It is difficult for our commonly used farm manure or compost to meet this carbon-to-nitrogen ratio. When applying organic fertilizers, it may be better to combine high carbon-to-nitrogen ratio organic fertilizer raw materials with low carbon-to-nitrogen ratio organic fertilizer raw materials, which is more conducive to fermentation. Organic fertilizer rot and microbial reproduction. For example, sheep dung can be mixed with corn stalk 6:4.
In addition, when the organic fertilizer raw material with high carbon to nitrogen ratio is rotted and fermented, you can also choose to add an appropriate amount of nitrogen fertilizer to control.
2. Choose the appropriate irrigation and fertilization method (drip irrigation fertilization as an example)
(1) Compared with flood irrigation, improving soil aeration, reducing soil compaction, salinization, etc., is conducive to the activities of soil microorganisms;
(2) Provide nutrients and water according to the needs of crops, balanced nutrition of crops, healthy growth of plants, and improve disease resistance;
(3) Improve the utilization efficiency of chemical fertilizers, reduce the application of chemical fertilizers, and use biological bacterial fertilizers, organic fertilizers, etc. to alleviate soil acidification and reduce the occurrence of some soil-borne diseases and insect pests.