Soil "eight strange", your have a few "strange"?
In recent years, soil problems occur frequently in sheds, which not only makes vegetables difficult to obtain high yield, but also affects the service life of sheds. Some experts with eight words summed up the main problems facing the current soil, to see if your greenhouse has been hit.
一Soil problem eight strange
1, board: soil hardening, the more the board
Soil "hardening" means that the soil structure is destroyed, the tillage layer becomes hard, and the water permeability is poor, seriously affecting the normal growth of crop roots
(1) Main reasons:
Organic fertilizer input is seriously insufficient. The soil organic matter content is low and the structure is poor, which affects the activity of microorganisms, thus affecting the formation of soil mass structure, leading to soil compaction.
Long-term excessive and partial application of chemical fertilizer. Long-term excessive application of large chemical fertilizer, destroyed the soil structure, soil organic matter can not be replenished in time, causing soil compaction and cracking.
(2) Main hazards:
A decrease in the root system capacity. In the case of soil compaction, hypoxia leads to the decline of root vitality, unable to develop normally, weakened respiration, and affects the absorption of nutrients.
2, greedy: mineral nutrition ratio imbalance, the more planted, the more greedy
The growth of crops needs 16 kinds of essential nutrients, but in daily management, only pay attention to the application of nitrogen, phosphorus and potassium fertilizer, ignoring medium and trace element fertilizer, resulting in the depletion of trace elements in the soil and the enrichment of a large number of elements.
(1) Main performance:
With more and more fertilizer input, the yield and quality of fruits and vegetables did not improve, but showed a downward trend.
(2) Main hazards:
Physiological deficiency disorder. Such as calcium, magnesium, iron, etc.
Poor growth of vegetables, reduced quality of agricultural products, etc.
3, poor: the lower the content of organic matter, the more poor
The organic matter of soil is an important part of soil structure and an important indicator of soil fertility.
(1) Main problems:
At present, the number of multiple cropping crops increases, and chemical fertilizer is applied in excess, while the application of organic fertilizer is seriously insufficient or the use method is unreasonable.
(2) Main hazards:
The serious loss of soil organic matter, the destruction of soil mass structure, and the reduction of soil water retention, fertilizer retention capacity, permeability and buffer performance, seriously affect the yield of crops and the economic benefits of planting shed.
4, shallow: the tillage layer becomes shallow, the more shallow
Due to the long-term use of rotary tillage machine, most of the soil tillage layer becomes shallow, and the effective active soil layer is only 15-2 cm.
The formation of "plough bottom" hinders the upper and lower circulation of soil water, nutrients and air, and hinders the extension of crop roots. The soil water storage capacity is getting worse and worse, and the drought resistance performance is constantly declining.
5, acid: soil acidification, the more the more acid
The normal, neutral soil pH value is around 7.
(1) Main reasons:
Precipitation or watering is large and concentrated.
Long-term heavy application of chemical fertilizers is an important cause of soil acidification, because most chemical fertilizers are acid fertilizers. (2) Main hazards:
Change the soil microbial environment: when soil acidification, the number of harmful microorganisms in the soil will increase, and the number of beneficial microbial populations will greatly decrease, thus increasing the incidence of root diseases.
Soil structure is destroyed: when the microbial environment in the soil is destroyed, the mass structure of the soil is destroyed accordingly.
The absorption rate of soil nutrients is generally the highest in the neutral or less acidic soil. When the pH is significantly increased or decreased, the absorption rate of soil nutrients will decrease.
Root knot nematode: root knot nematode likes acidic soil environment, when the soil becomes sour, the number of root knot nematode will become more, thus causing the occurrence of root knot nematode disease.
6, salty: soil salinity
Simply put, the soil contains too much salt. Say some reality, green frost, red frost, white frost, these phenomena have been seen? This is the intuitive manifestation of soil salinization.
(1) Main reasons:
Closed facility environment: under facility cultivation, crops have a large demand for soil water, which will make the salt in the deep soil move up to the surface layer with the water evaporation.
Unreasonable fertilization: excessive use of large fertilizers, and the use of unripe fermented manure, this is the main reason.
Unreasonable tillage method: the tillage layer becomes shallow, the formation of the plough layer, the salt is easy to accumulate in the tillage layer is difficult to penetrate, so that the salt content of the soil surface increases year by year.
(2) Main hazards:
Physiological toxicity of salt ions. Some amount of salt, causing crop poisoning.
Cause a physiological drought in crops. Like pickles, the water requirements for crops are difficult to meet.
Affect the nutrient uptake of crops. Too much soil salt seriously damages the physiological function of the root system, which seriously affects the nutrient absorption.
A decline in soil function. When the salt content in the soil is too high, it suppresses the activity of soil microorganisms and affects the soil function.
7, dirty: soil pollution, the more planted, the more dirty
The main types include heavy metal pollution and organic matter pollution.
(1) Main reasons:
The residue of chemical fertilizers, pesticides, agricultural film, organic fertilizer without fermentation and decay treatment, as well as continuous cropping and disease and insect pests pathogens, these pollutants residual soil for a long time, once beyond the soil itself purification capacity will cause soil pollution.
(2) Main hazards:
The soil ecological balance will be destroyed, a large number of soil beneficial microorganisms will die, soil physical, chemical and biological properties will deteriorate, soil activity will decline, and soil function will deteriorate.
8, miscellaneous: heavy stubble obstacle, the more planted, the more miscellaneous
A typical phenomenon, the new shed crop root disease is less, the old shed not only heavy disease, and the yield and quality are not ideal.
Main reason: the soil biological characteristics of the new shed are relatively good, and the harmful bacteria (miscellaneous bacteria) and beneficial bacteria are in a balanced state. When we keep planting and applying chemical fertilizers, the microbial bacteria in the soil begin to gradually imbalance, that is, the number of harmful bacteria (miscellaneous bacteria) accumulates more and more, the number of beneficial bacteria is less and less.
2. How to do the soil improvement?
From the soil physical structure, chemical traits and biological traits three aspects.
1. Improvement of soil physical structure
(1) Soil conditioner
The function of soil conditioner is to stick the broken soil particles into small particles, that is, to restore the structure of soil particles. Specific should be Is more convenient to use, farmers before or after turning, directly on the ground, and then water, soil conditioner under the action of water will become particularly sticky, a small particles will form soil colloid, the colloid formed the soil mass structure, guarantee soil permeability, fertilizer, root is more likely to go down.
Especially for 7-1 years of shed, the effect of straw is very good, better than the use of organic fertilizer alone. Now many vegetable farmers are still using unripe manure as organic fertilizer, the harm is relatively large. Whether chicken dung, cow dung, use can be fermented by adding straw. Take chicken manure as an example, which is rich in organic matter, nitrogen, phosphorus and potassium, a layer of chicken manure and a layer of straw, piled together rotten fermentation, not only can not only reduce the salt in chicken manure, but also more organic matter, while high temperature fermentation can eliminate a large number of pathogenic bacteria. In the plots with serious soil salinization, straw can be used in large quantities. And the process of straw decay can absorb a part of the salt and reduce the soil salinization.
2. Improvement of soil chemical traits
(1) It is not recommended to use cement and quicklime to adjust the pH value of the soil
Some vegetable farmers choose cement, quicklime as a conditioner to improve the soil chemical traits. If the soil is seriously acidified, after the use of cement and quicklime, the pH value will certainly increase, and the soil acidification on the surface has been solved. The disadvantage of this practice is that it cannot solve the salinization, and seriously damages the soil structure, leading to the deterioration of soil.
(2) To reduce the amount of chemical fertilizer, you can use some alkaline chemical fertilizer, such as magnesium hydroxide, which can adjust the soil pH value to a certain extent, and will not form precipitation.
(3) Improve the utilization rate of chemical fertilizer
Soil chemical properties and chemical fertilizer utilization rate are closely correlated. At present a lot of old shed compound fertilizer utilization rate is very low, some old shed alone use compound fertilizer, utilization rate of 15%, that is to use 1 catty compound fertilizer in the field, can be absorbed by crops only about 15 jins, the remaining 85 catties are wasted, this part of the waste fertilizer will increase soil salinization or acidification. It is suggested that in the process of vegetable planting, compound fertilizer is only used as base fertilizer, and water-soluble fertilizer is selected as far as possible.
For many vegetable fields, there is no shortage of fertilizer in the soil, only more nitrogen, phosphorus and potassium. The key problem now is: how to activate the remaining nitrogen, phosphorus and potassium in the soil, or that fixed by the soil, bit by bit, so that the crops can be absorbed and utilized, rather than excessive chemical fertilizers
Comtopdressing principle: topdressing is not more, absorption is the key. No matter how much it is, it is useless that the soil can not be absorbed. The amount is appropriate to ensure that the absorption and utilization rate of fertilizer is increased to 8%, and the damage to the soil will be less and less. The soil itself also has a buffer ability, so that the soil will be better and better.
3. Improvement of soil biological traits
To improve soil biological traits, we must start fundamentally, and the best way is to treat bacteria with bacteria. To increase crop yield, biological agents (biological fertilizer) need to be added to the soil. The most mature application in China is bacillus. Bacillus belongs to bacteria with many species. It is a particularly good bacterial group to alleviate the repeated soil stubble, which can reduce the occurrence of soil-borne diseases, which is a fundamental method.
The biological agents are mainly fungi, such as mycorrhizal bacteria, deep green wood mold. Compared with bacteria, the production process of fungi is more complex and more difficult to purify. Foreign manufacturers will also have some soil flora conditioner, using the principle of biological stimulator, rushed to the ground, can stimulate the soil, the formation of suitable for the soil flora, increase the content of beneficial bacteria, alleviate crop production and soil-borne diseases.
At present, the domestic fungus fertilizer market is uneven, vegetable farmers choose, regardless of large or small manufacturers, regardless of the level of bacteria, should do the test demonstration in advance.