Key factors affecting the healthy growth of crops
First of all, we should understand five key factors that affect the healthy growth of crops: root mineral nutrition, root water, root oxygen, leaf photosynthesis conditions and growth environment conditions. These five key factors are influenced by many sub-factors, and there are also complex cross-effects among them. Only these five key factors are most suitable for crops, and crops can grow healthily and vigorously. The higher the satisfaction of these five factors, the more stable the crops will be.
For example, soil acidification will affect the absorption and efficiency of nitrogen fertilizer. The more in this case, the easier it is for farmers to overuse nitrogen fertilizer, which will eventually lead to the imbalance of soil microorganisms, more acidification of soil, and even affect the physical structure of soil, which will eventually lead to a series of negative domino effects and eventually lead to crop weakness and death. To solve the problem, we should fundamentally find the reasons for inhibiting the role of nitrogen fertilizer, rather than rushing to supplement more nitrogen fertilizer. It is a common habitual procedure in our life to find the cause and solve the problem after it appears. But the crux of the problem is, are the proximate causes and countermeasures illusory? What are the derivative problems of immediate countermeasures?
Pests and diseases are frequent, so we should reflect on what happened to the breeding environment.
After the Second World War, in order to meet the needs of population and economic growth, agriculture has also been influenced by the form of industrialization, and has undergone a self-revolution, changing the previous farming methods of agriculture and becoming the mainstream of agricultural development in various countries. Due to human efforts in production, although the production efficiency has been improved and people's demand for food has been met for a period of time, many problems have also arisen, such as the deterioration of cultivated land soil, the excessive pesticide and fertilizer residues in agricultural products, the loss of cultivated land, the exhaustion of water sources and the decline of rural areas. Our country faced these problems earlier because of its large population base and frequent extrusion.
Agricultural definition? Pests? It is of great significance in essence. Specific insects and microorganisms are defined as pests and diseases because they affect the economic interests of human beings. Diseases and pests often occur in places where crops are weak or densely planted. But pests and diseases are really good teachers and friends of farmers, and they play an important role in resource recovery, weakening and retaining strength in the ecosystem. So, what we should think about is, what human factors caused the crop failure?
Insects, microorganisms, etc. Surround the crops intensively cultivated by human beings at any time and steal saprophyte without the consent of the farm owner. From the biological point of view, they just developed their own survival instinct and continued to carry out the important mission in life.
Large-scale crops deliberately planted by human beings do not exist in nature, and it is difficult to see large-scale single plants in the wild for a long time in nature. Even bamboo forests with strong vitality must be dug and smoked, otherwise they will die naturally within 20 years. So, the crops are borrowed naturally? Pest recycling is certainly reasonable. It must be noted that the positive actions used by human beings to resist natural forces often lead to irreversible despair due to ignorance and excessiveness.
Safety, traceability and sustainable development should be kept in mind.
Agriculture is not only an industry that provides food, but also has the functions of species protection, ecological stability, rural cultural inheritance, social stability and national security. When human beings only focus on agricultural production, farmers will inadvertently fall into the thinking of industrial production, continue to improperly influence people, and let the land continue to deteriorate. Let these functions be completely lost, and even the output and quality originally pursued are not as good as before.
Facing the trend of free trade competition all over the world, only by constantly improving ourselves, making the development of agriculture the ultimate and irreplaceable, and even combining the agricultural model of humanistic tourism, can we be free from the threat of free trade competition. Safety, traceable responsibility and sustainable development are the inevitable elements of agricultural development direction.
Agricultural development should not only rely on agricultural law to talk about ecological advantages and disadvantages
All farms can be regarded as an ecosystem, and the stability of the ecosystem depends on species diversity and systematic recycling of resources. If crops can be integrated into the local ecosystem of cultivated land, they can survive stably and stay away from pesticides and pollution. As long as the objectives and implementation plans are formulated, local agriculture has the opportunity to develop a stable regional ecosystem and let crops grow healthily.
The simple dichotomy in today's public opinion divides agricultural areas into lofty organic agriculture and ordinary agriculture with negative impression. We need to go back and review. Have we neglected everyone's responsibility in this process? Are you too lazy to expect the problem to be solved in an instant? The growth of crops and the growth of children are all accumulated and cultivated bit by bit, which can not be achieved by working overtime in factory production lines, nor can it be carved by artificial hard power. With the above ideas, agricultural operations, such as precision fertilization, can be properly evaluated and implemented.
Accurate fertilization, thinking ahead and rational fertilization
Chemical fertilizer has made great contributions to agricultural development, but it has been favored by ecological killers for a long time because of its excessive use on the balance of the ecosystem.
In order to slow down the ecological impact, in 20 15, China put forward the action plan of zero growth of chemical fertilizers and pesticides, striving to rationalize fertilization and reduce the impact of pesticides and fertilizers on the environment. But strictly speaking, in actual planting and farming, farmers still have to follow their feelings, their neighboring fields and their experiences.
Anyone with a little knowledge of fertilizer knows that phosphorus is not easy to leach or move, and can be used as an indicator of fertilizer residue in agriculture. The results show that the phosphorus content in farmland soil is in the range of 50 ~ 200 mg/kg. When the phosphorus content in field soil exceeds 200mg/kg, it means the waste of excessive phosphorus fertilizer and the immobilization of positive nutrients in agricultural soil, such as calcium, magnesium, potassium, ammonium, iron, manganese, copper and zinc. These phenomena can be seen everywhere in important agricultural producing areas. In addition, phosphate mining is often accompanied by heavy metals, such as arsenic and cadmium, which may also become harmful impurities in phosphate fertilizer.
The natural source of mineral nutrients needed by crops may be the parent material in the soil, and the quantity and rate of mineral nutrients released from these natural sources can certainly not meet the needs of human cultivation of crops, so artificial fertilization is regarded as an important means to improve yield and quality. Since there is a demand for fertilization in agriculture, both chemical fertilizers and organic fertilizers are at risk of ecological impact, so rational fertilization can not be limited to chemical fertilizers, but also must include organic fertilizers.
Next, through the advanced interpretation of precision fertilization, this paper expounds the rational fertilization, hoping to make fertilization develop in a more precise, more precise and less environmental impact direction, and also bring different thinking angles.
Regarding the highest principle of precise fertilization, I think that less is more. If you really want to give it, give it to crops, not to people who don't need it. More specifically, when crops show nutrient deficiency, we should first think about whether there is any way to solve the problem without importing materials or resources from outside. Fertilization should be the last choice to improve crop fertilizer deficiency, that is, fertilization should be considered when all measures and methods are ineffective.
All foreign materials or resources must be carefully thought out before they can be put into use, otherwise they can go on, but they can't get rid of them. The problem that many farmers often face is formed by this habit. Once the habit is formed, the environment is formed. How can there be some magical products that can easily improve their long-term difficulties?
After the fertilizer falls into the soil, it will react with the surrounding environment rapidly in physical, chemical and biological ways, and may have a far-reaching impact. In the past, there was a lack of linear thinking of directly supplementing element A, which is increasingly infeasible in the current situation of declining soil quality and abnormal climate. The accumulation of element A may not effectively improve the lack of element A, and even affect the effectiveness of element B, which is what we often say is fertilizer antagonism and synergy, and lead to more problems.
Even if you find the wrong fertilizer, you can't take it out like a broom to sweep the floor and dust. On the premise of easy access to fertilizers, the situation in excessive fertilization can be seen everywhere. For example, farmers are often worried that the sweetness of grapes is not enough and the color changes are poor in the later stage of grape growth, so they apply a large amount of phosphorus and potassium fertilizers in the later stage of grape growth. Excessive potassium fertilizer often causes calcium antagonism, which leads to rotten fruit in the later stage of grape; The accumulation of excessive phosphorus also easily leads to the lack of trace elements.
Fertilization is based on the principle of improving soil health.
For the following reasons, precision fertilization is of epoch-making significance in contemporary times. A large proportion of agricultural land is cultivated continuously, and the land often has the problem of nutrient deficiency, but it also often has the problem of fertilizer utilization. Many sources of fertilizer are minerals. Since it is a mineral, it is impossible for minerals to be mined endlessly, and the cost of fertilizer will inevitably rise. Therefore, producers can improve soil quality and crop health through precise fertilization; Improper fertilization will not only waste money and accumulate fertilizer pollution, but also affect soil health and waste other working hours.
The following factors must be considered in precision fertilization?
Besides fertilization, is there any other way to improve the problem of fertilizer deficiency? Priority should be given to implementation. Fertilization is more likely to be a good way to improve soil health, rather than as a mineral nutrient supply for annual crops. Whether the release time of fertilizer nutrients is close to the time when crops need fertilizer. The space of fertilizer nutrient release is close to that of crop fertilizer demand. Do you want to eliminate other fertilizer nutrient limiting factors? Will there be other problems after fertilization? Are fertilizer components antagonistic or synergistic? Other improvements that must be coordinated with fertilization. Soil fertility analysis is often used as a reference for fertilization, but the results only represent the fertility components of sampling samples and cannot evaluate other biological or physical properties of soil. The content of fertilization is not always the same, and it is possible to modify it constantly. If the artificial ability is not as accurate as expected, we might as well respect the mechanism of natural soil and restore the good appearance of soil. For example, improve deep drainage, let oxygen reach deeper, reasonably improve organic matter (which can be maintained at 3%), thicken effective soil layer and diversify microbial facies. The buffering properties of water, mineral nutrients, temperature and pH value in soil naturally increase. Crops and soil will keep close and accurate operation, without much attention. How to realize the above considerations in the practical field? Take the greenhouse cultivation of common vegetables as an example. Fixed facilities make it impossible for large plows to plow in the fields. The soil in these vegetable fields will have a plow bottom 30 cm deep. Coupled with the long-term lack of organic matter in soil, poor soil aggregate structure and poor permeability of oxygen and water, it will cause many unhealthy adversities to vegetable roots and soil environment.
Some experts pointed out that soil hardening will limit the length and density of rice roots and reduce the weight of roots. In other words, compaction and aeration stress will affect the normal growth of rice. Some experts also pointed out that the problem of saturation and compaction of pore water in root soil will lead to the increase of toxic risk of divalent manganese ions (Mn2+) in soil to crop roots and the volatilization of nitrogen in soil.
About the hypoxia in common vegetable greenhouses, especially after heavy rain or irrigation, soil hypoxia leads to four situations:
Nitrification is not good, and crops lack nitrate nitrogen. Even if there is a little nitrate nitrogen in the soil, it will be leached out quickly. Manganese poisoning. Denitrification and volatilization. Root adversity, such as simple hypoxia or hydrogen sulfide and methane damage. These reasons will slow down the growth of crops, such as wilting. Farmers often rush to fertilize, but the fertilizer can't be used effectively. Fertilizers that cannot be effectively used by crops will continue to accumulate and be fixed in the soil. Many soil test reports show that the ground is a fertilizer bank, but leafy plants are still malnourished, which is conclusive evidence.
Excessive accumulation of fertilizer will also increase the electrical conductivity (EC value) of soil, resulting in monotony of soil microbial phase, which will continue to deteriorate the biological structure of soil and lay the groundwork for uncontrollable pests and diseases in the future. The excessive accumulation of fertilizer can make weeds get enough nutrients, and the application of herbicides has become a necessary procedure, and a vicious circle has begun to operate.
In view of the common situation in vegetable planting mentioned above, how to implement precise fertilization? What is certain is that only by following science can there be a fundamental solution. Put forward the following countermeasures?
First of all, we should give priority to improving the problem of poor drainage and avoid hypoxia after heavy rain or irrigation, so as to change the four kinds of hypoxia mentioned above. When the root stress is relieved, the fertilizer utilization rate can be improved and the necessary fertilization amount can be reduced. Therefore, the necessity of fertilization should be confirmed before fertilization, and leafy crops can make good use of foliar fertilizer and effectively control fertilizer supply. By improving the problem of poor drainage, crop roots may take root deeply, water use efficiency will be improved, and unnecessary irrigation can be reduced. With the reduction of ground fertilization, the growth rate of weeds will also slow down, and even herbicides can be used less. Through soil testing and formula fertilization, we decide which fertilizer to control and which fertilizer to increase, and keep tracking and correcting it. Excessive nitrogen, phosphorus and potassium are common, so it is necessary to reduce the application amount. Appropriate supplement of crude fiber decomposed organic fertilizer or rotation of leguminous green manure crops. The problem of weak acid or alkalization of soil must be improved by reasonable measures. If it is acidification, it can be improved by applying lime and other substances; If there is soil alkalization problem, it can be gradually improved by applying physiological acid fertilizer during the growth process. Due to the convenience of obtaining chemical fertilizer raw materials and the failure to scientifically evaluate the application amount in actual application, many problems such as poor crop growth, pests and diseases, and even the safety of agricultural products have appeared.
Excessive fertilizer is pollution, so the application amount should be controlled.
Both chemical fertilizer and organic fertilizer are beneficial to crop growth, but improper use may also cause pollution. In Europe, because of its vast land, winding rivers and slow speed, pollutants in upstream countries may become a nightmare for downstream countries. In order to avoid interest disputes and environmental safety, EU member states strictly stipulate the annual dosage of agricultural soil phosphate fertilizer.
For example, Estonia stipulates that phosphate fertilizer can only be applied if there is a complete use record; The application amount of livestock manure or other organic fertilizers shall not exceed 1.6 kg/mu every year. Although chemical fertilizer can be used to supplement the demand for phosphorus, crop demand, soil texture, good agricultural practices (GAP) and so on must be considered in the specification. According to the soil phosphorus index, the upper limit of chemical phosphate fertilizer application is set. For another example, Germany stipulates that the phosphorus content in agricultural soil should be measured 1 time for at least 6 years. The total amount of phosphate fertilizer application must be balanced; Nitrate residue is also controlled.
Therefore, our country can also learn from the methods of European countries and strictly control the use of chemical fertilizers. Only in this way can we achieve accurate fertilization, promote crop growth, and realize sustainable agricultural development without affecting and threatening the environment.