What role does water and fertilizer management play in agricultural production?

Proverbs have clouds? Whether there is harvest depends on water, and whether it is more or less depends on water. This is the true knowledge that farmers have gained from thousands of years of agricultural practice, from which we can also see the importance of water and fertilizer management for agricultural production, which directly affects the yield and quality of crops. In actual cultivation management, water and fertilizer management is one of the topics that farmers are most concerned about, and it is also the most error-prone place in crop cultivation management. Therefore, it is necessary to understand some basic principles of nutrient absorption and apply them to actual water and fertilizer management.

Water and fertilizer are the basis for the healthy growth of crops.

First, water is the carrier of fertilizer (nutrient) absorption.

We often say that there is no distinction between water and fertilizer, because crops must have water to absorb nutrients.

1, fertilizer (nutrient) can't form ionic state without water.

As we all know, the purpose of fertilization is to make crops absorb more nutrients and promote their growth and development. Crops absorb nutrients through roots and leaves. The roots of different crops are different, but one thing is the same, that is, the root is the organ that absorbs the most nutrients and water.

In the tissue structure of root system, there is a very important tissue called root hair. Root hair is the most efficient part of the whole root system to absorb nutrients. Studies have shown that the absorption efficiency of root hair is several times that of other parts of the root system. Experienced farmers have this feeling. When we are farming, we hope to see many white roots and capillary roots in crops. The more white roots and capillary roots, the better the growth potential of crops. This is because the more white roots and capillary roots, the higher the efficiency of absorbing water and nutrients, which means that our crops are healthier and grow more vigorously.

The more vigorous the growth, the more developed the root system of the plant.

The root hairs are so small that they are almost invisible to the naked eye. If such a tiny tissue wants to absorb fertilizer, there is a premise that nutrients are ionic. If nutrients are not ionic, it is difficult for root hairs to absorb nutrients. In production practice, except for the emerging liquid fertilizer, our fertilizers, whether compound fertilizer or water-soluble fertilizer, are basically in solid form. When this fertilizer is applied near the root hairs, the root hairs cannot be absorbed. Therefore, only by transforming it into ionic state can it be absorbed by root hairs and finally transmitted to plants.

How can we change the nutrients in fertilizer into ionic state? In fact, it is very simple, that is, it will become ions after being dissolved in water. Otherwise, no matter how much fertilizer you apply, the activity of nutrients will be higher Without water as a carrier, fertilizer can't become ions, can't enter root cells, and can't be transferred to other parts of crops.

Root system is the most important organ for crops to absorb nutrients.

2. Nutrients must pass through water to reach the root system.

If the root system wants to absorb fertilizer, the premise is that nutrients must be within the effective absorption range of the root system, that is, nutrients must be transported to the root system. There are three main ways:

Interception: Interception means that nutrients can be directly absorbed by roots and are intercepted, which is called interception. Diffusion: the fertilizer applied is not far from the root system. If there is water as the medium, nutrients will spread from high concentration to low concentration and spread to the range that roots can absorb. Mass flow: Mass flow, as the name implies, means that minerals move near the root system with water, because our plants have transpiration tension, which causes water to move to the root system. In the process of flowing, water will bring nutrients far away from the root system to the root system. If these three ways want to play a role, they can't do without a very important carrier, that is water. If there is no water, the trapped nutrients will not become ions, and the roots cannot absorb them; Without water as a carrier, it is difficult for nutrients to diffuse from high concentration to low concentration; Without water, transpiration tension can't bring nutrients to the root zone.

Three ways for crops to obtain nutrients

Based on the above point of view, we can draw the following conclusions: the prerequisite for root system to absorb nutrients is that nutrients must reach the root system! The three ways for nutrients to reach the root system are inseparable from water. Without water, nutrients can't reach the roots, and the roots can't absorb nutrients.

3. Water is the carrier of fertilizer absorption and its application in water and fertilizer management.

I understand that fertilizers (nutrients) must be absorbed by crops and must be carried by water. Let's think again, in our actual agricultural production, whether fertilization follows this law, whether it is done according to this principle, and how to do it is correct.

(1) borrow rain for fertilization

It is also called "borrowing rain to send fertilizer" and "fertilizing according to weather forecast". Under the premise of no irrigation facilities, watch the weather forecast, apply fertilizer before it rains, turn fertilizer into ionic state through rain, and send it to the range that roots can absorb to promote crop growth. In fact, many of our practices are not through rainfall, but through artificial simulation of rainfall, and watering and fertilization are the same principle. After watering, the fertilizer is still loose to the range that the root system can absorb through interception, diffusion and mass flow. This is actually the integration of water and fertilizer, not to say that both drip irrigation and sprinkler irrigation are the integration of water and fertilizer. The real integration of water and fertilizer is a farming concept. Water and fertilizer can be sent to places where crops can be absorbed at the same time. If the economy permits, drip irrigation and sprinkler irrigation can be carried out. If conditions do not allow, the scene we mentioned above is actually the integration of water and fertilizer.

Application of rainwater fertilization in production

(2) applying fertilizer mixed with water

Fertilizer mixing with water is also a kind of precise fertilization to some extent, and the utilization rate of fertilizer is much higher than that of watering after spreading. Including fertilizing fruit trees with a fertilizer gun, which is a way to improve the utilization rate of fertilizer. In this way, fertilizer and water are dissolved in a certain proportion and transported to places where crops can absorb them.

(3) Water and fertilizer integration facilities

Of course, in fertilization, the best effect is the integrated facilities of water and fertilizer, such as drip irrigation and sprinkler irrigation. With the country's vigorous promotion of water and fertilizer integration technology, water and fertilizer integration has become theNo. 1 technology of China's agriculture and an indispensable part of China's agricultural modernization. According to statistics, by the end of 20 19, the irrigation area of water and fertilizer integration in China has reached1500,000 mu, and this data is still increasing. By 2030, the planting area of water and fertilizer integration in China may reach 300-500 million mu, and water and fertilizer integration must be an indispensable technology for modern agriculture in the future.

Unfortunately, many people think that the integration of water and fertilizer such as drip irrigation is only used for watering, and the real core of drip irrigation is to maximize the synergistic effect of water and fertilizer. Without increasing manpower, water and fertilizer can be sent to the place where crops can absorb it, reaching a certain concentration, realizing on-site irrigation and on-site fertilization, and improving the utilization rate of fertilizer. The advantages of water and fertilizer integration are labor-saving, water-saving and fertilizer-saving, increasing production, income and quality.

When it comes to the integration of water and fertilizer, one country has to be mentioned, and that is Israel. It can be said that the Israelis invented the integration of water and fertilizer and the drip irrigation. They turned the desert into an oasis and Israel into a European vegetable basket. Their water and fertilizer integration technology covers the whole world. The Israelis planted tomatoes on barren sandy land, and the integration of water and fertilizer made the yield of tomatoes reach more than 45 tons per mu, which was not only high in yield, but also very good in quality.

Application of Israel's water and fertilizer integration in agriculture

Second, fertilizers (nutrients) can only be absorbed if they are used in the right place.

If crops want to absorb nutrients, they must send nutrients to the range that can be absorbed near the root system. It is particularly important to note that in actual production, especially in areas where drip irrigation and water and fertilizer are integrated, there is a very common problem, that is, the location of fertilization is incorrect, some of which may be natural disasters and some are man-made disasters. Professionally, we call it fertilizer leaching, that is, fertilizer is leached from the range absorbed by the root system to the outside of the range absorbed by the root system, resulting in the root system not being able to absorb fertilizer normally.

1, what is the leaching of fertilizer?

There are two main reasons for fertilizer leaching: first, most of the time, only the aboveground part of crops is concerned, but not the underground part of crops, ignoring the depth of roots. But in fact, most of the fertilizer is absorbed by the roots. Therefore, when fertilizing, it is necessary to ensure that the fertilizer is absorbed by the root system. So farmers must get into the habit of looking at the roots of crops. The method is simple. Dig with a hoe, rinse with water, and see the roots clearly. The root depth of different crops is completely different. Therefore, fertilization and watering should be based on the depth of root system to ensure that water and fertilizer are within the absorption range of root system. The second is nutrient leaching caused by over-irrigation. As mentioned earlier, mass flow can transport nutrients to the root zone through water, and it can also transport nutrients from the root zone outside the effective range of root absorption. Especially nitrogen fertilizers, such as nitrate nitrogen and amide nitrogen, are particularly easy to leach.

Leaching effect of fertilizer

2. How to reduce the leaching loss of fertilizer?

The leaching phenomenon can be improved by some artificial ways when fertilizing.

Adjust fertilization time: First, adjust irrigation methods and fertilization time to prevent over-irrigation. The same urea, don't drip it first, then fertilize it, and finally water it a lot. The correct way is to drip water for a long time to fully wet the roots, drip fertilizer for one hour, and finally clean the pipeline for 5~ 10 minutes. Improve fertilization equipment: Eliminating some old fertilization equipment can better control the amount of fertilization. Detecting the position of fertilizer: key summary: fertilizer nutrients must be absorbed by the root system to be effective. Fertilizer is easily lost with water. Excessive moisture will leach the fertilizer out of the effective absorption range of the root system. In production, it is necessary to prevent fertilizer from leaching and elution due to over-irrigation. You can use simple detection tools to detect where the fertilizer has gone! Different fertilization sites have different fertilizer utilization rates.

Third, the root system has an appetite and the salinity should be moderate.

When people eat the food in their mouths, they pay attention to the difference between salty and light. If it is too salty, they can't eat it. If it is too light, they can't eat it! The roots of crops absorb fertilizers (nutrients) and pay attention to the difference between salty and light. Too salty to burn roots, too light to eat. For crop roots, fertilizer is food. Too high concentration of fertilizer will cause a series of problems such as root burning, and too low concentration will not conform to the normal growth and development of crops. For example, when the base fertilizer is applied too close to the root system, every watering will burn the root system, leading to plant death. In production, more problems are caused by too high concentration, which leads to the inhibition of plant growth.

Effect of fertilizer concentration on crop growth

Different concentrations of the same fertilizer have completely different effects on crop growth and development, so we must learn to apply fertilizer scientifically. How can we balance fertilization?

1, to understand the salt tolerance of crops.

Different crops have different salt tolerance. All fertilizers are essentially inorganic salts. Take wheat and corn for example. Under the same concentration of fertilizers and nutrients, their salt tolerance is different. When the salt content of irrigation water reaches 4%, it is most suitable for wheat, but for corn, its health will be affected. This tells us that when applying fertilizer, the concentration of fertilizer should be adjusted according to different crops, so that it can be better absorbed by crops.

Salt tolerance of field crops

Salt tolerance of fruit trees

Percentage represents the growth and health status of crops; Soil salt content; Salt content of ECw irrigation water. Effects of salt content in soil and irrigation water on growth and health of different crops.

2. Use tools to determine the concentration value of soil or fertilizer solution.

After understanding the salt tolerance of crops, we can use some tools to detect the salt value in fertilizer and soil, and use accurate data to guide our fertilization, so as to improve the utilization rate of fertilizer and avoid the waste of fertilizer.

Monopoly caused by excessive fertilizer concentration

In the actual fertilization management, we all know the basic principle of nutrient absorption, but this is also the most error-prone place. Therefore, when applying fertilizer, it is more important to apply these principles to actual production activities. Only in this way can the utilization rate of fertilizer be improved, energy conservation and emission reduction can be truly realized, and it is also the only way for the sustainable development of agriculture.