For many years, many experts and technicians have repeatedly advocated that the orchards cannot flood with water, but flooding is still widespread everywhere. The reasons for this are thought-provoking.
The first is ideological and cognitive issues. I have always believed that the key to the promotion of all technologies lies in people’s ideological understanding. This is no exception in the flooding issue. Many fruit growers do not realize the danger of flooding. Zhang Lixin, a famous expert on fruit trees, said that many fruit growers have been misunderstood on the issue of irrigation. They did not realize that irrigation is to “pour the tree†instead of “watering the land.†This is true in some places, even on the basis of the name—“ Go and pour the ground."
Many growers are affected by the management of field crops such as wheat and corn because field crops are generally flooded with irrigation. It is taken for granted that fruit trees can also be flooded with irrigation. It is not known that the roots, growth patterns, and water requirements of fruit trees are very different from those of field crops. Big differences, taking a flood of irrigation, have many disadvantages for fruit trees.
The second is the methodological problem. Many fruit growers cannot afford modern irrigation methods such as drip irrigation and percolation, but they are not aware of some simple and practical irrigation methods. Except for flood irrigation, many growers do not know how to irrigate.
There are also some fruit growers who have been given limited labour because they have to tell him how to make it. He is afraid of troubles. Especially during the busy season, it is impossible to attend to the work, or flooding is simple and the electric gates are opened.
To encourage fruit growers to water-saving irrigation, flood irrigation is no longer necessary, first of all to solve the problems of fruit farmers ideology, so, then we talk about flood irrigation.
First, fruit trees do not need so much water
Fruit trees need a certain amount of water, and too much or too little is not good. We know that soil is a complex of water, fertilizer, gas, and heat. Good soils and soils have a proper proportion of each element. If there is too much water, it will inevitably affect the other three aspects. Excessive water, soil Breathability will be poor, the roots of fruit trees will feel breathless, and in severe cases will cause root death; soil temperature is difficult to increase when there is too much water, the lower temperature is not conducive to the growth of fruit trees, in addition, some mobility is strong The nutrients will also be lost or infiltrated into the deep soil with water. Therefore, fruit trees don't need much water. Generally speaking, the soil moisture content of 45-60% of the maximum field capacity can meet the demand of fruit trees. For some Wangshu trees, it is sometimes necessary to moderately control moisture in production so as to facilitate flowering of fruit trees.
In this regard, Professor Wei Qinping, a famous expert on fruit trees in China, has done such an interesting experiment by planting an apple tree in the middle of four square flowerpots, that is, dividing the roots of fruit trees into four parts and watering them separately. The results showed that only one fruit tree (one-fourth watered) was poured at a time, the fruit tree had less vegetative growth and was easily flowered, and each time four flowerpots were watered fruit trees (ie, four molecules four). Watering), a large amount of growth, lush foliage, but it is difficult to flower. This experiment shows that moderately controlled watering of fruit trees can achieve ideal results.
Second, flood irrigation can easily cause root loss of fruit trees
We know that the topsoil of more than 30 centimeters in the rhizosphere of fruit trees is distributed with a large amount of roots. What is the root absorption? It is the roots of white hairy roots with a length of only a few millimeters that absorb roots. This is the most insignificant thing. It is the lifeblood of fruit trees. These root systems are very sensitive to changes in the environment. Temperature changes in the surface soil, droughts, and floods all cause root deaths. Studies have shown that, after flooding with large floods, the absorption of roots in the surface soil tends to cause a large number of deaths due to great changes in the aeration, temperature, and moisture content of the surface soil. However, the death of these roots will cause a temporary deficit in the nutrients of the fruit trees until the new roots grow. Therefore, some fruit trees will experience yellowing or fruit drop after flooding.
Third, flood irrigation will destroy the soil aggregate structure, resulting in soil compaction
Flood irrigation has a strong effect on soil erosion and compaction. Flood irrigation causes the air in the soil to be squeezed out. The soil is in an anoxic environment. Some roots and soil microorganisms die due to lack of oxygen, and the soil aggregate structure is also Destruction, causing soil compaction.
Fourth, flood irrigation will make the ground temperature rise slowly, affecting root growth and delaying apple ripening
Especially in the spring, due to the high specific heat of the water, after the orchard floods, the ground temperature rises slowly. Low temperature will directly affect the growth of fruit tree roots and the activities of soil microorganisms, delay the flowering time of fruit trees, and then postpone the ripening time of apples, especially for medium-early-maturing apples.
Fifth, flood irrigation can easily spread rot disease and other diseases
Many germs, such as rot, are transmitted along with water. After flooding in orchards, various bacteria such as rot germs will flow to the roots and stems of each fruit tree. If conditions are suitable, healthy fruit trees will be infested and the rot disease will become popular.
6, flood irrigation can easily cause fruit trees grow, it is difficult to flower
After the flood irrigation, due to the excess water absorbed by the fruit trees, the vegetative growth is greatly enhanced, a large number of strips and new shoots are prosperous. The prosperous growth of new shoots will consume too much photosynthetic nutrition and mineral nutrients. The nutrients allocated to fruits, roots, and flower buds will be relatively reduced, the fruits will be difficult to grow, the flower buds will be difficult to form, the growth of roots will be inhibited, and the new shoots will be excessively prosperous. Long, the accumulation of nutrients deteriorates, the shoots are not full, the resistance is reduced, the light is deteriorated, the inefficient foliage is increased, the utilization of light energy is reduced, and various diseases and insect pests are easily prevalent.
Seven, flood irrigation causes the waste of water and nutrients
According to the survey, flooding will require more than 120 tons of water for flooding an acre of land. However, the use of water-saving irrigation technology can save more than 75% of water. For countries with very scarce water resources in China, it promotes water-saving irrigation and opposes flooding. Flood irrigation is particularly important. For farmers, it can also save a lot of expenses. In addition, some of the mineral nutrients in the soil will be lost in the deep soil where the large water is lost or infiltrated (fruit trees cannot be used), resulting in great waste of nutrients.
Through the above analysis, we can see that flood irrigation is completely a measure of “going thanklessâ€. Therefore, in actual production, we must not carry out flooding.
So, what kind of method of irrigation orchard to avoid the above problems to achieve good results? I here to introduce a country's apple industry technology system to promote the "ridge covering, ditch irrigation grass" technology for your reference.
Orchard ditching irrigation, referred to as furrow irrigation, is a new method for water-saving irrigation in orchards. Generally, the ditching and ridging are carried out in cooperation. Under the peripheral projection of the fruit tree canopy, along the direction between the rows, dig a trench about 20 centimeters deep and wide on both sides of the tree line, covering the tree plate with the soil taken from the ditch. At the same time, it is recommended to ridicule in the tree tray. It is generally recommended that the ridge height of the old orchard be 10-20 cm, the new plantation be 20-30 cm, the height under the tree, the low between the rows, and the ridge width be 1-1.2 meters. The treatment time can be combined with the autumn application of basal fertilizer. Cover the grass with a ridge or cover it with a black mulch. Grasses can be planted between the rows of fruit trees. The grass grows to a certain extent and then covers the tree after being castrated.
After the treatment is completed, irrigation can be performed along the minor ditch, and each irrigation will only cover the small ditch on one side of the fruit tree. This method of irrigation saves more than 75% of water at a time compared with flood irrigation. The soluble solid content of the fruit is increased by 1-2 degrees, and at the same time it can prevent fruit cracking before harvest and control the growth of the tree.
When furrow irrigation only irrigates the concentrated distribution area where the fruit trees absorb roots, irrigation water can play a greater role. The 30-60 cm middle layer of soil in the fruit tree rhizosphere is the soil layer that provides moisture mainly for fruit trees. During the furrow irrigation, the irrigation water penetrates into the soil layer through the bottom of the trench and the wall of the trench. The surface soil structure will not be damaged, and the soil has good air permeability. , is conducive to soil microbial activity. During the furrow irrigation, water does not flow directly to the neck of the fruit tree, which can effectively prevent the spread of root and neck diseases. In addition, the humidity of the air around the trunk of fruit trees during furrow irrigation is low, which can reduce the damage of trunk rough skin disease and the canker disease of the lower canopy.
"Ridging cover, ditch irrigation grass" technology is simple, low investment (less than 1/10 of water saving facilities), easy to accept farmers; can effectively reduce soil evaporation and fruit tree transpiration, reduce water and fertilizer losses. Fruit trees are perennial and have a large root system, which is conducive to implementation. They have been built once and used for many years. This is not available in field crops.
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