Why too much salinity in the soil hurts flowers

There are two conditions for the formation of saline-alkali soil: first, the climate is arid and the groundwater level is high (above the critical water level); The other is low-lying and there is no way to drain the water. Groundwater contains a certain amount of salt, and if its surface is close to the ground, and the area is relatively arid, the water that rises to the surface due to capillary action evaporates, leaving behind salt

Over time, the salt content of the soil gradually increases, forming saline-alkali soil. If it is a depression and there is no drainage outlet, the water in the depression will evaporate, leaving salt and forming a saline-alkali land.

Saline-alkali effect 1, soil compaction and fertility decline. 2. It is not conducive to the absorption of nutrients by crops and hinders the growth of crops. The measures for the prevention and control of saline-alkali land include water conservancy improvement measures (irrigation, drainage, dredging, rice planting, seepage prevention, etc.); agricultural improvement measures (land leveling, improved tillage, soil application, fertilization, sowing, crop rotation, intercropping, etc.); biological improvement measures (planting salt-tolerant plants and pastures, green manure, afforestation, etc.); and chemical improvement measures (application of modified substances such as gypsum, phosphogypsum, calcium sulfite, etc.).

Four aspects. Since each measure has a certain scope of application and conditions, it is necessary to adapt measures to local conditions and comprehensively deal with them.

When the salt content of the soil surface layer is high, flower seedlings can be damaged; When the above is exceeded, most flowers do not grow properly. After the damage, the plant is dwarf, the leaves are small and dark green, the root system is poorly developed, and even the whole plant dies.

1) The main reason for the damage of flowers in saline soil is: Saline soil often forms a layer of white saline-alkali skin on the surface, which directly damages the rhizome junction tissue of seedlings, and causes the death of flower seedlings in severe cases. The concentration of salt is too high, which prevents the root system from absorbing water from the soil solution, causing the flower to die due to physiological drought.

Under the action of high concentration of salts, the leaf stomata cannot be closed, so that the flowers lose water and wither and die. The soil contains too much salt, and the cell protoplasm is damaged, which disrupts the normal metabolic function and poisons the cells.

2) Planting flowers in alkaline soil mainly showed symptoms such as weak growth, leaf greening, wilting and scorching after damage. The cause of the disease is that alkaline soil converts soluble iron into insoluble iron, so it cannot be absorbed and utilized by flowers, resulting in leaf loss and yellowing.

In the absence of iron, chlorophyll cannot be formed, which causes the leaf color to turn yellow. When the alkalinity is too large, it will form an alkalization layer with very poor water permeability, which expands and sticks heavily when wet, and is hard and hard when dry, so it is difficult for water to penetrate into it, and the seeds are not easy to unearth, and it is difficult for the root system to survive.

Methods for preventing and controlling flower salinity: the soil selected for potting plants generally uses humus soil and peat soil-based culture soil, so that the potting soil is slightly acidic or acidic will prevent salinity; When watering, use neutral or plum mill slightly acidic water for watering; Acidic or physiological acidic fertilizers are used for fertilization, and alkaline soils are suitable for applying chemical fertilizers such as potassium nitrate and ammonium sulfide, but alkaline fertilizers such as ammonia and carbon ammonia are not suitable for use. Then it is to choose flowers that are resistant to saline-alkali soil, and the flowers that are resistant to salt include Wannian Spring, Saxiwei Orchid, etc.

Most of the cactus plants, except for epiphytic cacti such as crab claw orchid, have a certain ability to resist alkali. Oleander, hibiscus, geranium, chrysanthemum, yueji, etc. also have a certain resistance to weak alkalinity. If there is a physiological disease, it is easy to show symptoms on the leaves.

The young leaves turn yellow or the lower leaves are yellow and constantly falling off, most of which are due to overwatering. However, the symptoms of soil damage caused by excessive alkaline soil are similar to those caused by drought, causing flowers and plants to grow slowly, and the leaves to turn green, shrivel and scorch.

The solution to the alkaline soil of the flower is as follows:

1) Application of sulfur powder per square meter of seedbed, mixed with 100 200g of sulfur powder, its acidic validity period can be maintained for 2 3 years.

2) Application of ferrous sulfate powder 150g of ferrous sulfate powder per square meter can reduce the pH value of the unit after application; For particularly clay soils, the dosage can be increased by 1 3.

3) Watering vinegar A small amount of potting soil at home, if its pH value is greater than 7, it can be watered with 150 200 times vinegar solution, and then watered once every 15 20 days, and the effect is good.

4) Mixing pine needle soil Mixing pine needle soil is a fast and effective way to improve alkaline soil. Pine coniferous soil is made of decaying pine and cypress needles, stumps and other litter, which is highly acidic. Generally, 1 5 1 6 pine needle soil is mixed with alkaline soil to plant acid-loving flowers.

5) Pouring potassium dihydrogen phosphate solution In alkaline soil, iron is easily fixed and becomes unusable, even if more iron is applied, the effect will not be ideal. Therefore, the potassium dihydrogen phosphate solution or other acidic fertilizer solution can be used to irrigate the soil to make the soil weakly acidic, which can promote the dissolution of iron in the soil, which will be conducive to the absorption and utilization of iron by the roots of flowering plants.

In fact, the method is relatively simple, that is, use ferrous sulfate watering, slowly pour the ferrous sulfate solution diluted with water along the edge of the pot, use it every five days, and water it three times in a row. Ferrous sulfate can not only neutralize the salinity in the alkalized soil, but also supplement iron, effectively improving the yellow leaves of flower plants caused by iron deficiency.

To use ferrous sulfate, slowly pour the ferrous sulfate solution diluted with water along the edge of the pot, and use it every five days, three times in a row.

There are two main harms of saline-alkali soil to plants: first, due to the accumulation of more salt in saline-alkali soil, the "water potential" of the soil solution is greatly reduced, and the water-holding capacity is increased, which makes it difficult for the roots of plants to absorb water. If plants don't get enough water, they die.

Second, in saline-alkali soils, there is often too much salt (such as sodium chloride), which will damage plants, which is called "single salt poisoning".

The harm of saline-alkali soil to plants is multifaceted. First of all, saline-alkali soil can cause physiological drought of plants, that is, due to the high amount of soluble salt in the soil, the soil osmotic pressure increases, and the plant cannot absorb water and eventually leads to plant death. Secondly, saline-alkali soil has a toxic effect on plants, which can poison plant cells, and due to the accumulation of salt in the plant body, the protoplasm is destroyed and protein synthesis is hindered, so that plant growth and development are stunted.

In particular, excessive salt also prevents the formation of starch in the stomatal guard cells, which in turn affects the stomatal closing, and the water in the plant is quickly dispersed, which is easy to cause the plant to wither. Finally, saline soils also have a direct killing effect on plant roots, such as sodium carbonate and potassium carbonate, which can lead to root death. In addition, saline-alkali soil also has a destructive effect on the structure of the soil.

Camellias, rhododendrons, gardenias, smiles, Milanese, jasmine and other flowers that prefer acidic soils grow poorly in alkaline soils and even die. Some people think that as long as the ferrous sulfate solution is poured frequently, the problem can be solved, but this is only one aspect, because the application of ferrous sulfate solution does work, and the effect is fast.

On the other hand, if the ferrous sulfate solution is regularly watered, the soil will have too much sulfur and available iron, and the flowers will be poisoned. The application of alum fertilizer water is helpful to overcome the disadvantages of excessive single ferrous sulfate solution, but alum fertilizer water is mainly suitable for the vigorous growth period of flowers and trees, and it is not suitable to apply more top dressing in other periods, otherwise it is easy to make flowers suffer from fertilizer. Therefore, in recent years, at the same time as the interval of pouring ferrous sulfate solution, the interphase pouring of potassium dihydrogen phosphate solution can also make the alkaline soil slightly acidic, so that the yellowing disease can be obtained.

At the same time, potassium dihydrogen phosphate also contains phosphorus and potassium, which is conducive to flower bud differentiation and improves flower quality. The most fundamental way to prevent and control strong alkaline soil is to carry out soil improvement. Alkaline soils can be improved by adding coniferous soils.

Coniferous soil is made from the needles and stumps of decaying pines and cypresses, and is highly acidic. The general alkaline soil is mixed with 1 5 or 1 6 coniferous soil, which is suitable for acid-loving flower pots. or 100 200 grams of sulfur powder mixed with 1 cubic clay for a period of 2 3 years.

In addition, for potting soil with pH greater than 7, it can also be watered with 150 200 times vinegar solution, watered every 15 20 days, or added 250 350 times of water before 8 a.m., or sprayed after 5 p.m., sprayed once every 10 days, 3 or 4 times in a row can make the leaves turn from yellow to green. When using vinegar, it should be noted that the vinegar used must be edible rice vinegar, not industrial chemical vinegar; It must be sprayed in the morning or evening to avoid the evaporation of acetic acid and its failure; It must be used in combination with other fertilizers.