The planting area of ​​wheat in China is relatively wide, and many farmers have planted it. Today, we will share with you about 5%-20% reduction of wheat freeze damage, and prevent early rescue! See the remedy!
Extremely cold weather may occur again this winter. Appropriate cold and cold is beneficial to wheat growth, but extremely cold weather will cause freezing damage to some wheat, affecting wheat growth and later yield. Therefore, it is necessary to prevent wheat frost damage.
Wheat grows very slowly during the wintering period. The yield of wheat is closely related to the growth of wheat seedlings during wintering. Generally, the wintering yield of the weak seedlings is low, the wintering yield of the seedlings is unstable, and the winter wheat yield of the strong seedlings is higher. Therefore, the main goal of wheat winter management is to cultivate strong seedlings.
Pre-winter seedling diagnosis method
Wheat is more affected by climate, and different fertility characteristics and morphological characteristics will be formed under different climatic conditions. Therefore, wheat should be managed in combination with environmental conditions, and the pertinence and predictability of cultivation management should be strengthened.
Diagnosing seedlings is the key to seeing seedling management. The diagnosis of seedlings should be based on the principle of “three investigations and two observationsâ€.
"Three investigations", that is, to check the basics, check the situation, and check the climate. The basis of the investigation is to check the level of fertility, the quality of the land preparation, sowing, watering and topdressing, which is also the basis for ensuring high yield. The grievances are mainly based on the soil moisture content of the wheat at different times. Checking the climate is to observe the effects of temperature, humidity and light on wheat.
"Looking at two" is to look at the looks and see the group. Look at the appearance, mainly observe the plant height, tiller number, leaf shape, leaf color, number of main stem leaves, and development status of young ears. Looking at the group is to observe the total number of plants and the ratio of the size of each plant. The combination of the two can not only see the current, but also estimate the development, so as to implement reasonable management measures.
Judging criteria for strong seedlings before winter
Strong seedlings before winter means that the plants grow well before wintering, and certain vegetative bodies have been formed, which can ensure that there is no such thing as prolonging and de-fertilization after Spring, but develop in the direction of high yield.
The main winter wheat seedlings have the following criteria: the main stem of spring varieties grows 6 leaves or 6 leaves 1 heart, and there are 3-4 individual plants, plus 4-5 main stems; semi-winter The variety grows 7 leaves or 7 leaves 1 heart, 5-6 per plant, plus 6-7 main stems; the total number of plants should be 10 million plants/hm2, of which 3 leafhoppers Plants should account for more than 1/2; single roots are strong, there are more than 10 secondary roots, long-term piers, plant height generally does not exceed 27 cm, but should not be less than 20 cm; panicle differentiation is normal, spring varieties should reach In the two-edge period, the semi-winter variety should reach above the single-edge period; the dry weight of the plant is about 1.2 g, and the dry weight is above 250 kg/hm2.
Winter strong seedling cultivation technology
Sowing at the right time
Early or late sowing of wheat is not conducive to the transformation to reproductive growth, shortening the formation and development of young ears; on the other hand, it hinders the normal nutritional function and leads to the uncoordinated organic and inorganic nutrition of wheat. The most timely planting is based on local climatic conditions and soil conditions to select suitable varieties for sowing. For thin and sandy land, the sowing period is narrower, and early sowing should be arranged; for the wheat field with deep soil layer, soil weight, water retention and fertility, the sowing period is wide, and the late sowing can be arranged appropriately.
Check seedlings
Checking seedlings and replenishing seedlings in time after sowing is an important measure to ensure a good group. During the three to four-leaf stage of wheat, it should be transferred to the diaper in time. Seeds of the same variety that are infiltrated can also be replanted early. The transplanting process must ensure that the depth of the soil is “not pressed, not exposedâ€. Watering should be done in time after replanting or replanting, and fertilizing properly.
Control Wang Miao
For the seedlings that are caused by too early sowing, the suppression of the seedlings can be taken. After the suppression, it is necessary to plan the watering and fertilization in time. For the seedlings caused by excessive seeding, it is necessary to timely release the seedlings, combined with watering, and at the same time supplement the appropriate amount of quick-acting fertilizer. If the variety is improperly selected, it can also cause the phenomenon of Wang Miao. For this kind of situation, it is necessary not only to cultivate early, to suppress, but also to take measures such as sealing the roots. For the seedlings caused by excessive fertilizer and water, when the main stem of the wheat seedling grows 5-7 leaves, part of the root system is cut to control the growth of the aerial part of the wheat seedling. For the extensive seedlings and the excessive seedlings in the wheat field, the suppression should be completed before the ground is frozen. The saline-alkali land should not be controlled by the suppression method, and the suppression of other soils should be carried out after noon.
Scientific management of water and fertilizer
The right amount of water can also play the role of crushing the clods, soiling the soil and eliminating pests. Therefore, it is very important to pour the winter water, especially in areas with poor soil quality. Watering before wintering should be carried out in the morning on a sunny day. The amount of watering should not be too large, but it must be poured. At the end of the watering, it is necessary to draw the time and remove the soil of the knot. Applying the base fertilizer is also an important guarantee for the safe wintering of wheat. Wheat fields suitable for the group and the soil are suitable for normal growth, and generally only need to be cultivated and paddy, without watering and topdressing. For wheat fields with insufficient fertilizer application, poor soil quality and obvious symptoms of lack of fertilizer, it is necessary to seize the favorable opportunity to carry out watering and topdressing before winter.
Timely elimination
In wheat seedling stage, the cost of elimination is the lowest, and the control effect is good. One application can basically control the weed damage in the whole process of wheat growth.
Herbicides should be used after the main weeds are basically emerged. It is best to remove the working time in wheat 3-5 leaves and weeds 2-4 leaves, choose sunny weather, the temperature is above 8 °C, and there is no frost and no rain on the date.
Broadleaf weeds can be sprayed with sharp super wheat and appropriate amount of water;
Gramineous weeds can be treated with 3% Shima emulsifiable concentrate, 7.5% priority, buckwheat and appropriate amount of water for stem and leaf spray control;
Mixed weeds should be mixed and sprayed with different ratios of the above two agents according to the specific conditions.
Wheat frost damage refers to the stagnation of wheat growth caused by continuous low temperature weather in wheat fields. After freezing, the lighter wheat field, the main stem of the wheat plant and the young ears of the big tiller were still frozen and still normal heading and fruiting; however, the number of kernels was significantly reduced.
When the freezing damage is heavy, the main stem, the big tiller, the young panicle and the heart leaf are frozen to death, and the rest can still grow; the wheat leaves and leaf tips of the wheat field with severe freezing damage are hard and brittle, and the green leaves are dry or blue and green. Stems, young ears shrink and die.
The main factors leading to the occurrence of wheat freezing damage
Wheat varieties, sowing date, sowing amount, climatic factors, seedling conditions, lyrics, and planting quality of the land will all affect the occurrence of wheat frost damage. The main wheat fields that are susceptible to freezing damage are:
1. Sowing seedlings that are too early;
2, the group is too big and long seedlings;
3. Wang Changmiao with excessive nitrogen fertilizer;
4. Extensive grounding and overhead hanging seedlings;
5. Seeding too shallow seedlings;
6. Dehydration seedlings caused by soil drought;
7. Weak seedlings caused by freezing damage;
8. Yellow thin and weak seedlings with insufficient soil fertility.
9, straw returned to the land, poor treatment of weak seedlings.
Wheat freeze damage is divided into four levels
The primary freezing damage is mild frost damage, mainly manifested by the tip of the 2-3 leaves or less than 1/2 of the leaves being frozen and yellowed;
The second and third grade freeze damage mainly manifests that more than half of the leaves are frozen and yellow;
The fourth-grade freeze damage is severely frosted. The main manifestation is that more than 30% of the main stems and large tillers are frozen. They have been jointed, and the stems are partially frozen and cracked. The young ears lose water and even die.
How to prevent wheat frost damage
1. Choose anti-freeze varieties, sow seeds in a timely manner, and cultivate strong seedlings.
2, early topdressing. Wheat fertilization in early spring can make up for winter soil fertility consumption, increase nutrient accumulation, promote the growth of wheat seedlings, and resist or reduce early spring frost damage, especially in the years when winter temperatures are high, wheat seedlings continue to grow, and soil fertility is high. Fertilization in early spring is especially important.
3. Timely strokes to promote growth. When the soil is re-slurry, the topping is carried out, which can play the role of loosening soil, protecting the mites, warming and weeding, and enhancing the ability of the wheat seedlings to protect against cold.
According to the experience of the past years, the average ground temperature in the 5 cm soil layer can be increased by 0.5-1 °C after 7-10 days, which is very beneficial to promote root development and nutrient conversion.
4, suppression and control, to ensure the steady growth of wheat. In the early spring, the wheat field can be crushed, and the cracks can be crushed to close the cracks, so that the wheat roots are in close contact with the soil, preventing cold air from invading and damaging the wheat seedlings.
At the same time, the suppression also has a lifting effect, which can increase the water content of the soil surface layer, and is beneficial to alleviate the low temperature chilling damage.
5, watering at the right time. Watering ahead of the cold current according to weather forecasts is an effective way to prevent or mitigate night frost damage. Watering can increase the humidity of the air near the plant, increase the dew point temperature, and easily cause the moisture to condense and release latent heat.
According to the experience of the past years, it is best to pour water in the first 5 days before the frost;
Watering within 5-10 days before frost will suffer from different degrees of freezing damage;
There is almost no antifreeze effect when watering for more than 10 days before the frost.
Wheat fields without watering conditions can be smoked and frosted in time when the cold current arrives, and there is also a certain antifreeze effect.
6. Strengthen post management. In the period of wheat returning to the body, the use of 15% paclobutrazol wettable powder 50-60 grams per acre, evenly sprayed, can inhibit the growth of wheat seedlings and enhance cold resistance. At the same time, strengthen the prevention and control of diseases, insects and waterlogging in the middle and late stages of wheat fields, prevent premature aging, and capture the harvest.
Main remedies after wheat freeze damage
1, timely topdressing, increase nutrition. After the soil with poor fertility is thawed in the field, 5 kg of urea and 2 kg of diammonium phosphate are applied per mu, preferably the ditch.
2. In the period of wheat greening and jointing, 10 kg of urea per mu is combined with pouring and water saving, and 400 g of potassium dihydrogen phosphate + 0.01% of Tianfengsu 10 ml of foliar spray per acre is used for prevention and control;
3, early spring and early strokes, improve the ground temperature, promote the return of wheat seedlings, improve the rate of tillering. Pay attention to the spraying and spraying before 15:00 in the afternoon after 10:00 in the morning. It has good control effect and therapeutic effect. The specific medication should be determined according to the actual situation of each household.
Measures taken in time after the year
1. Apply nitrogen fertilizer in time to promote the rapid growth of small tillers. The main stem and the large tiller have been frozen in the wheat field, and the wheat is fed back to the jointing stage to combine the watering and fertilizer application, and the urea is applied at 10 kg/mu.
2, generally affected by frozen wheat fields, only the leaves are frozen and dead, no dead cockroaches, early spring should be similar to the pre-winter remedy application (see above), to promote the return of wheat seedlings; in the rising period of topdressing watering, improve the tillering rate .
3. Strengthen the management of fertilizer and water in the middle and late stages to prevent premature aging. The frozen wheat field is prone to premature aging due to the consumption of nutrients in the plant.
On the basis of the first top dressing in spring, look at the growth and development of wheat seedlings, according to the needs of wheat seedlings, in the jointing stage or picking the flag period, the appropriate amount of foliar topdressing, promote the increase of grain size, increase the grain weight, and strive to reduce the damage of freezing damage to a minimum. To increase the annual output of wheat.
As wheat grows faster, the ability of wheat to withstand cold is reduced. The sudden drop in temperature is a significant feature of current temperature changes, which will have varying degrees of impact on wheat production. To this end, we must pay close attention to climate change, strengthen field management, correctly prevent wheat early spring frost damage, and ensure that summer grain increases production and income.
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