Variety selection should be appropriate for safer wintering and safer

2021-05-23

Alfalfa Growth Habits and Characteristics

Seedling contraction

Alfalfa began to shrink after 6-8 weeks of emergence. Contractile growth is due to the lateral growth of the seedling's hypocotyl and the primary root cells in the upper part, making it shorter and thicker, resulting in the first section of seedlings and cotyledons gradually retracted below the surface of the soil. This growth habit is called contractile growth.

This growth habit of alfalfa is closely related to its cold resistance, regenerative ability, ability to overwinter and branches. The study found that different varieties of alfalfa have different growth habits. Some varieties can extend from 6-8 weeks to 6-10 months, and some even 2-3 years. U.S. breeders have even cultivated root-in-ground varieties such as 3010 and Giant Energy 2 based on this characteristic and characteristic.

Root carbohydrate changes

According to observations by relevant departments, the carbohydrate content in the roots of alfalfa changes with changes in climate, season, and phenology period. Usually in the early spring, the content of carbohydrates in the roots of alfalfa began to decline with the growth of the roots, and the branches began to rise at the later stage, reaching the highest level during the buds.

Before spring alfalfa turns green, there are usually two sources of moisture in the alfalfa plants, namely endogenous water and exogenous water. Endogenous water refers to the water that the alfalfa plant itself absorbs from the soil through the lateral roots of the root system and the hair roots on the lateral roots. Exogenous water refers to the water that enters the body of the alfalfa plant from the injured parts of the main root, root and neck, and epidermis of the alfalfa plant due to precipitation, sprinkling, and the like.

Endogenous water is a safe, clean, and sterile water for alfalfa. Exogenous water is different. Bacteria and fungi that are usually brought into the soil, air, and water often cause yellowing, blackening, and even rot in the roots, roots, and roots of alfalfa.

Root, root crown and neck injury

The reason why alfalfa can't turn green in time in spring is that the roots, crowns and root necks of alfalfa are damaged by different reasons and different degrees. There are usually several cases of injury: the root crown victim, the root neck victim, and the central neck victim.

The damage to the root crown and root neck is due to the severe water shortage in the upper part of the plant, which results in the separation of some of the cytoplasmic walls of the upper tissue, that is, the separation of the cell wall from the cell membrane. Such cells have already died, and a large number of cell deaths have resulted. The necrosis of tissue provides conditions for the intrusion of bacteria, fungi, and bacteria in exogenous water, soil, and air, causing a large number of bacteria to invade the plants, causing the roots to become yellow, black, and even rot.

The damage to the root crown is shallow because of its damage, and often only affects the speed of returning green. The degree of victimization of root and neck damages generally affects the quality of returning greens, sometimes affecting production.

The damage in the middle of the neck is due to the change of temperature in early spring. During the day, the surface temperature is above zero and below zero at night, causing repeated freezing and thawing of the soil at a certain depth below the surface. This repeated freezing and thawing causes damage to the root of the corresponding site, and a large number of cells in the site. Death, tissue necrosis, bacterial invasion, and eventually the formation of a black circle (Figure 3). This kind of injury often affects the quality of returning green products and the output of the year.

Effect of Fertilization on High Yield and Overwintering

The relationship between fertilization and high yield is the relationship between input and output. It is best to measure soil fertilization, according to the nutritional needs of earthworms, what is missing in the soil. Applying a wintering fertilizer around the end of September each year is beneficial to safe wintering of alfalfa as it can affect the carbohydrate concentration and ion concentration of the alfalfa root at the same time, especially the potassium ion concentration plays an important role in the overwintering of alfalfa.

Overwintering success or failure 3 elements

The three elements of success or failure in wintering are: weather, winter tubes, and varieties (especially large plots, open spaces, sandy soils).

Weather factors are an important factor for all overwintering plants and are sometimes decisive factors. If winter snow is large, it can often make all overwintering plants safely winter. However, the weather factor is uncontrollable. Wintering management is also often affected by production conditions, equipment, weather factors, etc. Only species factors are controllable, so we must choose a suitable variety.

Green conditions

Alfalfa grows as the weather in the spring warms, the surface defroses, the roots first swell, the carbohydrates in the roots activate, and the active ions in the cytosol of root cells, such as potassium ions, first move, the signs of life begin, the winter buds sprout, and the alfalfa begins. Turn green.

Alfalfa frost resistance factor

Different varieties of alfalfa have different wintering abilities because of their different sensitivity to temperature. Because of their different root systems, Xinyi and Datong have different abilities to pass through the winter. The ion concentration of the aqueous solution in the soil affects the concentration of active ions in the cell fluid of the root cells, thereby affecting the osmotic pressure of the cells. Therefore, the higher the ion concentration of the soil aqueous solution and the total amount of carbohydrates in the root, the more beneficial it is for wintering.

The harsh environment and tenacious life:

Alfalfa is a perennial deep-rooted crop that is cold tolerant and drought-tolerant. It does not require high soil conditions. Sandy, light saline-alkali lands, and low-yielding fields can be planted. In the face of external infringement, life is also very tenacious, and life's hope has always existed.

Suggestions on safe wintering and returning to alfalfa

Misunderstanding

Some people think that winter is too cold, it is not good to go back to green, and it is too early to return to green water, and the planting density is too great. In fact, these are misunderstandings in understanding.

Some people think that the winter is too cold will affect the winter, in fact, the cold winter is conducive to soil water, conducive to winter.

Light back to the spring can effectively prevent the late spring. Return to Qingshui water early pouring water in time to replenish the soil. The high planting density is beneficial for controlling seedlings in sandy soil and controlling weeds in seedling stage.

Irrigation system

Winter irrigation: According to the medium and long-term weather forecast, fill the water before the soil is frozen.

Irrigation in spring: According to the soil moisture status, air temperature condition and ground temperature condition, formulate the irrigation system. Different irrigation purposes are different in irrigation method and water quantity. For the purpose of surface cooling, it should be a small number of times. For the purpose of root irrigation, it should be much less. Times.

Production season irrigation: According to the soil moisture status and production needs, it is best to integrate water and fertilizer.

Variety selection

After good field management is in place, the differences between alfalfa varieties can be fully reflected. When the weather conditions are relatively normal, the selection of species is particularly important. The fall-sleep status and cold-resistance index are the quantitative indicators for the selection of alfalfa varieties. In addition, the growth of varieties Habits, such as root-to-earth, root-type, etc., should also be considered when choosing a variety.

Alfalfa is a perennial crop. The selection and determination of varieties before planting alfalfa is an artificially controlled factor in production, and must be taken seriously.