1 Detailed explanation of Aegilops tauschii
Aegilops belongs to Gramineae and Panicum. The height of the culm can reach 40 cm. Leaf sheaths tightly phimosis, leaves slightly rough, sparsely pilose. Spikes are cylindrical, spikelets are cylindrical, and there are small flowers; Glumes, lemmas lanceolate, paleas as long as lemmas, ciliate on ridges. Flowering and fruiting in May-June. It is distributed in Guanzhong area of China, Shaanxi and Xinxiang of Henan, and mostly grows in barren grassland or wheat fields. The harm is more serious. Also known as Aegilops tauschii, it is a worldwide malignant weed.
2 characteristics of Aegilops tauschii
First, the depth of emergence is different. According to the investigation, the seeds of Aegilops tauschii are mainly concentrated in 3-8 cm soil layer.
Second, the seedling stage is long. There are two periods for the emergence of Aegilops tauschii in winter wheat field: one is the autumn seedling stage, which is mainly 15-20 days after wheat sowing, that is, from the end of 10 to the middle of 1 10, forming the peak of emergence before winter (weeds emerging in this period account for about 70% of the total); The other is the spring seedling stage (from late February to next March, some seedlings still emerge).
The third is to overwinter with seedlings or seeds. Aegilops tauschii overwinters mainly as seedlings in winter wheat fields, but also as seeds, tillers and seedlings per plant. There are 3-4 tillers in front of Ophiopogon japonicus, which emerge in autumn, and the number of tillers 10 is above. After the temperature rises in the next spring, the seeds that have not emerged can continue to emerge and tiller. The main stem and tillers can be heading and bearing fruit.
Fourth, strong vitality. Aegilops tauschii has strong tillering ability and vigorous growth. According to the investigation, in spring, Aegilops tauschii generally has 10-20 tillers per plant, with 36 tillers per plant at most.
3. The route of transmission of Aegilops tauschii
1. The long-distance cross-regional operation of wheat harvester is an important medium for the spread of Aegilops tauschii.
2. With the upgrading of new varieties and large-scale unified propagation and supply, it is inevitable that weed seeds such as Aegilops tauschii will be mixed and spread. Before 1996, Aegilops tauschii was extremely rare in wheat fields, but it spread because of a large number of introduction and seed adjustment from Aegilops tauschii occurrence areas.
3. Extensive farming system also aggravated the occurrence of Aegilops tauschii to some extent. Wheat-corn double cropping system is adopted in many areas. After wheat harvest, corn is planted with stubble without tillage, and most of the seeds of Aegilops tauschii are scattered on the surface. The deep ploughing area of autumn sowing is small, and most of the seeds of Aegilops tauschii are distributed in shallow soil because of the shallow tillage layer. In addition, when controlling weeds, we only pay attention to controlling weeds in the field, not weeds on the edge, roadside and field. When Aegilops tauschii is mature, it flows into farmland through wind and rain and shallow irrigation. There are also many farmers who were manually pulled out in the later period. Aegilops tauschii is basically mature, and Aegilops tauschii is randomly stacked on the edge of the field, and weed seeds continue to flow into the field.
4. Apply unpolished farmyard manure and re-enter the farmland. The seeds of Aegilops tauschii collected from wheat grains are directly composted, or raw and crushed Aegilops tauschii seeds are fed to poultry (domestic animals) to produce grass seeds of Aegilops tauschii in some unpolished farmyard manure.
5. The long-term use of a single herbicide makes the weed community in wheat field evolve continuously. The original main weeds in local wheat fields are broad-leaved weeds such as descurainia sophia and shepherd's purse. The continuous use of tribenuron-methyl herbicide for many years has brought the original dominant weeds under control, resulting in the increase of gramineous weeds such as Aegilops tauschii and becoming malignant weeds in high water and fertilizer wheat fields at present.
4 How to effectively control Aegilops tauschii
According to the occurrence characteristics, occurrence regularity and prevention practice in various places, it is necessary to "focus on prevention and comprehensive management" and implement measures such as chemical weeding and manual weeding before winter.
First of all, put an end to the spread of seeds and conduct quarantine. Aegilops tauschii has strong tillering ability and many transmission routes, and it is difficult to identify and manually pull out at seedling stage. At present, prevention should be given priority to. It is necessary to insist on not transporting seeds from the Aegilops tauschii occurrence area. At the same time, wheat seeds should be carefully selected to prevent weed seeds from spreading in Aegilops tauschii. (The seed shape of Aegilops tauschii is very similar to that of wheat, but the size is only about 1/3 of that of wheat, and the 1000-grain weight is much smaller than that of wheat, with an average of about 14.5g). Aegilops tauschii spreads through seeds. To control the spread, we must first strictly control the seeds. All seeds mixed with Aegilops tauschii must be carefully selected to prevent grass seeds from infecting areas that have not yet occurred.
Secondly, manual extraction and centralized incineration are carried out. Combined with wheat field management, Aegilops tauschii was completely uprooted. It is easy to identify the seedling stage and adult stage of Aegilops tauschii in the field. At seedling stage, the base is purplish red, and when the new leaves are pulled out, they roll into a tube shape, and the unfolded leaves are long, narrow and thin. After tillering, the leaf width is less than 1/2 of wheat, and the thickness is about 1/2 of wheat. After heading, the plant is slightly higher than wheat, and the ear type is obviously different (the ear is cylindrical). No matter the size, it should be pulled out in time, leaving no future trouble. Attention should be paid to taking the pulled Aegilops out of the field for centralized burning; At the same time, weeds in the field should be removed to reduce the spread.
First, the difference between wild wheat and wheat seedlings at seedling stage
First, see if it is consistent with the appearance of wheat in the field. If there are rows of seedlings narrower than the leaves of wheat seedlings in the wheat field, they may be gramineous weeds.
Distinguish carefully: the leaf sheath of wheat is white, and the leaves have no fluff. However, the leaf sheath of wild wheat is red or the leaves are fluffy.
Second, how to identify different wild wheat?
Further differentiation, if the rhizome is white, but the surface is hairy and there is no spike, it should be wild oats.
Wild oat seedling stage
If you want to distinguish Bromus from Aegilops tauschii, you can dig one out. If there is a barrel-shaped seed at the root, it is Aegilops tauschii. The seeds of other gramineous weeds are similar to those of wheat, but generally thinner than those of wheat.
Jiejiemai
Wheat seedling stage: the seedlings are dark green and the base is purplish red. When the new leaves are pulled out, they are rolled into a tube shape and the leaves are strip-shaped.