Comprehensive Control of malignant Weeds in Wheat Field

Aegilops tauschii is a malignant weed in the world. Aegilops tauschii was first seen in Weixian County in 1996, and then increased year by year, generally 5: 10 plants per square meter, as high as 28 plants per square meter. Most of the weeds occur in high water and fertilizer wheat fields. Due to strong adaptability, large reproduction, poor control and improper seed management, the occurrence area of Aegilops tauschii continues to expand, and the harm is gradually aggravated, which seriously affects the safety of wheat production.

First, the occurrence characteristic is that the emergence depth is different. According to the investigation in the field, the seeds of Aegilops tauschii sprouting are mainly concentrated in the soil layer of 3 cm to 8 cm. Second, the emergence period is long. The emergence of Aegilops tauschii in winter wheat field has two main periods: autumn emergence period, mainly 15-20 days after wheat sowing, and a pre-winter emergence peak from late October to mid-November, during which weeds account for about 70% of the total; from late February to March of the following year, some seedlings still emerged. Third, overwintering with seedlings or seeds. Aegilops tauschii overwinters mainly as seedlings or seeds in winter wheat fields. Before the emergence of Ophiopogon japonicus in autumn, there are generally 3-4 tillers, more than 10 tillers. Both tiller seedlings and single seedlings can survive the winter and rarely die. After the temperature rises in the next spring, the unemerging seeds can still emerge, and the overwintering seedlings can also produce tillers. The main stem and tiller are generally capable of heading and bearing seeds. Fourth, it has strong vitality. Aegilops tauschii has strong tillering ability and exuberant growth. According to the investigation, Aegilops tauschii in spring generally has 20 tillers per plant, up to 36 tillers per plant. And the occurrence amount of Aegilops tauschii increased with the improvement of water and fertilizer conditions.

Second, the reason for the occurrence is that the long-distance cross-regional operation of ① wheat harvester is an important medium for the spread of wheat. When ② changes new varieties, it is inevitable that new weed seeds invade and spread. Before 1996, Aegilops tauschii was rarely seen in the local wheat field, and then spread due to the introduction and adjustment of a large number of varieties from the occurrence area. The extensive farming system of ③ also aggravated the occurrence of Aegilops tauschii to some extent. The local wheat-corn double cropping system, the grain field rarely with other crops rotation. After wheat harvest, corn was planted with no-tillage and stubble, and most of the seeds of wheat were scattered on the ground. Machine ploughing is widely used after autumn harvest. Because the ploughing layer is shallow and rarely turned deeply, the seeds of Aegilops tauschii are mostly distributed in the shallow surface of the soil, creating a good ecological environment for its emergence. In addition, in the control, only control weeds in the field, not weeds in the fields, canals, roads and fields. After maturing, Aegilops tauschii invades farmland through wind, shallow irrigation and so on. When many farmers pulled out in the later stage, the wheat was basically mature, and the wheat was randomly piled up on the edge of the field, the ground, and the road, and the grass seeds continued to flow into the field after ripening. ④ reentered the farmland with the application of immature farm manure. Some farmers pour the seeds of Aegilops tauschii collected from wheat grains directly into pigs, sheep, chickens and other poultry and livestock pens, or feed poultry (livestock) with unprocessed and crushed seeds of Aegilops tauschii. As a result, there are grass seeds of Aegilops tauschii in some unrotten farm manure. ⑤ Aegilops tauschii seeds can pass the summer locally and accumulate continuously, which aggravates the damage. After maturing, the seeds of Aegilops tauschii naturally fall off to the soil and survive after summer dormancy. There are 20-30 seeds per panicle, the natural shedding rate in the field is 80%, and the natural emergence rate after summer is 65%. It only takes 2-3 years from sporadic occurrence to serious damage. The long-term use of single herbicide ⑥ led to the evolution of weed community in wheat field. The original main weeds in local wheat fields are broad-leaved weeds such as Artemisia annua and celery. The long-term use of herbicides such as benzosulfuron has controlled the original early weeds, resulting in the rise of grass weeds to become the main weeds and become malignant weeds in the local wheat field.

3. Control technology according to the occurrence and harm characteristics and control practice of wheat field, we must implement the policy of "prevention first, comprehensive control" and actively popularize chemical weeding techniques before winter and other comprehensive control measures.

1. Agricultural prevention and control measures.

① selects wheat seeds to put an end to seed transmission. Aegilops tauschii is spread by seeds, and the seeds must be strictly guarded to control the spread. The seeds transported must be quarantined, and all seeds mixed with wheat must be carefully selected to prevent grass seed infection in areas where grass seed infection has not yet occurred. Self-reserved seeds should also be selected.

② exerts the ecological inhibition effect of wheat field. Less wheat and more grass, more wheat and less grass is the law of competition between weeds and crops. therefore, reasonable close planting, scientific fertilization, strive for strong seedlings and form the advantage of population growth in wheat field can have the effect of ecological grass suppression and grass suppression.

③ was removed manually. Combined with wheat field management, the wheat was pulled out before the wheat was ripe. Pull out in time, size and size, leaving no future trouble. The pulled Aegilops tauschii must be taken out of the field, dried and crushed, and burned centrally. At the same time, the weeds in the ridges and ditches should be removed to reduce the source of spread.

④ organic fertilizer was put into the field after ripening. Wheat straw shell and livestock and poultry fertilizer must be composted and retted, and then applied to farmland after high temperature fermentation and ripening, and livestock and poultry feed should also be processed and crushed to make grass seeds lose their vitality.

two。 Chemical control technology.

Before the wheat overwintered and after the weeds came out, 30 ml of 3% Shima oil suspension emulsion (methyl disulfuron) 20 ml / mu plus 60 ml of auxiliary agent was sprayed to 30 kg of water. The effect of spraying in this period is the best, most of the weeds have been unearthed, the weed tissue is young, the drug resistance is weak, the temperature is high, and the pesticide can give full play to its efficacy. In addition, the coverage of the wheat field is small, and the spraying solution has a large contact area with weeds. It is beneficial for weeds to absorb more chemicals and ensure the effect of weeding. It can also be sprayed with 30 ml of Shima oil suspension emulsion and 60 ml of auxiliary agent per mu before jointing after the wheat turns green in spring, but the control effect and safety are not as effective as those of autumn and winter, and manual pulling is recommended.