Comprehensive Control Methods for the Malignant Weed Jointed Goatgrass in Wheat Fields
Comprehensive Control of the Malignant Weed Jointed Goatgrass in Wheat Fields
(Agricultural Wealth Network) Jointed goatgrass is a malignant weed worldwide. It was first observed in Wei County in 1996, and has increased year by year since then, generally at 5-10 plants/sq m, with the highest reaching 28 plants/sq m. This weed mostly occurs in wheat fields with high water and fertilizer levels. Because of its strong adaptability and high reproductive capacity, inadequate control, and improper seed management, the area affected by jointed goatgrass has continued to expand and the damage has gradually worsened, seriously affecting the safety of wheat production.
I. Occurrence Characteristics First, the emergence depth varies. According to field surveys, germinating jointed goatgrass seeds are mainly concentrated in the 3-8 cm soil layer. Second, the emergence period is long. Jointed goatgrass in winter wheat fields has 2 main emergence periods: the autumn emergence period, mainly 15-20 days after wheat sowing, from late October to mid-November, forming a peak of pre-winter emergence, during which about 70% of the total weeds emerge; from late February to March of the following year, some still emerge. Third, it overwinters as seedlings or seeds. Jointed goatgrass in winter wheat fields mainly overwinters as seedlings, and can also overwinter as seeds. Jointed goatgrass that emerges in autumn produces tillers before winter, generally 3-4 tillers, with more than 10 in some cases. Both tillered seedlings and single seedlings can overwinter, and rarely die. After temperatures rise in spring of the following year, ungerminated seeds can still emerge, and overwintered seedlings can still produce tillers. The main stem and tillers generally can all head and set seed. Fourth, it has strong vitality. Jointed goatgrass has strong tillering ability and vigorous growth. According to surveys, in spring jointed goatgrass generally has 10-20 tillers per plant, with up to 36 tillers per plant. Moreover, the occurrence of jointed goatgrass increases as water and fertilizer conditions improve.
II. Causes of Occurrence (1) Long-distance cross-regional operation of wheat combine harvesters is an important medium for the spread of jointed goatgrass. (2) When replacing new varieties, it is inevitably accompanied by the intrusion and spread of new weed seeds. Before 1996, jointed goatgrass was extremely rare in local wheat fields, but later, due to large-scale introduction and transfer of seeds from areas where jointed goatgrass occurred, it spread and expanded. (3) Extensive tillage systems have also aggravated the occurrence of jointed goatgrass to a certain extent. The local system is a wheat-maize double cropping system, and grain fields are rarely rotated with other crops. After wheat harvest, maize is planted no-till directly into the stubble, and most jointed goatgrass seeds are scattered on the soil surface. After autumn harvest, mechanical tillage is generally used; because the plough layer is shallow and deep ploughing is rare, most jointed goatgrass seeds are distributed in the shallow surface layer of the soil, creating a good ecological environment for its emergence. In addition, during control, only weeds in the main field are controlled, while weeds along field edges, canals, roadsides and field corners are not controlled. After jointed goatgrass matures, it invades farmland through wind, shallow irrigation and other means. Many farmers also pull it up in the later period, when jointed goatgrass is basically mature, and pile it casually along field edges, field corners and roadsides, so after the grass seeds mature they continue to flow into the main field. (4) It re-enters farmland with the application of undecomposed farmyard manure. Some farmers directly dump jointed goatgrass seeds cleaned out from wheat grains into pig, sheep, chicken and other poultry and livestock pens, or feed poultry (livestock) with unprocessed and uncrushed jointed goatgrass seeds, causing some undecomposed farmyard manure to contain jointed goatgrass seeds. (5) Jointed goatgrass seeds can overwinter through summer locally and continuously accumulate, aggravating the damage. After jointed goatgrass seeds mature, they naturally fall into the soil and survive summer dormancy. Each spike sets 20-30 seeds, the natural shattering rate in the field is 80%, and the natural emergence rate after surviving summer is 65%. It takes only 2-3 years to go from sporadic occurrence to serious damage. (6) The long-term use of a single herbicide variety has caused the weed community in wheat fields to evolve. The original main weeds in local wheat fields were broadleaf weeds such as flixweed and celery, and the long-term use of herbicides such as tribenuron-methyl brought the original early weeds under control, causing the grass weed jointed goatgrass, formerly a secondary weed, to rise to a main weed and become a malignant weed in local wheat fields.
III. Control Techniques According to the occurrence and damage characteristics of jointed goatgrass in wheat fields and control practice, control must implement the policy of "prevention first, comprehensive control" and actively promote comprehensive control measures such as pre-winter chemical weed control technology.
1. Agricultural control measures.
(1) Carefully select wheat seed and eliminate seed transmission. Jointed goatgrass spreads by seed, so controlling its spread must first strictly guard the seed gate. Seed transfer must undergo quarantine. All seeds mixed with jointed goatgrass must be carefully selected to prevent grass seeds from infesting areas where it has not yet occurred. Self-retained seeds must also be carefully selected.
(2) Give play to the ecological inhibitory effect of wheat fields. Fewer wheat plants and more weeds, or more wheat plants and fewer weeds, is the rule of competition between weeds and crops. Therefore, rational close planting and scientific fertilization to strive for uniform and strong seedlings and form the population growth advantage of the wheat field can produce an ecological weed-suppressing effect and suppress weeds with wheat.
(3) Manual pulling. Combined with wheat field management, pull up jointed goatgrass before it matures. Pulling must be timely, pulling large and small plants together, leaving no future trouble. Pulled jointed goatgrass must be taken out of the field, sun-dried, crushed and centrally burned. At the same time, clear weeds from field ridges and ditches to reduce sources of spread and diffusion.
(4) Apply organic fertilizer to the field after it is decomposed. Wheat straw and husks and livestock and poultry manure must be composted and retted, and applied to farmland only after high-temperature fermentation and decomposition. Livestock and poultry feed must also be processed and crushed so that grass seeds lose their vitality.
2. Chemical control techniques.
Before wheat overwintering, after the weeds have all emerged, use 20-30 ml of 3% Shima oil suspension concentrate (mesosulfuron-methyl) per mu plus 60 ml of the adjuvant Banbao, mixed with 30 kg of water, and spray for control. Applying the pesticide at this stage gives the best effect: most weeds have emerged, weed tissues are young and their resistance to the pesticide is weak, and the temperature is relatively high, so the pesticide can fully exert its efficacy. In addition, the wheat field coverage is small, and the sprayed liquid has a large contact area with the weeds, which helps the weeds absorb more pesticide and ensures the weed control effect. It can also be sprayed after wheat turns green in spring and before jointing, using 30 ml of 3% Shima oil suspension concentrate per mu plus 60 ml of the adjuvant Banbao mixed with 30-40 kg of water, but the control effect and safety are not as good as autumn-winter control, so manual pulling is recommended.
I. Occurrence Characteristics First, the emergence depth varies. According to field surveys, germinating jointed goatgrass seeds are mainly concentrated in the 3-8 cm soil layer. Second, the emergence period is long. Jointed goatgrass in winter wheat fields has 2 main emergence periods: the autumn emergence period, mainly 15-20 days after wheat sowing, from late October to mid-November, forming a peak of pre-winter emergence, during which about 70% of the total weeds emerge; from late February to March of the following year, some still emerge. Third, it overwinters as seedlings or seeds. Jointed goatgrass in winter wheat fields mainly overwinters as seedlings, and can also overwinter as seeds. Jointed goatgrass that emerges in autumn produces tillers before winter, generally 3-4 tillers, with more than 10 in some cases. Both tillered seedlings and single seedlings can overwinter, and rarely die. After temperatures rise in spring of the following year, ungerminated seeds can still emerge, and overwintered seedlings can still produce tillers. The main stem and tillers generally can all head and set seed. Fourth, it has strong vitality. Jointed goatgrass has strong tillering ability and vigorous growth. According to surveys, in spring jointed goatgrass generally has 10-20 tillers per plant, with up to 36 tillers per plant. Moreover, the occurrence of jointed goatgrass increases as water and fertilizer conditions improve.
II. Causes of Occurrence (1) Long-distance cross-regional operation of wheat combine harvesters is an important medium for the spread of jointed goatgrass. (2) When replacing new varieties, it is inevitably accompanied by the intrusion and spread of new weed seeds. Before 1996, jointed goatgrass was extremely rare in local wheat fields, but later, due to large-scale introduction and transfer of seeds from areas where jointed goatgrass occurred, it spread and expanded. (3) Extensive tillage systems have also aggravated the occurrence of jointed goatgrass to a certain extent. The local system is a wheat-maize double cropping system, and grain fields are rarely rotated with other crops. After wheat harvest, maize is planted no-till directly into the stubble, and most jointed goatgrass seeds are scattered on the soil surface. After autumn harvest, mechanical tillage is generally used; because the plough layer is shallow and deep ploughing is rare, most jointed goatgrass seeds are distributed in the shallow surface layer of the soil, creating a good ecological environment for its emergence. In addition, during control, only weeds in the main field are controlled, while weeds along field edges, canals, roadsides and field corners are not controlled. After jointed goatgrass matures, it invades farmland through wind, shallow irrigation and other means. Many farmers also pull it up in the later period, when jointed goatgrass is basically mature, and pile it casually along field edges, field corners and roadsides, so after the grass seeds mature they continue to flow into the main field. (4) It re-enters farmland with the application of undecomposed farmyard manure. Some farmers directly dump jointed goatgrass seeds cleaned out from wheat grains into pig, sheep, chicken and other poultry and livestock pens, or feed poultry (livestock) with unprocessed and uncrushed jointed goatgrass seeds, causing some undecomposed farmyard manure to contain jointed goatgrass seeds. (5) Jointed goatgrass seeds can overwinter through summer locally and continuously accumulate, aggravating the damage. After jointed goatgrass seeds mature, they naturally fall into the soil and survive summer dormancy. Each spike sets 20-30 seeds, the natural shattering rate in the field is 80%, and the natural emergence rate after surviving summer is 65%. It takes only 2-3 years to go from sporadic occurrence to serious damage. (6) The long-term use of a single herbicide variety has caused the weed community in wheat fields to evolve. The original main weeds in local wheat fields were broadleaf weeds such as flixweed and celery, and the long-term use of herbicides such as tribenuron-methyl brought the original early weeds under control, causing the grass weed jointed goatgrass, formerly a secondary weed, to rise to a main weed and become a malignant weed in local wheat fields.
III. Control Techniques According to the occurrence and damage characteristics of jointed goatgrass in wheat fields and control practice, control must implement the policy of "prevention first, comprehensive control" and actively promote comprehensive control measures such as pre-winter chemical weed control technology.
1. Agricultural control measures.
(1) Carefully select wheat seed and eliminate seed transmission. Jointed goatgrass spreads by seed, so controlling its spread must first strictly guard the seed gate. Seed transfer must undergo quarantine. All seeds mixed with jointed goatgrass must be carefully selected to prevent grass seeds from infesting areas where it has not yet occurred. Self-retained seeds must also be carefully selected.
(2) Give play to the ecological inhibitory effect of wheat fields. Fewer wheat plants and more weeds, or more wheat plants and fewer weeds, is the rule of competition between weeds and crops. Therefore, rational close planting and scientific fertilization to strive for uniform and strong seedlings and form the population growth advantage of the wheat field can produce an ecological weed-suppressing effect and suppress weeds with wheat.
(3) Manual pulling. Combined with wheat field management, pull up jointed goatgrass before it matures. Pulling must be timely, pulling large and small plants together, leaving no future trouble. Pulled jointed goatgrass must be taken out of the field, sun-dried, crushed and centrally burned. At the same time, clear weeds from field ridges and ditches to reduce sources of spread and diffusion.
(4) Apply organic fertilizer to the field after it is decomposed. Wheat straw and husks and livestock and poultry manure must be composted and retted, and applied to farmland only after high-temperature fermentation and decomposition. Livestock and poultry feed must also be processed and crushed so that grass seeds lose their vitality.
2. Chemical control techniques.
Before wheat overwintering, after the weeds have all emerged, use 20-30 ml of 3% Shima oil suspension concentrate (mesosulfuron-methyl) per mu plus 60 ml of the adjuvant Banbao, mixed with 30 kg of water, and spray for control. Applying the pesticide at this stage gives the best effect: most weeds have emerged, weed tissues are young and their resistance to the pesticide is weak, and the temperature is relatively high, so the pesticide can fully exert its efficacy. In addition, the wheat field coverage is small, and the sprayed liquid has a large contact area with the weeds, which helps the weeds absorb more pesticide and ensures the weed control effect. It can also be sprayed after wheat turns green in spring and before jointing, using 30 ml of 3% Shima oil suspension concentrate per mu plus 60 ml of the adjuvant Banbao mixed with 30-40 kg of water, but the control effect and safety are not as good as autumn-winter control, so manual pulling is recommended.