2、 Technical measures

（1） Belt intercropping of soybean and corn

In southwest China, there is abundant rainfall, many types of weeds, and it is difficult to control them. Corn is sown before soybeans, and the use of herbicides should be “sealed and combined”. After sowing and before seedling, the soil shall be sealed with metolachlor (or acetochlor)+thiofensulfuron methyl and other agents. If there are weeds in the field before sowing, the field can be sprayed with glyphosate spray; If the soil sealing effect is not ideal and the stem and leaf spray treatment is needed, nicosulfuron methyl+chlorofluoropyranoxyacetic acid (or dichloropyridic acid, methimaxone) can be used to direct the stem and leaf spray (in the corn planting area) at the third to fifth leaf stage of the corn seedlings.

Three days before sowing of soybean, directional spray of glyphosate was carried out in the field. After sowing, before seedlings are planted, pesticides such as promethazine (or acetochlor)+thiophensulfuron are selected for soil sealing treatment. If the soil sealing effect is not ideal and needs to be treated by stem and leaf spray, quinclovir

（2） Belt intercropping of soybean and corn

In the Yellow River, Huaihai River, the middle and lower reaches of the Yangtze River, and northwest regions, soybean and corn are sown simultaneously. The use of herbicides is mainly based on soil sealing treatment before seedlings after sowing, which is required to be completed within 2 days after sowing. The soil is sealed with agents such as promethamide (or metolachlor, acetochlor)+azosulfochlor (or thiophenuron). When the soil in the field where the previous crop is wheat is closed with herbicide, it is best to perform rotary tillage to eliminate the stubble, create moisture, and then sow and apply the herbicide before planting; For direct seeding fields with wheat stubble, it is necessary to increase the water consumption per mu, and if conditions permit, timely watering should be carried out after the application of pesticides; In arid and windy areas such as the northwest, it is best to mix soil after applying herbicides, and timely water areas where conditions permit.

When the soil sealing effect is not ideal and the stem leaf spray treatment is required, it can be used in the 3~5 leaf stage after the corn seedling, the 2~3 leaf stage of soybean, the 2~5 leaf stage of weeds. According to the local grass conditions, nicosulfuron (or oxazolone)+bentazone (or cloflupyroxyacetic acid) In the soybean field, quinoxal (or high efficiency flumetafop-p-ethyl)+dimethasone (or ethyl flumetafop-ethyl) are used for stem and leaf directional spray weeding (physical curtains are used to separate corn and soybean). In the later stage, weeds that are difficult to control can be manually removed.

(Unfinished, to be continued)