Planting ecologically complex Maize according to Local conditions in Southwest China

Editor's note: there are great differences in ecological conditions in southwest China, which leads to great changes in the growth period of maize. Southwest corn region, which includes Sichuan, Yunnan, Guizhou, Chongqing, western hilly areas of southern Shaanxi, Guangxi, Hunan, Hubei and a small part of Gansu Province, is the third largest corn producing area in China. The climate, topography and ecological conditions of this region are very complex. More than 90% of the land is hilly mountains and plateaus, while river valley plains and intermountain flatlands account for only 5%. Planting patterns are complex and diverse. Corn is mainly sown in spring and summer, as well as autumn and winter sowing. From river valleys to mountains of 3200 meters above sea level, there are obvious differences in temperature and accumulated temperature in different areas, showing a trend of gradually increasing from northwest to southeast as a whole. At present, some areas have completed sowing, and some areas are preparing for sowing. In view of this situation, experts from Sichuan, Yunnan, Guizhou and Chongqing have all made plans on how to do a good job in service. Liu Yonghong, a post scientist in the technological system of modern agricultural corn industry, Ren Hong, director of Guiyang Comprehensive Experimental Station, Huang Jimei, director of Yunnan Qujing Comprehensive Experimental Station, Yang Hua, director of Chongqing Comprehensive Experimental Station, and other experts answered reporters' questions on how local farmers should carry out spring ploughing production.

Sichuan seedlings grow slowly and pay attention to pest control

Reporter: the sowing of spring corn in Sichuan Province has basically ended, and the corn in most areas is in the stage from emergence to seedling. Since March, due to less rainfall in most corn producing areas, higher daily maximum temperature than in previous years, and drought in some areas, how should local farmers deal with it?

Experts in maize industrial system: affected by drought and other factors, the main problems in maize production at present are: weak seedling potential, slow seedling growth, desalination in some fields, overgrowth of weeds in the fields, serious occurrence of underground insect pests and so on. In view of the above problems, the following technical suggestions are put forward:

Comprehensive prevention and control of underground pests. Maize seedling stage is the main period of underground pest occurrence. The harm of underground pests such as ground tiger, grub, mole cricket and so on is greater. Insecticide spraying or rhizome spraying is generally used to control underground pests, mainly to kill the pre-3rd instar larvae, and pyrethroid insecticides and organophosphorus insecticides should be the main choice. 2.5% deltamethrin EC 2000 times or 20% fenvalerate EC 2000kg / mu can be used, or 2.5% trichlorfon powder 1.5kg / mu can be directly sprayed on corn seedlings; or 48% chlorpyrifos EC or 50% phoxim EC, 1000 times liquid, can be sprayed directly on the rhizome of corn seedlings, and it is appropriate for the medicine solution to infiltrate into the soil, and the water consumption per mu is 50kg / mu. In addition, it can also comprehensively control underground pests by spreading poisonous soil, artificially catching larvae, bait and killing, timely removal of weeds in the field and so on.

Check seedlings and fill gaps in time. After the emergence of maize seedlings, the emergence status of maize should be checked in time, and it should be replanted or replanted in time when it is found that there is a lack of seedlings and ridges. If the seedlings are deficient before the 2-leaf stage, the full seeds can be soaked and watered after sprouting; after the 2-leaf stage, the seedlings can be replenished by the method of transplanting with soil, which should be carried out in overcast, rainy or evening, watering after planting and covering soil to preserve soil moisture. In addition, double plants can also be left near the lack of seedlings to ensure the basic density.

Seedlings should be fixed at the right time. The use of artificial direct seeding of the field, should be suitable time seedlings, fixed seedlings. Seedlings are generally carried out at 3-4 leaves, and weak, white, yellow, diseased, inferior and miscellaneous seedlings are removed; seedlings are generally fixed at 5-6 leaves, strong seedlings are kept according to the planned density, and excess seedlings are removed in time to prevent competition for water and fertilizer.

Strengthen chemical weeding. Chemical weeding at seedling stage should strictly select the types of herbicides, grasp the best use period, and accurately control the dosage. Before the emergence of corn seedlings after sowing, pre-bud herbicides, such as Acetochlor, can be used with 70 grams of active ingredients per mu to 40 kilograms of water, or 40% ethyl A mixture, 200 milliliters per mu to 50 kilograms of water, evenly sprayed on the surface, can effectively control annual Gramineae weeds; when corn seedlings are in 5-6 leaves, corn special herbicides can be selected and directional spraying between rows.

Topdressing and fertilizing seedlings. Topdressing at seedling stage has the effect of promoting root, strong seedling, promoting leaf and strong culm. When 5 leaves of maize seedlings are spread, urea 4kg / mu and potassium chloride 5kg / mu are used to fertilize the seedlings. There should be some differences in topdressing, using water to deliver fertilizer, re-applying small seedlings and weak seedlings, paying attention to side application, promoting "small seedlings to catch up with big seedlings and weak seedlings to drive strong seedlings", so as to realize the balanced growth of maize at seedling stage.

Ploughing at the right time. Timely ploughing of corn at seedling stage can play the role of "controlling up and promoting down". Zhong Teng should be "shallow beside the seedlings, deep in the middle", not only to remove weeds, but also not to press the seedlings, the depth is generally 3-5 cm.

Rush to sow in the middle ploughing and high mountain areas in the shallow hilly area of Chongqing

Reporter: there are great ecological differences in corn production areas in Chongqing. Sowing has been completed in shallow hills and Pingba areas, and corn growth is in the seedling stage or has entered the jointing stage. It is understood that due to drought and little rain, seedlings in most areas are relatively weak. But the mountain areas above 800 meters have not yet sown seeds, how should farmers produce?

Yang Hua, stationmaster of Chongqing Comprehensive Experimental Station: corn sowing and seedling management in Chongqing are under intense progress. At present, the following production measures should be taken:

Maize seedlings in shallow hills and Pingba areas have weak growth due to drought, so weeding should be done in time or special herbicides should be used in corn fields and clear dung water should be applied to promote seedlings. Generally, 5kg urea per mu should be used to drench 750 kg pig manure. In the jointing stage, the fertilization of soil cultivation and booting fertilizer should be done well. About 15 cm away from the maize plant, the fertilizer should be applied into the hole, generally about 10 kg of urea, and covered with medium ploughing soil to thicken the soil layer at the root of the maize plant. form a high ridge of about 10 to 20 centimeters, in order to prevent the lodging of corn caused by wind and rain and the use of drainage during the rainy period.

The unfinished sowing of corn in high mountain areas should be speeded up; in the emergence stage, the control of underground pests should be strengthened, and if underground pests occur, insecticides such as 800 times liquid can be used to control underground pests at seedling stage. and timely check seedlings and replenish seedlings to ensure yield-increasing density.