Key points of current and late management techniques for planting wheat

Due to the early drought in some wheat fields in our province, the secondary roots are few and short, the number of populations is insufficient, and the drought still exists in some plots. In view of this situation, at the provincial spring agricultural production work conference held on April 7, Yu Zhenwen, academician of the Chinese Academy of Engineering, leader of the wheat expert guidance group of the Ministry of Agriculture and professor of Shandong Agricultural University, introduced the current and later management techniques of wheat in our province.

Do a good job in fertilizer and water management

Do a good job in fertilizer and water management and chemical control during the start-up period. At present, wheat in Jiaodong, central and northern Shandong and other areas of our province is still in its infancy, for this part of the land, we should continue to do a good job in fertilizer and water management according to local conditions. Especially for the second type of wheat field, the third type of wheat field without topdressing in the early stage, or the first kind of wheat field with poor soil fertility, it is necessary to focus on fertilizer and water in the starting period. The starting period of wheat is also an effective period for using chemical control agents to control prosperity and prevent lodging. For plots with large population or general population but high soil fertility, we should pay attention to timely spraying chemical control agents.

Do a good job in fertilizer and water management at jointing stage. Jointing stage is the key period of wheat field management, especially in high-yield wheat field, jointing fertilizer and water must be well applied. The period from Qingming Festival to April 20 is the key period for applying jointing fertilizer and watering and saving water in the whole province. This time, water and fertilizer play an important role in increasing the number of spikes and grains per spike of wheat. A kind of seedlings without spring fertilizer and water management should highlight topdressing and watering at jointing stage.

According to the law of fertilizer demand of wheat in spring, urea should be the main fertilizer, and the nitrogen content of compound fertilizer is low, so it is not suitable for topdressing in spring. The application of potash fertilizer at jointing stage has obvious effect of preventing lodging and increasing yield, and high-yield plots can be combined with nitrogen fertilizer and topdressing potash fertilizer of 6-12 kg per mu at jointing stage.

Do a good job in fertilizer and water management at flowering and filling stages. After heading, the number of spikes per mu of wheat has become a foregone conclusion, but the number of grains per spike and grain weight still change greatly, because about 2/3 of the starch accumulated in grain number comes from photosynthesis after flowering, so this stage is the key period to determine grain weight. The direction of management is to protect roots and leaves, prolong the duration of high photosynthetic value of leaves, delay senescence and increase grain weight.

First of all, it is necessary to water the flowering water or grouting water. The water consumption of wheat from flowering to maturity accounts for 1/4 of the total water consumption in the whole growth period, which needs to be watered to meet the supply. Drought will not only affect grain weight, heading and flowering, but also affect the number of grains per ear. Therefore, on the basis of irrigated jointed water, watering once in the period from flowering to filling according to the soil moisture in the wheat field can meet the requirements of wheat growth in the later stage. However, excessive soil moisture before maturity will affect root activity and reduce grain weight, so wheat should be stopped from watering 10 days before maturity.

Secondly, to spray foliar fertilizer, foliar fertilizer can not only make up for the deficiency of root absorption and meet the nutrients needed for wheat growth and development, but also improve field microclimate, reduce the harm of dry and hot wind, enhance leaf function and delay senescence. Increase grain filling rate, increase grain weight and increase wheat yield. Therefore, foliar fertilizer spraying can be carried out from booting stage to early filling stage. Foliar topdressing had better be carried out after 4: 00 p. M. on a sunny day, spray again at an interval of 7-10 days, 24 hours after spraying, and make up for spraying once in case of rain. In order to simplify the operation, it can be combined with other field operation measures, such as mixing insecticides, fungicides and foliar fertilizer into a mixture and foliar spraying, which can prevent disease, insect and dry hot air at the same time.

Prevent the cold in late spring

In recent years, frost damage often occurs in April in our province. After wheat jointing in April, the ability to resist the low temperature below 0 ℃ was completely lost. When the cold wave came, the surface temperature plummeted below 0 ℃, and frost injury occurred in early spring.

The preventive and remedial measures for freezing injury in early spring are as follows:

First, irrigation to prevent frost damage in early spring. Because the heat capacity of water is larger than that of air and soil, watering before the cold current in early spring can increase the water vapor in the air near the ground layer, release latent heat when condensation occurs, and reduce the variation of surface temperature. At the same time, after irrigation, soil moisture increased, soil thermal conductivity and temperature increased.

Second, the remedial measures after freezing injury in early spring are fertilization and watering. Wheat should be applied with available nitrogen fertilizer and watering immediately after freezing in early spring. The coupling effect of nitrogen and water can promote early tillering, small tillers catch up with large tillers, increase the panicle rate of tillers and reduce the damage of freezing injury.

Integrated control of diseases and insect pests

Drought is beneficial to the occurrence of wheat spiders and wheat aphids. Wheat aphids and wheat spiders occur more seriously in northern and southern Shandong before winter, and some of them have caused harm. The overwintering base numbers of wheat sheath blight, powdery mildew, underground pests and gray planthopper in rice stubble wheat field in the south are also on the high side. After wheat jointing, with the increase of temperature, all kinds of diseases and insect pests gradually enter the high incidence period, we should pay attention to do a good job in prediction and timely prevention and control. The focus of control is wheat aphids, wheat spiders, underground pests, sheath blight, powdery mildew, total erosion, root rot, leaf rust, gray planthopper and other diseases and pests, and guard against the prevalence of wheat stripe rust.

To control wheat spiders, 0.9% avermectin EC 3000 times can be used to control wheat trematodes. In the first and middle of April, 1-1.5kg of 5% methyl isophosphates granules or 150,200ml of 40% methyl isophosphates EC were used to spread 30-40kg of fine sand or fine sandy soil on the ground and plough hoe, and the effect of watering was better.

For the control of underground pests, 40% methyl isophosphates EC or 50% phoxim EC can be used to spray wheat stems with 40-50 ml per mu.

To control wheat aphid, 10% imidacloprid EC can be used to spray 10-15 grams per mu, and to control gray planthopper.

To control wheat trematode, during the peak period of adult occurrence from wheat heading to the early flowering stage, 50% cypermethrin EC 20-30 ml was sprayed on water, and the first generation of cotton bollworm was treated.

To control sheath blight, use 5% Jinggangmycin water 150-200 ml per mu to spray 75-100 kg of water at the base of the wheat stem, and spray again at intervals of 10-15 days.

To control powdery mildew and rust, you can use 20% trimethoprim EC 50-75 ml per mu.

To control gibberellin, leaf blight and glume blight, 50% carbendazim wettable powder can be sprayed 75-100 grams per mu, and the mixture of the above diseases and pests can be used to control the disease and insect pests.

For the plots with more weeds, manual methods should be used, and herbicides should not be used to control them, because the use of herbicides after wheat jointing is not effective on the one hand, and it is easy to cause drug damage to wheat on the other hand.