Fertilization techniques for pest control of wheat in winter and spring

When the temperature is low in winter and early spring, the following two points should be paid attention to in pest control and fertilization in wheat fields:

Spraying omethoate is more effective than dimethoate in pest control, such as aphids and red spiders. Because the toxicity of dimethoate to pests decreased significantly with the decrease of temperature, while the efficacy of omethoate was less affected by temperature, and it could play a normal insecticidal effect below 15 ℃. Similar to omethoate, fenvalerate was more effective at 15 ℃ than at 25 ℃.

Fertilizing and topdressing ammonium bicarbonate is better than urea. Ammonium bicarbonate can be directly absorbed by wheat after being applied to the soil, while urea needs to be converted to ammonium carbonate under the action of urinary bacterial enzymes in the soil to be absorbed by roots. The rate of urea conversion mainly depends on the soil temperature at that time; under normal circumstances, all urea applied into soil is converted into ammonium carbonate, which takes 7 to 10 days when the soil temperature is 10 ℃. It can be seen that the effect of applying ammonium bicarbonate is faster than that of urea in winter or early spring. If urea is applied, the growth of wheat seedlings will often be affected because the fertilizer effect is slow.