Can Chemical Fertilizers Be Mixed with Pesticides? A Clear Explanation of the Precautions in One Article

The mixed use of chemical fertilizers and pesticides can both provide crop nutrients and prevent diseases, control pests, and kill weeds, and is a technique widely adopted in recent years. Its benefits include:

① Improving pesticide efficacy. For example, adding 0.3-0.4 kg of urea to sodium salt can significantly improve the weed-killing effect. This is because adding chemical fertilizer can promote the absorption of sodium salt, thereby improving the weed-killing effect;

② Improving fertilizer efficacy.For example, mixing prometryn with nitrogen fertilizer can improve the effect of nitrogen fertilizer;

③ Improving work efficiency.When applying the first nitrogen fertilizer topdressing to early rice, mixing in the herbicide fucaxing can both supply nutrients and control weeds. Although the mixed use of fertilizers and pesticides has many advantages, not all fertilizers and pesticides can be mixed. Whether they can be mixed should be based on two principles: First, do not reduce fertilizer efficacy and pesticide efficacy. For example, ammonium nitrogen fertilizer or water-soluble phosphorus fertilizer cannot be mixed with alkaline pesticides such as Bordeaux mixture, otherwise the effective components of the fertilizer will be reduced; Second, after mixing, it must be harmless to crops. Usually, when highly selective herbicides, such as phenoxy acid herbicides, are mixed with chemical fertilizers, they not only do not cause harm to crops, but also improve the weed control effect. 

Looking at trials in various places, the following fertilizers and pesticides can be mixed:

① Mancozeb can be mixed with urea, magnesium sulfate, ammonium sulfate, etc.;

② Herbicides such as MCPA, trifluralin, bensulfuron-methyl, fucaxing, and butachlor can be mixed with urea or compound fertilizer;

③ Plant growth regulators such as gibberellin, triacontanol, and duoshouduo can be mixed with urea, potassium dihydrogen phosphate, and boric acid for spraying. When fertilizers and pesticides are mixed, attention must be paid to the mixing method. If both the chemical fertilizer and the pesticide are solid and both are applied to the soil, the two can be directly mixed together, spread on the surface, and then plowed into the soil. If the pesticide is a wettable powder, first moisten the surface of the fertilizer with a small amount of water, then add the pesticide powder and mix thoroughly. If the pesticide is an emulsifiable concentrate or aqueous formulation, it can be poured directly onto the fertilizer and mixed; if it is too wet, a small amount of dry fine soil can be added. If foliar spraying is needed, the emulsifiable concentrate, aqueous formulation, or wettable powder pesticide can be mixed with the chemical fertilizer into a solution before application.