By Ankit Yadav
Key Takeaways
Residual herbicides don't behave the same in every field. Soil texture, organic matter and pH all influence herbicide performance.
More isn't always better. Herbicide rates are adjusted for soil conditions because clay and organic matter can bind herbicides and reduce their effectiveness.
Know your soil pH before choosing products. Soil pH can affect herbicide activity, crop safety and rotational crop restrictions, particularly for atrazine, isoxaflutole and several Group 2 herbicides.
Read both your soil test and the label. Matching herbicide selection and rates to your field conditions is essential for effective, safe weed control.
Why do the same herbicides perform differently from one field to another? The answer often comes down to soil properties and weather conditions.
Soil-applied residual herbicides — also known as pre-emergence herbicides — are a cornerstone of integrated weed management in corn production fields (Figure 1). By controlling weeds as they germinate, residual herbicides reduce early-season crop–weed competition, protect yield through the critical weed-free period, and widen the window for post-emergence herbicide applications.
Yet a residual herbicide's performance depends on more than the herbicide itself. To control germinating weeds, the herbicide must remain available in the soil long enough to reach emerging seedlings at an effective concentration. This means both weed control and crop safety depend on soil and environmental factors: soil texture, organic matter, cation exchange capacity (CEC, a measure of a soil's ability to hold nutrients), moisture, microbial activity, temperature, and the timing of the rainfall or irrigation that fully activates residual herbicide.
Source : unl.edu