Which of the following methods can reduce soil compaction before applying fumigants?

Soil cultivation to create air pockets is an effective method to reduce soil compaction before applying fumigants. This process involves loosening the soil structure, which increases porosity and allows for better air circulation and the movement of fumigants. By breaking up compacted soil layers, cultivation helps to improve the overall soil health and enhances the efficacy of the fumigants, ensuring they can penetrate the soil more effectively.

In contrast, heavy rainfall can actually increase soil compaction as it can lead to waterlogging and create a denser soil structure. Over-irrigation has a similar effect, as excessive water can cause soil particles to compact further, making it harder for fumigants to move through the soil. Removing all vegetation can leave the soil exposed, potentially leading to erosion and further compaction due to the lack of root structure that supports soil aeration and integrity. Thus, creating air pockets through cultivation stands out as the most beneficial practice before the application of fumigants.