Bimal Bahadur Kunwar You can try microwave treatment of your soil samples.
Reference:
Brodie, G. (2022). Controlling Weeds with Microwave Energy. In: Horikoshi, S., Brodie, G., Takaki, K., Serpone, N. (eds) Agritech: Innovative Agriculture Using Microwaves and Plasmas. Springer, Singapore. https://doi.org/10.1007/978-981-16-3891-6_8
You can give heat treatment to your soil sample but it can also kill beneficial microorganisms, so use it with caution. One more method you can take is Solarization by using transparent plastic sheet. It is particularly effective during hot summer months.