Building soil fertility is part of project opportunity 3.1 : Improving year-round vegetable production and resilience, and this area can be improved.
Unfortunately, obtaining the baseline data specific to this topic was not part of EWB Challenge’s scoping process. This journal provides a good background of the nutrient status of Cambodian soils, and you might find this a good starting point in your research.
Regarding the tools they use in farming, you can check the variety of tools in the Interactives: Site Walkthroughs.
I hope this helps.
All the best,