4. Conclusions The results indicate that the bio fertilizer, made from PK rocks plus earthworm compound inoculated with free diazo trophic bacteria (NPKB), and the bio protector (NPKP), produced from NPKB by the addition of fungi chitosan C. elegans, are effective on melons by promoting an increase in certain important commercial characteristics of fruit and in the NPK uptake. We conclude that NPKP and NPKP may be an alternative for NPK mineral fertilization.