Different countries could have R&D policies of evaluatiing indigenously available materials which could be incorporated with fertilizers to enhance their use efficiency as well as reduce adverse effects on environment. For eg. research has been done in India on using indigenous materials such as neem (Azadirachta indica) cake, pyrites and natural essential oils and derivatives for enhancing N-use efficiency in a variety of cropping systems and soil conditions. Government of India has taken a poilicy decision to coat all the manufactured urea with neem oil in the country ( Prakasa Rao et al., 2017). The paper is attached.
Д-р. E.V.S. Prakasa Rao