Natural resources management, resource recovery & reuse, urban agriculture, safe wastewater use, soil fertility & plant nutrition.
International Board for Soil Research and Management (IBSRAM). Pay served as scientific and technical advisor for WHO, FAO, DGIS, IDRC, SIDA, UN-Water and EU funded projects and expert groups and supervised a large number of graduate and postgraduate students. Pay authored or co-authored nearly 350 publications, half in peer-reviewed books and journals. He has worked extensively in West and East Africa, and South and South-East Asia. After longer stays in Thailand, Rwanda and Ghana, Pay is based since 2009 at IWMI HQ in Sri Lanka.
English, German and French