The use of isotopes and radiation in research on soil-plant relationships

The main points made the FAO/IAEA International Symposium on the Use of Isotopes and Radiation in Research on Soil-Plant Relationships, held in Colombo, Sri Lanka, in December 1978, are reviewed. Full proceedings are being published by the IAEA. Papers were presented on isotope studies on soil and fertilizer nitrogen, N losses, fertilizer use and efficiency as applicable to various soils, crops and fertilizers. ¹⁵N was used in many studies. Salinity control in irrigated dry regions was discussed. A unique system for evaluating the dynamics of soil salinization and desalinization involving ²²Na in plexiglass column columns on soil was reported from Iraq. The synthesis and degradation of organic matter in soils were studied using isotopes. Much attention was paid to micronutrients in plant nutrition and the availability of different forms of P to crops. The range of isotopic methods employed in soil-fertility investigations on flooded rice soils was described. A variety of analytic methods were considered in some detail.