CHANGES OCCURING IN NUTRIENT-CONTENTS OF SOILS FOLLOWING STEAM STERILIZATION
In recent years, a large number of works have been devoted to the effects of steam sterilization on physical and chemical characteristics of the soil and of the cultural substratum (Howlett 1964, Wiebe & Wetzold —1969, Single & Pathac — 1970, Woods & Cowerkers 1972, Raicu & Lacatus 1972, Maianu & Ghidia — 1975). Conclusions are in agreement upon the evolution of nitrogen and of manganese. However it comes to phosphorus, potasium and magnezium conclusions are far from being as clean, being often inconsistent. Owing to the high temperatures and humidity levels which prevail during such treatments; phenomena accuring in the soil are very complex and depend on several physical, chemical and biological factors. The large range of results may thus be explained, from both qualitative and quantitative standpoints. Therefore efforts to solve these problems are essential.