[en] An artificial rainfall spiked with tritium, marks the boundary between older rain-water below and younger rain-water above. When the tracer mark has reached a certain depth the amount of soil water above the tracer mark gives that fraction of the rain fallen since the date of tracer input, which is still present in the soil. The principles of the method have been dealt with in a preceding paper. The present paper contains new data. This includes field experiments in sands showing larger dispersion effects than found previously. Larger dispersion is usually combined with a scatter in the position of the tracer maximum in parallel cores. A theoretical discussion of dispersion is given. Among recent improvements in sample processing is a newly developed plant to distill six samples simultaneously, which makes it possible to process several hundred samples a month without much handling. The change in stable isotope composition of the soil water during the downward movement has also been studied in detail. Experiments show that plant transpiration results in practically no isotopic enrichment of the soil water. The considerable average velocity with which the water moves upwards from the root to the leaves through the fine leads of the stem makes this possible despite the heavy enrichment of the water in the leaves. Under Central European conditions a bare soil may, however, show a deuterium enrichment up to about 20 per mille in the top layers. It is obvious that evaporation from the soil, and therefore enrichment, is strongly suppressed by plant cover (grass etc.) especially during summer. This seems to be the reason that the resulting enrichment in densely planted soil is quite small (less than 5 per mille for deuterium). Owing to the lack of a reliable reference value this is difficult to detect. A bare soil under the same conditions as a planted one showed in a number of measurements an extra deuterium enrichment of about 10 per mille on the average compared with the latter. Laboratory experiments on bare-soil evaporation are also presented. With the help of information obtained by tracer experiments on the seasonal variation of groundwater recharge it is now possible to explain the absolute value found for the deuterium content of Central European groundwater. (author)