Contribution of plant root respiration to the CO2 emission from soil

The respiration activity of roots was studied in field experiments on gray forest and soddy-podzolic soils and under cropland and natural vegetation. It was shown that the contribution of roots to the CO2 emission from the soil surface depends significantly on the method of determination. The contributions of fine and coarse roots to the total root respiration were approximately similar in forest ecosystems. The use of the method of substrate-induced respiration made it possible to obtain the best estimates of the contributions of root respiration and respiration of microorganisms. The application of glucose in the form of a dry mixture with sand or talc instead of in the water-soluble form appeared to be the optimal procedure for determining the root respiration under field moisture conditions.