The Role of Soil Organic Matter and Manures in Sustainable Nutrient Cycling - Sustainable Management of Soil Organic Matter - page 262

Fig. 4.5.3. DOC concentrations in runoff and drainage waters with daily rainfall. Note the
response of DOC to rainfall intensity. See Table 4.5.1 for notation.
in exported water with daily levels of rainfall over the whole 2-month period
did not show any significant relationships. Explanations for this include:
(i) grab samples were taken only once per day and flow rates at the time of
sampling may not have reflected the amount of rainfall measured for that
day (e.g. heavy rain during an evening, night or weekend may have gone
through the system before the next sampling took place); and (ii) concen-
trations of DOC in runoff from the undrained plots gradually declined with
time (see Fig. 4.5.3 for example).
A subsequent intensive (sampling every hour over 12 h) study of drain
flow rates and the organic composition of the runoff and drainage waters