The data presented were gathered in May-June 2009 over a wheat field near Merken, Germany in the framework of the TransRegio32 program. With the DBLS installed in homogeneous areas, turbulence is averaged both in time and space, allowing short averaging flux intervals down to a couple of seconds. When determining the averaging-time-dependent systematic and random errors in the H2O and CO2 fluxes, we found that eddy-covariance is not apt to measure 1-minute averaged fluxes, whereas our new method is. Even for 1-minute averaging intervals, our new method does not have a averaging-time-dependent systematic error and the random error is only halve that of the eddy-covariance method. Thus, we demonstrate that our new method reproduces reliable estimates of H2O and CO2 fluxes for 1-minute averaging intervals and show that not only individual plants, but also at field scales wheat responds rapidly to changes in solar radiation.