In situ Method for Measurement of the Stem Flow of Maize

Measurement of stem flow is important for analyzing the water balance and evaluating the soil erosion in agricultural fields with crop stands under precipitation. Most used methods for stem flow measurement now are ex situ, this may yield big error because plant canopy structure is greatly modified. In this study, anin situ method was proposed for measuring stem flow of water for maize plant under natural condition. In this method, a high-water-adsorption-sheet (HWAS) was wrapped around the stem base, and the stem flow amount is the mass differences of HWAS measured before and after rainfall event. Results showed that the measured stem flow was approximately 41% of the total precipitation and canopy interception capacity was approximately 0.63 mm when the maize height is 220 cm and the leaf area index is 4.5. These results of stem flow rate and canopy interception capacity are confirmed by the data in the published literatures. The HWAS method is easy performance and reliable and is therefore recommended for in situ stem flow measurement as an alternative to the current methods.