Quantifying the influence of management strategies on surface radiation budgets and energy patterns in tea fields

Abstract

The surface energy balance from canopy to landscape scales in crop fields plays an essential role in surface–atmosphere interactions, and it is strongly influenced by the management strategies and field practices of farmers. To characterize how different agricultural practices of farmers affect the microenvironment in perennial crop fields, long-term observation of the radiation budget and energy components under different field practices was undertaken in two neighboring tea fields with different management strategies (a conventional operation and an organic-certified field managed by different farmers) in northern Taiwan. The results showed that the difference in the radiation budget in these two tea fields was minor (only 1% for net radiation), but the differences in the energy components were more significant (sensible heat was 10% lower and latent heat was 25% higher in the organic-certified field than in the conventional field) due to highly distinct practices in these two fields. This finding implies that the organic-certified application could lower the partitioning of sensible heat flux and increase the latent heat flux, thereby reducing the temperature variation and decreasing the vapor pressure deficit. The organic-certified field reduced the surface heating in terms of the long-term energy patterns. This study’s findings also indicate that field practices in a conventional field can increase the sensible heat flux (51.5% at noon time) on short-term time scales, compared with only 9.6% in an organic-certified field. Furthermore, this study offers a comprehensive understanding of tea field practices, a scientific basis for in-field water conservation, and a quantitative analysis for modeling from micro to regional scales.

Keywords

• canopy structure
• organic agriculture
• perennial crop
• energy partitions