Agriculture is the biggest consumer of water resources worldwide.Water conservation requires an effective and rational control of evaporation (E). Both evapotranspiration (ET) partitioning and water source prediction, i.e. the primary soil layers that provide water for root water uptake, are necessary for arranging irrigation schedules.
Researchers from Xishuangbanna Tropical Botanical Garden (XTBG) combined modeling and micrometeorological approaches as a way to provide an integrated analysis of ET partitioning. An improved Shuttleworth-Wallace (SWH) model and the MixSIAR model were used for ET partitioning and water source prediction in an irrigated cropland in the North China Plain. Specifically, performance of the SWH model was evaluated using the micro-lysimeter measurements.
The experiments were conducted at the Luancheng Agro-ecosystem Experimental Station (37°50′ N, 114°40′ E, 50m), located in the North China Plain.
Using isotopic labels, the researchers assessed plant water sources for winter wheat over one growing season. Water fluxes for various pools were calculated according to water conservation principles. Based on the MixSIAR model, they calculated proportional contributions of each water source to winter wheat.
Combined with the eddy covariance technique, the SWH model had satisfactory estimates of E in a winter wheat cropland.
Evaporation of the SWH model was similar to micro-lysimeter results. T/ET was 71.4% for the growing season based on the model results. Wheat derived 78.1±8.9% of its water from the 0–50cm soil depths.