Evaluation of Crop Water Status and Vegetation Dynamics For Alternate Partial Root-Zone Drip Irrigation of Alfalfa: Observation With an UAV Thermal Infrared Imagery

Abstract

Characterization of the spatiotemporal patterns of crop water status and vegetation dynamics are a prerequisite to overcome water scarcity and obtain precise agricultural water management. Based on high-resolution aerial thermal imagery, we estimated crop water stress index (CWSI), transpiration rate (T), and crop growth status. The research was conducted with conventional subsurface drip irrigation (abbreviated as R) and alternate partial root-zone drip irrigation (abbreviated as P) under four different irrigation quotas: 0 mm, 10 mm, 20 mm, and 30 mm, which are denoted as CK, R10 (P10), R20 (P20), and R30 (P30), respectively. Results indicate that the CWSI is a suitable tool to define alfalfa water status under different irrigation regimes. The CWSI values reflect CK > R10 > R20 > P10 > P20 > R30 > P30, with values of 0.57, 0.41, 0.26, 0.24, 0.18, 0.17, and 0.13, respectively. The T values show that CK < R10 < P10 < R20 < P20 < R30