Using UAV-thermal imaging to calculate crop water use and irrigation efficiency in a flood-irrigated pecan orchard

Pecans are a major crop in New Mexico’s Lower Rio Grande Valley (LRGV) where about 30 % of pecans are produced in USA. Due to low amount of precipitation in the LRGV, pecans are highly depended on irrigation from surface and ground water. The area has gone through two decades of drought which has significantly reduced the availability of surface water. There is an urgent need for proper estimation of crop water use and irrigation scheduling to improve water use efficiency and productivity. The objective of this study is to extend a recently developed model for calculating real time pecan water use (ETa) from UAV-thermal imaging when the canopy cover is variable. The extended methodology was used to calculate ETa and seasonal irrigation efficiency. The calculated seasonal irrigation efficiency was compared with irrigation efficiency estimated by chloride tracing method. The results showed the proposed methodology can be used to calculate ETa and on-farm irrigation efficiency in the area when pecan canopy cover is changed. •Pecans are a major crop in southern New Mexico.•The recent UAV-thermal imaging based ET model was developed.•The real time pecan ET was calculated for the flood irrigation using the developed model.•Irrigation efficiency was calculated and compared with the chloride tracing method.