Spatial and temporal variability of irrigation water demand of processing tomato in the Northwest Arid Region of China

Abstract

【Objective】 Study on the spatial and temporal variability in water demand of processing tomato in the Northwest Arid Region of China is very essential for local agricultural water management and optimal allocation. 【Method】 Based on the meteorological data measured from 40 weather stations in 1985—2014 within the study region, the evapotranspiration (ETc) and irrigation water demand (Ic) were calculated for the processing tomato, using the modified crop coefficients and water balance equation. 【Result】 Spatially from the west to the east, the ETc and Ic of the processing tomato during different growing stages increased first and then decreased, with its value peaking in eastern Xinjiang, Gansu and Northwestern Ningxia and Inner Mongolia. The annual average ETc during the growing period of the tomato in Xinjiang, Gansu, Ningxia and Inner Mongolia were 460.98-1 202.69 mm, 591.14-749.92 mm, and 530.63-878.66 mm, respectively. Meanwhile, the annual average Ic in these three regions were 187.21-1 180.98 mm, 508.69-702.97 mm, and 354.94-851.14 mm, respectively. On the time scale of 30 years, the ETc and Ic in tomato growing period increased at a rate ranging from 0 to 30.0 mm/10 a. In particular, the ETc in Xinjiang and Gansu showed a significant increase, while the ETc in Ningxia and Inner Mongolia increased insignificantly. Additionally, the trend of average Ic in Ningxia and Inner Mongolia was not obvious. 【Conclusion】 The ETc and Ic over whole growing period of processing tomato in the study region showed strong spatial and temporal variability, and there is an urgent need to implement water-saving irrigation technology and strengthen the optimal allocation of water resources under the environment of climate change.

Keywords

• irrigation water demand
• processing tomato
• evapotranspiration
• spatial and temporal variability