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Water Use Dynamics in Double Cropping of Rainfed Upland Rice and Irrigated Melons Produced Under Drought‐Prone Tropical Conditions
Author(s) -
Morillas L.,
Hund S. V.,
Johnson M. S.
Publication year - 2019
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2018wr023757
Subject(s) - environmental science , agronomy , irrigation , cropping , melon , upland rice , water use , dry season , cropping system , crop , agriculture , biology , oryza sativa , horticulture , ecology , biochemistry , gene
Agricultural expansion and intensification is occurring in seasonally dry regions of Central America, while droughts are intensifying due to increasing water demand and climatic change. Empirical measurements of water consumption of major crops in this region are scarce but crucial to assess agricultural water use dynamics in the light of increasing regional water conflicts. We empirically quantify total crop water use (CWU) and water footprints (WFs) of rainfed upland rice (wet season) and groundwater‐irrigated melons (dry season) grown sequentially as a double cropping system, one of the major cropping systems in the seasonally dry province of Guanacaste in northwestern Costa Rica. Data for this study cover 2 years and were measured with a state‐of‐the‐art eddy covariance water and carbon flux station. Upland rice only consumed green water (CWU green = 383 L/m 2 ), while melons only consumed blue water (CWU blue = 177 L/m 2 ). Irrigation was found to be 1.5 times larger than the actual melon water consumption, with better irrigation efficiencies than reported for melon farms in Brazil but slightly inferior to farms in Spain. Melon WF blue was 79 m 3 /t, a much lower value than global and regional estimates reported but similar to values reported for melons produced in Brazil or Spain. Upland rice WF green (681 m 3 /t) was reported for the first time and was proven to be much lower than flood irrigated‐rice WF blue‐green . Our results demonstrated lower overall water demand for upland rice‐melon double crop compared to the two other major monocultures of the region (flood‐irrigated rice and irrigated sugar cane).