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The potential of the spectral ‘water balance index’ ( WABI ) for crop irrigation scheduling
Author(s) -
Rapaport Tal,
Hochberg Uri,
Cochavi Am,
Karnieli Ar,
Rachmilevitch Shimon
Publication year - 2017
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.14718
Subject(s) - vineyard , environmental science , sunflower , irrigation , irrigation scheduling , water balance , agronomy , deficit irrigation , chemistry , horticulture , biology , irrigation management , geotechnical engineering , engineering
Summary Hyperspectral sensing can detect slight changes in plant physiology, and may offer a faster and nondestructive alternative for water status monitoring. This premise was tested in the current study using a narrow‐band ‘water balance index’ ( WABI ), which is based on independent changes in leaf water content (1500 nm) and the efficiency of the nonphotochemical quenching ( NPQ ) photo‐protective mechanism (531 nm). The hydraulic, photo‐protective and spectral behaviors of five important crops – grapevine, corn, tomato, pea and sunflower – were evaluated under water deficit conditions in order to associate the differences in stress physiology with WABI suitability. Rapid alterations in both leaf water content and NPQ were observed in grapevine, pea and sunflower, and were effectively captured by WABI . Apart from water status monitoring, the index was also successful in scheduling the irrigation of a vineyard, despite phenological and environmental variability. Conversely, corn and tomato displayed a relatively strict stomatal regime and/or mild NPQ responses and were, thus, unsuitable for WABI ‐based monitoring. WABI shows great potential for irrigation scheduling of various crops, and has a clear advantage over spectral models that focus on either of the abovementioned physiological mechanisms.