Energy balance and crop water stress in winter maize under phenology-based irrigation scheduling |
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Authors: | Gouranga Kar Ashwani Kumar |
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Institution: | (1) Department of Agro Meteorology, Water Technology Center for Eastern Region (ICAR), P.O.: S.E Railway Project Complex, Chandrasekharpur, Bhubaneswar, Orissa, 751023, India;(2) Department of Agricultural Engineering, Water Technology Center for Eastern Region (ICAR), Bhubaneswar, India |
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Abstract: | In eastern India, cultivation of winter maize is getting popular after rainy season rice and farmers practice irrigation scheduling
of this crop based on critical phenological stages. In this study, crop water stress index of winter maize at different critical
stages wase determined to investigate if phenology-based irrigation scheduling could be optimized further. The components
of the energy budget of the crop stand were computed. The stressed and non-stressed base lines were also developed (between
canopy temperature and vapor pressure deficit) and with the help of base line equation, (T
c − T
a) = −1.102 VPD − 3.772], crop water stress index (CWSI) was determined from the canopy-air temperature data collected frequently
throughout the growing season. The values of CWSI (varied between 0.42 and 0.67) were noted just before the irrigations were
applied at critical phenological stages. The soil moisture depletion was also measured throughout the crop growing period
and plotted with CWSI at different stages. Study revealed that at one stage (silking), CWSI was much lower (0.42–0.48) than
that of recommended CWSI (0.60) for irrigation scheduling. Therefore, more research is required to further optimize the phenology-based
irrigation scheduling of winter maize in the region. This method is being used now by local producers. The intercepted photosynthetically
active radiation and normalized difference vegetation index over the canopy of the crop were also measured and were found
to correlate better with leaf area index. |
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Keywords: | |
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