Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
from summer rains. The normal onset of monsoon occurs during third week of September and
prolonged dry spells are very common in this region mainly in August and September
coinciding with the vegetative and reproductive stages of the major rainfed crops such as
pearlmillet, castor, clusterbean, greengram and cowpea. The texture of the soil is sandy to sandy
loam. Even though FAO Penman-Monteith method has been recommended as the sole standard
method for ETo calculation (Allen et al., 1998), based on data availability for future scenarios,
the Hargreaves and Samani (1985) method was used in the present study. The runoff was
estimated spatially and temporally for a period of 63 years from 1951 to 2013 using IMD data
and also under changing climatic scenarios(2030s) using ENSEMBLE data of CMIP 5
corresponding to RCPs 4.5 and 6.0.
Results
Spatial and temporal variation of rainfall and irrigation requirement of major crops in the
current and climate change scenarios
Long term data from 63 years (1951 to 2013) is analyzed spatially and temporally to find the
variability of rainfall patterns. At the Northern Gujarat zone, most of the sub-districts have rainfall
ranged from 480 to 860 mm. The spatial and temporal variation in rainfall was analysed during 21
years interval (1951-1971, 1972-1992, and 1993-2013). There was an increase in the number of
high rainfall blocks. This shows the climate change impacts and there is an increased potential for
rainwater harvesting and its utilization in the region, especially in the high rainfall blocks. Under
climate change scenarios, irrigation requirements of major crops such as pearlmillet, castor,
clusterbean, cowpea and green gram are predicted. An increase in the irrigation requirement of
pearl millet is predicted for all the districts by 2030s compared to the baseline period under RCP
4.5 and 6.0. Other crops have an increase in the irrigation requirementin some areas where as
decrease in other areas by 2030s as in case of castor, clusterbean and greengram under both the
scenarios. In case of castor and greengram, only a slight increase is noted in some areas and in case
of clusterbean, the increase is negligible. Based on the irrigation requirement, water availability in
the region and net profit from different crops, the optimization models were formulated for
determining the optimal cropping patterns to enhance the farmers' income from the study area under
the current scenario.
Conclusion
In this study, the irrigation requirement of major crops was determined using Hargreaves method
and GIS during 1951-2013 and for 2030s using ENSEMBLE data of CMIP 5.0. There was an
increase in the number of high rainfall blocks. An increase in the irrigation requirement of pearl
millet is predicted for all the districts by 2030s under RCP 4.5 and 6.0 compared to baseline period.
Other crops have an increase in the irrigation requirementin some areas whereas decrease in other
areas by 2030s as in case of castor, clusterbean and greengram under changing climatic scenarios.
Resilience through land and water management interventions, water management and governance
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