Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
T1-06R-1005
Enhancement of Rainfed Cotton Production Through Supplemental
Irrigation in Vertisols Tract of Southern Tamil Nadu
M. Manikandan* 1 , S. Manoharan 1 , K. Baskar 1 , V. Sanjivkumar 1 , G. Guru 1 and
G. Ravindra Chary 2
1 AICRP for Dryland Agriculture, Kovilpatti Main Centre, ARS, TNAU, Kovilpatti – 628 501
2 ICAR- Central Research Institute for Dryland Agriculture, Hyderabad-500 059, Telangana
* manikandan.m@tnau.ac.in
Rainwater harvesting through farm ponds in the rainfed areas is one of the most promising
technology for enhancing crop productivity. Farm ponds would help the farmers to use stored
water for managing the dry spells during the season. Studies have revealed that providing SI
during dry periods at different stages of crop growth has improved the yields by 29 to 114 per
cent for different crops. SI not only increases the yield but also improves water productivity
when SI and rainwater are used conjunctively. Though sufficient records are available for SI
as an effective practice to alleviate dry spell effects, some challenges of SI are to plan the timing
and depth of water to be applied and the practical feasibility of storing and retaining water till
the period when crops needed despite heavy seepage and evaporation losses (Oweis and
Hachum, 2012). This study aims to assess the feasibility of using the farm pond water for giving
supplemental irrigation to rabi cotton, particularly for farmers having small size land holdings
in the rainfed areas.
Methodology
This research was conducted in AICRPDA Kovilpatti main centre at Agricultural Research
Station, Kovilpatti, Tamil Nadu in India from 2011 to 2021. Vertisols constitute nearly 70 per
cent of the total area. The depth of soil varies from 110 to 150 cm and the rate of infiltration is
0.9 cm hr -1 . Soil develops typical cracks at least one cm wide and reaches a depth of more than
50 cm during the period moisture stress. Annual average rainfall was 711 mm in 42 rainy days,
with respect to seasonal rainfall, the main contribution was from north east monsoon (NEM)
i.e. 393 mm. The experiment was conducted in rainfed cotton with two treatments viz. (i)
providing supplemental irrigation to the crop and (ii) pure rainfed crop. Cotton (KC3) was
grown with a spacing of 45 x 15 cm on the ridges, furrows were formed by 45 cm spacing.
Crops were cultivated and all the practices were followed as per the crop production guide of
Tamil Nadu State. A rectangular shaped farm pond of 25 m x 13 m x 1.5 m, lined with random
rubble masonry was used for harvesting runoff from a one ha catchment area. A 5 HP diesel
engine was used for pumping water from the pond. One raingun with tripod stand having
discharge rate of 3.5 lps and radius of throw of 20 m was used for sprinkling water. Changes
in water level in the farm pond were observed during the rainy season and runoff drained into
26 | Page Resilience through land and water management interventions, water management and governance