INFLUENCE OF ENSO ON LENGTH OF GROWING PERIOD OVER TAMIL NADU

M. VENGATESWARI¹*, V. GEETHALAKSHMI², K. BHUVANESHWARI³, S. PANNEERSELVAM^4
1Subject Matter Specialist, ICAR-Krishi Vigyan Kendra, Ramanathapuram, 623 407, Tamil Nadu Agricultural University, Coimbatore, 641 003, Tamil Nadu, India
²Directorate of Crop Management, Tamil Nadu Agricultural University, Coimbatore, 641 003, Tamil Nadu, India
³Subject matter specialist, ICAR-Krishi Vigyan Kendra, Santhiyur, Salem, 636 203, Tamil Nadu Agricultural University, Coimbatore, 641 003, Tamil Nadu, India
⁴Water Technology Centre, Tamil Nadu Agricultural University, Coimbatore, 641 003, Tamil Nadu, India
* Corresponding Author : vengateswariagmet@gmail.com

Received : 15-01-2020     Accepted : 27-01-2020     Published : 30-01-2020
Volume : 12     Issue : 2       Pages : 9458 - 9460
Int J Agr Sci 12.2 (2020):9458-9460

Keywords : ENSO, Onset, Cessation, Soil moisture, LGP
Academic Editor : Argha Ghosh
Conflict of Interest : None declared
Acknowledgements/Funding : Authors are thankful to ClimaAdapt - The Ministry of Foreign Affairs in Norway and the Royal Norwegian Embassy. Authors are also thankful to Tamil Nadu Agricultural University, Coimbatore, 641 003, Tamil Nadu, India
Author Contribution : All authors equally contributed

Variability is a very important intrinsic characteristic of climate and it varies on all timescales, it can also be described as a combination of some preferred spatial patterns. Climate variability affects weather and climate on many spatial and temporal scales. The seasonal cycle is the most significant periodic climate variability mode. The opposite is true during La Niña. Daily rainfall data at district scale obtained from India Meteorological Department (IMD) for a period of 43 years (1971-2013) was categorized based on the ENSO episodes for assessing the impact of ENSO on seasonal rainfall variability and length of growing period (LGP) for rainfed cropping period (RCP, September-December). LGP was calculated in each district by estimating number of days between onset and cessation in addition to support from soil moisture for crop growth from the last spell of rainfall. The results revealed that the El Nino condition positively influenced the rainfed cropping period rainfall and vice-versa during La Niña years. Tamil Nadu experiences the LGP between 91 and 126 days (13-18weeks). The LGP was higher under El Nino followed by neutral and La Niña conditions.

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