Authors: S. Syed Imran1 and K. Baghyalakshmi2
1Scientist, Agricultural Mechanization Division, ICAR-Central Institute of Agricultural Engineering, Bhopal, Madhya Pradesh
2Scientist, Division of Crop Improvement, ICAR- Central Tobacco Research Institute, Rajahmundry, Andhra Pradesh
Climate is the main factor that influences any agricultural operation starting from field preparation to harvesting. Agriculture which relays on the climatic condition contributes to 10 per cent of Gross Domestic Product and provides employment for about 60 percent of the rural work force in Tamil Nadu. Temperature, humidity, rainfall, wind, atmospheric pressure, precipitation and other metrological condition decides the climatic condition of a particular place. Since the past few years the cropping pattern is experiencing a change due to the weather prevailing in the area. The effects of climate change have been found to have implications for dryland and irrigated crop yields as well as irrigation water use (Rosenzweig and Iglesias, 1994). Except rainfall, all other climatic factors are uniform and have little influence on crop yield. The drastic changes in the rainfall pattern of Tamil Nadu affect the significant area under cultivation.
Tamil Nadu is the eleventh largest and the seventh most populous state (6%) in the country. The cultivated area of the state is 4.7 million ha, comprising 36% of the total geographical area. The irrigated area covering 2.15 million ha is 46% of the cultivated area. The cropping intensity is around 113%. The red and black soils are deficient in nitrogen, phosphorus and zinc. The major crops are rice, jowar, bajra, maize, cotton, groundnut, mungbean, urdbean, banana and sugarcane (www.tn.gov.in). A clear knowledge on rainfall of a particular area, it would be possible to plan the production strategies suitable to that area in a better way. The major amount of rainfall is obtained through northeast monsoon followed by southwest monsoon. The table below shows the rainfall, production and productivity of major categories of food crops for the past four years.
| Year | Rainfall | Cereals | Pulses | Oilseeds (Groundnut) | ||||
| South west | North east | Productivity Kg/ha | Production ‘000 Tonnes | Productivity Kg/ha | Production ‘000 Tonnes | Productivity Kg/ha | Production ‘000 Tonnes | |
| 2012-13 | 245 | 370 | 2526 | 5393 | 415 | 213 | 2314 | 786 |
| 2013-14 | 325.4 | 294.3 | 3907 | 10389 | 752 | 614 | 2721 | 916 |
| 2014-15 | 305.5 | 430.3 | 4419 | 12028 | 868 | 767 | 2753 | 925 |
| 2015-16 | 309.4 | 341.1 | 4429 | 13800 | 815 | 900 | 2464 | 1385 |
| 2016-17 | Rainfall deficit of about 19 to 57 per cent was observed in different areas of the state | |||||||
From the above table, it is clear that there was a drought during 2012-13 where both southwest and northeast monsoons failed to give the expected rainfall. The failure in both the monsoon had greater impact on the production and productivity of all the food grains. There was approximately 50% decrease in production of cereals, 70% decrease in pulses and 10% decrease in oilseed compared to next year. In the year 2013-14, there was low rainfall during NE monsoon while the SW monsoon yielded normal rainfall. The failure in NE monsoon had an impact on rice cultivation whereas the pulse which is grown during summer was not affected to a greater extent. The following year 2014-15 there was normal rainfall pattern hence production of all food grains are higher than previous years. The data on rainfall and crop yield is yet to be published for the year 2016-17. It was estimated a rainfall deficit of about 19 to 57 per cent in different areas of the state (www.agritech.tnau.ac.in). This will have a considerable effect on the production of the food grains. On January 2017, Tamil Nadu government declared a drought situation in the state. Tamil Nadu had targeted 14.5 lakh hectares under rice in 2016-17, but only 7.18 lakh hectares had been sown until January 5, 2017. It is 3.5 lakh hectares or 33% less than the four year sowing average of 10.68 lakh hectares ( www.indiaspend.com).
Conclusion
The impact of climate change is expected to be negative overall, threatening global food security. For a state like Tamil Nadu, rainfall decides the food grains production and productivity in the significant area in both rainfed and irrigation agriculture. It is identified that the monsoon rainfall are very useful to agriculture production. Predicting the monsoon and deciding the crops as per the monsoon will increase the production of food grains. The catchment reservoirs could be cleaned before the raining season to increase the water holding capacity of the dams which serves as a major irrigation source for the agricultural lands. The government should take the action of national level river linking system/Project soon to save or preserve the agricultural land.
References:
Rosenzweig, C. and A. Iglesias (eds). (1994). Implications of Climate Change for International Agriculture: Crop Modeling Study. EPA 230-B-94-003.
www.agritech.tnau.ac.in
www.indiaspend.com
www.tn.gov.in
About Author / Additional Info:
I am currently working as Scientist at ICAR- Central Institute of Agricultural Engineering, Bhopal.