Amid concerns that this year’s drastic fall in the mango crop yield in Andhra Pradesh is a fallout of climate change, a team of scientists predicted more such devastations by 2050. The scientists predict that the drought-prone regions of Andhra Pradesh are expected to experience a rainfall increase of 6.4-37.8 per cent by 2050 with negative economic consequences.
The study was done under the aegis of the Agricultural Model Intercomparison and Improvement Project (AgMIP), an international collaborative effort to improve agricultural modelling and to understand climate impacts on the agricultural sector at global, national and regional levels.
Climate change and mango yield
Koduru area in Rayachoti district, Andhra Pradesh, is known for its quality Benishan mangoes. But now the cultivation is under threat. This year, the yield came down to less than 50 per cent. Farmers dumped thousands of tonnes of mangoes in the local river as the fruit was damaged by insect attacks. This year, according to local horticultural officer Harinath Reddy, the pest and insects have compounded the problem of low yield. Reddy said, “The mango crop was badly hit by unseasonal rains between November 2021 and January 2022 that resulted in late flowering. Again, a sudden dry spell led to the withering of inflorescence. So, the yield was very low in the Koduru area. Now pests have attacked the crop,” he said.
A similar problem was faced in the neighbouring district of Chittoor as well, which is also known for mango cultivation. The yield was affected by late flowering and fruit set because of unseasonal rains in the region. According to the officials of the horticultural department, to sustain the crop, farmers applied high doses of chemicals that increased the number of male flowers, affecting the yield.
Both, Rayachoti and Chittoor districts are part of the rain-shadow region of Rayalaseema, which of late is experiencing unseasonal and heavy rains. In November 2021, the region received 11.1 cm of rainfall against the normal 3.2 cm, an increase of 250 per cent. The situation continued into January 2022, impacting the mango crop cycle which made the crop susceptible to pests and insects.
According to Dr Amit P Kesarkar, a scientist at National Atmospheric Research Laboratory (NARL) at Gadanki, Chittoor district, the Rayalaseema region, which normally receives rains from June to September, is now receiving more rains from October to December. “This is because of a south-ward shift in south-west monsoon emanating from the Arabian Sea,” he said.
Impact on Kurnool district
Against this backdrop, The AgMIP’s six-member team, consisting of scientists from ICRISAT and Tamil Nadu Agricultural University, warns that more than 60 per cent of chickpea (Bengal gram) farmers in the Kurnool district of Andhra Pradesh are expected to be hit by climate change by 2050. Kurnool district is also part of the rain-shadow Rayalaseema region.
The team was led by Prof Geethalakshmi, vice-chancellor, TNAU. The other members were Dr Dakshina Murthy, Dr Swamykannu Nedumaran, Dr Kumara Acharyulu, Dr Ponnuswamy Paramasivam and Dr Arunachalam Lakshmanan.
The findings of the team, which studied the cultivation of fallow chickpea under various possible climate scenarios, suggest that the majority of the fallow chickpea households (64 per cent in warmer climates and 48 per cent in wet climates) are vulnerable to climate change under the current production systems.
The team also predicted a per capita income decreased by 12 per cent in the hot-dry climate model. What makes the findings significant is that the majority of the farmers likely to be affected by climate change are small and marginal.
Talking to The Federal, team member Dr Swamikannu Nedumaran said the Kurnool district was chosen because fallow-chickpea farming is predominantly practiced under rain-fed conditions in the district and chickpea was the mandate crop of ICRISAT.
“Our main objective was to understand the climate change impacts on the rain-fed farming system in Andhra Pradesh. Kurnool district, which has a vast area under chickpea cultivation under rain-fed conditions, presents an ideal scenario for the study,” Nedumaran said. Because of the soil nature, agriculture in the district is predominantly a ‘fallow-chickpea’ cropping system.
For the study, the district was divided into low rainfall (less the 500 mm) and medium or high rainfall (between 700 mm to 800 mm) regions. All the models used in the study predicted higher temperatures in the 2050s in the district. The higher emission scenarios project warmer temperatures than the lower emission scenarios. All projections have predicted increased rainfall with a slight variation — 3 per cent to 27 per cent higher rainfall under one set of climate scenarios and 6 per cent to 40 per cent higher rainfall across other sets of climate scenarios.
Chickpea cultivation on the rise
“Major crops grown in the district are chickpea, groundnut, sunflower, rice, sorghum, cotton, pigeon pea, black gram and onions. Over the last 20 years, there has been a significant shift in crops grown in the district. Low rainfall, labour scarcity, increasing wage rates and a lack of available irrigation sources have encouraged farmers to farm water-efficient rainfed crops that require minimal labour. As a result, the amount of land dedicated to chickpea, groundnut and sunflower has increased. In 1991-1993, only 2.45 per cent of farmed land grew chickpea, but by 2008-2010, that percentage had increased to 23 per cent,” he said.
According to the Bengal gram Outlook Paper, 2021, prepared by Acharya NG Ranga Agricultural University, chickpea is cultivated in 1,56,000 ha in the Kurnool district which is far higher than in other districts.
Rise in temperature
The team has used an array of 29 climate models to analyse projected substantial warming over the district and precipitation increase in both the low and high rainfall regions. Five focus models selected by the team have predicted temperature rise from 0.51˚C-1.93˚C under the mid-range moderate emission scenario, and 0.46˚C-3˚C under the worst-case high emission scenario. The rainfall increase predicted is in the range of 2.9-26.7 per cent under the moderate emission scenario and 6.4-47.8 per cent under the high emission scenario, which makes the black soil unsuitable for chickpea cultivation.
“These climate scenarios are also characterised by higher carbon dioxide concentration, which is likely to interact with temperature and precipitation changes to impact plant growth cropping system responses,” the study said.
Stating that the climate variability and the inconsistent distribution of rainfall across the Kurnool district is the biggest challenge the rain-fed farmers face today, the team prescribes the adaptation packages as a possible solution to climate change. The adaptation package is meant to encourage climate-smart and resilience-focused farming methods. According to the team, the adaptation package includes the use of genetic improvements for crop yields, improved management practices and the use of new crops like small millet, etc.