Drier pre-monsoon can have a harmful impact on crop production
Pre-monsoon rainfall was in the ‘large deficient’ category in 18 of the 36 hydrological sub-divisions as of April 19, according to the latest data by the India Meteorological Department, Pune (IMD).
Two divisions — East Uttar Pradesh and Saurashtra and Kutch — after March 1 had no rainfall, the data showed.
Only eight sub-divisions had ‘large excess’ rainfall. Madhya Maharashtra and Arunachal Pradesh were the only two subdivisions with ‘normal’ rainfall, according to IMD.
Rainfall in sub-divisions (March 1-April 19, 2022)
Source: IMD
Even in the peninsular region of India, which till April 19 had a wetter pre-monsoon, the variation is stark. The western sub-divisions of peninsular India experienced ‘excess’ to ‘large excess’ rainfall, the IMD data showed. The eastern sub-divisions Telangana, coastal Andhra Pradesh and Yanam as well as Rayalaseema had a drier pre-monsoon.
Hydrological sub-divisions of IMD are demarcations based on the climate of a region.
The country as a whole experienced a drier pre-monsoon season, with a current deficiency of 32 per cent compared to what it normally receives at this time of the year (March 1 to April 19, 2022).
A month-wise analysis showed that the country had a rainfall departure of a little over -70 per cent in the month of March. But in April (1 to 19), the country saw a normal pre-monsoon, with rainfall departure of 17 per cent over the normal, according to IMD.
The overall normal pre-monsoon in April can be attributed to the peninsular region of India as well as the east and northeast regions recording a large excess rainfall of 81 per cent and 72 per cent respectively. Northwest and central India, on the other hand, recorded a ‘large deficient’ rainfall of -94 per cent and -66.5 per cent, respectively.
This trend of large variation in rainfall departure across the country is highlighted when analysing the pre-monsoon period from March 1 to April 19. The country witnessed a ‘deficient’ pre-monsoon — 32 lower than normal — according to IMD. But peninsular India and the east and northeast India received ‘excess’ and ‘normal’ rainfall respectively.
There is no clear trend illustrating how a drier pre-monsoon affects the onset of the southwest monsoon. But from an agricultural perspective, pre-monsoon rainfall is important for a lot of crops.
Rainfall during this period, called ‘tea shower’ in Assam, is very important for tea plantations across the northeastern state for increasing the quality and aroma of the flush as well as productivity.
In West Bengal, the pre-monsoon showers are called ‘Kalboishaki’ and are important for spring rice crops.
In southern India and along the Konkan coast, where it is called ‘mango showers’, the pre-monsoon rainfall helps in the ripening of the mangoes, while also preventing the fruit from falling off the branches before they ripen.
Pre-monsoon rainfall also has an effect on the quality of both litchi and coffee crops.
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