Detection of delay in post-monsoon agricultural burning across Punjab, India: potential drivers and consequences for air quality

Abstract

<p>Since the Green Revolution in the mid-1960s, a widespread transition to a rice-wheat rotation in the Indian state of Punjab has led to steady increases in crop yield and production. After harvest of the summer monsoon rice crop, the burning of excess crop residue in Punjab from October to November allows for rapid preparation of fields for sowing of the winter wheat crop. Here we use daily satellite remote sensing data to show that the timing of peak post-monsoon fire activity in Punjab and regional aerosol optical depth (AOD) has shifted later by approximately two weeks in Punjab from 2003-2016. This shift is consistent with delays of 11-15 days in the timing of maximum greenness of the monsoon crop and smaller delays of 4-6 days in the timing of minimum greenness during the monsoon-to-winter crop transition period. The resulting compression of the harvest-to-sowing period coincides with a 40% increase in total burning and ~50% increase in regional AOD. Potential drivers of these trends include agricultural intensification and a recent groundwater policy that delays sowing of the monsoon crop. The delay and amplification of burning into the late post-monsoon season suggest greater air quality degradation and public health consequences across the densely-populated Indo-Gangetic Plain.</p>

Impact of Urban Growth on Air Quality in Indian Cities Using Hierarchical Bayesian Approach

“…Checking relative contributions for the month of November across the years shows that contribution of agricultural fires has increased from the 2001-2005 period (2.5%) to the 2010-2015 period (5.2%). This is due to recent groundwater related policy that suggests delay in sowing of the crop [87]. It is also seen that contribution of residential areas has increased from 2001 (29.7 ± 8.0%) to 2015 (40.0 ± 10.9%).…”

Crop residue burning practices across north India inferred from household survey data: bridging gaps in satellite observations

“…Following Zhang et al (2014) and Liu et al (2019b), we estimate the start, midpoint, and end of the cumulative FRP during each post-monsoon burning season from 2003-2018:…”

“…The practice of agricultural burning in north India gained traction with the rise of combine harvester use in the mid-to-late 1980s (Badarinath et al 2006, Liu et al 2019b. Mechanical harvesting generates abundant root-bound and loose crop residues that are difficult to manage manually, and steady increases in crop production have added to the volume of excess residues.…”

“…Mechanical harvesting generates abundant root-bound and loose crop residues that are difficult to manage manually, and steady increases in crop production have added to the volume of excess residues. For many farmers, burning is a convenient, cost-effective method to remove crop residues and quickly transition between the monsoon (kharif) and winter (rabi) crops; observations of active fires and burned area shows increases of ~40-142% from 2003-2016 in the western Indo-Gangetic Plain (IGP) (Liu et al 2019a(Liu et al , 2019b. Both satellites and ground-based monitors have detected enhanced aerosol loading downwind of smoke plumes from agricultural fires across north India in recent years (Badarinath et al 2009, Kaskaoutis et al 2014, Jethva et al 2018, Sarkar et al 2018.…”

“…Much of the focus in the literature so far has been on agricultural fires in Punjab and Haryana, two northern states that account for over 90% of post-monsoon fire intensity in India (Vadrevu et al 2013, Sarkar et al 2018, Liu et al 2019b. Less is known about burning practices elsewhere in north India, such as Uttar Pradesh (UP) and Bihar, where many farmers also follow a rice-wheat rotation (Singh et al 2011).…”