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

Abstract

In north India, agricultural burning adversely affects local and regional air quality during the post-monsoon season (October to November), when the prevailing meteorology is favorable for smog and haze formation. Quantifying the contribution of smoke to air pollution in this region, however, is challenging. While the Moderate Resolution Imaging Spectroradiometer (MODIS), aboard NASA’s Terra and Aqua satellites, provides a nearly 20-year record of global fire activity, the sensor cannot adequately capture small, short-lasting agricultural fires due to its moderate spatial resolution (500 m to 1 km) and limited overpasses (twice daily for each satellite), as well as the hazy conditions that typically obscure the north India land surface at this time of year. Moreover, current global fire emissions inventories based on MODIS observations can differ by up to an order of magnitude in this region. Here we incorporate household survey data to bridge gaps in MODIS observations and improve estimates of fire emissions over the states of Punjab, Haryana, Uttar Pradesh, and Bihar during the 2003-2018 post-monsoon burning seasons. We develop a novel method that adjusts MODIS Fire Radiative Power (FRP) for: (1) small fires detected by the Visible Infrared Imaging Radiometer Suite (VIIRS) at 375-m spatial resolution, (2) cloud/haze gaps in satellite observations, (3) partial-field burning practices, and (4) the diurnal cycle of fire activity. Adjusting FRP for the fire diurnal cycle yields the largest boost to emissions due to the short lifetime of the fires (~1/2 hour) and the brief windows of satellite detection. Using adjusted FRP, we estimate on average 10.8 ± 2.7 Tg dry matter (DM) burned each year, yielding emissions of 68 ± 17 Gg organic carbon (OC), 5.8 ± 1.5 Gg black carbon (BC), 821 ± 206 Gg CO, and 15.4 ± 3.9 Tg CO2. On average, our OC+BC emissions are ~250% higher than estimates from five widely used global fire emissions inventories. Our estimate for Punjab, which contributes two-thirds of emissions in the region, is consistent with our bottom-up validation, which uses burn rates from the household survey and government crop production statistics in 2016 and 2017. We spatially disaggregate the state-level emissions to construct a gridded inventory at daily, 0.25° x 0.25° resolution over north India from 2003-2018. The inventory, SAGE-IGP (Survey Constraints on FRP-based Agricultural Fire Emissions in the Indo-Gangetic Plain), improves modeling assessments of air quality impacts from agricultural burning, thus supporting effective policy development.

Air quality impacts of crop residue burning in India and mitigation alternatives

“…1, 31). This is supported by observations of elevated PM 2.5 levels during burning seasons in large cities downwind of agricultural fires 12 , 14 , 16 , 17 , 20 – 22 .

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“…mechanized alternatives is that there is a limited window of time, around two to three weeks, to manage crop residue between harvesting and sowing 9 , 13 , 16 . A water table preservation policy instituted in Punjab and Haryana in 2009 to align rice irrigation with the summer monsoon further shortened this window, which may have further intensified burning activities as farmers seek to ensure timely sowing for the next planting season 17 , 22 . This suggests that promoting burning earlier or later in the season may be unattractive or unachievable 10 , 13 , 17 .…”

Field Crop Residue burning Induced Particulate Pollution in NW India – Policy Challenges & Way Forward

“…Punjab and Haryana widely practice mechanized harvesting (~ 90% & ~75% of the sown area, respectively) through combine harvesters which leaves a substantial portion of the crop stem root-bound [17] [20] with a longer decomposition time. The shorter turnaround time, of 20-25 days, between rice harvesting and sowing of wheat, urges farmers for open field stubble [22] [23], which is a quick, economical, and efficient way to prepare the soil bed for next crop. The rice residue with high silica content and low calorific value is not a suitable animal feed [24] [25] further supports the motive for rice residue burning.…”

“…The study employs data with 'nominal' and 'high' confidence values to overcome sunlight and water surface reflection (https://lpdaac.usgs.gov/documents/132/ VNP14_User_Guide_v1.3.pdf). The thermal datasets retrieved from NASA remote sensing instruments are suitable for evaluating the regional active fire trends [23]. Researchers have also employed MODIS datasets to assess crop residue burning [13]…”

Liquid State Anaerobic Co-digestion of Cattle Manure and Wheat Straw at Various Mix Ratios for Optimal Biogas Production

“…Similarly, the cattle manure produced from dairy farms is either stored in a manure pile or burned when it gets dry. Such improper management results in emission of greenhouse gases such as carbon dioxide and methane along with other pollutants 4 . This study aimed to produce valuable resources (biogas and natural fertilizer) from agriculture residue and cattle manure through anaerobic digestion.…”