From debris to wealth? Paradoxes of sustainability from india’s breadbasket

ABSTRACTBiomass burning has been identified as an important contributor to the degradation of air quality because of its impact on ozone and particulate matter. One component of the biomass burning inventory, crop residue burning, has been poorly characterized in the National Emissions Inventory (NEI). In the 2011 NEI, wildland fires, prescribed fires, and crop residue burning collectively were the largest source of PM2.5. This paper summarizes our 2014 NEI method to estimate crop residue burning emissions and grass/pasture burning emissions using remote sensing data and field information and literature-based, crop-specific emission factors. We focus on both the postharvest and pre-harvest burning that takes place with bluegrass, corn, cotton, rice, soybeans, sugarcane and wheat. Estimates for 2014 indicate that over the continental United States (CONUS), crop residue burning excluding all areas identified as Pasture/Grass, Grassland Herbaceous, and Pasture/Hay occurred over approximately 1.5 million acres of land and produced 19,600 short tons of PM2.5. For areas identified as Pasture/Grass, Grassland Herbaceous, and Pasture/Hay, biomass burning emissions occurred over approximately 1.6 million acres of land and produced 30,000 short tons of PM2.5. This estimate compares with the 2011 NEI and 2008 NEI as follows: 2008: 49,650 short tons and 2011: 141,180 short tons. Note that in the previous two NEIs rangeland burning was not well defined and so the comparison is not exact. The remote sensing data also provided verification of our existing diurnal profile for crop residue burning emissions used in chemical transport modeling. In addition, the entire database used to estimate this sector of emissions is available on EPA’s Clearinghouse for Inventories and Emission Factors (CHIEF, http://www3.epa.gov/ttn/chief/index.html).Implications: Estimates of crop residue burning and rangeland burning emissions can be improved by using satellite detections. Local information is helpful in distinguishing crop residue and rangeland burning from all other types of fires.

A study was conducted to evaluate the effects of N fertilization, wheat (Triticum aestivum L.) stubble burning, and organic amendments on the density of downy brome (Bromus tectorum L.) seed in soil of a winter wheat-fallow crop rotation. The site was part of a long-term study that has been conducted since 1931 near Pendleton, OR. The study consists of a winter wheat-fallow crop rotation with both a fallow and cropped portion of each treatment present each year. The objective of the original long-term study was to document changes over time in soil physical and chemical properties due to the addition of inorganic and organic sources of N fertilizer, and repeated burning of crop residues. A weed seedbank component was added to this study in 1992. To measure effects on the weed seedbank, soil samples were taken in the fall after winter wheat harvest and after winter wheat planting in the fallow and cropped portions, respectively, from 1992 through 1994. From these samples downy brome seed content was analyzed using a sieving-flotation seed extraction technique. Long-term use of inorganic N fertilizer increased the downy brome seedbank compared with an unfertilized control. Crop residue burning reduced the downy brome seedbank and downy brome plants in the wheat crop. Addition of steer manure or green pea [Pisum sativum (L.) subsp. sativum] vines as an N source did not increase downy brome in the seedbank compared with use of inorganic N fertilizer. This was, perhaps, due to factors such as improved soil health resulting from use of organic soil amendments, or differences in application timing or source of inorganic and organic N fertilizer. The organic form of N from manure may have been applied at a more. opportune time for winter wheat than for downy brome. In addition, plots receiving steer manure produced a higher yielding wheat crop that was likely to be more competitive against downy brome, thereby limiting seed production. Research Question Downy brome is a major constraint to winter wheat production in most production areas of the USA. Wheat production practices such as N fertilization and stubble burning affect downy brome populations in winter wheat. Differences in downy brome populations were observed in a long-term N fertilization and stubble burning experiment and led to a study to determine the effects of inorganic and organic sources of N fertilization, and crop residue burning on downy brome seed in the soil in a dryland winter wheat-fallow crop rotation. Soil samples were taken and downy brome seed content was determined using a sieving-flotation seed extraction technique and counting. The effects of N fertilization rate and source, and crop residue burning on downy brome population dynamics were determined. Literature Summary Practices that affect the distribution, number, or viability of seeds in the seed-bank have a direct impact on subsequent weed plant populations. For example, the primary tillage method used for seedbed preparation directly affects dawny brome seed distribution in the soil and subsequent plant density. Crop rotation has been shown to affect downy brome populations. Nitrogen fertilizer, if improperly timed, can indirectly increase downy brome populations by increasing downy brome growth and, presumably, seed production. Burning of wheat crop residue after harvest has commonly been used as a method of controlling downy brome. One objective of field burning is to destroy downy brome seed produced in the previous wheat crop. Study Description A 3-yr field study was conducted near Pendleton, OR, to document the effects of repeated applications of inorganic and organic sources of fertilizer N, and repeated burning of crop residues on the downy brome seedbank. Soil samples were taken in the fall after winter wheat harvest and after winter wheat planting in the fallow and cropped portions from 1992 through 1994. From these samples, downy brome seed content was analyzed using a sieving-flotation seed extraction technique. Comparisons were made of downy brome seedbank counts between plots receiving repeated N fertilizer rates, organic amendments, or burning of wheat crop residue. Applied Question How much does N fertilization and stubble burning affect downy brome seed numbers in the soil in a winter wheat-fallow crop rotation? From soil samples taken in a winter wheat-fallow crop rotation near Pendleton, OR, the number of downy brome seed in the soil and subsequent downy brome plant density were substantially higher in unburned plots than in burned plots where N fertilizer was applied. When no N fertilizer was applied, few differences occurred in the downy brome seedbank between burned and unburned treatments. Inorganic N fertilization in the absence of burning resulted in substantially increased downy brome seedbank counts. Organic N sources did not increase downy brome seedbank counts. The source and application rate of N fertilizer had a more pronounced effect on the downy brome seedbank than did burning of crop residue.

It has been noticed during the last four–five years that the national capital of India, New Delhi faces a peculiar problem of high air pollution and smog during Kharif season when crops are harvested in the nearby states of Punjab, Haryana, Uttar Pradesh and Rajasthan. It is believed that open and direct burning of agricultural crop residues by the farmers of these states is one of the responsible factors for this annual crisis. The emission of greenhouse gases during burning of crop residues is a prime factor responsible for deterioration of ambient air quality and environmental health hazard. A study has been carried out to find out an economic and optimal solution of the problem. During the process of finding a feasible solution, a novel method of on-site conversion of crop residues into a product called biochar has been developed. The method is based on the concept of thermal conversion, wherein the crop residues are subjected to a process of pyrolysis either in the absence or little presence of oxygen. The most important feature of this method is its adoptability. The farmers can easily convert their crop residues into biochar at their own fields and the biochar so produced can be further applied to the soils to improve the soil properties, which eventually lead to increased crop yield. Hence, there is a need to create awareness among the farmers about this method of biochar production and application. The novel method of producing biochar and the effect of utilizing biochar on the soil properties have been presented in this paper, which will prove useful for the Indian context where large quantities of agricultural waste are produced that create environmental air pollution when directly burnt in the fields.KeywordsCrop residuesGreenhouse gasesPyrolysisBiocharSoil properties

This paper reviews the literature on crop residue burning - a widespread practice in many regions in South Asia. Specifically, we examine evidence from studies highlighting the scale of the practice in South Asia, the environmental implications, the drivers of the practice and the remedies to the problem. The studies provide evidence that the Indo-Gangetic Plain (IGP) is a hot-spot for atmospheric pollutants, with seasonal crop residue burning being a major contributor. The burning of crop residue is reported to degrade the soil, increase the risk of erosion, and increase the soil temperature, consequently decimating soil microorganisms. This subsequently impacts the monetary cost involved in recovering the soil fertility and the potential for further pollution through the increased use of fertilizer. The review shows that farmers’ reasons for burning crop residues are mainly the high cost of incorporating, collecting, transporting, and processing crop residues in South Asia. Labour shortages, the marketability of the crop residue and the short time interval between harvest and next cropping seasons also influence farmers decision to burn crop residue. To address this problem, there is the need to encourage the use of agricultural machines capable of sowing crops in standing stubble, adopting in-situ practices and changing crop varieties to those with short duration. In addition, education and awareness are needed to change beliefs and perceptions on crop residue burning. Crucially, when promoting alternative sustainable uses of crop residue, the economic benefits should be prioritized, and support towards initial investments that accompany the adoption of alternative practices should be provided.

Emission characterization, environmental impact, and control measure of PM2.5 emitted from agricultural crop residue burning in China

The crop residue burning in India particularly North-western India is responsible for air pollution episodes and public health concerns; greenhouse gases emissions and radiation imbalance; and declining soil organic matter and soil productivity. The objectives of this paper are to estimate the crop residue burning and emissions from crop residue burning, to recommend interventions in crop residue management and to propose a crop residue management-bioeconomy model incorporating strategies to sustainably manage the crop residues through interventions that enable waste valorization, food and nutritional security, farmers’ livelihood and sustainable agricultural production system. A national inventory on crop residue burning including the pollutant species was prepared using the IPCC methodology. The crop types included for the estimation are cereals, pulses, oilseeds, sugarcane, cotton, jute and Mesta. The total amount of crop residues generated and burned for the year 2017–18 was estimated at 516 million tonnes and 116 million tonnes respectively. It is estimated that 116.3 Tg of crop residues burning released about 176.1 Tg of CO2, 10 Tg of CO, 313.9 Gg of CH4, 8.14 Gg of N2O, 151.14 Gg of NH3, 813.8 Gg of NMVOC, 453.4 Gg of PM2.5, and 935.9 Gg of PM10. The emission estimates can be a proxy to prepare the national level inventory of air pollutant species from crop residue burning. The crop residue management (CRM) demands a transition from the traditional zone of CRM to bioeconomy zone of CRM, wherein the interventions aim at the sustainability of agroecosystem. The proposed bioeconomy model has a four-pronged strategy that includes smart agriculture practices, waste bioeconomy involving aspirational principles of bioeconomy, capacity building of stakeholders’ and proactive government policy. Sustainable agricultural bioeconomy provides ample opportunities to reduce crop residue burning, increase farmers’ livelihood and decarbonize the agricultural production. India’s efforts and policies can provide lessons for other agricultural regions having similar environmental constraints.

Agricultural crop residue burning is a very common practice of managing the crop residues in Central India (Madhya Pradesh). Generation of crop residues from India is around 500 million tons per year out of which around 33.18 million tons per year from Madhya Pradesh itself. In Madhya Pradesh mainly wheat crop residue burnt during month of April and May. Burning of these agricultural crop residues emits a large number of pollutants as well greenhouse gases. However, this study mainly focused on impact of agricultural crop residue burning on climate of a rural area, Indore, India. To study the topic mainly two parameters is considered, CO2 and Temperature. Data were collected for the three period namely before crop residue burning (February March), during crop residue burning (April-May) and after crop residue burning (June-July). Last 10year data (2006–2015) was accessed for the above mentioned three periods for CO2 and temperature with the help of Giovanni web, Atmospheric Infrared Sounder (AIRS).Study results show that burning of agricultural crop residues plays an important role in climate change, although its effect is minor. Study also reveals that every year from 2006 to 2015 both CO2 and temperature were high during crop residue burning period than before burning period.

Degraded air quality shortens the lives of millions in India, where the burning of crop residue is an important contributor to air pollution and public health burden. Despite government bans, fines and subsidies for no-burn practices, agricultural fires remain widespread. This paper aims to help inform alternative interventions to crop residue burning that are both straightforward to implement and attractive to the farmers community while mitigating health impacts. Unlike traditional studies of Indian air pollution which start by assuming an intervention, such as removing the entire emissions from a source, and then calculating its effects, we used inverse modeling to start from the air quality effects of agricultural fires and then quantify the potential benefit of actions at district- and hourly level. Instead of focusing on a single hot spot such as Delhi, where air quality problems have been notoriously serious, we focus on the whole Indian population - since impacts of air pollution are not limited to one location and epidemiological evidence shows no threshold of PM2.5 under which no harm to humans is observed.  From 2003 to 2019, we find that Indian agricultural residue burning caused an annual average of 69,000 PM2.5 exposure-related premature deaths, of which Punjab, Haryana, and Uttar Pradesh states contribute 67–90%. These health impacts, valued at 23 billion USD annually, are equivalent to 38% of the total health expenditure, or 7.8% of the gross value added from agricultural activity in India. Over 17 years, these two ratios have increased from 29% to 40%, and from 6.1% to 9.2%. The average air quality impacts attributable to agricultural fires is 2.4% lower in drought years, 4.8% higher in flood years, and close to 17-year average in years with normal rainfall. We show that six districts are responsible for 40% of annual burning-related air quality impacts in India. Burning a few hours earlier during the day could also avert a significant number of premature deaths each year. Our findings support the use of targeted and potentially low-cost interventions to mitigate crop residue burning in India, motivating further research regarding cost-effectiveness and feasibility.  

A high-resolution emission inventory of air pollutants from primary crop residue burning over Northern India based on VIIRS thermal anomalies

A serious air pollution episode during 28–29 Oct. 2008 in Nanjing and surrounding regions was analyzed by using the data of air pollutant species, API (Air Pollution Index), satellite fire hotspots and the methods of backward trajectory simulations and air quality model WRF-CMAQ simulation. The results indicate that the air pollution event was mainly contributed by the releasing of crop residue burning in central and north of Jiangsu province. The synoptic situations of uniform pressure field, the inversion layer, low horizontal and vertical wind were not favorable for the advection of air pollutants. The emission inventory releasing from crop residual opening burning over YRD was constructed, which was coupled into WRF-CMAQ air quality modeling system. After considering the emission from crop residual opening burning, the simulated results of air pollutants were much closed to observations.

Rice-wheat cropping system (RWCS), one of the prominent agricultural production systems, at an area of ~26 M ha is confined to the Indo-Gangetic Plains (IGPs) in South Asia and China. Crop residues obtained from field crops are essential sources of nutrition and organic carbon (40% of total dry biomass constituted by C) for the next crops, and hence they not only increase the agricultural productivity but also are responsible for the better quality of soil, water, and air. Perhaps the most important challenge facing exhaustive RWCS in all regions of the world is effective management of post-harvest crop residues. Disposal of wheat residue is easy as it can be used to feed animals. However, due to the presence of high silica content, rice residue is usually burned. Residue burning is the main method of disposal in areas under combined harvesting in the IGPs of eastern India as it reduces cost. However, burning of crop residue (CR) is not eco-friendly as it results in fast degradation of soil organic matter and nutrients and increased CO2 emission creating intense air pollution as well as global warming. Therefore, exploitation of CR is a crucial element for a sustainable production system, and it has generated much interest in the recent years by reducing the consequence of residue burning and increasing the soil organic matter (SOM) and the nutrient-supplying capacity. CR retention infield can be considered a key element in promoting soil health with increased physical, chemical, and biological properties. In RWCS, residue management can be done by (1) wheat residue retention in rice and its residual effect in succeeding wheat crop, (2) rice straw retention in wheat and its residual impact in following rice, and (3) wheat straw retention in rice and rice straw retention in wheat (cumulative effect). All these crop residue management systems depend on a systematic understanding of the factors that control residue decomposition and their careful application. Significant factors, such as tillage/CR management, influence soil microbial activity and biomass, bulk density, soil moisture content, porosity, soil structure stability, and nutrient-supplying capacity of the soil. Thus, the variations in soil properties consequently bring change in soil C and N dynamics and have an impact on plants’ nutrient uptake capacity.

Better understanding the complex mechanisms underlying the variations in crop residue burning (CRB) intensity and patterns is crucial for evaluating control strategies and developing sustainable policies aimed at the efficient recycling of crop residues. However, the intricate interplay between the CRB practices, climate variability, and human activities poses a significant challenge in this endeavor. Here, we utilize the high spatiotemporal resolution of satellite observations to characterize and explore the dynamics of summer CRB in North China at multiple scales. Between 2003 and 2012, there was a significant intensification of summer CRB in North China, with the annual number of burning spots increasing by an average of 499 (95% confidence interval, 252–1426) spots/year. However, in 2013, China promulgated the stringent Air Pollution Prevention and Control Action Plan, which led to a rapid decrease in the intensity of summer CRB. Local farmers also adjusted their burning practices, shifting from concentrated and intense burning to a more dispersed and uniformly intense approach. Between 2003 and 2020, the onset of summer CRB shifted earlier in North China by 0.75 (0.5–1.1) days/year, which is attributed to the combined effects of climate change and anthropogenic controls. Specifically, the onset time is found to be significantly and negatively correlated with spring temperature anomalies and positively correlated with anomalies in the number of spring frost days. Climate change has led to a shortened crop growing season, resulting in an earlier start to summer CRB. Moreover, the enhanced anthropogenic controls on CRB expedited this process, making the trend of an earlier start time even more pronounced from 2013 to 2020. Contrary to the earlier onset of summer CRB, the termination of local wheat residue burning experienced a notable delay by 1.0 (0.8–1.4) days/year, transitioning from mid-June to early July.

Management Options for Optimizing Nutrient Cycling and Reducing Greenhouse Gas Emissions from Smallholder Rice Farms in Vietnam

Wheat residue burning, while traditionally common in North India, is becoming increasingly prevalent in Central India, especially in key wheat-producing states like Madhya Pradesh, Maharashtra, and Chhattisgarh. It is driven by a steady rise in wheat cultivation and production. This practice, primarily used for clearing land after harvest, releases harmful pollutants, including particulate matter (PM2.5 and PM10), carbon monoxide (CO), nitrogen oxides (NOx), and volatile organic compounds (VOCs), which have serious health implications for local populations. Short-term pollution spikes, particularly during the post-harvest months from March to May, lead to increased respiratory and cardiovascular diseases, disproportionately affecting vulnerable groups such as children, the elderly, and those with pre-existing health conditions. Despite the negative environmental and health consequences, wheat residue burning remains prevalent due to its low cost and lack of effective alternatives. This review examines the rise in wheat production, crop residue generation, and the adverse effects of residue burning on air quality and public health in central India. The article explores potential solutions, including the adoption of sustainable agricultural practices such as zero-till farming, residue management technologies, and alternative disposal methods like composting and mulching. Additionally, the review highlights the importance of policy interventions, farmer education, and public awareness campaigns to reduce crop residue burning and its harmful effects. Addressing this issue requires a coordinated approach from farmers, policymakers, and public health professionals to mitigate air pollution and protect both human health and the environment in the region.

Of late, intensive farming for higher food production is often associated with many negative implications for soil systems, such as decline of soil organic matter (SOM), increase in risks of soil erosion by wind and/or water, decline in soil biological diversity, increase in degradation of soil physical quality, lower nutrient-use efficiency, high risks of groundwater pollution, falling water tables, increasing salinization and waterlogging, in-field burning of crop residues, pollution of air and emission of greenhouse gases (GHG), leading to global warming, and decline in factor productivity. These negative implications necessitate an objective review of strategies to develop sustainable management practices, which could not only sustain soil health and ensure food security, but also enhance carbon sequestration, decrease GHG emissions, and offer clean and better ecosystem services. Conservation agriculture (CA), that includes reduced or no-till practices along with crop residue retention and mixed crop rotations, offers multiple benefits. Adoption of a system-based CA conserves water, improves and creates more efficient use of natural resources through the integrated management of available soil nutrients, water, and biological resources, and enhances use efficiency of external inputs. Due to apparent benefits of CA, it is increasingly being adopted and now covers about 180 million hectares (Mha) worldwide. However, in South Asia its spread is low (<5 Mha), mostly concentrated in the Indo-Gangetic Plains (IGP). In this region, one of the serious issues is “residue burning” with severe environmental impacts. A huge amount of crop residue left over after the combine harvest of rice has forced farmers to practice widespread residue burning (∼140 M tonnes) to cope with excessive stubble and also for timely planting/sowing of succeeding crops. In rice-wheat cropping systems, which cover more than 10 Mha in the IGP, CA practices are relatively more accepted by farmers. In these systems, any delay in sowing leads to yield penalty of 1–1.5% per day after the optimum sowing date of wheat. The strong adoption of CA practices in IGP is mainly to overcome delayed sowing due to the field preparation and control of weeds, timely planting, and also escape from terminal heat during the grain-filling stage. Major challenges to CA adoption in South Asia are small land holdings (<1 ha), low technological reach to farmers, nonavailability of suitable farm implements for small farm holders, and the staunch conventional farming mind-set. South Asia region consists of many countries of diverse agro-ecologies with contrasting farming systems and management. This region, recently known for rapid economic growth and increasing population, necessitates higher food production and also hot-spots for adoption of CA technologies. Therefore, in this review critically explores the possibility, extent of area, prospects, challenges, and benefits of CA in South Asia. HIGHLIGHTS Conservation agriculture (CA), consisting of reduced or no-tillage and crop residue retention, is a self–sustainable system which offers an alternative to crop residue burning. The CA approach improves soil health by increasing soil organic carbon (SOC) and aggregation and also conserves soil, water and energy than conventional farming systems. South Asian countries are suitable for adoption of CA practices but the area under CA remains low (<5 Mha) as compared to the global area (180 Mha). Adoption of CA in South Asia has skewed distribution, mainly in Indo-Gangetic Plains (IGP) in India, Pakistan, Nepal and Bangladesh in South Asia. Development of herbicide-resistant weed species and weed shift by continuous application of herbicides are the major challenges in adoption of CA. The traditional-farming mind-set, socio-economic conditions, small farm-holdings, weed and residue management, and non-availability of suitable machinery are key constraints to the low adoption of CA practices in South Asia.