Major Agricultural Crops Research Articles

Forecasting of Potato Prices of Hooghly in West Bengal: Time Series Analysis Using SARIMA Model

Potato is one of the most important food crops in India. Potato is also one of the principal cash crop, it gives handsome returns to the farmers. West Bengal is a state in India where potato is one of the major agricultural crops. But potato markets are more volatile due to fluctuation in production rather than Stable. So price of potato is fluctuating in nature. Thus, the time series analysis and price forecast may help producers in acreage allocation and timing of sale of potato. The present study was conducted to know the statistical investigation of price behaviour of potato in Hooghly district of West Bengal. In the present study, Box-Jenkins Seasonal Auto Regressive Integrated Moving Average (SARIMA) modeling is deployed in forecasting of monthly average price of potato in Hooghly of West Bengal up to October 2020 based on data from November 2008 to October 2018 (a period of 120 months). Seasonal indices calculated showed that generally the price is low from January to April and it starts picking up from May and reaches the maximum in November. The best model has been selected based on the Bayesian Information Criteria (BIC), Root Means Square Error (RMSE), Mean Absolute Percent Error (MAPE), Mean Absolute Error (MAE) and highest R-Square. The estimated best SARIMA model is (1,1,0)(4,1,0)12. Root Mean Square Error (RMSE), Mean Average Percentage Error (MAPE), Mean Absolute Error (MAE) and BIC for Hooghly district are 184.10, 19.08, 118.98 and 10.69 respectively. Short term forecasts based on this model are close to the observed values and the behaviour of forecasted price of potato truly reflected the actual price as well as market tendency.

English

English

Water impacts of U.S. biofuels: Insights from an assessment combining economic and biophysical models.

Biofuels policies induce land use changes (LUC), including cropland expansion and crop switching, and this in turn alters water and soil management practices. Policies differ in the extent and type of land use changes they induce and therefore in their impact on water resources. We quantify and compare the spatially varying water impacts of biofuel crops stemming from LUC induced by two different biofuels policies by coupling a biophysical model with an economic model to simulate the economically viable mix of crops, land uses, and crop management choices under alternative policy scenarios. We assess the outputs of an economic model with a high-resolution crop-water model for major agricultural crops and potential cellulosic feedstocks in the US to analyze the impacts of three alternative policy scenarios on water balances: a counterfactual ‘no-biofuels policy’ (BAU) scenario, a volumetric mandate (Mandate) scenario, and a clean fuel-intensity standard (CFS) scenario incentivizing fuels based on their carbon intensities. While both biofuel policies incentivize more biofuels than in the counterfactual, they differ in the mix of corn ethanol and advanced biofuels from miscanthus and switchgrass (more corn ethanol in Mandate and more cellulosic biofuels in CFS). The two policies differ in their impact on irrigated acreage, irrigation demand, groundwater use and runoff. Net irrigation requirements increase 0.7% in Mandate and decrease 3.8% in CFS, but in both scenarios increases are concentrated in regions of Kansas and Nebraska that rely upon the Ogallala aquifer for irrigation water. Our study illustrates the importance of accounting for the overall LUC and shifts in agricultural production and management practices in response to policies when assessing the water impacts of biofuels.

Raising crop yields: The missing links from molecular biology to plant breeding

Rapid advances in molecular biology and functional genomics during the last two decades have created considerable optimism about their potential to increase global food production by raising the yields of major agricultural crops via breeding of new crop varieties. However, yield increases achieved so far have come largely through conventional plant breeding. This brief review outlines reasons why genetic transformations at the sub-cellular level in single plants grown in controlled environments may not necessarily translate in to yield increases of plant populations in the field. Expected advantages of sub-cellular molecular interventions are either dampened or reversed at the plant population level when crop yields are determined. This could happen due to complex interactions, feedbacks and trade-offs across different levels of plant organization at both spatial- and temporal scales, dependence on specific environmental requirements for expression of introduced genes, unrealistic experimental conditions used to generate trascriptomes and mis-matches between strategies required to achieve superior performance in single plants and plant populations. It is argued that an understanding of the physiological basis of yield determination at the plant population/community level, a tight linkage of genetic modifications to specific yield components and a thorough evaluation of feedbacks and trade-offs during up-scaling across different levels of plant organization is needed to harness the undoubted potential of molecular genetics towards crop yield improvement.

AgriSeqDB: an online RNA-Seq database for functional studies of agriculturally relevant plant species

BackgroundThe genome-wide expression profile of genes in different tissues/cell types and developmental stages is a vital component of many functional genomic studies. Transcriptome data obtained by RNA-sequencing (RNA-Seq) is often deposited in public databases that are made available via data portals. Data visualization is one of the first steps in assessment and hypothesis generation. However, these databases do not typically include visualization tools and establishing one is not trivial for users who are not computational experts. This, as well as the various formats in which data is commonly deposited, makes the processes of data access, sharing and utility more difficult. Our goal was to provide a simple and user-friendly repository that meets these needs for data-sets from major agricultural crops.DescriptionAgriSeqDB (https://expression.latrobe.edu.au/agriseqdb) is a database for viewing, analysing and interpreting developmental and tissue/cell-specific transcriptome data from several species, including major agricultural crops such as wheat, rice, maize, barley and tomato. The disparate manner in which public transcriptome data is often warehoused and the challenge of visualizing raw data are both major hurdles to data reuse. The popular eFP browser does an excellent job of presenting transcriptome data in an easily interpretable view, but previous implementation has been mostly on a case-by-case basis. Here we present an integrated visualisation database of transcriptome data-sets from six species that did not previously have public-facing visualisations. We combine the eFP browser, for gene-by-gene investigation, with the Degust browser, which enables visualisation of all transcripts across multiple samples. The two visualisation interfaces launch from the same point, enabling users to easily switch between analysis modes. The tools allow users, even those without bioinformatics expertise, to mine into data-sets and understand the behaviour of transcripts of interest across samples and time. We have also incorporated an additional graphic download option to simplify incorporation into presentations or publications.ConclusionPowered by eFP and Degust browsers, AgriSeqDB is a quick and easy-to-use platform for data analysis and visualization in five crops and Arabidopsis. Furthermore, it provides a tool that makes it easy for researchers to share their data-sets, promoting research collaborations and data-set reuse.

Agrometeorology in Croatia

ABSTRACTMeteorological and Hydrological Service was established 70 years ago and agrometeorological activities (soil temperature measurements and phenological observations) started in 1951. Scientific research is divided into an agricultural meteorology, forest meteorology and plant phenology. The basic purpose of research is the impact of regional climate change on the crop production, on the phenological stages of different plants as forest trees and shrubs, fruit-trees, olive-trees, grapevine and maize, and on the potential wildfire risk. In the operational tasks short-range and medium-range forecasts have been produced for TV and internet since 2004, radio since 1990 and specialized journals since 1988. For further development of Croatian agrometeorology, future plans are using monthly and seasonal forecasts for prediction of the development of yield of major agricultural crops, for irrigation purposes, as well as for potential risk of wildfires and applying satellite data and nowcasting for warning purposes in agriculture and in forest protection against fire.

Review of the vertebrate-mediated dispersal of the Date Palm, Phoenix dactylifera

As a major agricultural crop in the semi-arid and arid zone of North Africa and the Middle East, drupes (“fruits”) of the Date Palm Phoenix dactylifera form with their high carbohydrate content of the flesh and oils in the seed a major part of the diet of resident and migratory bird species and fruit bats. This paper reviews the range of known instances of drupe predation by volant and non-volant vertebrate vectors. While documented dispersal distances range from tens of metres to about 50 km, the efficacy of that dispersal has not been assessed in any of the papers under review. While volant animals, primarily birds, make up the greatest number of dispersal vectors and also account for the greatest number of seeds dispersed, long distance dispersal of a larger quantity of seeds per dispersal event seems to rely on terrestrial animals, primarily canids, but also bears and flightless birds, such as the Emu (Dromaius novaehollandiae).

Genetic diversity and prevalence of Varroa destructor, Nosema apis, and N. ceranae in managed honey bee (Apis mellifera) colonies in the Caribbean island of Dominica, West Indies

Honey bees (Apis mellifera) are arguably the most important insect pollinators of major agricultural crops around the world. Therefore, it is important to assess the health of managed honey bees in every region, particularly in areas where this information remains unknown. In 2015 and 2016, several managed apiaries were surveyed on the Caribbean Island of Dominica, West Indies. We measured the levels of the ectoparasitic mite, Varroa destructor, and analyzed the levels of Nosema apis and Nosema ceranae using spore counts and qPCR. Colonies sampled in 2015 were also analyzed for subspecies composition using mitochondrial DNA. Varroa levels were low overall (1–7 mites per 100 bees), with many colonies exhibiting no mites. In apiaries where varroa counts were performed in both years, there were significantly more mites in 2016 than in 2015. Overall, colonies exhibited low Nosema spp. spore counts, with only 1.33% of the bees analyzed scoring positive for spores. qPCR revealed that of the 30 colonies analyzed, all but six (82.3% of the total) were infected with low levels of N. apis. The prevalence of N. ceranae infection was higher, with 97.1% of the bees analyzed being infected. The majority of colonies analyzed (84.4%) exhibited the M4 haplotype (A. m. mellifera), while the remaining (15.6%) exhibited the C1 haplotype (A. m. ligustica). We did not find any colonies that had the African A. m. scutellata haplotype. This study is the first survey conducted to assess the genetic structure and health status of managed honey bees in Dominica.Diversidad genética y prevalencia de Varroa destructor, Nosema apis y N. ceranae en colmenas domesticadas de la abeja Apis mellifera en la isla Caribeña de Dominica, Antillas OccidentalesLa abeja Apis mellifera es el insecto polinizador más importante de cultivos agrícolas al rededor del mundo. Por esta razón, es importante saber su estado de salud en cada región, particularmente en areas donde no han sido estudiadas. En 2015 y 2016 se hizo un censo en varios apiaros en la isla Caribeña de Dominca en las Antillas Occidentales. Medimos los niveles del ácaro ectoparasitoide Varroa destructor, y se analizaron los niveles de Nosema apis y N. ceranae por medio de conteo de esporas y qPCR. En 2015 también se analizaron colmenas para determinar la composición de subspecies usando ADN mitochondrial. Los niveles de varroa fueron por lo general bajos (de 1 a 7 ácaros por cada 100 abejas) y en muchas de las colmenas no se encontraron ácaros. En apiarios en los que el conteo de varroa fue hecho ambos años se hayaron más ácaros en 2016 que en 2015. En general se encontró un bajo número de esporas de Nosema spp., y en solo el 1.33% de las abejas analizadas se visualizaron esporas. El qPCR reveló que de las 30 colmenas analizadas, todas menos seis (el 82.3% del total) estaban infectadas con niveles bajos de N. apis. La prevalencia de infección de N. ceranae fue más alta, pues 97.1% de las abejas analizadas estaban infectadas. La mayoría de las colmenas (84.4%) salió con el haplotipo M4 (A. m. mellifera) y el resto (15.6%) salió con el haplotipo C1 (A. m. ligustica). No se encontraron colmenas con el haplotipo Africano A. m. scutellata. Este es el primer estudio sobre la estructura genética y el estado de salud de abejas domesticadas en Dominica.

Identification of GmSALT3 haplotypes and development of molecular markers based on their diversity associated with salt tolerance in soybean

Soybean [Glycine max (L.) Merr.] is a major agricultural crop and generally known as a salt-sensitive crop. In a previous study, GmSALT3 was identified as a salt tolerance gene in soybean, and its nine haplotypes (H1 to H9) were reported in Chinese soybean accessions. In the present study, we aimed to identify new haplotypes of GmSALT3 in soybean accessions and to develop molecular markers for selection of salt-tolerant and -sensitive accessions. To do so, we examined genomic variations in the GmSALT3 coding region of 216 accessions of G. max and G. soja from Korea, China, and Japan. As a result, 40 different haplotypes, including three known haplotypes (H1, H2, and H5), were identified. Performing salt tolerance tests for the haplotypes, we were able to classify them into salt-tolerant (8) and salt-sensitive (32) categories. We also found that more variations in the haplotype composition of G. soja accessions exist than in that of G. max accessions. Quantitative expression analysis showed that almost all of the salt-tolerant haplotypes had much higher levels of GmSALT3 expression than the salt-sensitive haplotypes did. Finally, we developed molecular markers and applied them to screen salt tolerance of soybean accessions. The molecular markers performed well with an accuracy of 98.8% in identifying phenotypes of soybean accessions.

Effect of Temperature on the Development, Survival, and Fecundity of Heliothis viriplaca (Lepidoptera: Noctuidae).

Heliothis viriplaca (Hüfnagel) (Lepidoptera: Noctuidae) is worldwide an important economic pest of major agricultural crops. The effect of temperature on the biology, in particular the duration of the different developmental stages, of this insect pest was examined. The development, survival, and fecundity of H. viriplaca at five different temperatures (22, 25, 28, 31, and 34°C) were investigated, and experimental population life tables calculated. The results show that the developmental time of larvae, pupae, pre-oviposition, adults, and the entire generation decreases with increasing temperature. Larvae emerged fastest from the eggs at 28°C. The percentage of larvae that reached the seventh instar stage was 32.69, 38.60, 19.67, 3.61, and 20.88% at 22, 25, 28, 31, and 34°C, respectively. The developmental threshold temperature of the eggs, larvae, pupae, pre-oviposition and total pre-oviposition period was 10.53, 12.34, 5.60, 11.47, and 10.01°C, respectively. The effective accumulative temperature was 42.90, 239.68, 309.19, 77.72, and 767.64 degree-days, respectively. The population trend index (I) and the intrinsic rate of increase (r) of H. viriplaca were the highest at 31°C (133.97 and 0.12 d−1, respectively). The results of this study may be useful for predicting the population dynamics of H. viriplaca and thus provides information on this important insect pest that may assist in its management.

Water Scarcity in Vietnam: a Point of View on Virtual Water Perspective

This paper quantifies water consumption of Vietnam in agricultural products on virtual water perspective. The calculation of water footprint and virtual water in four major agricultural crops is first implemented for seven regions of the country. The domestic and international trades of virtual water are subsequently investigated to demonstrate the commodity and virtual water flows among regions. The analysis reveals that Mekong River Delta is an important exporter of virtual water in rice product for both domestic and international trades while Central Highland is the main virtual exporter in coffee. The paper also proposes a new water stress index such that it considers both direct and indirect water use given transboundary water resources. The proposed water stress index indicates the actual water scarcity in Vietnam in which the water-rich regions i.e. Red River Delta and Mekong River Delta are in severe water stress.

Halotolerant Exiguobacterium profundum PHM11 Tolerate Salinity by Accumulating L-Proline and Fine-Tuning Gene Expression Profiles of Related Metabolic Pathways.

Salinity stress is one of the serious factors, limiting production of major agricultural crops; especially, in sodic soils. A number of approaches are being applied to mitigate the salt-induced adverse effects in agricultural crops through implying different halotolerant microbes. In this aspect, a halotolerant, Exiguobacterium profundum PHM11 was evaluated under eight different salinity regimes; 100, 250, 500, 1000, 1500, 2000, 2500, and 3000 mM to know its inherent salt tolerance limits and salt-induced consequences affecting its natural metabolism. Based on the stoichiometric growth kinetics; 100 and 1500 mM concentrations were selected as optimal and minimal performance limits for PHM11. To know, how salt stress affects the expression profiles of regulatory genes of its key metabolic pathways, and total production of important metabolites; biomass, carotenoids, beta-carotene production, IAA and proline contents, and expression profiles of key genes affecting the protein folding, structural adaptations, transportation across the cell membrane, stress tolerance, carotenoids, IAA and mannitol production in PHM11 were studied under 100 and 1500 mM salinity. E. profundum PHM11 showed maximum and minimum growth, biomass and metabolite production at 100 and 1500 mM salinity respectively. Salt-induced fine-tuning of expression profiles of key genes of stress pathways was determined in halotolerant bacterium PHM11.

The evolution of floral sonication, a pollen foraging behavior used by bees (Anthophila).

Over 22,000 species of biotically pollinated flowering plants, including some major agricultural crops, depend primarily on bees capable of floral sonication for pollination services. The ability to sonicate (“buzz”) flowers is widespread in bees but not ubiquitous. Despite the prevalence of this pollinator behavior and its importance to natural and agricultural systems, the evolutionary history of floral sonication in bees has not been previously studied. Here, we reconstruct the evolutionary history of floral sonication in bees by generating a time‐calibrated phylogeny and reconstructing ancestral states for this pollen extraction behavior. We also test the hypothesis that the ability to sonicate flowers and thereby efficiently access pollen from a diverse assemblage of plant species, led to increased diversification among sonicating bee taxa. We find that floral sonication evolved on average 45 times within bees, possibly first during the Early Cretaceous (100–145 million years ago) in the common ancestor of bees. We find that sonicating lineages are significantly more species rich than nonsonicating sister lineages when comparing sister clades, but a probabilistic structured rate permutation on phylogenies approach failed to support the hypothesis that floral sonication is a key driver of bee diversification. This study provides the evolutionary framework needed to further study how floral sonication by bees may have facilitated the spread and common evolution of angiosperm species with poricidal floral morphology.

Environmental Risks and Challenges Associated with Neonicotinoid Insecticides.

Neonicotinoid use has increased rapidly in recent years, with a global shift toward insecticide applications as seed coatings rather than aerial spraying. While the use of seed coatings can lessen the amount of overspray and drift, the near universal and prophylactic use of neonicotinoid seed coatings on major agricultural crops has led to widespread detections in the environment (pollen, soil, water, honey). Pollinators and aquatic insects appear to be especially susceptible to the effects of neonicotinoids with current research suggesting that chronic sublethal effects are more prevalent than acute toxicity. Meanwhile, evidence of clear and consistent yield benefits from the use of neonicotinoids remains elusive for most crops. Future decisions on neonicotinoid use will benefit from weighing crop yield benefits versus environmental impacts to nontarget organisms and considering whether there are more environmentally benign alternatives.

The Effects of the Insect Growth Regulators Methoxyfenozide and Pyriproxyfen and the Acaricide Bifenazate on Honey Bee (Hymenoptera: Apidae) Forager Survival.

The honey bee (Apis mellifera L. (Hymenoptera: Apidae)) contributes an essential role in the U.S. economy by pollinating major agricultural crops including almond, which depends entirely on honey bee pollination for successful nut set. Almond orchards are often treated with pesticides to control a variety of pests and pathogens, particularly during bloom. While the effects to honey bee health of some insecticides, particularly neonicotinoids, have received attention recently, the impact of other types of insecticides on honey bee health is less clear. In this study, we examined the effects to honey bee forager survival of three non-neonicotinoid pesticides widely used during the 2014 California almond bloom. We collected foragers from a local apiary and exposed them to three pesticides at the label dose, or at doses ranging from 0.5 to 3 times the label dose rate. The selected pesticides included the insect growth regulators methoxyfenozide and pyriproxyfen, and the acaricide bifenazate. We simulated field exposure of honey bees to these pesticides during aerial application in almond orchards by using a wind tunnel and atomizer set up with a wind speed of 2.9 m/s. Experimental groups consisting of 30-40 foragers each were exposed to either untreated controls or pesticide-laden treatments and were monitored every 24 hr over a 10-d period. Our results revealed a significant negative effect of all pesticides tested on forager survival. Therefore, we suggest increased caution in the application of these pesticides in almond orchards or any agricultural crop during bloom to avoid colony health problems.

New World spittlebugs (Hemiptera: Cercopidae: Ischnorhininae): Dated molecular phylogeny, classification, and evolution of aposematic coloration

The spittlebug family Cercopidae (Hemiptera: Auchenorrhyncha: Cicadomorpha: Cercopoidea) is distributed worldwide, with highest species diversity in the tropics. Several included species are economically important pests of major agricultural crops and cultivated pasture grasses. Taxonomically, Cercopidae is divided into two subfamilies: the paraphyletic Old World Cercopinae and the monophyletic New World Ischnorhininae. Results are here presented from an investigation of phylogenetic relationships within Ischnorhininae based on DNA sequences from seven loci (18S rDNA, 28S rDNA, Histone 2A, Histone 3, Wingless, Cytochrome Oxidase I, and Cytochrome Oxidase II) generated from exemplars of 119 spittlebug species. The resulting topology is used to test alternative higher-level classification hypotheses of Ischnorhininae and, with fossil-calibration, dates were estimated for major events in the evolutionary history of Cercopidae, including a much earlier divergence date (around 68–50 Mya) than previously reported in the literature. In addition, for the first time in Cercopidae, ancestral states of some predation avoidances strategies were reconstructed, with results suggesting an origin of aposematic coloration in the Cercopidae ancestor, with subsequent independent losses of aposematic coloration in multiple lineages.

Compatibility improvement method of empty fruit bunch fibre as a replacement material in cement bonded boards: A review

The utilization of oil palm empty fruit bunch (OPEFB) fibre on bio-composite product has been introduced to replace current material mainly wood fibre. OPEFB is widely available as palm oil is one of the major agricultural crops in Malaysia. EFB fibre are lignocellulosic materials that could replace other natural fibre product especially cement bonded board. However, the contains of residual oil and sugar in EFB fibre has been detected to be the reason for incompatibility issue between EFB fibre and cement mixtures. Regarding on the issue, a study has been conducted widely on finding the suitable pre-treatment method for EFB fibre to remove carbohydrate contained in the said fibre that are known to inhibit cement hydration. Aside from that, cement accelerator was introduced to enhance the hydration of cement when it was mixed with natural fibre. Hence, this paper will summaries the previous findings and in-depth study on the use of EFB fibre as a replacement material in cement bonded fibre boards.

ENSO climate risk: predicting crop yield variability and coherence using cluster-based PCA

The El Nino–Southern Oscillation (ENSO) has, in recent years, contributed to increases in the yields of major agricultural (annual) crops like wheat and barley in Canada. How such forcing alters the pattern of yield variation across different geographic scales and across large agricultural landscapes like the Canadian Prairies is less understood. Yet, such questions are of major importance in forecasting future cereal crop production. We explore the potential impact of ENSO on wheat and barley across the Canadian Prairies/Western Canada using a multi-scale, cluster-based principal component analysis (PCA) model that integrates machine-learning (K-means clustering) to predict areas of high climate risk. These risk areas are separable clusters of subregions that show similar ENSO-yield correlation response (spatial coherency). Benchmarking this spatial model to non-spatial models indicates that spatial coherency leads to gains in prediction skill. Incorporating spatial coherency increased the skill in predicting crop yield; reducing RMSE error by up to 26–34% (spring wheat) and 2–4% (barley). We infer that accounting for spatial coherency improves the accuracy and reliability of crop yield forecasts.

Cataloging Plant Genome Structural Variations.

Structural variation (SV) is a type of genetic variation identified through the comparison of genome structures which often have direct and significant associations with phenotypic variations. Building on the next generation sequencing (NGS) technologies, research on plant structural variations are gaining momentum and have revolutionized our view on the functional impact of the 'hidden' diversity that were largely understudied before. Herein, we first describe the current state of plant genomic SV research based on NGS and in particular focus on the biological insights gained from the large-scale identification of various types of plant SVs. Specific examples are chosen to demonstrate the genetic basis for phenotype diversity in model plant and major agricultural crops. Additionally, development of new genomic mapping technologies, including optical mapping and long read sequencing, as well as improved computational algorithms associated with these technologies have helped to pinpoint the exact nature and location of genomic SVs with much better resolution and precision. Future direction of plant research on SVs should focus on the population level to build a comprehensive catalog of SVs, leading to full assessment of their impact on biological diversity.

PM2.5 emissions and source profiles from open burning of crop residues

Wheat straw, rice straw, and corn stalks, the major agricultural crop residues in China, were collected from six major crop producing regions, and burned in a laboratory combustion chamber to determine PM2.5 source profiles and speciated emission factors (EFs). Organic carbon (OC) and water-soluble ions (the sum of NH4+, Na+, K+, Mg2+, Ca2+, Cl−, NO3− and SO42−) are major constituents, accounting for 43.1 ± 8.3% and 27.4 ± 14.6% of PM2.5, respectively. Chloride (Cl−) and water-soluble potassium (K+) are the dominant ionic species, with an average abundance of 14.5 ± 8.2% and 6.4 ± 4.4% in PM2.5, respectively. The average K+/Cl− ratio is ∼0.4, lower than 2.8–5.4 for wood combustion. Similarity measures (i.e., Student's t-test, coefficient of divergence, correlations, and residual to uncertainty ratios) show the crop profiles are too similar for the species measured to be resolved from one another by receptor modeling. The largest difference was found between rice straw and corn stalk emissions, with higher OC and lower Cl− and K+ abundances (50%, 8%, and 3% of PM2.5, respectively) for corn stalks; lower OC, and higher Cl− and K+ abundances (38%, 21%, and 10% of PM2.5, respectively) for rice straw. Average EFs were 4.8 ± 3.1 g kg−1 for OC, 1.3 ± 0.8 g kg−1 for Cl− and 0.59 ± 0.56 g kg−1 for K+. Flaming and smoldering combustions resulted in an average modified combustion efficiency (MCE) of 0.92 ± 0.03, and low elemental carbon (EC) EFs (0.24 ± 0.12 g kg−1). OC/EC ratios from individual source profiles ranged from 12.9 ± 4.3 for rice straw to 24.1 ± 13.5 for wheat straw. The average K+/EC ratio was 2.4 ± 1.5, an order of magnitude higher than those from residential wood combustion (0.2–0.76). Elevated emission rates were found for OC (387 Gg yr−1) and Cl− (122 Gg yr−1), accounting for 44% and 14% of 2008 PM2.5 emissions in China.