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Globally, phytonematodes cause significant crop losses. Understanding the functions played by the plant rhizosphere soil microbiome during phytonematodes infection is crucial. This study examined the distribution of phytonematodes in the paddy fields of five provinces in Thailand, as well as determining the keystone microbial taxa in response to environmental factors that could be considered in the development of efficient biocontrol tactics in agriculture. The results demonstrated that Meloidogyne graminicola and Hirschmanniella spp. were the major and dominant phytonematodes distributed across the paddy fields of Thailand. Soil parameters (total P, Cu, Mg, and Zn) were the important factors affecting the abundance of both nematodes. Illumina next-generation sequencing demonstrated that the levels of bacterial diversity among all locations were not significantly different. The Acidobacteriota, Proteobacteria, Firmicutes, Actinobacteriota, Myxococcota, Chloroflexi, Verrucomicrobiota, Bacteroidota, Gemmatimonadota, and Desulfobacterota were the most abundant bacterial phyla observed at all sites. The number of classes of the Acidobacteriae, Clostridia, Bacilli, and Bacteroidia influenced the proportions of Hirschmanniella spp., Tylenchorhynchus spp., and free-living nematodes in the sampling dirt, whereas the number of classes of the Polyangia and Actinobacteria affected the amounts of Pratylenchus spp. in both roots and soils. Soil organic matter, N, andMnwere the main factors that influenced the structure of the bacterial community. Correlations among rhizosphere microbiota, soil nematodes, and soil properties will be informative data in considering phytonematode management in a rice production system. [ABSTRACT FROM AUTHOR]

The aging process of transmission lines has a direct impact on the reliability and safety of the power grid. Therefore, an accurate age estimation method is imperative for effective maintenance planning and infrastructure investment. This paper introduces a systematic methodology for estimating the age of overhead transmission lines, utilizing the percentage statistical health index (%SHI) and the failure probability curve-fitting (FPCF) method. The %SHI, employing a scoring and weighting approach derived from test results and inspections, is used to assess the actual condition of transmission line equipment. Additionally, the FPCF approach is applied to illustrate the connection between the SHI and the likelihood of failure, facilitating the assessment of transmission line age by fitting failure probability curves to the SHI data. This age is directly associated with the probability of experiencing a failure. The evaluation was conducted on 924 towers situated along four transmission lines connecting the 115 kV substations S1–S2, S3–S4, S5–S6, and S7–S8. These transmission lines are in four regions with diverse terrain and environments such as mountains, rice fields, and more. In the SHI calculation, practical testing results and historical failure data were applied. The results clearly indicate that there were notable disparities in the age estimations for transmission lines in diverse geographical regions of Thailand when compared to their actual ages. These discrepancies can be attributed to various factors, including the local environment, such as rainfall, flooding, and salt-laden air as well as specific geographical features like mountainous and coastal terrain. To mitigate the deterioration of transmission lines in all regions, it is essential to implement a proactive maintenance strategy. This strategy should involve more frequent inspections, the use of advanced monitoring technologies, and the establishment of robust maintenance procedures, with which it would become possible to enhance the accuracy of equipment condition assessments, ultimately resulting in an overall improvement in the reliability of transmission lines. [ABSTRACT FROM AUTHOR]

Rice fields present a unique ecosystem characterized by seasonal fluctuations in soil, water conditions, rice growth, and associated organisms including algae and invertebrates. This study analyzed zooplankton diversity and abundance patterns between organic and conventional chemical rice fields over a growing season in a paddy field site in Buri Ram Province, Thailand. The aim of this study is to compare differences in zooplankton community structure based on cultivation method and temporal changes along a growing season. Environmental parameters and zooplankton samples were collected from adjacent 3 organic and 3 chemical rice fields between September and November 2019. A total of 67 zooplankton taxa encompassing 3 major groups were identified (55 rotifers, 8 cladocerans, and 4 copepod larval stages). Overall, zooplankton abundance showed no significant differences between organic and chemical rice fields. However, organic fields exhibited higher Shannon-Weiner diversity and supported more zooplankton taxa compared to chemical fields. Margalef species richness and Pielou evenness were similar between rice field types. In terms of temporal variability, zooplankton did not show statistically difference in overall mean abundance, but Shannon-Weiner diversity and evenness showed a slight drop in October when compared to September. Although total abundance was comparable, differences in zooplankton community composition and diversity metrics highlight distinctions between organic and conventional cultivation that may arise from contrasting agricultural practices. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: Cadmium contamination in rice grains with a maximum concentration 19 times the national food standard at sites downstream of zinc mines in Thailand has been reported since 2005. These cultivated rice grains are consumed by local residents and have increased the risk of renal dysfunction in residents. Decreasing negative health effects by reducing cadmium accumulation in rice should be considered. Since the soil characteristics affecting the toxicity and accumulation of cadmium in rice cultivated in cadmium-contaminated soils have never been reported, this study was conducted to investigate the soil characteristics affecting the plant availability and mobility of cadmium in paddy soils and the impacts of these soil characteristics on rice seed germination and accumulation in rice. METHODS: The study area is the Mae Tao Subdistrict, Mae Sot District, Tak Province, located downstream of abandoned zinc mines in northwestern Thailand. A total of 36 paddy fields that were reported to produce rice grain with cadmium contents exceeding the national standard for cadmium in rice (0.4 milligrams per kilogram) were randomly selected for composite soil sample collection. The physicochemical characteristics of the soils, including soil texture, redox potential, cation exchange capacity, potential of hydrogen, organic matter, total cadmium concentration, and chemical speciation and concentration of plant-available cadmium, were analyzed. The toxicity of cadmium to rice and the cadmium accumulation ability in rice were assessed through the germination of Khao Dok Mali 105, a popular rice variety for cultivation and consumption in the study area. FINDINGS: Total cadmium concentrations of 0.20 to 89.87 milligrams/kilogram were found in the soils, with 64 percent of all samples containing values greater than the national background value in agricultural soils. Up to 74.2 percent and 99.5 percent of total cadmium was found in the forms of mobile- and plant-available cadmium, respectively. Plant-available cadmium caused significant reductions in the number of seeds germinated and root length. Cadmium toxicity to rice was positively affected by the concentrations of exchangeable, plant-available and total cadmium. The concentrations of plant-available, exchangeable, carbonate-bound, and total cadmium strongly affected the accumulation of cadmium in germinated roots. Cluster analysis showed that plantavailable cadmium was the main factor responsible for high cadmium accumulation in rice. CONCLUSION: Based on the overall analyses of soil characteristics affecting the mobility and plant availability of cadmium in soils and its toxicity and accumulation in germinated rice, the immobilization of plant-available cadmium in soils by adding organic matter-rich amendments to soils is recommended. In addition, oxidizing soil conditions should be maintained during rice cultivation to reduce the phytoavailability of Cd in soils. [ABSTRACT FROM AUTHOR]

Maize is being considered as an alternative crop for off-season rice production in Thailand due to increasing water scarcity. The objective of this study was to evaluate the agronomic characteristics and root-zone soil properties of 4 hybrid maize varieties grown in paddy soil during off-season rice cultivation, in order to assess their growth and development after the flooded-rice harvest and the associated soil microorganisms. The randomized complete block design with 4 treatments and 4 replications was used. The 4 treatments were 2 new maize varieties (Suwan 5731 and Suwan 5819), 1 check variety (Suwan 4452), and 1 local use variety (PAC 789). Suwan 5819 showed significantly higher plant height than Suwan 4452, Suwan 5731 and PAC 789, with the highest plant height recorded for Suwan 5819 (221 cm). Similarly, Suwan 5819 exhibited significantly higher estimated leaf area index than Suwan 4452, Suwan 5731 and PAC 789, with differences of 32.67, 42.57 and 29.29 % at VT, respectively. These superior performances of Suwan 5819 could be attributed in part to increased dry matter and nutrient accumulation at the VT stage. The grain yield for PAC 789 was 13.71 t ha-1, Suwan 4452 was 13.23 t ha-1, Suwan 5731 was 12.83 t ha-1, and Suwan 5819 was 12.25 t ha-1. However, there was no significant difference in the grain yields among the 4 varieties. The soil in the root zone of Suwan 5819 at VT was significantly less acidic (pH 5.08) than Suwan 4452 (pH 4.58), PAC 789 (pH 4.61) and Suwan 5731 (pH 4.75). The nitrogen-fixing bacteria were most abundant in PAC 789 (84 %), phosphate-solubilizing bacteria in Suwan 4452 (15 %), and potassiumsolubilizing bacteria in Suwan 5819 (16 %). Overall, the study suggests that Suwan 5819 is a promising maize variety for agronomic performance in the tested region. [ABSTRACT FROM AUTHOR]

Rice fields are dynamic ecosystems with complex niche structures for organisms, and they have been hypothesised to have high biodiversity. Accordingly, in this study, the diversity of zooplankton in rice fields in Suphan Buri Province, a large area of rice plantations in the central region of Thailand, was examined. A total of 100 species, including 52 rotifers, 18 cladocerans, and 30 copepods, were recorded, including Mesocyclops kayi, which was a new record in Thailand. A high Simpson's diversity index (0.63) and a low Pielou's species evenness index (0.02) confirmed various potential niches for zooplankton in this ecosystem, leading to a low Jaccard similarity index both among the current rice fields and those in other regions. Moreover, the species richness estimators suggested that more species are expected to be discovered in the rice fields. Rotifer and copepod communities are influenced by local environmental variables, including dissolved oxygen, salinity, conductivity, and chlorophyll a. The results of this study fill a gap in the knowledge regarding the diversity and ecology of zooplankton in rice fields. However, further research is needed to fully comprehend the function of this ecosystem and the actual diversity in Thailand. [ABSTRACT FROM AUTHOR]

A revision of the genus Cenchrus (Poaceae) in Thailand is reported. Seven species, i.e. C. brownii, C. ciliaris, C. clandestinus, C. echinatus, C. pedicellatus, C. purpureus and C. setosus are described in this taxonomic treatment. This genus is an exotic species and distributed throughout the floristic regions. All the species have become naturalised to Thailand as a weed and found growing in wastelands, open areas by the roadside, disturbed sites, the edge of rice fields and the edge of deciduous and evergreen forests at elevations between 0 and 2,650 m alt. Pennisetum macrostachyum, a synonym of Cenchrus purpureus is lectotypified. Detailed morphological descriptions, illustrations and a key to the species are presented, along with information on distributions, habitats, ecology, phenology, vernacular names and specimens examined. [ABSTRACT FROM AUTHOR]

This study presents image classification techniques using Sentinel-1A microwave SAR-C imagery to detect agricultural vulnerability area resulting from a massive flood in Ubon Ratchathani province, Thailand, which occurred in 2019. Two time series of selected images were used in analytical processes: namely S1A_IW_GRDH acquired on August 10th, 2019, representing the pre-flood event, and S1A_IW_GRDH acquired on 9th September 2019 represents the massive flood in this area. Prior to the classification, these data were preformed pre-processing processes, such as calibration, speckle filtering and terrain correction. The preprocessed data were then classified using 3 machine learning classifier algorithms, namely, Random Forest (RF), K-Dimensional Tree (KDTree KNN), and Maximum Likelihood for comparing classification accuracy derived from each classifier. There are 4 land use/land cover (LULC) classes derived from the dataset, i.e., (1) paddy rice, (2) water body, (3) residential area, and (4) vegetation, respectively. The second map was used to determine the extent of flooding and non-water area based on backscattering coefficient derived from Sigma0_VV polarization using band math calculation obtained from the histogram. The extracted flooded area aimed at creating the flooded water mask for overlaying with the classified LULC maps derived from each classifier. Finally, the LULC maps were overlaid with flooded event map that occurred on September 9, 2019, for quantifying affected area. The results indicated that paddy rice was damaged by flooded with the area of 98 km2 classified by RF achieving the overall accuracy of 94.60%. The KDTree KNN classifier identified the affected area of 85 km2 with the overall accuracy of 93%, while the Maximum Likelihood classifier detected the flooded area of 91 km2 with the overall accuracy of 93.36%, respectively. [ABSTRACT FROM AUTHOR]

Photosynthetic performance and biomass at different growth stages of the salt-sensitive KDML105 rice cultivar, three improved lines (RD73, CSSL8-94, and TSKC1-144), and the salt-tolerant standard genotype (Pokkali) were investigated under non-saline, semi-saline, and the heavy-saline field conditions in the northeast of Thailand. In the non-saline field, net photosynthesis rates (Pn) of all genotypes remained high from the early vegetative stage to the milky stage and then dramatically reduced at maturity. In contrast, in both saline fields, Pn was the highest at the early vegetative stage and continuously declining until maturity. Leaf chlorophyll content remained high from the early vegetative to milky stage then reduced at maturity for all three field conditions. During the reproductive phase, Pn of KDML105 and the improved lines were reduced by 4–17% in the heavy-saline field, while that of Pokkali was increased (11–19% increase over that of the non-saline). Pokkali also showed a prominent increase in water use efficiency (WUE) under salinity. Nevertheless, rice leaves under saline conditions maintained the PSII integrity, as indicated by the pre-dawn values of maximum quantum yield of PSII photochemistry (Fv/Fm) of higher than 0.8. Pokkali under the semi-saline and the heavy-saline conditions exhibited 51% and 27% increases in final biomass, and 64% and 42% increases in filled grain weight plant−1, respectively. In the semi-saline condition, RD73, TSKC1-144, CSSL8-94, and KDML105 showed moderate salt tolerance by displaying 24%, 18.6%, 15%, and 11.3% increases in final biomass, and 24%, 4%, 13%, and 6% increases in filled grain weight plant−1, respectively. In contrast, in the heavy-saline field, final biomass of RD73, KDML105, CSSL8-94, and TSKC1-144 showed 48%, 45%, 38%, and 36% reductions from that in the non-saline field, while the filled grain weight plant−1 were reduced by 45%, 58%, 35%, and 32%, respectively. This indicated that the improved lines carrying drought- and/or salt-tolerance genes achieved an increased salt tolerance level than the parental elite cultivar, KDML105. [ABSTRACT FROM AUTHOR]

Simple Summary: Fire is traditionally used by farmers for clearing fields when the fallow period is short. Soil chemical properties changed significantly after burning and returned to prefire levels after 1 year. Bacillus, HSB OF53-F07, Conexibacter, and Acidothermus abundances increased immediately after burning and then significantly declined, with lower levels 1 year after burning. Anaeromyxobacter and Candidatus Udaeobacter dominated at 1 year after burning. Burning under high soil moisture conditions and within a very short time caused no effect to the bacterial soil communities. Rice straw and stubble burning is widely practiced to clear fields for new crops. However, questions remain about the effects of fire on soil bacterial communities and soil properties in paddy fields. Here, five adjacent farmed fields were investigated in central Thailand to assess changes in soil bacterial communities and soil properties after burning. Samples of soil prior to burning, immediately after burning, and 1 year after burning were obtained from depths of 0 to 5 cm. The results showed that the pH, electrical conductivity, NH4-N, total nitrogen, and soil nutrients (available P, K, Ca, and Mg) significantly increased immediately after burning due to an increased ash content in the soil, whereas NO3-N decreased significantly. However, these values returned to the initial values. Chloroflexi were the dominant bacteria, followed by Actinobacteria and Proteobacteria. At 1 year after burning, Chloroflexi abundance decreased remarkably, whereas Actinobacteria, Proteobacteria, Verrucomicrobia, and Gemmatimonadetes abundances significantly increased. Bacillus, HSB OF53-F07, Conexibacter, and Acidothermus abundances increased immediately after burning, but were lower 1 year after burning. These bacteria may be highly resistant to heat, but grow slowly. Anaeromyxobacter and Candidatus Udaeobacter dominated 1 year after burning, most likely because of their rapid growth and the fact that they occupy areas with increased soil nutrient levels after fires. Amidase, cellulase, and chitinase levels increased with increased organic matter levels, whereas β-glucosidase, chitinase, and urease levels positively correlated with the soil total nitrogen level. Although clay and soil moisture strongly correlated with the soil bacterial community's composition, negative correlations were found for β-glucosidase, chitinase, and urease. In this study, rice straw and standing stubble were burnt under high soil moisture and within a very short time, suggesting that the fire was not severe enough to raise the soil temperature and change the soil microbial community immediately after burning. However, changes in soil properties due to ash significantly increased the diversity indices, which was noticeable 1 year after burning. [ABSTRACT FROM AUTHOR]

For an extended period, rice has held a significant position as the staple food of Thailand, serving as a crucial economic crop that contributes substantially to the country's revenue. Farming is the primary occupation of the majority of Thai people. This study aims to identify both the factors influencing farmers' decisions and the specific factors that play a role in their decision-making process for highland paddy rice planting in Chiang Mai Province. The study involved a sample group of 398 ethnic farmers cultivating paddy rice in the highland areas of Chiang Mai. The data was collected using a structured questionnaire and analyzed using descriptive statistics, including percentage, mean, standard deviation, Likert scale, and logit model. The results of the general information study revealed that most of the farmers were males, aged 40 to 49, completing primary education. The planting area was less than 10 rai. Upon analyzing the results of the study concerning the factors influencing farmers' decisions to plant paddy in the highlands, it was found that the group of farmers in Chiang Mai Province expressed a moderate overall opinion about the factors impacting their decision-making process. Regarding the factors that influenced the decision-making process for cultivating highland paddy rice, the study considered six variables: age, income, experience, selling price, customer requirements, and distribution channel. These variables were analyzed at a confidence level ranging from 95 to 99 percent. The primary challenge confronted by highland farmers in Chiang Mai is the scarcity of paddy seeds available for planting. In light of this issue, it is imperative for relevant agencies to intervene and actively encourage farmers to produce their own rice seeds for personal use. [ABSTRACT FROM AUTHOR]

The upper area of Sathing Phra peninsula of Thailand has been affected every year by saltwater intrusion at > 1.5 grams/liter from Songkhla Lake, during April - June. Over 50% of the rice field area has been ruined by the intrusions. Recently, practices of the farmers to adapt to and cope with the saltwater intrusions into rice fields were assessed to be medium level effective. However, there were two adaptations rated at high levels. Those were "monitoring news on saltwater intrusions" and "supplementary careers instead of doing only rice farming". The farmers' guidelines to cope with the saltwater intrusions into rice fields were:1) alternating rice farming system, 2) adjusting the government support policies, 3) changing rice varieties, 4) growing other crops in the rice fields after rice farming season, 5) raising animals along with rice farming, 6) creating supplementary incomes, and 7) grouping farmers. The guidelines that most farmers agreed to practice were: 1) growing rice varieties that met household consumption, 2) growing high-value rice varieties, and 3) growing some saltwater tolerant plants after the rice-farming season. Coping with the problem of saltwater intrusions was rated at a high level. The study found that growing rice varieties that met household consumption along with the promoted rice varieties was preferred by the farmers. The second highest ranked was growing rice according to policies for the management of rice economic zone and mixed farms. These are guidelines that could be managed at the household level to maintain independent farming in the affected areas. [ABSTRACT FROM AUTHOR]

This research attempts to evaluate drought impact on vegetation dynamics using various drought indices including the vegetation condition index (VCI), the temperature condition index (TCI), the vegetation health index (VHI) and The standardized precipitation index (SPI). Monthly VCI, TCI and VHI values were obtained from multi-temporal Terra/MODIS products from 2000 to 2017. Temporal and spatial scales of drought occurrences were detected from seasonal variations and drought severity maps generated from these drought indices. The correlation analysis was analyzed to identify the dominant factors that control vegetation variability. The results found that VHI was better to detect vegetation health in the mountainous areas at higher altitudes and lower temperatures. VCI and SPI captured drought occurrences for paddy fields in the southern part of the region where there was lower rainfall and vegetation cover. The result can be applied for crop and drought early warnings in the region. [ABSTRACT FROM AUTHOR]

Dwindling carbon (C) and nitrogen (N) levels in paddy soils decreases rice production and threaten human food security globally. The efficient maintenance of C and N fluxes in soil-rice systems is a crucial prerequisite for agricultural and environmental sustainability. Herein, we examined the C and N fluxes from 63 rainfed rice paddy fields under conventional farming (CF) and organic farming (OF) systems in Thailand. The C and N fluxes were measured based on a detailed analysis of relevant influxes (fertilizer, manure, and biomass addition) and effluxes (biomass harvest and greenhouse gas emission). The results demonstrated that the harvested grain and straw contributed to the most abundant C and N effluxes for both farming systems. The CH4 effluxes were moderate, whereas the N2O effluxes were meager relative to their total effluxes. Stubble incorporation and animal manure addition to soil were the most extensive C influxes. However, the primary N influxes were stubble incorporation and animal manure addition for the OF system, and chemical-N fertilizers for the CF system. Net C depletions were observed in both the CF and OF systems. However, net N was depleted and accumulated in the CF and OF systems, respectively. Straw incorporation to soils could restore the net C accumulations for the CF and OF systems and elevate the net N accumulation for both systems. This study highlighted that complete straw removal has exacerbated the C and N stock in soil-rice systems, inducing insecurity for the environment and the agricultural systems. Effective straw management is a simple approach for sustaining paddy rice production. [ABSTRACT FROM AUTHOR]

Background: Micronutrient deficiency is currently the major cause of declining productivity in rice‐growing countries, including Thailand. A pot experiment was conducted to determine limiting micronutrients (Fe, Mn, Zn, and Cu) for Khao Dawk Mali 105 (KDML 105) rice, in four soil types. Soil micronutrient speciation and in‐soil extracts were examined to identify the species controlling the availability to the plant and the efficiency of soil extract to assess the availability indices of multi‐micronutrients for KDML 105 rice. Results: Micronutrients in the studied soils were in the order Fe > Mn > Cu > Zn, mostly in stable forms accounting for 96.8%–99.7%, 81.3%–96.5%, 95.6%–97.6%, and 83.3%–98.0%, respectively, and in available fractions of only 0.32%–3.2%, 3.55%–18.66%, 2.44%–4.42%, and 2.03%–16.74% respectively. The omitted Fe had the greatest effect on limiting the rice grain yield with a significant reduction of 24.12%–46.46%, whereas the omitted Zn had the least effect. To assess the availability for KDML 105 rice, DTPApH 7.3 was the most suitable multipurpose extractant for Fe, Mn, and Cu, while HCl was superior to other extractants for Zn. All oxide fractions were responsible for supplying available Fe, Mn, and Cu, while Zn was generated from the organic and exchangeable fractions. Conclusions: The yield of KDML 105 rice can be increased by adding each of these micronutrients but yield magnitude was different depending upon their deficient levels in soils. The oxide‐bonded micronutrients were the species controlling its availability and DTPApH 7.3 was suggested as the multipurpose extractant for micronutrient availability indices indicators. [ABSTRACT FROM AUTHOR]

Xanthomonas oryzae pv. oryzae (Xoo) is a widespread pathogen causing bacterial leaf blight (BLB) disease, devastating rice productivity in many cultivated areas of Thailand. A specific and simple method for Xoo detection is required to improve surveillance of disease transmission and outbreak. This study developed a recombinase polymerase amplification (RPA) assay assisted with CRISPR-cas12a assay (RAC) for Xoo detection from bacterial cell suspension of infected rice samples without DNA extraction. The efficiency of the RAC system for Xoo detection using either Xoo80 or Xoo4009 locus was optimized to amplify and determine the sensitivity and specificity using a Xoo DNA template from bacterial cell suspension of infected rice samples without DNA extraction. The RAC system using the Xoo4009 locus gave a higher specificity than Xoo80 locus, because only Xoo species was amplified positive RPA product with fluorescence signal by cas12a digestion, which indicated no cross reactivity. Optimal RAC using the Xoo4009 locus enabled diagnosis of Xoo presence from both plant extracted samples of Xoo artificially inoculated rice leaves within 3 d post-inoculation without symptomatic BLB appearance, and Xoo naturally infected rice. Findings exhibited that RAC using the Xoo4009 locus offered sensitivity, specificity and simplicity for Xoo detection, with low intensities of Xoo -DNA (1 × 103 copies/μL) and Xoo -cell (2.5 × 103 cfu/mL). This developed RAC system showed significantly potential for Xoo detection at point-of-care application for early signs of BLB disease outbreak in rice fields. [ABSTRACT FROM AUTHOR]

Organic rice production (ORP) has been promoted as a means of sustaining both farmers and the ecology of paddy fields, so this research aims to evaluate soil properties and soil elements in the ORP and general rice production (GRP) systems in the Thung Kula Ronghai (TKR) zone in Thailand. Soil samples were collected in Roi-et province from fields classified as ORP (5 fields) or GRP (4 fields), and interviews were also conducted with the field owner about rice yield and rice production. Data from the ORP and GRP groups were compared by t-test, and soil enhancement practices were measured by one-way analysis of variance (ANOVA) for variances. Results indicate there were 14 indicators of soil element control in the TKR. All indicators in the ORP and GRP systems were lower than the rate in soil that is suitable for rice production. The macroelement content in the TKR zone was total nitrogen > total potassium > phosphorus available at a ratio of 338: 3: 1, and the soil organic matter (SOM)/soil organic carbon (SOC) ratio is about 3.45. The soil improvement techniques used in the ORP systems--manure only and manure combined with green manure--have a higher pH value (p < 0.05) than the fertilizer only input but a lower TK value (p < 0.05) than the fertilizer only input. As a result, the ORP yield was higher than that of the GRP systems (p < 0.05), greatly affecting farmers' practices. [ABSTRACT FROM AUTHOR]

Aims: The loss of soil organic matter (SOM) has widely been reported in the tropics after changing land use from shifting cultivation to continuous cropping. We tested whether continuous maize cultivation accelerates SOM loss compared to upland rice and forest fallow. Methods: Because litter sources include C4 plants (maize in maize fields and Imperata grass in upland rice fields) in Thailand, C3-derived and C4-derived SOM can be traced using the differences in natural 13C abundance (δ13C) between C3 and C4 plants. We analyzed the effects of land use history (cultivation or forest fallow period) on C stocks in the surface soil. Soil C stocks decreased with the cultivation period in both upland rice and maize fields. Results: The rate of soil organic carbon loss was higher in maize fields than in upland rice fields. The decomposition rate constant (first order kinetics) of C3-plant-derived SOM was higher in the maize fields than in the upland rice fields and the C4-plant-derived SOM in the forest fallow. Soil surface exposure and low input of root-derived C in the maize fields are considered to accelerate SOM loss. Soil C stocks increased with the forest fallow period, consistent with the slow decomposition of C4-plant-derived SOM in the forest fallows. Conclusions: Continuous maize cultivation accelerates SOM loss, while forest fallow and upland rice cultivation could mitigate the SOM loss caused by continuous maize cultivation. [ABSTRACT FROM AUTHOR]

Hunting for the wild meat trade, medicines and other human uses has decimated Indo‐Burma's vertebrate biota and has led to widespread defaunation. Yet, there is surprisingly little data on how hunting impacts wild bird assemblages in different landscapes here. Based on concurrent snapshot surveys of bird hunting, food markets and hunting attitudes across six Indo‐Burma countries, we found that hunting threatens species not only in forested landscapes but also wetlands and farmlands such as orchards and paddy fields—ecosystems overlooked by past studies, with at least 47 species associated with wetlands and agricultural lands identified from market surveys across the region. High rates of mortality are suffered when hunting tools such as nets are used to exclude perceived bird pests in both aquaculture and agricultural landscapes, with over 300 individual carcasses of at least 29 identifiable species detected in one aquaculture landscape sampled in Thailand. We warn that the potentially unsustainable trapping of species for consumption and trade in Indo‐Burma, coupled with high incidental mortalities, could decimate the populations of erstwhile common and/or legally unprotected species. There is an urgent need for stronger regulatory oversight on the hunting take of wild birds and the use of hunting tools such as nets. Alongside this, conservation practitioners need to better engage with rural communities to address unsustainable hunting practices, especially outside of protected areas. [ABSTRACT FROM AUTHOR]

Although rice is a major agricultural product in northeast Thailand, its productivity is low and unstable because rice is cultivated under rainfed conditions and there are issues with soil salinization. In this region, some of the paddy fields have been abandoned because of severe soil salinization. Therefore, effective agricultural management strategies are needed to manage soil salinization for achieving stable agricultural production. To realize effective management strategies, it is necessary to understand the spatiotemporal distribution of soil salinization. To evaluate and update the spatiotemporal soil salinization using remote sensing data, we first evaluate the relationship between soil electrical conductivity (ECe) and soil moisture content (SMC) during dry seasons. Subsequently, the effect of changes in this relationship on the normalized difference salinity index (NDSI) derived from remote sensing data for estimating soil ECe is evaluated. The relationship between ECe and NDSI, depending on the soil moisture conditions in the study area, is clarified. The findings of this study indicate that for estimating ECe using the NDSI, it is necessary to consider not only soil moisture conditions but also its quality at the time of satellite observation. [ABSTRACT FROM AUTHOR]

Background: Freshwater snails serve as intermediate hosts for a variety of trematodes that cause illness in the human and animal populations. Several species of freshwater snails in Thailand have been found to have larval trematode infections. We aimed to investigate a freshwater snail in Phitsanulok Province and report on its current status of larval trematode infection. Methods: Freshwater snails were collected from six localities (rice field and irrigation canal) by handpicking and using a count per unit of time sampling approach. The snails were identified by their external shell morphology. The shedding method was applied to observe the cercariae, which were photographed under a light microscope to determine their morphological types. Results: A total of 211 snails were classified into seven genera. The most abundant snail species was Lymnaea sp., representing 31.3% of the sample, followed by Physella sp., Bithynia sp., Pomacea canaliculata, Filopaludina martensi, Indoplanorbis exustus, and Melanoides tuberculata, in that order. From the sample, 21 snails (9.95%), including Bithynia sp., Lymnaea sp., I. exustus, and M. tuberculata, were infected with cercarial trematodes, which could be categorized into four types, namely amphistome, parapleurolophocercous, echinostome, and xiphidiocercaria. Amphistome emerged from Bithynia sp., and I. exustus was the most common cercaria to be recovered, representing 80.9% of all infected snails. Conclusion: This study presents the current prevalence of cercariae in infected snails within the studied area. It is important to manage intermediate host snails in order to restrict trematode life cycle completion. [ABSTRACT FROM AUTHOR]

Cyanobacteria are distributed worldwide, and many new cyanobacterial species are discovered in tropical region. The Nostoc-like genus Amazonocrinis has been separated from the genus Nostoc based on polyphasic methods. However, species diversity within this genus remains poorly understood systematically because only one species (Amazonocrinis nigriterrae) has been described. In this study, two novel strains (NUACC02 and NUACC03) were isolated from moist rice field soil in Thailand. These two strains were characterized using a polyphasic approach, based on morphology, 16S rRNA phylogenetic analysis, internal transcribed spacer secondary structure and ecology. Phylogenetic analyses based on 16S rRNA gene sequences confirmed that the two novel strains formed a monophyletic clade related to the genus Amazonocrinis and were distant from the type species A. nigriterrae. The 16S rRNA gene sequence similarity (<98.1%) between novel strains and all other closely related taxa including the Amazonocrinis members exceeded the cutoff for species delimitation in bacteriology, reinforcing the presence of a new Amazonocrinis species. Furthermore, the novel strains possessed unique phenotypic characteristics such as the presence of the sheath, necridia-like cells, larger cell dimension and akinete cell arrangement in long-chains and the singularity of D1-D1', Box-B, V2, and V3 secondary structures that distinguished them from other Amazonocrinis members. Considering all the results, we described our two strains as Amazonocrinis thailandica sp. nov. in accordance with the International Code of Nomenclature for Algae, Fungi and Plants. [ABSTRACT FROM AUTHOR]

Indole‐3‐acetic acid (IAA) synthesis is a major property of rhizosphere bacteria. The IAA‐producing ability of rhizobacteria may be influenced by agricultural management. We therefore evaluated the IAA‐producing potential of rhizobacteria isolated during organic rice farming (ORF) and conventional rice farming (CRF) in Thung Kula Rong Hai areas of Thailand. The results indicated that ORF gave a significantly higher percentage of IAA producers (95·8%) than CRF (69·9%). The average IAA values of the ORF isolates were around two times higher than those of the CRF isolates both in the absence (12·8 and 5·8 μg IAA ml−1, respectively) and presence of L‐tryptophan (L‐Trp) (35·2 and 17·2 μg IAA ml−1, respectively). The 16S rRNA gene sequence analysis indicated that the 23 selected isolates belonged to 8 different genera—Sinomonas sp., Micrococcus sp., Microbacterium sp., Fictibacillus sp., Bacillus sp., Burkholderia sp., Leclercia sp. and Enterobacter sp. Interestingly, only three ORF isolates, i.e. ORF15‐20 (Micrococcus sp.), ORF15‐21 (Sinomonas sp.) and ORF15‐23 (Sinomonas sp.), exhibited high IAA production ability without L‐Trp (128·5, 160·8 and 174·7 μg IAA ml−1, respectively). Meanwhile, a slight decrease in IAA production with L‐Trp was noticed, suggesting that the L‐Trp was not used for the IAA synthesis of these isolates. Biopriming with rhizobacterial isolates significantly enhanced the rate of germination of KDML 105 rice seeds compared to the control. [ABSTRACT FROM AUTHOR]

The objectives of the study were to evaluate the impact of pesticide exposure on farmer health during non-active rice farming and active rice farming periods and present the change in the individual cholinesterase activities (%reduction) on the geographic information system (GIS) mapping in Nakhon Ratchasima Province, Thailand. Acetyl- and butyryl-cholinesterase (AChE and BuChE) activities were monitored during both study periods using Test-mate ChE (Model 400). The location of paddy fields was specified using Garmin geographic positioning system MAP 62s. Fifty-eight farmers who participated in this study had an average age of 49.2 ± 6.9 years. Higher prevalence of all health symptoms was observed among farmer participants during the active rice farming period comparing to the non-active rice farming period (p < 0.01). Furthermore, farmers had significantly lower activities of AChE and BuChE during the active rice farming period comparing to the non-active rice farming period (p < 0.01). Our findings indicate that the GIS mapping indicate that the cases with a significant enzyme inhibition have dispersed across the agricultural and the nearby residential areas. This, investigation can be used to promote safer use of pesticides among farmers and mitigate pesticide exposure among residents living in close proximity to a rice field. [ABSTRACT FROM AUTHOR]

Information on the local rice varieties grown in each Tambon (subdistrict), community or part of Thailand is still outdated. The present pilot work aimed to determine physical characteristics (grain dimensions, 1000-grain weight and color parameters) of paddy and dehusked rice in order to enhance the nutritional quality of these varieties. Moreover, it further supports cultivation of local Hawm Gra Dang Ngah (HGDN) rice in Narathiwat to ultimately develop to commercial premium quality. The nutritional values of dehusked rice were also compared among Tambons, as well as between the dehusked rice of local HGDN versus pure line selection HGDN PTNC09002-59. The study analysed rice samples grown locally in 4 Tambons: Bangkhunthong, Phron, Praiwan and Salamai in Takbai Amphoe (district), Narathiwat, Thailand. The main findings in this study revealed that medium and long types of both paddy and dehusked rice were all found in each Tambon. Moreover, local dehusked HGDN grain was darker red-brown color. All Tambons were found to contain comparable nutrient levels. High levels of dietary fiber were detected in all Tambons. Overall, the dehusked HGDN rice grown in Bangkhunthong showed the highest levels of vitamin B2 and calcium. The dehusked HGDN (100 g/dry weight) in Bangkhunthong, Phron, Praiwan and Salamai contains protein; 8.73±0.01, 7.65±0.00, 8.22±0.03 and 6.83±0.03, iron; 8.73±0.01, 7.65±0.00, 8.22±0.03 and 6.83±0.03, ash; 1.19±0.00, 0.75±0.00, 1.10±0.00 and 1.34±0.00. These findings provide new information about local HGDN, and may be utilized to support the agricultural community in Takbai, enabling the selection of optimal HGDN varieties for local commercial use, as well as in breeding programs, to facilitate the promotion of local HGDN in the national Thai rice market. [ABSTRACT FROM AUTHOR]

Sustainable rice cultivation is the goal of agricultural development in Thailand. With that in mind, the Thai rice department started the Sustainable Rice Platform (SRP) in Ubon Ratchathani Province, one of the most important jasmine rice production areas of Thailand. Previous studies have shown that most of the paddy fields were in the essential level or "working towards sustainable rice cultivation", the intermediate level of sustainability, while non-paddy fields achieved an overall Sustainable Rice Platform (SRP) score that allowed them to claim to be sustainable rice farms. The purpose of this study was to identify the significant factors that affected sustainability in the group of practices called "SRP theme" and the constraints of rice cultivation development. The study was conducted on 85 farmers in Det Udom district, Ubon Ratchathani Province, Thailand. Questionnaires and in-depth interviews were collected. The results showed that farm size had a significant effect on the Pre-planting theme (a group of pre-plating activities), water management and nutrient management for the SRP score; a larger farm can lead to higher scores. The integrated farming system had a significant effect on farm management, harvest and postharvest theme. Paddy fields that used the integrated farming system accomplished higher scores. The certified rice program had a highly significant effect on farm management, preplanting, harvest, and post-harvest theme, including the health and safety theme. Moreover, certified rice programs for farmers (Organic, Good Agricultural Practice - GAP and Sustainable Rice Platform-SRP farmers) enabled higher sustainability rice cultivation scores. [ABSTRACT FROM AUTHOR]

We studied the future land changes for sustainable land use planning within 20 years in Nakhon Ratchasima province, Thailand. CA-Markov integrated model with GIS was applied to forecast land use changed. The land use map from the Land development department, Thailand years 2007, 2011, and 2015 classified to 9 classes were used. Classes selected from major pollution sources and area sizes were urban and built-up land, paddy field, corn, sugarcane, cassava, other agriculture, forest, water body, and miscellaneous land. land use map year 2019, 2023, 2027, 2031, and 2035 are the destination of the land use prediction. Percent accuracy was 91.46% with 0.016% of total area error between predicted and actual land use map of 2015. The results of this simulation showed that the area and characteristics of each LU type of each predicted year. However, the area of urban and built-up land, cassava cultivation, and water body were increased by 4. 22%, 8. 29%, and 0. 8% respectively. Meanwhile, corn cultivation, other agriculture, and sugarcane were decreased by 24.15%, 11.76%, and 6.89% respectively. The area for paddy field, forests, water body appear low changed or no changed. The distribution of community forms has expanded from the center of Nakhon Ratchasima, which is a large urban community and spread out along the major roads. The most other agricultural distribution that does not include paddy field spread out on the west, east, and southeast of the province. The most increasing area is cassava that substitutes the area of corn, sugarcane, and other agriculture. [ABSTRACT FROM AUTHOR]

An agricultural land suitability map was developed for rice (Oryza sativa L.) cultivation of land severely contaminated with heavy metals at Mae Tao, Thailand, as a representative area from which more than 300 soil samples and 100 rice grain samples were collected. The average concentrations for As, Cd, Pb, and Zn in the soil were 20.99, 2.66, 19.92, and 115.62 mg/kg, respectively The geo accumulation index (Igeo) values for As, Cd, Pb, and Zn indicated that this area was highly contaminated with Cd. Land suitability maps were developed for three scenarios: I—following conventional factors in the Storie index; II—adding factor D (heavy metal contamination) with the same weighting for four heavy metals; and III—with factor D focusing on As contamination. The results revealed that adding factor D in the Storie index decreased the suitable area for rice cultivation. Taking into account heavy metal contamination of the soil in land suitability mapping, it reduced the areas of highly suited, suited, and marginally suited by 15%. However, the concentration of heavy metals in rice grain in highly suited and suited land was lower than the Codex standard for food safety and quality. This was confirmed by the hazard index (HI) for rice grain planted in scenarios including factor D (HI < 1). Our research should lead to agricultural land management to protect human health from the danger of consuming rice contaminated with heavy metals. [ABSTRACT FROM AUTHOR]

Human activity and land-use changes have affected the water quality of Kwan Phayao, Upper Ing watershed, due to the associated high sediment load and eutrophication. This study aims to identify suitable LULC allocation scenarios for minimizing sediment and nutrient export into the lake. For this purpose, the LULC status and change were first assessed, based on classified LULC data in 2009 and 2019 from Landsat images, using the SVM algorithm. Later, the land requirements of three scenarios between 2020 and 2029 were estimated, based on their characteristics, and applied to predict LULC change using the CLUE-S model. Then, actual LULC data in 2019 and predicted LULC data under three scenarios between 2020 and 2029 were used to estimate sediment and nutrient export using the SDR and NDR models. Finally, the ecosystem service change index identified a suitable LULC allocation for minimizing sediment or/and nutrient export. According to the results, LULC status and change indicated perennial trees and orchards, para rubber, and rangeland increased, while forest land and paddy fields decreased. The land requirements of the three scenarios provided reasonable results, as expected, particularly Scenario II, which adopts linear programming to calculate the land requirements for maximizing ecosystem service values. For sediment and nutrient export estimation under the predicted LULC for the three scenarios, Scenario II led to the lowest yield of sediment and nutrient exports, and provided the lowest average ESCI value among the three scenarios. Thus, the LULC allocation under Scenario II was chosen as suitable for minimizing sediment or/and nutrient export into Kwan Phayao. These results can serve as crucial information to minimize sediment and nutrient loads for land-use planners, land managers, and decision makers. [ABSTRACT FROM AUTHOR]

Life cycle assessment was applied to a riceberry rice product to support decisions on the development of an innovative, healthy, and low-carbon product to move toward a low-carbon society. The cultivation and processing stages were identified as the key activities generating substantial greenhouse gas emissions. To reduce the life cycle greenhouse gas emissions, several strategies were proposed at the cultivation stage: (1) converting from nonorganic to organic rice farming systems, (2) using a seeding machine instead of manual seeding, and (3) employing a drone for spraying pesticides/herbicides to replace ground-based. Other reduction strategies were: (4) using a low-fat and low-sodium formula seasoning, (5) re-designing the packaging, (6) changing the material of the corrugated box, and (7) recycling the corrugated boxes. The results showed that the carbon footprint values could be reduced from 260 to 233 g CO2e per pack of 50 g net weight. These strategies could also reduce the impacts on water scarcity by 84%, freshwater eutrophication by 57%, cancer human health effects by at least 30%, and land use by 3%. The results confirmed that the life cycle design minimizing the carbon footprint value did not shift the impact from global warming to other environmental concerns. [ABSTRACT FROM AUTHOR]

Melioidosis is a life-threatening disease in humans caused by the Gramnegative bacterium Burkholderia pseudomallei. As severe septicemic melioidosis can lead to death within 24 to 48 h, a rapid diagnosis of melioidosis is critical for ensuring that an optimal antibiotic course is prescribed to patients. Here, we report the development and evaluation of a bacteriophage tail fiber-based latex agglutination assay for rapid detection of B. pseudomallei infection. Burkholderia phage E094 was isolated from rice paddy fields in northeast Thailand, and the whole genome was sequenced to identify its tail fiber (94TF). The 94TF complex was structurally characterized, which involved identification of a tail assembly protein that forms an essential component of the mature fiber. Recombinant 94TF was conjugated to latex beads and developed into an agglutination-based assay (94TF-LAA). 94TF-LAA was initially tested against a large library of Burkholderia and other bacterial strains before a field evaluation was performed during routine clinical testing. The sensitivity and specificity of the 94TF-LAA were assessed alongside standard biochemical analyses on 300 patient specimens collected from an area of melioidosis endemicity over 11months. The 94TF-LAA took less than 5 min to produce positive agglutination, demonstrating 98% (95% confidence interval [CI] of 94.2% to 99.59%) sensitivity and 83% (95% CI of 75.64% to 88.35%) specificity compared to biochemical-based detection. Overall, we show how a Burkholderiaspecific phage tail fiber can be exploited for rapid detection of B. pseudomallei. The 94TF-LAA has the potential for further development as a supplementary diagnostic to assist in clinical identification of this life-threatening pathogen. [ABSTRACT FROM AUTHOR]

Many egg‐laying reptiles possess temperature‐dependent sex determination (TSD) in which outcome of gonadogenesis is determined by incubation temperature during a temperature‐sensitive period of development. Prior studies on Malayemys macrocephala showed that incubation temperatures influence gonadal development and suggested that M. macrocephala exhibits TSD. However, information on the temperature‐sensitivity period in this species was unknown until the current study. Turtle eggs were collected from rice fields in central Thailand from December 2016 to February 2017. In the laboratory, eggs were incubated at male‐biased temperature (26 °C) and shifted to female‐biased temperature (32 °C), or vice versa. Single shift experiments were performed systematically during embryonic stages 13–21. After hatching, sex of individual turtles was determined by histological analysis. We found that the sex determination of M. macrocephala is affected by temperature up to stage 16 of embryonic development. [ABSTRACT FROM AUTHOR]

This paper aims at assessing the effect of land use on nitrogen flows from a significant land-use area in the Chi River basin (Maha Sarakham region) in Thailand. The Chi River is one of the main rivers, and many land use categories affect the quality of the river. Statistical data and referred data was collected as the secondary data from credible sources to identify the flows. The data show a strong effect of land use on nitrogen with the highest load dominated by paddy field (66,597.51 tonne/year), and the lowest value in the community (1,005.71 tonne/year). Nitrogen flow increased with the fertilizer application in paddy field and farm plants (34,834.07 tonne/year). Paddy field discharged nitrogen to the Chi River 47 tonne/year in form of surface runoff. Also, the community without wastewater collection system takes part in a non-point source (NPS) of nitrogen to the Chi River at 299 tonne/year. The management's suggestion is to control fertilizer application, burning of agricultural residue such as rice straw, and wastewater treatment before disposal. [ABSTRACT FROM AUTHOR]

Khao Dawk Mali 105 (KDML105) is a premium fragrant rice variety and is widely grown in Thung Kula Rong Hai (TKR), northeast Thailand. In the present study, the influence of organic and conventional rice farming (ORF and CRF, respectively) in TKR farmers' paddy fields on soil properties and their relationship with 2-acetyl-1-pyrroline (2AP) in KDML105 rice grains were investigated. The results indicated that the ORF system had a strong positive effect on major soil quality indicators and the 2AP content in the rice grains. The soil organic matter (SOM) was approximately twice as much in the ORF than in the CRF system, thus leading to much higher total nitrogen (TN), humic acid (HA), and microbial populations in the ORF system. The higher SOM in the ORF system not only enhanced the soil quality indicators but also contributed to approximately 3.5 times higher 2AP than in the CRF system. Principle component analysis indicated a close correlation among SOM, TN, HA, and microbial population under the ORF system; these variables exhibited strong correlations with the 2AP contents in KDML105 rice grains. [ABSTRACT FROM AUTHOR]

Understanding of the long-term soil fertility trends is the basis for rational and sustainable management of the soil resources in agricultural fields. In tropical Asia, the Green Revolution initiated in the late 1960s contributed to a drastic increase in both food production and human population. Among the tropical Asian countries, Thailand is known as a rice-exporting country, but the country's rice yield is still relatively low. Therefore, this research aimed to investigate the effect of the Green Revolution on the changes in paddy soil fertility status in Thailand over the last 50 years. In total, 65 surface soil samples were collected in 2015 and 2016 from paddy fields in the northeast, north, central plain, and Bangkok Plain of Thailand. To compare the fertility-related data of the samples with those of soils collected from 1964 to 1972, the sampling sites in the 2010s were placed at or near the same locations of the original sites. Over the last 50 years, the mean pH, total C, total N, available N, available P, and exchangeable K values increased significantly (p < 0.01). In particular, the available P content dramatically increased from 3.19 to 42.8 mg kg–1, reflecting the rapid increase in fertilizer application. Contrarily, the mean exchangeable Mg and clay content values decreased significantly (p < 0.05). Regionally, the total C and total N contents of the soils in the northeast were significantly lower than those in the other regions (p < 0.05), and the available P, exchangeable K, and available Si contents were often evaluated as deficient, reflecting the very sandy texture of the soils. In conclusion, the fertility status of the paddy soil in Thailand has improved considerably over the last 50 years, and the increase in total C suggests the potential of paddy soil for C sequestration, even in the tropics. These trends should be considered to achieve more sustainable food production and environmental conservation in Thailand. [ABSTRACT FROM AUTHOR]

Rice agriculture is the foundation of Asian civilizations south of the Yangtze River. Although rice history is well documented for its lower Yangtze homeland area, the early southward expansion of paddy rice farming is poorly known. Our study investigates this process using a compilation of paleoenvironmental proxies from coastal sediment cores from southeast China to Thailand and Island Southeast Asia. We propose that a shortage of land suitable for paddy fields, caused by marine transgression, constrained rice agriculture during the mid-Holocene. Rapid expansion of coastal plains, particularly in deltaic basins, over the past three millennia has coincided with increases in land suitable for rice cultivation. Our study also helps explain the past population movements of rice farmers. [ABSTRACT FROM AUTHOR]

Tropodiaptomus megahyaline sp. nov. is described and illustrated based on materials collected from a rice field near Songkhram River Basin, Bueng Kan Province, Northeastern Thailand. This new species can be distinguished from its congeners by features of the male such as (1) antepenultimate segment of the right antennule with straight spinous process reaching middle of next segment; (2) basis of the right P5 with three process; (3) basis of both right and left P5 with longitudinal hyaline lamella, length about 1/3 as long as basis on the inner margin; (4) second segment of exopod of the right P5 trapezoidal, with two semicircular hyaline knobs, and one triangular process on distal outer margin of dorsal surface; and (5) inner margin of the exopod of the left P5 with the proximal part larger than the distal part. Differences among Asian Tropodiaptomus species are noted, and an identification key for both females and males of this genus is proposed. [ABSTRACT FROM AUTHOR]

• A paddy field in Thailand contaminated with Cd (41.02 mg kg−1) was restored. • BZVI decreased Cd accumulation in rice grains by 83 %. • BZVI as soil amendment enriched Fe and Zn accumulation in rice grains by 10 %. • ZVI corrosion enhanced by biochar is the key to BZVI success. • This technique is suitable for community-driven soil restoration. Consuming rice grown in contaminated soil that has an elevated level of cadmium (Cd) is a health risk. This study revealed that using a combination of biochar and zerovalent iron (BZVI) reduces the concentration of Cd and enhances that of the essential elements zinc (Zn) and iron (Fe) in rice. The Cd concentration in brown rice grain cultivated in an untreated paddy was 0.84 ± 0.20 mg kg−1, double the acceptable level (0.4 mg kg−1). Soil amendment with BZVI successfully decreased Cd in brown rice by 83 % compared to the untreated field presumably due to the Cd sorption on biochar (BC) and enhanced ZVI corrosion by-products while ZVI and BC alone achieved only 40 % and 74 % reduction, respectively. Moreover, while using ZVI or BC alone decreased Fe in rice grain by 8–14 %, BZVI enhanced the Fe concentrations in rice grain by 11 % because of Fe2+/Fe3+ release from BC-enhanced ZVI corrosion. Similarly, the presence of BC in BZVI enhanced Zn accumulation in rice grain by 8% due to competitive sorption of Cd2+ on BZVI, which may desorb Zn2+, promoting Zn translocation to rice. Using ZVI alone decreased Zn in rice by 19 %. [ABSTRACT FROM AUTHOR]

The multi-functional agroforestry system associating rainfed lowland rice and sugar palm (RLR-SP) hedges has been sustaining emblematic cultural landscapes in the Indianized countries of Southeast Asia for centuries. Often established in areas facing very constrained soil–water conditions, it played a crucial role in the agro-ecological, social and economic resilience of these agrarian systems. Recent changes in communication infrastructure, commercialization, urbanization, state interventions and private initiatives have driven the transformations of these iconic cultural landscapes, but analyses of their socio-ecological impacts on household livelihoods and landscapes features are lacking. In this study, we quantified and analysed the transformations of a coastal RLR-SP cultural landscape in Southeast Thailand. We used remote sensing data to characterize and quantify land-use change during 1983–2015, and interviews with diverse stakeholders to understand the impacts of the driving factors of change on livelihood systems. After the mid-1980s, market integration facilitated by the construction of bridges and all-weather roads led to the diversification of farming and off-farm activities, increasing the mobility of farm labourers sizing wage-earning opportunities in neighbouring urban centres. In the 1990s, the RLR-SP system faced the introduction of an irrigation canal, shrimp farming, tree plantations, and the partial conversion of deep-water rice areas into mixed gardens. More recently, the demand for sugar palm fruits by the caning industry has revived an interest in sugar palm groves. A policy to raise the farm incomes associated with palm oil companies supported the conversion of paddy fields into small oil palm plantations, which is the most important recent land-use change and future threat to the survival of the RLR-SP system. Like in other Southeast Asian coastal areas, the increased frequency of extreme climatic events is another major threat faced by this emblematic but increasingly vulnerable cultural agroecosystem. The profitable and land/water resource efficient association of the RLR-SP system with commercial vegetable production on diversified smallholdings is a promising way towards a more sustainable landscape management that could be supported by improving on-farm water storage. [ABSTRACT FROM AUTHOR]

Tetragnatha spiders are common predators in rice ecosystems. However, changes in their population numbers and availability of prey types at each rice growth stage are poorly understood. Therefore, this study assessed the population dynamics of Tetragnatha spiders and their prey composition during four stages of rice growth, including vegetative, reproductive, ripening, and after-harvesting in semi-organic rice fields in Songkhla Province of southern Thailand. The results showed that species richness and abundance of spiders were significantly higher in the reproductive stage than in other stages. Main prey families captured by Tetragnatha spiders varied with different growth stages. Chironomidae and Corixidae were the main prey in the vegetative and reproductive stages, while Delphacidae was the most common prey in the ripening stage and there was dominant prey in the after-harvesting stage. Overall, the different growth stages provided different rice structures for web attachment and different prey, which influenced both the spider populations and prey composition. [ABSTRACT FROM AUTHOR]

The loads of biochemical oxygen demand (BOD) in the Chao Phraya River Basin (CPRB), Thailand were analyzed in terms of how they were generated (BODgen), stocked in the environment (BODen-stock), and discharged into the Chao Phraya River (BODCPR) using material flow analysis. BODgen from the industrial sector was the highest; however, BODen-stock and BODCPR from this point source were not significantly higher than those from the domestic sector. BODgen, BODen-stock, and BODCPR from swine farming and aquaculture across the river basin were lower than those from the domestic and industrial sectors. Of the total 251,884 tons per year (t/year) BODCPR, 49,614 t/year were in the upper river section, 35,976 t/year in the middle river section, and 166,294 t/year in the lower river section. These amounts were more than the carrying capacities of the relevant river sections (i.e., 7230 t/year, 18,380 t/year, and 37,851 t/year of the BOD loads for the upper, middle, and lower river sections, respectively). The first priority in BOD reduction in the CPRB should emphasize domestic wastewater by increasing wastewater treatment efficiency and onsite installations of wastewater treatment systems, while the second should be on paddy fields and other nonpoint sources. Specific best management practices may be considered, e.g., creating constructed wetlands or preserving riverbank vegetation as natural swales to alleviate BOD discharge from agricultural activities into water sources. [ABSTRACT FROM AUTHOR]

Background Melioidosis is an infectious disease commonly found in Thailand. This infectious disease is caused by Burkholderia pseudomallei in soil. This study aims to analyze the association between spatial soil factors and B. pseudomallei detection, as well as to map the probability of B. pseudomallei contamination based on indicator kriging in paddy soil. Methods Seventy-eight soil samples were collected randomly on 22 April 2018 in various paddy fields. Oxidase, Gram staining and monoclonal antibody-based latex agglutination assays were performed to confirm the presence of B. pseudomallei in soil samples. The association between B. pseudomallei detection and spatial soil factors including soil temperature, soil pH, soil texture and soil drainage were analyzed by the Mann–Whitney U test and χ2 test. Subsequently, a semivariogram model and indicator kriging were used to map the probability of B. pseudomallei contamination. Results Of the 78 samples, B. pseudomallei was detected in 32 (41.03%). The presence or absence of B. pseudomallei was not significantly associated with spatial soil factors. The semivariogram model showed that the lag distance between positive B. pseudomallei samples was 90.51 m. Conclusion The empirical semivariogram and indicator kriging are an alternative option for predicting the spatial distribution of B. pseudomallei in soil. [ABSTRACT FROM AUTHOR]

Studies on the starch production rates and starch yields of cassava genotypes provide valuable information for planting in upper paddy fields during the offseason of rice. The objective of this study was to evaluate the starch production of different cassava genotypes grown in different upper paddy fields during the offseason of rice. Four cassava genotypes (Kasetsart 50, Rayong 9, Rayong 11, and CMR38-125-77) were planted in four different upper paddy fields during the offseason of rice in Thailand. A randomized complete block design with four replications was used for each experimental site. The number of storage roots, storage root dry weight, starch content, starch production rate, starch yield, area under curve (AUC) for starch yields, and weather data were recorded. Results revealed no statistically significant difference for genotype × environment in starch content at 120, 150, and 180 days after planting (DAP). Early storage root formation, rapid starch production rate, and high starch yield accumulation were relevant traits for cassava to become a top yielder. The CMR38-125-77 genotype produced significantly greater starch contents at 120 DAP and starch yields at 120 and 180 DAP than the others. This genotype showed outstanding AUCs for starch yield, starch production rate, starch yield at 150 DAP, number of storage roots at 150 DAP, number of storage roots at 180 DAP, and weight per storage root at 120 DAP, leading to the opportunity of the CMR38-125-77 as a preferred genotype and a parental source for cassava production during the off-season of rice. [ABSTRACT FROM AUTHOR]

Agricultural intensification and homogenization of land use are known to have a negative impact on biodiversity. Bat activity was monitored in five land use types that included paddy fields, field crops, forests, settlements, and water bodies from November 2015 to October 2016 in central Thailand. We recorded 37,610 one-minute intervals with bat calls and 623 feeding buzzes that represented 16 bat species. Bat foraging activity was dominated by open space and edge species. Bat activity was significantly higher over water bodies but was not correlated with insect biomass. There was a significantly higher bat activity index (two-fold) in the hot-dry season than at other times, especially over water bodies. This pattern was obvious in Myotis siligorensis, Taphozous melanopogon, and Chaerephon plicatus. High feeding activity during the hot-dry season could reflect higher nutrient and water demand of lactating females. Maintaining water bodies and forest patches in farmland is important for bat conservation. [ABSTRACT FROM AUTHOR]

Biochar application and alternate wetting and drying (AWD) are emerging as promising technologies recommended for reducing CH4 emissions and water consumption in rice cultivation. In this study, we hypothesized that both technologies could be practiced in combination and this could further reduce CH4 emissions and water consumption when compared to practicing alone. The effects of biochar application and its co-application with chemical fertilizer or compost under conventional or AWD water management on CH4 emissions, productivity of rice, water use, and SOC stock, as well as cost and income were investigated. The experiment was carried out in an irrigated paddy field in the central plain of Thailand during both in the wet and dry seasons. Relative to control (CT), biochar application (BI), its co-application with compost (BC) or chemical fertilizer (BF) reduced seasonal CH4 emissions by 40.6%, 29.5%, and 12.3%, respectively. BI and BC significantly (p < 0.05) reduced grain yield by 19.9% and 10.8%, respectively, while BF significantly increased grain yield by 3.70%. In addition, BI, BC, and BF significantly enhanced soil organic carbon (SOC) stock by 21.2%, 21.4%, and 18.3%, respectively. Compared to the CT, higher production costs were found in BC and BF, but the farmer's net incomes were also higher in BF because of its higher grain yield. On the other hand, water management in all amendment treatments under AWD was resulted in the reduction of CH4 emissions by the average of 18.8% as compared to the conventional system. AWD decreased rice yield by an average of 2.29%. It significantly reduced irrigation water use by an average of 11.9%, resulting in reducing production cost for water pumping. The results show that the practice that combined biochar application, AWD and chemical fertilizer are feasible for CH4 emission mitigation, SOC stock increase and irrigation water saving without significant effects on yield and farmer income. [ABSTRACT FROM AUTHOR]

Background: Thailand is the world highest prevalence's of Opisthorchis Viverrini (OV) infection. This study aimed to determine the spatial association of geographic factors with OV infection in the highest prevalence region, the Northeast (NE) of Thailand. Method: This study was conducted using four geographic factors data sets of years 2016 and 2017. A Moran's I and Local Indicators of Spatial Association (LISA) were used to identify the spatial autocorrelation between geographic factors and OV infection within the region. Results: Among the total of 189,231 participants in the NE, the regional prevalence of OV infection was 10.60%. The results indicated a spatial global autocorrelation of geographical factors with OV infections, those geographical factors included water sources including dams, reservoirs, weirs, canals and lagoons; proportion of rice field areas and number of dogs and cats per village, (Moran's I values of 0.28, 0.34, 0.11, 0.40 and 0.17, respectively). The LISA analysis identified significant positive spatial local autocorrelation of water resource: one of high-high cluster for the numbers of dams and reservoirs, three low-low clusters for the number of weirs and two of high-high clusters for the numbers of canals and lagoons. In addition, there were two high-high clusters and three low-low clusters of the proportion of rice field areas, and one low-low cluster of dogs and cats with OV infection. Conclusion: There were spatial associations between physical geographic factors and OV infection in the NE of Thailand which should be taken into new policy recommendations for OV infection control. Especially, in the province with more rice fields, big water resources and had more dogs and cats. [ABSTRACT FROM AUTHOR]

Land use and land cover change (LULCC) by unplanned and uncontrolled urban expansion have a significant effect on ecosystem service values (ESVs). Objectives of the study were (1) to extract LULC status and its change between 2006 and 2016; (2) to predict two different LULC scenarios in 2026 and; (3) to assess LULCC impact on ESVs. Herein, Landsat imageries in 2006, 2011 and 2016 were used to classify LULC types by object-based image analysis (OBIA) and the derived results were applied to predict LULC in 2026 of two scenarios by CLUE-S model and to assess the impact of LULCC on ESVs. Results revealed that paddy field and field crop notably decreased while urban and built-up areas and rangeland dramatically increased over the study periods whereas total ESVs declined from about 145 MM USD in 2006 to 132 MM USD in 2026 of Scenario II and the ESVs of three dominant ecosystem service functions (waste treatment, water supply, and climate regulation) continuously decreased. The impact of LULCC on ESVs remarkably differed among the LULC types. In conclusion, land use and city planners should try to minimize the effect of LULCC on ESVs during the planning process. [ABSTRACT FROM AUTHOR]

Local villagers in Mae Sot District, Tak Province, Thailand are at risk of diseases related to cadmium (Cd) due to excessive consumption of rice contaminated with Cd due to zinc mining. This study verifies the hypothesis that to achieve safe rice cultivation, magnet-assisted soil washing followed by soil amendment using zero-valent iron (ZVI) is required not only for rapid remediation of the existing Cd contamination but also for the prevention of Cd recontamination caused by contaminated run-off from an upgradient contaminated paddy. Accordingly, this study conducted a pilot-scale demonstration of the combined technique to restore a real Cd-contaminated paddy (41.02 ± 5.47 mg/kg−1) and compared it with remediation using only soil amendment with ZVI or only magnet-assisted soil washing. The Cd concentration in rice grains from the contaminated rice field without treatment was 0.86 ± 0.01 mg/kg−1, and thus higher than the acceptable level of 0.4 mg/kg−1. Even though the use of magnet-assisted soil washing without amendment initially removed all the bioavailable Cd from the soil, it failed to reduce Cd uptake by the rice plants. This failure was caused by heavy off-season rain, which flooded and re-contaminated the experimental fields with Cd-contaminated run-off from an upgradient contaminated field, leading to a Cd concentration in rice grains of 1.21 ± 0.01 mg/kg−1. Similarly, the use of ZVI as a soil amendment without magnet-assisted soil washing could not ensure safe rice cultivation during the off-season flood, as Cd concentration in the rice grains was still 0.60 mg/kg−1. However, magnet-assisted soil washing followed by soil amendment using ZVI successfully removed Cd from soil and sequestered Cd from Cd-contaminated run-off, resulting in protection against Cd re-contamination in soil and the reduction of Cd content in rice grains to 0.33 mg/kg−1, representing a 60% removal efficacy. Also, this combined technique remained positive for rice growth compared to non-treatment. [Display omitted] • Magnet-assisted soil washing by ZVI removed all bioavailable Cd in a paddy soil. • Yet, the soil washing alone failed to restore safe rice cultivation. • Off-season flood re-contaminated the treated soil with Cd from untreated areas. • Using ZVI amendment after the soil washing help alleviate Cd re-contamination. • Combining the two techniques provided safe rice production under climate fluctuation. [ABSTRACT FROM AUTHOR]

• GHG emissions from paddy fields under different water and RS management practices analyzed. • CH 4 emissions from RS-B and RS-I plots under AWD was reduced by 36–63% and by 37–39%, respectively, compared to the corresponding plots under CF. • Water and RS management did not influence the average flux of N 2 O emissions from paddy fields. • Yield-scaled GWP was higher from plots with RS incorporation or burning in comparison with no RS incorporated plots. • AWD irrigation without any RS application is recommended to reduce water use and GHG emissions while maintaining yield. Rice-rice (double-rice) cropping in the Central Plain region of Thailand relies heavily on irrigation water inputs for cultivation under flooded conditions, which is increasingly constrained by water scarcity. In this production system, farmers often burn or incorporate rice straw (RS) in the field. The effects of the combined use of water and RS management on irrigated lowland double-rice cropping, with respect to irrigation water savings, grain yields, and greenhouse gas (GHG) emissions, remain largely unknown. Field experiments of two consecutive rice-growing seasons in 2016–2017 were conducted at the Ayutthaya Rice Research Center in Ayutthaya, Thailand, to investigate the effects of different water and RS management practices on irrigation water savings, rice grain yields, and GHG emissions. The treatments consisted of two water regimes (continuous flooding [CF], alternate wetting and drying [AWD; 15 cm threshold water level below the soil surface for irrigation]) and three RS management practices (RS incorporation [RS-I], RS burning [RS-B], without RS incorporation and burning [WRS]). Parameters such as irrigation water inputs, soil characteristics (pH, temperature, water content), above-ground biomass, and grain yields were measured. The static vented flux chamber technique was used to measure GHG emissions (CH 4 and N 2 O fluxes). AWD irrigation significantly reduced water inputs compared to CF in both growing seasons; however, there were more water savings in the dry season. AWD also resulted in higher grain yields compared to CF in both growing seasons. The average CH 4 emissions from WRS plots were significantly lower compared to both RS-I and RS-B plots, regardless of the growing seasons. However, RS-I and RS-B plots under AWD had 39% and 63% lower CH 4 emissions, respectively, in the wet season, while the corresponding values were 37% and 36%, respectively, in the dry season compared to the average CH 4 emissions from these RS treatments under CF. Water and RS management did not significantly influence the average flux of N 2 O emissions from paddy fields in the wet season; however, CF had a lower average N 2 O flux than AWD in the dry season. The average flux of N 2 O emissions were very low compared to the CH 4 emissions flux in both seasons. Averaged across two seasons, the yield-scaled global warming potential (GWP) under AWD was reduced by 34% compared to CF, and under WRS it was reduced by 36% and 29% compared to RS-I and RS-B, respectively. RS application, either as soil incorporation or open-field burning, had little or no effect on irrigation water savings and grain yields; however, the yield-scaled GWP was significantly higher from plots with RS-I or RS-B than WRS plots. Among the water regime and RS management practices tested, AWD irrigation without any RS application (soil incorporation or burning) can be employed for maintaining the yield-scaled GWP of irrigated lowland double-rice cropping at a low level. [ABSTRACT FROM AUTHOR]