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Suitable nitrogen (N) fertilisation is key for economic and environmental sustainability of croplands, and little is known on the potential of slow-release N sources to mitigate nitrous oxide ([N.sub.2]O) and methane (C[H.sub.4]) emissions in paddy rice growing in subtropical lowlands. We assessed the impact of controlled-released N fertiliser (CRNF) on partial global warming potential (pGWP) and yield-scaled greenhouse gas (GHG) emissions (GHG emission per unit of yield) in comparison to common urea in irrigated rice growing in a Typic Albaqualf in southern Brazil. The field experiment comprised four treatments: (1) control; (2) common urea applied into three splits, and CRNF applied at rice sowing; (3) on soil surface; and (4) in the seeding furrow. The N fertilisers did not increase [N.sub.2]O emissions when compared to control with exception of CRNF at the seeding furrow. However, N fertilisation increased C[H.sub.4] emissions, with exception of the CRNF applied to the seeding furrow. Rice grain yields (7954-8637 kg [ha.sup.-1]) were not affected by N sources. The pGWP (11 683-14 297 kg C[O.sub.2] eq [ha.sup.-1]) and the yield-scaled GHG (1.47-1.74 kg C[O.sub.2] eq [kg.sup.-1] grain) were similar among N sources. N fertilisation is a crucial practice to obtain high rice yields, which did not affect negatively the yield-scaled GHG emissions in this subtropical environment under continuous flood irrigation. CRNF applied at rice sowing provides rice grain productivity and agronomic efficiency similar to common urea applied into three splits. Keywords: Brazil, fertiliser management, greenhouse gases, methane, nitrogen fertiliser, nitrous oxide, soil nitrogen cycling, urea., Introduction Agriculture is responsible for approximately 11% of greenhouse gas (GHG) emissions at global level (IPCC 2014). In Brazil, where agriculture is widespread through the whole country, the contribution of [...]

Although there is growing evidence that the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) can lower soil nitrous oxide ([N.sub.2]O) emissions in temperate environments, there is little evidence of its efficacy in subtropical or tropical environments where temperatures and rainfall intensities are typically higher. We investigated [N.sub.2]O emissions in field-grown aerobic rice in adjacent fields in the 2013-14 and 2014-15 seasons in a subtropical environment. Crops were topdressed with 80 kg nitrogen (N) [ha.sup.-1] before rainfall, as either urea, urea + DMPP (at 1.6 kg DMPP [t.sup.-1] urea: 'urea-DMPP') or a blend of 50% urea and 50% urea- DMPP in the 2013-14 season, and urea, ureaDMPP or polymer (3 month)-coated urea (PCU) in the 2014-15 season. DMPP-urea significantly (P Additional keywords: aerobic rice, enhanced efficiency fertiliser, polymer-coated urea, upland rice, urea., Introduction Agricultural soils are a major source of anthropogenic nitrous oxide ([N.sub.2]O) emissions, and account for ~60% of total [N.sub.2]O emissions (Smith et al. 2007). One of the major factors [...]

Commercial rice (Oryza sativa L.) buyers and a growing consumer market for sustainable agricultural products are driving agriculture to be more conscious about production practices and associated environmental effects, such as greenhouse gas emissions. Globally rice production has been identified as a significant source of atmospheric methane (CH4) emissions. This study extends current knowledge by using a procedure to quantify spatial differences in CH4 emissions as well as CH4 efficiency levels (kg rice [kg CH4-C]-1) across the mid-southern United States, where over 75% of all US rice is produced. This study focuses on existing rice production practices that are known to directly affect CH4 emissions: variety selection, crop rotation, and soil texture. Historical data on varietal selection, crop rotations, and soil texture were used to estimate CH4 emissions from 2005 through 2014. Results showed that rice produced on clay-textured soils with a rice-soybean rotation sown with a hybrid variety has the largest CH4 emissions efficiency among the management practice combinations evaluated. Results also demonstrated that any deviation from this optimal combination cannot be mitigated through realistic increases in yields, as it would take a 177% increase in yield for the hybrid-clay-rice to achieve the same efficiency as the hybrid-clay-soybean [Glycine max (L.) Merr.] combination. Results of this study provide commercial rice buyers, producers, and consumers with critical information regarding the drivers of spatial variations in sustainable rice production. Furthermore, these results give insights to producers and policymakers regarding which production practices and locations could benefit from increased demand for sustainable products and more restrictive environmental policies. [ABSTRACT FROM AUTHOR]

To enhance productivity, alleviate environmental and management constraints, and enhance farmers' incomes in the rice-wheat cropping system of the Indo Gangetic Plains, new approaches that are labour-saving, more productive and sustainable need to be developed. Most systems of rice cultivation use puddling to prepare the seedbed and control weeds in rice fields of rainfed, stress-prone environments. This practice might be helpful to reduce weed pressure and obtain slightly higher productivity, but might have negative impacts on soil physical properties. A better understanding is needed of the comparative advantage of unpuddled rice fields for maintaining good soil physical properties. To study the effect of different rice establishment methods on soil physical properties in a rice-wheat cropping system, we analysed soil samples in 2 years (2012-13 and 2013-14) from an experiment testing puddled and unpuddlcd rice-establishment methods. The treatments were: (i) puddled, transplanted with best management practices; (ii) puddled, transplanted with the system of rice intensification; (Hi) unpuddled, transplanted; and (iv) unpuddled, direct-seeded. Omission of puddling improved soil physical properties such as bulk density, penetration resistance, aggregation stability and cracking behaviour. The absence of soil disturbance also improved soil aggregation, average mean-weight diameter and water-stable aggregates. Thus, unpuddled conditions increased the macro-aggregate fraction by 18-33%. By contrast, the higher frequency of smaller macro-aggregates (0.053-0.25 mm diameter) in puddled conditions clearly indicated the breakdown of larger macroaggregates (>0.25 mm) into smaller size fractions. Puddled treatments were also characterised by a hard pan and wider, longer and deeper cracks, with a crack volume more than three times higher in puddled conditions. Unpuddled treatments recorded slightly higher nutrient contents in the topsoil. The study reveals that puddling deteriorates soil health. However, a long-term study is required for a better understanding of the soil changes related to different rice establishment technologies. Additional keywords: crop establishment methods, productivity, rainfed drought-prone ecology, rice-wheat cropping system, soil physical properties, unpuddled transplanting. Received 25 November 2015, accepted 9 February 2016, published online 13 July 2016, Introduction Among countries growing rice (Oryza sativa L.), India has the largest area (42.5 Mha) producing 29% of the nation's calorie requirements, making it the most staple food crop of [...]

Hairy vetch (Vicia villosa Roth) is cultivated during the cold fallow season in paddy soils of temperate countries such as South Korea and Japan, mostly as animal feed and green manure. Information on the effect of ageing of hairy vetch incorporation in relation to greenhouse gas (GHG) emissions and global warming potential (GWP) is not available. Therefore, hairy vetch biomass of ages 183, 190, 197, and 204 days was incorporated in paddy soil to estimate GWP during rice cultivation. The emission rates of methane (C[H.sub.4]), carbon dioxide (C[O.sub.2]), and nitrous oxide ([N.sub.2]O) gases were monitored once a week by using the closed-chamber method. The net ecosystem carbon budget was used to estimate pure C[O.sub.2] emission fluxes. Biomass production of hairy vetch was 6.5 Mg [ha.sup.-1] at 204 days, which was similar to other treatments. The GWP was lower with the 204-day-old vetch biomass incorporation than with other treatments. High content of cellulose and lignin in 204-day-old hairy vetch might have affected decomposition rate and subsequently reduced GHGs emissions during rice cultivation. Our results suggest that hairy vetch can be allowed to grow for 204 days before incorporation at 3 Mg [ha.sup.-1] without sacrificing rice yield, while maximising biomass production and minimising GWP during rice cultivation. Additional keywords: composition of green manure, greenhouse gas emission, rice field, soil. Received 22 May 2014, accepted 27 July 2015, published online 14 April 2016, Introduction The monocrop culture in temperate countries such as Korea and Japan is mainly rice-based, and cover crops are mostly grown in winter as animal feed or as a green [...]

Transcriptional profiling is a prevalent and powerful approach for capturing the response of crop plants to environmental stresses, e.g., response of rice to drought. However, functionally interpreting the resulting genome-wide gene expression changes is severely hampered by the large gaps in our genomic knowledge about which genes work together in cellular pathways/processes in rice. Here, we present a new web resource - RECoN - that relies on a network-based approach to go beyond currently limited annotations in delineating functional and regulatory perturbations in new rice transcriptome datasets generated by a researcher. To build RECoN, we first enumerated 1,744 abiotic stress-specific gene modules covering 28,421 rice genes (>72% of the genes in the genome). Each module contains a group of genes tightly coexpressed across a large number of environmental conditions and, thus, is likely to be functionally coherent. When a user provides a new differential expression profile, RECoN identifies modules substantially perturbed in their experiment and further suggests deregulated functional and regulatory mechanisms based on the enrichment of current annotations within the predefined modules. We demonstrate the utility of this resource by analyzing new drought transcriptomes of rice in three developmental stages, which revealed large-scale insights into the cellular processes and regulatory mechanisms involved in common and stage-specific drought responses. RECoN enables biologists to functionally explore new data from all abiotic stresses on a genome-scale and to uncover gene candidates, including those that are currently functionally uncharacterized, for engineering stress tolerance. [ABSTRACT FROM AUTHOR]

Harnessing stem carbohydrate dynamics in grasses offers an opportunity to help meet future demands for plant-based food, fiber and fuel production, but requires a greater understanding of the genetic controls that govern the synthesis, interconversion and transport of such energy reserves., We map out a blueprint of the genetic architecture of rice ( Oryza sativa) stem nonstructural carbohydrates ( NSC) at two critical developmental time-points using a subpopulation-specific genome-wide association approach on two diverse germplasm panels followed by quantitative trait loci (QTL) mapping in a biparental population., Overall, 26 QTL are identified; three are detected in multiple panels and are associated with starch-at-maturity, sucrose-at-maturity and NSC-at-heading. They tag Os HXK6 (rice hexokinase), ISA2 (rice isoamylase) and a tandem array of sugar transporters., This study provides the foundation for more in-depth molecular investigation to validate candidate genes underlying rice stem NSC and informs future comparative studies in other agronomically vital grass species. [ABSTRACT FROM AUTHOR]

Uptake and translocation of imidacloprid (IMI), thiamethoxam (THX) and difenoconazole (DFZ) in rice plants ( Oryza sativa L.) were investigated with a soil-treated experiment at two application rates: field rate (FR) and 10*FR under laboratory conditions. The dissipation of the three compounds in soil followed the first-order kinetics and DFZ showed greater half-lives than IMI and THX. Detection of the three compounds in rice tissues indicated that rice plants could take up and accumulate these pesticides. The concentrations of IMI and THX detected in leaves (IMI, 10.0 and 410 mg/kg dw; THX, 23.0 and 265 mg/kg dw) were much greater than those in roots (IMI, 1.37 and 69.3 mg/kg dw; THX, 3.19 and 30.6 mg/kg dw), which differed from DFZ. The DFZ concentrations in roots (15.6 and 79.1 mg/kg dw) were much greater than those in leaves (0.23 and 3.4 mg/kg dw). The bioconcentration factor (BCF), representing the capability of rice to accumulate contaminants from soil into plant tissues, ranged from 1.9 to 224.3 for IMI, from 2.0 to 72.3 for THX, and from 0.4 to 3.2 for DFZ at different treated concentrations. Much higher BCFs were found for IMI and THX at 10*FR treatment than those at FR treatment, however, the BCFs of DFZ at both treatments were similar. The translocation factors (TFs), evaluating the capability of rice to translocate contaminants from the roots to the aboveground parts, ranged from 0.02 to 0.2 for stems and from 0.02 to 9.0 for leaves. The tested compounds were poorly translocated from roots to stems, with a TF below 1. However, IMI and THX were well translocated from roots to leaves. Clothianidin (CLO), the main metabolite of THX, was detected at the concentrations from 0.02 to 0.5 mg kg −1 in soil and from 0.07 to 7.0 mg kg −1 in plants. Concentrations of CLO in leaves were almost 14 times greater than those in roots at 10*FR treatment. [ABSTRACT FROM AUTHOR]

Metabolism of sulfur (S) is suggested to be an important factor for the homeostasis and detoxification of Cu in plants. We investigated the effects of S fertilizers (S 0 , Na 2 SO 4 ) on Cu translocation and biotransformation in rice plants by using multiple synchrotron-based techniques. Fertilization of S increased the biomass and yield of rice plants, as well as the translocation factor of Cu from root to shoot and shoot to grain, resulting in enhanced Cu in grain. Sulfur K-edge X-ray near edge structure (XANES) analysis showed that fertilization of S increased the concentration of glutathione in different rice tissues, especially in rice stem and leaf. Copper K-edge XANES results indicated that a much higher proportion of Cu (I) species existed in rice grain than husk and leaf, which was further confirmed by soft X-ray scanning transmission microscopy results. Sulfur increased the proportion of Cu (I) species in rice grain, husk and leaf, suggesting the inducing of Cu (II) reduction in rice tissues by S fertilization. These results suggested that fertilization of S in paddy soils increased the accumulation of Cu in rice grain, possibly due to the reduction of Cu (II) to Cu (I) by enhancing glutathione synthesis and increasing the translocation of Cu from shoot to grain. [ABSTRACT FROM AUTHOR]

Methane (CH4) and nitrous oxide (N2O) fluxes were measured from paddy-upland rotation (three years for soybean and three years for rice) with different soil fertility due to preceding compost application for four years (i.e., 3 kg FW m-2 year-1 of immature or mature compost application plots and a control plot without compost). Net greenhouse gas (GHG) balance was evaluated by integrating CH4 and N2O emissions and carbon dioxide (CO2) emissions calculated from a decline in soil carbon storage. N2O emissions from the soybean upland tended to be higher in the immature compost plot. CH4 emissions from the rice paddy increased every year and tended to be higher in the mature compost plot. Fifty-two to 68% of the increased soil carbon by preceding compost application was estimated to be lost during soybean cultivation. The major component of net GHG emission was CO2 (82-94%) and CH4 (72-84%) during the soybean and rice cultivations, respectively. Net GHG emissions during the soybean and rice cultivations were comparable. Consequently, the effects of compost application on the net GHG balance from the paddy-upland rotation should be carefully evaluated with regards to both advantages (initial input to the soil) and disadvantages (following increases in GHG). [ABSTRACT FROM AUTHOR]

In the present paper was carried out radiography of the rice market in Romania, during 2007-2015. Romanian culinary tradition has a strong impact on the evolution of the rice market in our country. Rice is an important food for about 50% of the planet's population and its consumption has beneficial effects on the health of the population. In order to highlight the evolution of the rice market in Romania and the changes that have taken place on this market, a series of relevant indicators have been used, such as: rice areas cultivated at national and macro-regional level; Total rice production at national and macro-regional level; Average rice production at national and macroregional level; Rice prices; Consumption of rice at national level; Imports and exports of rice. During the analyzed period there was a positive evolution of this market because, on the one hand, we are witnessing an increase of rice surfaces and production, and on the other hand, we have identified changes in the consumption behavior of rice. Consumers in our country are aware of the rice-specific nutritional properties and have begun to use a range of varieties of this product. Rice consumption in Romania is about 4 kg rice / year /per capita. The statistical data used in the paper was provided by the National Institute of Statistics. [ABSTRACT FROM AUTHOR]

Many studies have been performed to compare different straw-returning methods that could provide environmental benefits. However, few studies have focused on the greenhouse gas emissions from straw returning under winter water-stored fields (flooded conditions) and winter fallow fields (non-flooded conditions), which are the common land use types after the rice harvest in southern China. Thus, in the present microcosm incubation experiment, C[O.sub.2], C[H.sub.4] and [N.sub.2]O emissions were compared under flooded and non-flooded soil conditions, following straw incorporation. Straw application stimulated C[O.sub.2] cumulative emission, and this effect was exacerbated by flooding (1818 and 4271 mg[kg.sup.-1] under non-flooded and flooded conditions, respectively). Although the application of straw can mitigate [N.sub.2]O cumulative emissions under flooded conditions (10152 [micro]g [kg.sup.-1] without and -51 [micro]g [kg.sup.-1] with straw incorporation, respectively), higher C[O.sub.2] and C[H.sub.4] production was detected (4271 and 149.20 mg [kg.sup.-1] for C[O.sub.2] and C[H.sub.4] cumulative emissions, respectively). In contrast, straw application under non-flooded conditions had a relatively low global warming potential value (1836 mg C[O.sub.2] Eq [kg.sup.-1]). Consequently, winter fallow field is recommended after the integrated application of straw and nitrogen fertiliser because of its low global warming potential. However, different strategies may be required for long-term reduction in global warming potential values. Additional keywords: flooded and non-flooded conditions, global warming potential, paddy soil, residue incorporation., Introduction Returning crop straw back to fields is an important step towards conserving and sustaining soil productivity (Li et al. 2003; Ladha et al. 2004). Thus, the returning of straw [...]

Boron (B) toxicity is a nutritional disorder affecting crop production in many parts of the world. This study explored genetic factors associated with B tolerance in rice (Oryza sativa L.) through an integrated genome mapping and transcriptomic approach. Variation in B tolerance was first evaluated by screening a panel of 137 indica genotypes in B toxic conditions (+2 mM B), followed by genome-wide association study (GWAS). Leaf bronzing and greenness were significantly correlated with shoot and root dry weight, but B uptake was not correlated with any stress phenotype. Single nucleotide polymorphism (SNP) markers exceeding a significance value of -log10P>4.0 were obtained for four traits, namely leaf bronzing, shoot dry weight, root dry weight, and root length. Linkage disequilibrium block analysis of the corresponding chromosomal regions revealed candidate loci containing 75 gene models. Two contrasting genotypes from the panel were selected for transcriptomic analysis, which included gene ontology enrichment analysis of differentially regulated genes and investigating transcriptional responses of GWAS candidate genes. Characteristic expression patterns associated with tolerance or sensitivity were seen in genes related to biochemical binding, transport, transcriptional regulation, and redox homeostasis. These results advance the understanding of genetic and physiological factors associated with B tolerance in rice. [ABSTRACT FROM AUTHOR]

Much research has considered the influence of biochars on the availability and phytoaccumulation of potentially toxic elements (PTEs) from soil. However, the vast majority of these studies use, what are arguably, unrealistic and unpractical amounts of biochar (10, 50 and even up to 100 t/ha). To offer a more realistic insight into the influence of biochar on PTE partitioning and phytoaccumulation, a field study, using modest rates of biochar application (1.5, 3.0 t/ha), was undertaken. Specifically, the research investigated the influence of sewage sludge biochar (SSBC) on the accumulation of Cd into rice ( Oryza sativa L.) grown in Cd contaminated (0.82 ± 0.07 mg/kg) paddy soil. Results indicated, Cd concentrations in rice grains to significantly ( p < 0.05) decrease from 1.35 ± 0.09 mg/kg in the control to 0.82 ± 0.07 mg/kg and 0.80 ± 0.21 mg/kg in the 1.5 t/ha and 3.0 t/ha treatments, respectively. Accordingly, the hazardous quotient (HQ) indices for Cd, associated with rice grain consumption, were also reduced by ∼40%. SSBC amendment significantly ( p < 0.05) increased grain yields from 1.90 ± 0.08 g/plant in the control to 2.17 ± 0.30 g/plant and 3.40 ± 0.27 g/plant in the 1.5 t/ha and 3.0 t/ha treatments, respectively. Thus, the amendment of SSBC to contaminated paddy soils, even at low application rates, could be an effective approach to mitigate Cd accumulation into rice plants, to improve rice grain yields, and to thereby improve food security and protect public health. [ABSTRACT FROM AUTHOR]

Heavy metal stress will induce the change of the bio-parameters like chlorophyll, nitrogen and water content of rice. In this paper, we analyzed the traditional spectral index which has strong relationship in general with the three bio-parameters using hyperspectral data acquired by ASD. It is found that some indies do not work well when the heavy metal stress exists, however, some indies still has ability to estimate the above three bio-parameters. A new interpretation is proposed to classify the stress level based on both the physical mechanism analysis and the statistic model after we describe and discuss studies on the expression of spectral indices of rice under heavy metal stress. The 3-axes spectral indices spaces, which are constructed of 3 spectral indices sensitive to rice's chlorophyll concentration, nitrogen concentration and water concentration respectively, are used to visualize the linkage between heavy metal stress and spectrum of rice canopy. [ABSTRACT FROM AUTHOR]

Three hundred and eight samples of rice purchased from retail markets in six different provinces in Iran from March 2012 to January 2013 were surveyed for the presence of ochratoxin A (OTA) using enzyme-linked immunosorbent assay. The recovery percentages of OTA from spiked rice samples at concentrations of 5 and 10 ng/g were found to be 85.3% and 86.7%, respectively. Analytical results showed a 9.4% frequency of contamination from total analyzed rice samples with a mean OTA level of 3.60 ± 2.66 ng/g. Concentrations of OTA in positive samples ranged from 0.84 ng/g to 11.37 ng/g, and in 17.3% of contaminated rice samples the concentrations exceeded the maximum tolerance limit set by European regulations for OTA in cereals (5 ng/g). Based on the results of this study, the estimated daily intake of OTA in rice was 0.62 ng/kg body weight/day for Iranian consumers. [ABSTRACT FROM AUTHOR]

The temperature rise is one of issues of climate change that has the effect of rice production in Indonesia, especially to the development and growing of plants. This research used the Model of Shierary Rice with Geographical Information System (GIS) to estimate the decreasing of rice production in every province in Indonesia based on some scenarios of temperature rise. The model used the Shierary Rice to estimate the rice production and Shierary Weather to forecast the weather on the certain location based on the condition of normal climate. The result of research showed that temperature rise would make the age of rice the shorter and decrease the rice yields. This research pointed out that irrigated farm having less impact from temperature rise compared with rainfed farm which had the decreasing of rice yield for 11.1%/OC and 14.4%/OC sequentially as well. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate organophosphorus pesticides (OPs) concentrations in rice grains and estimate potential health risk to inhabitants. A total of 102 rice samples were collected from the Irrigated Area of Songhua River, located in Jilin province, one of the most important rice production areas and a key agricultural area in China. The twelve OPs were determined by gas chromatography coupled with flame photometric detector. Results showed that OPs concentrations in rice grains did not exceed maximum residue limit. The mean concentrations obtained for the detected twelve OPs in µg kg−1were as follows: omethoate (0.60), diazinon (0.56), parathion-methyl (0.54), dimethoate (0.38), isocarbophos (0.38), phorate (0.31), fenitrothion (0.24), parathion (0.23), fenthion (0.23), malathion (0.13), dichlorvos (0.13), and methamidophos (0.08). Diazinon (39.2%), omethoate (31.4%), and parathion-methyl (25.5%) had the highest frequency in the detected twelve OPs. 69.6% of samples contained more than one OP, 24.5% of samples detected one OP, and only 5.9% samples did not find any OPs. The average target hazard quotients were all less than one and average hazard index for adults and children were 0.273 and 0.238, respectively. Overall, results indicated that the intake of rice may be safe for consumers. [ABSTRACT FROM AUTHOR]

Numerous estimates for the coming decades project changes in precipitation resulting in more frequent droughts and floods, rise in atmospheric CO and temperature, extensive runoff leading to leaching of soil nutrients, and decrease in freshwater availability. Among these changes, elevated CO can affect crop yields in many ways. It is imperative to understand the consequences of elevated CO on the productivity of important agricultural crop species in order to devise adaptation and mitigation strategies to combat impending climate change. In this study, we have modeled rice phenology, growth phase, and yield with the 'Decision Support System for Agrotechnology Transfer (DSSAT) CERES rice model' and arrived at predicted values of yield under different CO concentrations at four different locations in Eastern India out of which three locations were irrigated and one location was rainfed. The ECHAM climate scenario, Model for Interdisciplinary Research on Climate (MIROC)3.0 climate scenario, and ensemble models showed different levels of yield increase with a clear reduction in yield under rainfed rice as compared to irrigated rice. A distinct regional and cultivar difference in response of rice yield to elevated CO was seen in this study. Results obtained by simulation modeling at different climate change scenarios support the hypothesis that rice plant responses to elevated CO are through stimulation of photosynthesis. Realization of higher yields is linked with source sink dynamics and partitioning of assimilates wherein sink capacity plays an important role under elevated CO conditions. [ABSTRACT FROM AUTHOR]

Rice is the most important food crop in Asia, and the timely mapping and monitoring of paddy rice fields subsequently emerged as an important task in the context of food security and modelling of greenhouse gas emissions. Rice growth has a distinct influence on Synthetic Aperture Radar (SAR) backscatter images, and time-series analysis of C-band images has been successfully employed to map rice fields. The poor data availability on regional scales is a major drawback of this method. We devised an approach to classify paddy rice with the use of all available Envisat ASAR WSM(Advanced Synthetic Aperture Radar Wide Swath Mode) data for our study area, the Mekong Delta in Vietnam. We used regression-based incidence angle normalization and temporal averaging to combine acquisitions from multiple tracks and years. A crop phenology-based classifier has been applied to this time series to detect single-, double- and triple-cropped rice areas (one to three harvests per year), as well as dates and lengths of growing seasons. Our classification has an overall accuracy of 85.3% and a kappa coefficient of 0.74 compared to a reference dataset and correlates highly with official rice area statistics at the provincial level (R² of 0.98). SAR-based time-series analysis allows accurate mapping and monitoring of rice areas even under adverse atmospheric conditions. [ABSTRACT FROM AUTHOR]

Flood mapping, particularly hazard and risk mapping, is an imperative process and a fundamental part of emergency response and risk management. This paper aims to produce a flood risk proxy map of damaged rice fields over the whole of Bangladesh, where monsoon river floods are dominant and frequent, affecting over 80% of the total population. This proxy risk map was developed to meet the request of the government on a national level. This study represents a rapid, straightforward methodology for estimating rice-crop damage in flood areas of Bangladesh during the large flood from July to September 2007, despite the lack of primary data. We improved a water detection algorithm to achieve a better discrimination capacity to discern flood areas by using a modified land surface water index (MLSWI). Then, rice fields were estimated utilizing a hybrid rice field map from land-cover classification and MODIS-derived indices, such as the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). The results showed that the developed method is capable of providing instant, comprehensive, nationwide mapping of flood risks, such as rice field damage. The detected flood areas and damaged rice fields during the 2007 flood were verified by comparing them with the Advanced Land Observing Satellite (ALOS) AVNIR-2 images (a 10 m spatial resolution) and in situ field survey data with moderate agreement (K = 0.57). [ABSTRACT FROM AUTHOR]

Saline-alkali mixed stress is a widespread environmental problem in agriculture. To examine the effects of silicon on rice under saline-alkali stress, the effects of silicon on germination, morphogenesis, chlorophyll content, soluble protein content, malondialdehyde (MDA) content, and antioxidases including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activities were investigated in rice seedlings. The results showed that germination percentage, germination rate, and germination index were increased significantly by the silicon compared with the nonsilicon treatment. Meanwhile, silicon application improved the growth of rice seedlings remarkably under saline-alkali stress, which was consistent with the elevation of chlorophyll contents. The MDA contents were decreased markedly with different silicon treatments. In contrast, the activities of SOD and POD were enhanced significantly with appropriate silicon treatment, which were in accordance with the increasing of soluble protein contents. All the analysis showed that 5 and 10 mmol/L silicon concentrations were more effective in alleviating the injury of rice seedlings under saline-alkali stress. [ABSTRACT FROM PUBLISHER]

To investigate human Hg exposure by food consumption and occupation exposure in a compact fluorescent lamp (CFL) manufacturing area, human hair and rice samples were collected from Gaohong town, Zhejiang Province, China. The mean values of total mercury (THg) and methylmercury (MeHg) concentrations in local cultivated rice samples were significantly higher than in commercial rice samples which indicated that CFL manufacturing activities resulted in Hg accumulation in local rice samples. For all of the study participants, significantly higher THg concentrations in human hair were observed in CFL workers compared with other residents. In comparison, MeHg concentrations in human hair of residents whose diet consisted of local cultivated rice were significantly higher than those who consumed commercial rice. These results demonstrated that CFL manufacturing activities resulted in THg accumulation in the hair of CFL workers. However, MeHg in hair were mainly affected by the sources of rice of the residents. [ABSTRACT FROM AUTHOR]

We integrated recent research on cardinal temperatures for phenology and early leaf growth, spikelet formation, early morning flowering, transpirational cooling, and heat- and cold-induced sterility into an existing to crop growth model ORYZA2000. We compared for an arid environment observed potential yields with yields simulated with default ORYZA2000, with modified subversions of ORYZA2000 and with ORYZA_S, a model developed for the region of interest in the 1990s. Rice variety ‘IR64’ was sown monthly 15-times in a row in two locations in Senegal. The Senegal River Valley is located in the Sahel, near the Sahara desert with extreme temperatures during day and night. The existing subroutines underestimated cold stress and overestimated heat stress. Forcing the model to use observed spikelet number and phenology and replacing the existing heat and cold subroutines improved accuracy of yield simulation from EF = −0.32 to EF =0.70 (EF is modelling efficiency). The main causes of improved accuracy were that the new model subversions take into account transpirational cooling (which is high in arid environments) and early morning flowering for heat sterility, and minimum rather than average temperature for cold sterility. Simulations were less accurate when also spikelet number and phenology were simulated. Model efficiency was 0.14 with new heat and cold routines and improved to 0.48 when using new cardinal temperatures for phenology and early leaf growth. The new adapted subversion of ORYZA2000 offers a powerful analytic tool for climate change impact assessment and cropping calendar optimisation in arid regions. [ABSTRACT FROM AUTHOR]