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Torbick N.,Applied Geosolutions Llc | Salas W.,Applied Geosolutions Llc | Chowdhury D.,Applied Geosolutions Llc | Ingraham P.,Applied Geosolutions Llc | Trinh M.,Institute for Agricultural Environment
Carbon Management | Year: 2017

Rice greenhouse gas (GHG) emissions in the Red River Delta, Vietnam, were mapped using multiscale satellite imagery and a processed-based biogeochemical model. Multiscale synthetic aperture radar (SAR) and optical imagery were fed into a random forest classifier using field observations and surveys as training data to map rice extent. Time series analysis then generated geospatial information on crop calendar, hydroperiod and cropping intensity to use as parameters for the denitrification–decomposition (DNDC) model to estimate emissions. Results show a 2015 rice extent of 583,470 ha with total harvested area of 1,078,783 ha and total methane emissions for the delta at 345.4 million kg CH4-C equivalent to 11.5 million tonnes CO2e (carbon dioxide equivalent). Satellite remote sensing was able to accurately map water management and improve model parameterization to understand the impacts of decisions such as irrigation practices, changes in GHG emissions, and mitigation initiatives. The approach described in this research provides a framework for using open-access SAR to derive maps of rice and landscape characteristics to drive process models like DNDC. These types of tools and approaches will support the next generation of monitoring, reporting, and verification (MRV) efforts to combat climate change and support robust and transparent policy decisions. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Nguyen H.V.,Soils and Fertilizers Research Institute | Nguyen H.M.,Soils and Fertilizers Research Institute | Vu D.T.,University of Queensland | Fletcher A.,University of Queensland | Bui L.P.,Institute for Agricultural Environment
Understanding the Geological and Medical Interface of Arsenic, As 2012 - 4th International Congress: Arsenic in the Environment | Year: 2012

Industrial, agricultural and commercial activities have led to significant Arsenic (As) contamination of soils and waterways. Phytoremediation is one of several techniques employed to remediate As contaminated soils. This study aimed to enhance As phytoremediation from contaminated mined soils by combining As hyperaccumulators (fern species) and Arbuscular Mycorrhizal Fungi (AMF). Arsenic contaminated soils were inoculated with AMF strains before planting with two indigenous fern species. Plant biomass and consequently As uptake were higher in Pteris vittata than in Pittyrogramma calomelanos. Inoculation of active AMF into soils significantly increased plant growth and As uptake. In particular, plant accumulated As increased by 100 to 124% in AMF inoculated plants/pots. © 2012 Taylor & Francis Group.


Rose M.T.,University of Sydney | Rose M.T.,Japanese International Research Center for Agricultural science | Deaker R.,University of Sydney | Potard S.,University of Sydney | And 4 more authors.
World Journal of Microbiology and Biotechnology | Year: 2011

Achieving specific counting of plant growth promoting (PGP) microorganisms maintained at high numbers in inert carriers such as peat is an important objective for the inoculation of field crops such as cereals. In this paper, methods based on selective media together with strain-specific counting using enzyme-linked immunoassay (ELISA) were examined. Selective plate counting was developed by screening four commercial PGP biofertiliser strains for resistance to antibiotics. ELISAs for each strain were developed and calibrated by purifying polyclonal antibodies, testing sample pre-treatment strategies, and investigating the effect of culture age on standard curves. Selective plate counting proved to be more accurate than the ELISA methodology, confirming that all microbial strains survived for at least 1 month in sterile peat without loss in viable numbers, and further demonstrated growth inhibition of the strain Candida tropicalis HY when co-inoculated with the other strains Pseudomonas fluorescens 1 N, Bacillus amyloliquefaciens E19 and Bacillus subtilis B9. This is the first known study to have investigated the dynamics of PGP microorganisms in multi-strain inoculants and demonstrates the utility and hitherto unmentioned drawbacks of two different low-cost counting methods for biofertiliser quality control. Such information is vital for the adoption and success of non-rhizobial PGP biofertilisers for sustainable agriculture. © 2010 Springer Science+Business Media B.V.


Van Phi Hung N.,Niigata University | Van Phi Hung N.,Japan Atomic Energy Agency | Van Phi Hung N.,Institute for Agricultural Environment | Watanabe S.,Niigata University | And 7 more authors.
Soil Science and Plant Nutrition | Year: 2013

The quantitative analysis of the initial transport of fixed isotope 15-nitrogen (15N) in intact nodulated soybean plants (Glycine max [L.] Merr. cv. Williams) was investigated at the vegetative stage (36 days after planting, DAP) and pod-filling stage (91 DAP) by the 15N pulse-chase experiment. The nodulated roots were exposed to N2 gas labeled with a stable isotope 15N for 1 h, followed by 0, 1, 3 and 7 h of exposure with normal air. Plant roots and shoots were separated into three sections (basal, middle and distal parts) with the same length of the main stem or primary root. Approximately 80 and 92% of fixed N was distributed in the basal part of the nodulated roots at the vegetative and pod-filling stages by the end of 1 h of 15N2 exposure, respectively. In addition, about 90% of fixed 15N was retained in the nodules and 10% was exported to root and shoot after 1 h of 15N2 exposure at 91 DAP. The percentage distribution of 15N in the nodules at the pod-filling stage decreased from 90% to 7% during the 7 h of the chase period, and increased in the roots (14%), stems (54%), leaves (12%), pods (10%) and seeds (4%). The 15N distribution was negligible in the distal root segment, suggesting that N fixation activity was negligible and recycling fixed N from the shoot to the roots was very low in the initially short time of the experiment. © 2013 © Japanese Society of Soil Science and Plant Nutrition.


Nguyen S.G.,Jeju National University | Nguyen S.G.,Vietnam Academy of Science and Technology | Guevarra R.B.,Jeju National University | Kim J.,Jeju National University | And 3 more authors.
Water, Air, and Soil Pollution | Year: 2015

Methane production by methanogenic microbes under anaerobic condition is affected by the types of fertilizers, which determine carbon availability, used in rice fields. In addition, irrigation management controls oxygen availability in soil. Thus, irrigation management and types of fertilizers are major driving forces for methane emission in rice fields. While these factors affect paddy microbial communities over the course of cultivation, little is known about the effects of fertilizers and irrigation conditions on initial paddy microbial communities. In this study, we investigated the initial impacts of fertilizers and irrigation systems on paddy microbial communities and methane emission. At early stages of rice cultivation (2 weeks after transplanting 15-day-old rice seedlings), a high amount of methane was emitted from rice fertilized with swine manure. In addition, pre-transplantation flooding increased methane emission by 30 %. Although these conditions did not affect the overall paddy soil microbial communities, 126 operational taxonomic units (OTUs) were found to be significantly more abundant in paddy soils fertilized with swine manure. These OTUs included archaeal methanogenic species and bacterial substrate providers for biomethane production. Shared-OTU analysis with swine fecal microbial communities indicated swine manure as the origin of key methane-producing microbes. In conclusion, the applications of swine manure and permanent flooding irrigation introduce active methane producers and enhance methane emission, respectively, and should therefore be avoided. © 2015 Springer International Publishing Switzerland.


Mai V.T.,Wageningen University | Mai V.T.,Institute for Agricultural Environment | Van Keulen H.,Wageningen University | Roetter R.,Wageningen University
Water, Air, and Soil Pollution | Year: 2010

The environmental and economic consequences of nitrogen (N) lost in rice-based systems in Vietnam is important but has not been extensively studied. The objective of this study was to quantify the amount of N lost in major cropping systems in the Red River Delta. An experiment was conducted in the Red River Delta of Vietnam, on five different crops including rose, daisy, cabbage, chili, and a rice-rice-maize rotation during 2004 and 2005. Core soil samples were taken periodically in 20-cm increments to a depth of 1 m and analyzed for nitrate-nitrogen and ammonium-nitrogen. The results indicate appreciable leaching losses on N in high-rainfall and irrigation conditions, especially when fertilizer application was not well synchronized with crop N demand. Highest annual leaching losses of N were recorded in flowers with 185-190 mm of percolation and 173-193 kg N ha-1, followed by vegetable (cabbage and chili) with 120-122 mm of percolation and 112-115 kg N ha-1, while it was lowest in rice with about 50 kg N ha-1. We developed a simple N transport model that combined water and N movement through the soil profile. In most cases, the model accurately predicted the seasonal dynamics of N as well as N flow between soil layers and the amounts of N lost from the soil profile. The simulated results of N leaching with soil "puddling" conditions illustrate the advantage of an impermeable or hardpan layer in increasing water and nutrient use efficiencies in these soils. These model results also showed that it is possible to accurately estimate N losses with only a few parameters and helped us identify the risks of N leaching. © 2009 Springer Science+Business Media B.V.

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