Paddy Field Water Research Articles

Spatial-uniform application method of methane fermentation digested slurry with irrigation water in the rice paddy field

Promoting biomass utilization, the objectives of this study were to clarify the spatial distribution of nitrogen, one of the most important fertilizer components in the methane fermentation digested slurry (i.e., the digested slurry), and to establish an effective method to apply spatial-uniformly digested slurry with irrigation water in the rice paddy field. A numerical model describing the unsteady two-dimensional flow and solution transport of paddy irrigation water was introduced. The accuracy of this model was verified with a field observation. The tendencies of the TN simulated in inlet and outlet portions had good agreement with the measured data and the accuracy of the numerical model could be verified. Using the numerical model, scenario analyses were conducted to determine the method for spatial-uniform application of the digested slurry with irrigation water. The simulated results indicated that drainage of the surface water and trenches at the soil surface were effective for spatial-uniform application of the digested slurry with irrigation water in the rice paddy fields. The effect of the trenches was maximized when the surface water of the rice paddy field was drained adequately.

Measurement of Density for Xanthomoanas oryzae pv. oryzae Cell Using Real Time PCR

We developed a new measurement method for the density of Xanthomonas oryzae pv. oryzae(Xoo), a casual pathogen of bacterial leaf blight of rice. The new method used real time PCR with the highly characterized and specific Xan_PahgeF & Xan_PahgeR primer and Xan_Pahge FAM MGB probe primer pairs derived from phage-related integrase gene. The method was effective when tested with a variety of templates including isolated Xoo DNA, pure colonies or liquid culture sources, and could also work on contaminating water. A main advantage of this assay is to accurately and rapidly quantitate the population density of Xoo in paddy field water containing inhibitors.

The influence of soil and water physicochemical properties on the distribution of Nostoc sphaeroides (Cyanophyceae) in paddy fields and biochemical comparison with indoor cultured biomass

A survey on the distribution of Nostoc sphaeroides, an edible cyanobacterium, growing in mountain paddy fields of Zouma Town in China was carried out in May 2012. The physical and chemical properties of paddy field soil and water were analyzed. We found that in a paddy field in which N. sphaeroides historically did not grow when the water was acidic (pH 6.30) and showed the lowest conductivity, and the soil contained the lowest content of total phosphorus (TP) and available phosphorus (AP) compared to other fields where N. sphaeroides did grow. The nitrogen (N) contents in both water and soil samples were sufficient compared with the high N. sphaeroides yield paddy fields. These results suggest that an acidic water environment, as well as low TP and especially low AP, was the main limiting factors for the distribution of N. sphaeroides. In addition, comparison of the biochemical composition of field-harvested, short-term-cultivated, and long-term-cultivated N. sphaeroides showed that the contents of photosynthetic pigments (chlorophyll a and carotenoids) and soluble protein including phycobiliproteins increased gradually from wild habitat to long-term indoor cultivation N. sphaeroides, while both total and soluble carbohydrates showed a decreasing trend during indoor cultivation.

Assessment of heavy metals (Cd and Pb) and micronutrients (Cu, Mn, and Zn) of paddy (Oryza sativa L.) field surface soil and water in a predominantly paddy-cultivated area at Puducherry (Pondicherry, India), and effects of the agricultural runoff on the elemental concentrations of a receiving rivulet

The concentrations of toxic heavy metals-Cd and Pb and micronutrients-Cu, Mn, and Zn were assessed in the surface soil and water of three different stages of paddy (Oryza sativa L.) fields, the stage I-the first stage in the field soon after transplantation of the paddy seedlings, holding adequate amount of water on soil surface, stage II-the middle stage with paddy plants of stem of about 40cm length, with sufficient amount of water on the soil surface, and stage III-the final stage with fully grown rice plants and very little amount of water in the field at Bahour, a predominantly paddy cultivating area in Puducherry located on the southeast Coast of India. Comparison of the heavy metal and micronutrient concentrations of the soil and water across the three stages of paddy field showed their concentrations were significantly higher in soil compared with that of water (p < 0.05) of the fields probably because of accumulation and adsorption in soil. The elemental concentrations in paddy soil as well as water was in the ranking order of Cd > Mn > Zn > Cu > Pb indicating concentration of Cd was maximum and Pb was minimum. The elemental concentrations in both soil and water across the three stages showed a ranking order of stage II > stage III > stage I. The runoff from the paddy fields has affected the elemental concentrations of the water and sediment of an adjacent receiving rivulet.

A review of improvements to methods for the measurement of dissolved oxygen, pH, and soil redox potential and the discovery of convective flow in ponded water of paddy fields

A review of improvements to methods for the measurement of dissolved oxygen, pH, and soil redox potential and the discovery of convective flow in ponded water of paddy fields

水田湛水層におけるCO&lt;SUB&gt;2&lt;/SUB&gt;,溶存酸素(DO)，pHおよびRpHの日変動とその相互関係

水田湛水層におけるCO&lt;SUB&gt;2&lt;/SUB&gt;,溶存酸素(DO)，pHおよびRpHの日変動とその相互関係

Dissipation of Propanil and 3,4 Dichloroaniline in Three Different Rice Management Systems

This study focused on the dissipation of propanil and 3,4 dichloroaniline (3,4 DCA) over time in the soil, field water, inlet water, and outlet water of paddy fields under three management systems: conventional water seeding (CON), conventional water seeding with supplied liquid manure (LMA), and dry seeding (DRY). Propanil dissipation in water was also investigated under laboratory conditions. The field study was conducted from 2004 to 2006 at Vercelli, northern Italy. Propanil and 3,4 DCA showed rapid dissipation in water and soil environments both in the field and in the laboratory. Under controlled conditions, chemical hydrolysis was not detected for either compounds for up to 100 d at pHs of 5, 7, and 9. In the laboratory, the half-life of propanil in irrigation water was 1.1 d; its half-life in soil was routinely measured at <1.0 d (between 0.17 and 1.77 d). 3,4 DCA was found to persist much longer. Measured in all three study years at 50 d after treatment, its concentration ranged between 44 μg kg (CON) and 140 μg kg (DRY). Propanil and 3,4 DCA concentrations in paddy water were particularly high in samples collected at 4 d (2004) and 2 d (2005) after treatment. Maximum concentrations were 54.4 μg L (CON) for propanil (2005) and 113.7 μg L (LMA) for 3,4 DCA (2004). The concentrations of propanil and 3,4 DCA in inlet water were never above 1.1 and 0.3 μg L, respectively, whereas the highest concentration of each compound in outlet water was in samples collected first after treatment in 2005 and 2006. Both chemicals dissipated rapidly in all the soil-water environments but displayed no important differences among the three management systems. In conclusion, propanil and 3,4 DCA did not persist longer in paddy fields. A risk of water network contamination by these compounds may occur only early after herbicide spraying. A water-holding period after herbicide spraying may reduce this risk.

Azolla pinnata Growth Performance in Different Water Sources

Azolla pinnata R.Br. growth performance experiments in different water sources were conducted from May until July 2011 at Aquaculture Research Station, Puchong, Malaysia. Four types of water sources (waste water, drain water, paddy field water and distilled water) each with different nutrient contents were used to grow and evaluate the growth performance of A. pinnata. Four water sources with different nutrient contents; waste, drain, paddy and distilled water as control were used to evaluate the growth performance of A. pinnata. Generally, irrespective of the types of water sources there were increased in plant biomass from the initial biomass (e.g., after the first week; lowest 25.2% in distilled water to highest 133.3% in drain water) and the corresponding daily growth rate (3.61% in distilled water to 19.04% in drain water). The increased in biomass although fluctuated with time was consistently higher in drain water compared to increased in biomass for other water sources. Of the four water sources, drain water with relatively higher nitrate concentration (0.035 +/- 0.003 mg L(-l)) and nitrite (0.044 +/- 0.005 mg L(-1)) and with the available phosphate (0.032 +/- 0.006 mg L(-1)) initially provided the most favourable conditions for Azolla growth and propagation. Based on BVSTEP analysis (PRIMER v5), the results indicated that a combination of more than one nutrient or multiple nutrient contents explained the observed increased in biomass of A. pinnata grown in the different water sources.

Monitoring of Selected Pesticides Residue Levels in Water Samples of Paddy Fields and Removal of Cypermethrin and Chlorpyrifos Residues from Water Using Rice Bran

Consumption of pesticides associated foods increased in recent decades in Bangladesh. Most of the pesticides come from paddy, as rice is the main food items here and about 70 % pesticides are used only on paddy fields. Water samples of paddy fields and Kaliganga River of Manikganj district were analyzed to provide base line data on cypermethrin, chlorpyrifos and diazinon residue by using high performance liquid chromatography. Levels of Cypermethrin, chlorpyrifos and diazinon detected in the paddy field water samples were (0.605 ± 0.011 μg/L), (0.06 ± 0.001 μg/L) and (0.039 ± 0.002 μg/L), respectively. 0.11 ± 0.003 μg/L of cypermethrin and 0.012 ± 0.0006 μg/L of chlorpyrifos were also identified in the water samples of Kaligonga River. Diazinon residue was not detected in the river water samples. The detected concentrations of pesticide residues in the river water were below the accepted maximum residue limit (MRL) value of drinking water (0.1 μg/l) adopted by the FAO/WHO Codex Alimentarius Commission. Cypermethrin and chlorpyrifos were chosen for decontamination through rice bran, as it was found in river water. Two gm rice bran could easily decontaminated 95.6 % and 96.4 % of cypermethrin and chlorpyrifos. The result of this study showed that pesticide residue was detected in water samples were below the MRLs value, which can easily be decontaminated through absorption of rice bran.

Responses of Iron-Reducing Bacteria to Salinity and Organic Matter Amendment in Paddy Soils of Thailand

In paddy soils of Thailand, the addition of organic matter (OM) is used to efficiently limit the effect of salinity on rice culture and production. OM used as an amendment and fertilizer promotes the reduced condition and increases iron solubilization without provoking ferrous toxicity. In this study, the intricate biogeochemical role of iron-reducing bacteria (IRB) involved in the quality of water and soil of paddy fields, particularly when the paddy fields were subject to salinity and organic matter addition, were studied in paddy fields of Thailand. The results demonstrated that the addition of OM increased the proliferation of cultivable IRB and their specific activity. Cultivable IRB communities decreased in the presence of salt. The presence of salt modified the structure of the bacterial populations by favoring the development of alkaline and moderately halophilic bacteria (Virgibacillus spp., Oceanobacillus spp., and Paenibacillus spp.). The paddy soils studied contained very diversified (halosensitive, halotolerant, and halophilic) IRB populations that could be adapted to a variety of salinity conditions (0–90 g L−1 NaCl) using different organic substrates (glucose, acetate, and soil organic matter) to maintain significant activities under extreme conditions of salinity. The rhizosphere of rice stimulated IRB community growth without organic matter, whereas organic matter addition limited the rhizosphere effect on IRB cultivable number in saline condition. The interactive action of salinity and organic amendment had a negative impact on the rhizosphere effect. The presence of specific iron-reducing populations (fermentative, iron-respiring, anaerobic, and facultative anaerobic), having different behaviors under salt and redox stresses, appeared to be a key factor that contributed to the control or enhancement of the quality of water and soil in paddy fields.

Photolytic and photocatalytic degradation of quinclorac in ultrapure and paddy field water: Identification of transformation products and pathways

Quinclorac (QNC) is an effective but rather persistent herbicide commonly used in rice production. This herbicide presents a mean persistence in the environment so its residues are considered of environmental relevance. However, few studies have been conducted to investigate its environmental behavior and degradation. In the present work, direct photolysis and TiO2 photocatalysis of the target compound in ultrapure and paddy field water were investigated. After 10h photolysis in ultrapure water, the concentration of QNC declined 26% and 54% at 250 and 700Wm−2, respectively. However, the amount of quinclorac in paddy field water remained almost constant under the same irradiation conditions. QNC dissipated completely after 40min of TiO2 photocatalysis in ultrapure water, whereas 130min were necessary to degrade 98% of the initial concentration in paddy field water.Possible QNC photolytic and photocatalytic degradation pathways are proposed after structure elucidation of the main transformation products, through liquid chromatography–electrospray ionization–quadrupole time-of-flight mass spectrometry and exact mass measurements. Pyridine ring hydroxylation at C-9 followed by ring opening and/or oxidative dechlorination were the key steps of QNC degradation.

Isotopic determination of U, Pu and Cs in environmental waters following the Fukushima Daiichi Nuclear Power Plant accident

Concentrations of the radionuclides, U, Pu, and Cs were measured in water samples (10-20 L) to study analyte dispersion and migration following the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident. A total of 8 water samples including oceanic water and paddy-field water were collected in the vicinity of the plant. Determinations of U, Pu and Cs isotopes were performed by accelerator mass spectrometry (AMS), inductively coupled plasma mass spectrometry (ICP-MS), and γ-ray spectrometry. The 236U/238U atom ratio was in the range 1.83-8.20 × 10-9 for fresh water and around 0.57 × 10-9 for seawater while the concentration of 236U was about 104-105 and 106 atoms/kg, respectively. Plutonium (239,240Pu) was detected in one riverine sample and the marine samples at very low levels and with large uncertainty. The concentrations of 137Cs in fresh riverine samples were 0.02-0.46 Bq/kg which are more than three orders of magnitude larger than the global fallout level. As for seawater samples within 80 km offshore of the FDNPP, the concentrations of 137Cs were 10-20 times higher than that of the Japan Sea water. Also 134Cs and 137Cs were of similar concentrations in all samples. The results show that volatile and refractory nuclides such as Cs, U and Pu exist in the dissolved phase, which can be readily assimilated by plants/humans. However the environmental impact of Pu and U in the vicinity of the FDNPP is considered to be low in comparison to that of the volatile radionuclide Cs.

A MODEL-BASED EVALUATION OF DISSOLVED NITROGEN DYNAMICS IN A PADDY FIELD IN THE RED RIVER DELTA, VIETNAM

ISHS XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on Engineering the Modelling, Monitoring, Mechanization and Automation Tools for Precision Horticulture A MODEL-BASED EVALUATION OF DISSOLVED NITROGEN DYNAMICS IN A PADDY FIELD IN THE RED RIVER DELTA, VIETNAM

国際水田・水環境ネットワーク (INWEPF) の設立と展望

国際水田・水環境ネットワーク (INWEPF) の設立と展望

Identification and isolation of active N2O reducers in rice paddy soil

Dissolved N(2)O is occasionally detected in surface and ground water in rice paddy fields, whereas little or no N(2)O is emitted to the atmosphere above these fields. This indicates the occurrence of N(2)O reduction in rice paddy fields; however, identity of the N(2)O reducers is largely unknown. In this study, we employed both culture-dependent and culture-independent approaches to identify N(2)O reducers in rice paddy soil. In a soil microcosm, N(2)O and succinate were added as the electron acceptor and donor, respectively, for N(2)O reduction. For the stable isotope probing (SIP) experiment, (13)C-labeled succinate was used to identify succinate-assimilating microbes under N(2)O-reducing conditions. DNA was extracted 24 h after incubation, and heavy and light DNA fractions were separated by density gradient ultracentrifugation. Denaturing gradient gel electrophoresis and clone library analysis targeting the 16S rRNA and the N(2)O reductase gene were performed. For culture-dependent analysis, the microbes that elongated under N(2)O-reducing conditions in the presence of cell-division inhibitors were individually captured by a micromanipulator and transferred to a low-nutrient medium. The N(2)O-reducing ability of these strains was examined by gas chromatography/mass spectrometry. Results of the SIP analysis suggested that Burkholderiales and Rhodospirillales bacteria dominated the population under N(2)O-reducing conditions, in contrast to the control sample (soil incubated with only (13)C-succinate). Results of the single-cell isolation technique also indicated that the majority of the N(2)O-reducing strains belonged to the genera Herbaspirillum (Burkholderiales) and Azospirillum (Rhodospirillales). In addition, Herbaspirillum strains reduced N(2)O faster than Azospirillum strains. These results suggest that Herbaspirillum spp. may have an important role in N(2)O reduction in rice paddy soils.

Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography–quadrupole-linear ion trap-mass spectrometry

A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L −1 and from 2 to 150 ng L −1, respectively. Correlation coefficients for the calibration curves in the range 0.1–50 μg L −1 were higher than 0.99 except for diazinon (0.1–25 μg L −1). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to7.20 μg L −1.

Estimation of Denitrification Capacity of Paddy Field - A Case Study in Lake Inbanuma Area -

Nitrate-nitrogen concentrations of groundwater and paddy field water were observed for five years (2005 to 2009) and the potential for purifying of itrate-nitrogen (denitrification) of paddy fields located arround Lake Inbanuma was estimated. Consequently, it became clear that the paddy fields surrounding the Lake Inbanuma were able to purify 286ton of nitrate-nitrogen per year, which corresponds to 24% of the nitrogen load discharged from the Lake Inbanuma basin per year.

Development and validation of an analytical method for determination of endocrine disruptor, 2,4‐D, in paddy field water

The acidic herbicides are an important class of chemical compounds that are used to control a variety of weeds that threaten many crops. Owing to their low microbial activity levels, the acidic herbicides exhibit a residual activity remaining for periods of up to several months in soils and water. The principal objective of this study was to develop an analytical method based on liquid-liquid and solid-phase extraction followed by HPLC, for the determination of 2,4-D in paddy field water. The residues were verified via tandem mass spectrometry (MS/MS) in negative-ion electrospray ionization (ESI) mode. Linearity was good over a concentration range of 1-100 µg/L with a correlation coefficient (r(2) ) of 0.999. The mean recovery rates of triplicate results ranged from 85.2 to 90.85%. The limits of detection and quantitation were 0.4 and 1.0 µg/L, respectively. The method proposed herein was applied to field samples acquired from Hampyung and Sunchang counties, Republic of Korea. The analyte was detected at a concentration range of 6.8-12.8 and 3.55-24.0 µg/L, respectively.

Life cycle assessment of a rice production system in Taihu region, China

In this study, a life cycle assessment (LCA) method was used to examine the environmental impact of the rice production system in Taihu region, China. The LCA considered the entire system required to produce 1 t of rice. The analysis included raw material extraction and transportation, agrochemical production and transportation, and arable farming in the field. The result shows that the significance of environmental impacts, followed by aquatic eutrophication, water depletion, global warming, acidification, and energy depletion. As such, reducing nitrogen (N) fertilizer intensity and increasing utilization efficiency are the key points to control the life cycle environmental impacts of rice, which would decrease resource consumption and emissions not only directly in the arable farming subsystem but also indirectly in the upstream production stage. Strengthening water management, especially in the early growth stage, and reduction of paddy field water discharge are also significant measures with which to minimize N and phosphorus (P) runoff losses and control acidification potential (AP) and aquatic eutrophication potential (AEP), so as to reduce life cycle environmental impacts of the rice production system.

Laboratory and field evidence of the photonitration of 4-chlorophenol to 2-nitro-4-chlorophenol and of the associated bicarbonate effect

Photochemical processes can decontaminate the aqueous environment from xenobiotics, but they also produce secondary pollutants. This paper presents field and laboratory evidence of the transformation of 4-chlorophenol (4CP) into 2-nitro-4-chlorophenol (2N4CP). Field monitoring of 4CP and 2N4CP was carried out by solid phase extraction coupled with liquid chromatography-multiple reaction monitoring mass spectrometry. Laboratory irradiation experiments were carried out under a UV-Vis lamp, and the time evolution of the compounds of interest was followed by liquid chromatography. The purpose of this study was elucidating the pathways leading to 2N4CP from 4CP in paddy field water. The field monitoring results suggest that 4CP can be transformed into 2N4CP in the paddy field water of the Rhône delta (Southern France). The laboratory study indicates that the transformation can take place via photonitration by (*)NO(2). The nitration process is inhibited by bicarbonate, possibly due to basification that favours the occurrence of the 4-chlorophenolate. The latter could consume (*)NO(2) without being nitrated. Photonitration in the presence of bicarbonate could account for the observed transformation in the field. Photonitration of 4CP to 2N4CP by (*)NO(2) could account for the observed interconversion of the two compounds in paddy fields. The results are of concern because 2N4CP is biorecalcitrant and toxic. Bicarbonate can modulate the photonitration of 4CP into 2N4CP, which can be very significant in bicarbonate-poor waters.