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1.
Water shortage has become an important issue for Korean agriculture. Korea suffers from a limited agricultural water supply,
and wastewater reuse has been recommended as an alternative solution. This study examined the concentrations of toxic heavy
metals and Escherichia coli in a paddy rice field irrigated with reclaimed wastewater to evaluate the risk to farmers. Most epidemiological studies have
been based on upland fields, and therefore may not be directly applicable to paddy fields. In this study, a Beta-Poisson model
was used to estimate the microbial risk of pathogen ingestion. The risk value increased significantly after irrigation and
precipitation. The results of the microbial risk assessment showed that risk values of groundwater and reclaimed wastewater
irrigation were lower than the values of effluent directly from wastewater treatment plants. The monitoring results of heavy
metals for each irrigated paddy fields did not show specific tendency. A risk assessment for toxic heavy metals was performed
according to various exposure pathways; however, the results of the carcinogenic and noncarcinogenic risk estimation showed
that the risk from reclaimed wastewater-irrigated paddy fields was the lowest. 相似文献
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Jae Young Cho Jae Gwon Son Chang Hoon Song Seon Ah Hwang Young Min Lee Se Young Jeong Byung Yeoup Chung 《Paddy and Water Environment》2008,6(3):263-273
This study was conducted in an attempt to determine the proper nitrogen and phosphorus application levels, nitrogen split
application ratio, and application method for environmental-friendly rice production in a salt-affected rice paddy field,
which was located in the Saemangeum reclaimed tidal belt on the western coast of South Korea, between April 1, 2003 and October
10, 2004. All treatments were replicated three times in a randomized block design (5 m × 4 m plot) with 11 treatments (total
33 plots). We designed three treatments for the evaluation of reasonable application levels of nitrogen and phosphorus fertilizers
(A1–A3); five treatments to evaluate the nitrogen split application system (T1–T5); and three treatments to determine the
proper application for chemical fertilizer (M1–M3). There was no significant difference of amylose and protein content among
the application levels, application methods, and nitrogen split application ratios (P < 0.05). No significant differences in grain yield and yield components of rice were observed among the different application
levels, application methods, and nitrogen split application ratios (P < 0.05). In order to save labor in agricultural households, preserve or enhance the grain quality of rice, and reduce nutrient
losses, we determined that the optimum application level of nitrogen fertilizer was 140 kg ha−1; the application split ratio of nitrogen fertilizer at four different periods was 40% for basal fertilization, 20% for maximum
tilling stage, 30% for the panicle formation stage, and 10% for the booting stage; and the best application methods were deep
layer application and whole layer application. 相似文献
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Hydraulic resistance in plants is one of the most important factors responsible for changes in leaf water potential that is an indicator of plant water stress. Although the hydraulic resistance to passive water transport (Rpa) is a robust index in paddy rice (Oryza sativa), measurement is both time-consuming and labour-intensive. Here, we describe on a quick method to measure hydraulic resistance to osmotic water transport (Ros) by measuring the xylem sap exudation rate and osmotic water potential. In a greenhouse experiment, Ros responded significantly to soil temperature, but under field conditions soil temperature varied considerably less than air temperature. In the field experiment, Ros of six rice cultivars at two growth stages was strongly positively correlated with Rpa. We conclude that measuring Ros could be used to evaluate root water transport capacity in paddy rice under conditions with adequate soil water. 相似文献
6.
The multi-functionality of paddy field and irrigation water has become a hot issue recently in Asian monsoon regions. Asian people know why they have to conserve the paddy farm where the sustainable functions have been historically inherited and maintain the rural community where the unique cultures have been traditionally created. But, the real value of multi-functionality has not been clearly highlighted as much worthy as it has. We should evaluate the characteristics of multi-functionality of paddy farming correctly and transmit them to the people of Western countries under quite different conditions of upland fields. In Korea, several studies on the multi-functionality of paddy farming have been performed with positive and negative viewpoints. This paper shows the results and the discussion of the researches to get global recognition on the multi-functionality of paddy farming.
相似文献
Tai-Cheol KimEmail: |
7.
Delivery management water requirement (DMWR) is the use of bypass water in paddy field irrigation to help maintain desired water levels in irrigation canals and to distribute water to paddy plots in a uniform manner. Diverted irrigation water (DIW), DMWR, and the DMWR/DIW ratio were investigated for concrete lined irrigation ditches with large-sized paddy plots (100 m×100 m) during irrigation periods (May to mid-September). DIW and DMWR were measured at 5- to 10-day intervals at the inlets and outlets of irrigation ditches on stable water supply days. The mean DMWR/DIW ratios in irrigation ditches L1 and L2 over 3 years were 36 and 34%, respectively. The mean DMWR/DIW ratios displayed month-to-month and year-to-year variation. The monthly mean DMWR/DIW ratios were highest (55 and 71%) in June and lowest (<20%) in August and September. The annual mean DMWR/DIW ratios during a dry year markedly decreased to 11%, compared with 42% in other years. The decrease was due to the small DIW and farmers water management to maximize capture of limited irrigation water during the drought. The DMWRs in May and June were significantly (p<0.01) correlated with the DIWs, indicating that high DMWR in May and June are attributed to excessive DIW. 相似文献
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Hung Dao Trong Banfield Callum C. Dorodnikov Maxim Sauer Daniela 《Paddy and Water Environment》2022,20(1):93-105
Paddy and Water Environment - Optimization of land-use practices of rice cultivation for the mitigation of the most significant greenhouse gas (GHG) emissions from agriculture methane (CH4) and... 相似文献
9.
Jae Young Cho Jae Gwon Son Jin Kyu Choi Chang Hoon Song Byung Yeoup Chung 《Paddy and Water Environment》2008,6(2):211-219
The present study was carried out to evaluate nutrient losses that occur during the course of agricultural activity from rice
paddy fields of reclaimed tidal flat. For this study, we chose a salt-affected rice paddy field located in the Saemangeum
reclaimed tidal area, which is located on the western South Korean coasts. The plot size was 1,000 m2 (40 m × 25 m) with three replicates. The soil belonged to the Gwanghwal series, i.e., it was of the coarse silty, mixed,
mesic type of Typic Haplaquents (saline alluvial soil). The input quantities of nitrogen and phosphorus (as chemical fertilizer)
into the experimental rice paddy field were 200 kg N ha−1 and 51 kg P2O5 ha−1 per annum, and the respective input quantities of each due to precipitation were 9.3–12.9 kg N ha−1 and 0.4–0.7 kg P ha−1 per annum. In terms of irrigation water, these input quantities were 4.5–8.2 kg N ha−1 and 0.3–0.9 kg P ha−1 per annum, respectively. Losses of these nutrients due to surface runoff were 22.5–38.1 kg N ha−1 and 0.7–2.2 kg P ha−1 for the year 2003, and 26.8–29.6 kg N ha−1 and 1.6–1.9 kg P ha−1 for the year 2004, respectively. Losses of these nutrients due to subsurface infiltration during the irrigation period were
0.44–0.67 kg N ha−1 and 0.03–0.04 kg P ha−1 for the year 2003, and 0.15–0.16 kg N ha−1 and 0.05–0.06 kg P ha−1 for 2004. When losses of nitrogen and phosphorus were compared to the amount of nutrients supplied by chemical fertilizers,
it was found that 11.3–19.1% of nitrogen and 0.5–1.7% of phosphorus were lost via surface runoff, whereas subsurface losses
accounted to 0.2–0.8% for nitrogen and only 0.02–0.04% for phosphorus during the 2-year study period. 相似文献
10.
Inhong Song Jung-Hun Song Jeong Hoon Ryu Kyeung Kim Jeong-Ryeol Jang Moon Seong Kang 《Paddy and Water Environment》2017,15(1):59-69
Curbing nutrient loads from rice cultivation has been an issue for the water quality management of surface water bodies in the Asian monsoon region. The objectives of this study were to develop paddy BMP scenarios and to evaluate their effectiveness on nutrient loads reduction using long-term model simulation. Totally five BMP scenarios were developed based on the three paddy farming factors of drainage outlet height, fertilizer type, and application amount and were compared with conventional practices. CREAMS-PADDY model was chosen for the paddy nutrient simulation, and two-year field experimental data were used for the model calibration and validation. The validated model was used to evaluate the developed BMP scenarios for the 46 years of simulation period. The observed nutrient loads were 15.2 and 1.45 kg/ha for nitrogen and phosphorus, respectively, and mainly occurred by early season drainage and rainfall runoff in summer. The long-term simulation showed that the soil test-based fertilization and drainage outlet raising practice were the two most effective methods in nutrient loads reduction. The combination of these two resulted in the greatest loads reduction by 29 and 37 % for T-N and T-P, respectively (p value < 0.001). Overall the effectiveness of the BMP scenarios was decreased in the wet season. As the conclusion, outlet height control and soil nutrient-based fertilization were suggested as the effective practices in paddy loads reduction and their combination can be a practicable BMP scenario for the paddy nutrient management. 相似文献
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Kozue Yuge Hiroki Maeda Munehiro Tanaka Mitsumasa Anan Yoshiyuki Shinogi 《Paddy and Water Environment》2014,12(3):335-342
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. 相似文献
13.
A field experimental study was performed during the growing season of 2001 to evaluate water and nutrient balances in paddy
rice culture. Three plots of standard fertilization (SF), excessive fertilization (EF, 150% of SF), and reduced fertilization
(RF, 70% of SF) were used and the size of treatment plot was 3,000 m2, respectively. The hydrologic and water quality was field monitored throughout the crop stages. The water balance analyses
indicated that approximately half (47–54%) of the total outflow was lost through surface drainage, with the remainder consumed
by evapotranspiration. Statistical analysis showed that there was no significant effect of fertilization rates on nutrient
outflow through the surface drainage or rice yield. Reducing fertilization of rice paddy may not work well to mitigate the
non-point source nutrient loading in the range of normal farming practices. Instead, the reduction in surface drainage could
be important to controlling the loading. Suggestive measures that may be applicable to reduce surface drainage and nutrient
losses include water-saving irrigation by reducing ponded water depth, raising the weir height in diked rice fields, and minimizing
forced surface drainage as recommended by other researchers. The suggested practices can cause some deviations from conventional
farming practices, and further investigations are recommended. 相似文献
14.
Predicting water surface evaporation in the paddy field by solving energy balance equation beneath the rice canopy 总被引:1,自引:0,他引:1
The energy flux on the ground surface depends not only on climatological and biophysical controls in the vegetative canopy, but also on the available energy and energy partitioning beneath the canopy. Quantifying the evaporation and energy partitioning beneath the canopy is very important for improving water and energy utilization, especially in arid areas. In this study, we measured meteorological data, the net radiation and latent heat flux beneath the rice canopy, and then applied the radiation and energy balance equations to get the water surface temperature beneath the rice canopy. To apply the equations, we constructed shortwave and longwave radiation beneath the canopy sub-models and a bulk transfer coefficient sub-model. A plant inclination factor was parameterized with plant area index for the shortwave and longwave radiation sub-models. Bulk transfer coefficient was parameterized by plant area index and soil heat flux was predicted by the force restore model. With calculated water surface temperature and constructed sub-models, we reproduced net radiation and latent heat flux beneath the rice canopy. As a result, the reproduced water surface temperature, net radiation, and latent heat flux beneath the rice canopy were very close to the measured values and no significant differences were found according to 2-tail t test statistical analysis. Therefore, we conclude that these constructed sub-models could successfully represent water surface temperature, net radiation, and latent heat flux beneath the rice canopy. 相似文献
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Laphatphakkhanut Rapeepong Puttrawutichai Songsak Dechkrong Punyavee Preuksakarn Chakkrit Wichaidist Bittawat Vongphet Jutithep Suksaroj Chaisri 《Paddy and Water Environment》2021,19(4):699-707
Paddy and Water Environment - Rice is the staple food and one of Thailand's economic crops. However, rice cultivation consumes a large amount of water. Therefore, it is necessary to reconsider... 相似文献
16.
Chen-Wuing Liu Shih-Wei Zhang Hsing-Pin Yao Kuo-Hua Lin Wei-Taw Lin 《Paddy and Water Environment》2010,8(3):207-216
The study synthesizes the spatiotemporal changes of the multifunctionality and benefit of Taiwanese paddy. The internal and
external economic values of the paddy are quantitatively determined. Nationwide as well as regional variation of multifunctionality
and benefits from 1999 to 2007 were considered. The substitution cost method was adopted to quantify the external economical
values of rice paddy. Moreover, the compensating variation concept was applied to appraise the rational green subsidy of rice
paddy in Taiwan. The result shows that the multifunctional benefits of rice paddy from 1999 to 2007 reduce 55, 18, 31, 13,
and 28% in north, center, south, east regions, and nationwide of Taiwan, respectively. The reduction is mainly attributable
to the significant decrease of rice-planting area. The external benefit may be further diminished if the fallow area increases
continuously. In order to maintain the multifunctionality of rice paddy, we appraise a reasonable green subsidy to the cultivated
paddy farmers. According to the results of the amount of green subsidy evaluated by the compensating variation concept, the
estimated green subsidy is 21,000 NT$/ha for the nationwide paddy farmers. The government may consider to award the appraised
green subsidy to paddy farmers directly for the sustainable management of rice paddy in Taiwan. 相似文献
17.
Yoshiyuki Shinogi Yutaka Kanri Yuichi Hirose Kaneto Inoue 《Paddy and Water Environment》2005,3(3):165-170
Due to the recent regulation of rice production in Japan, it has become necessary to convert rice paddy to other field crops
production. To achieve this, drainage conditions, especially for surface drainage, must be improved. We propose the introduction
of a slight slope to improve surface drainage, but the optimal slope must be determined in order to prevent soil erosion caused
by excessive slope, as well as increased cost. In Japan, a 0.1% slope has recently come into widespread use and, therefore,
the impact on surface drainage must be quantified. In this report, observations were carried out to quantify the impact of
a 0.1% slope for converted rice paddy and the following results were obtained: (1) An approximate 0.1% slope enables improvement
of 46% of the soil surface saturation area as compared to flat conditions about 10 h after inundation; and (2) Inundated water
remains on a flat field, while it moves downward toward the end on a sloped field. These results give a basis for determining
a slope on a rice paddy in terms of surface drainage improvement. However, the optimal slope should be decided from various
perspectives including engineering, agronomy, and economics etc. 相似文献
18.
Paddy and Water Environment - The soil sample of a paddy field was found to be contaminated by copper (Cu). The application of wastewater as the nitrogen fertilizer was identified as the cause in... 相似文献
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Water shortage has become a major agricultural concern, and “The Sustainable Water Resources Research Program” in Korea is currently addressing this problem through the development of treatment systems for reclaiming wastewater and the assessment of human health risks associated with its reuse. Through this program, started in 2001, many studies have examined various water resources. Reclaiming wastewater is one way to alleviate water-shortage pressures, and one of the major potential uses of reclaimed water is irrigation. However, the main concern with reusing reclaimed wastewater is the increased likelihood of human contact that might result in exposure to pathogens and increased health risks. Relatively few studies have examined the toxic risks using reclaimed wastewater for irrigation in rice paddy fields. This study provides an overview of methods for quantitative microbial risk assessment and toxic risk assessment of heavy metal concentrations developed in the previous studies that can be applied to the evaluation of rice paddy fields irrigated with reclaimed wastewater in South Korea. 相似文献