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Paddy rice is the staple food in Taiwan, where rice farming always plays an important role in agricultural activities. The paddy fields and irrigation activities hold diversified functions, such as production, eco-environmental and living-associated functions. This paper is to provide information regarding the potential magnitude and monetary value of seven functions of paddy fields in Taiwan, including flood mitigation, fostering water resources, preventing soil erosion, purifying water, cooling air temperature, refreshing atmosphere and recreation. For quantification of the above values, replacement cost method (RCM), contingent valuation method (CVM), and the travel cost method (TCM) are adopted. In addition, the ratio of monetary value and their rice production commodity value (R) was also estimated. The results indicated that the flood mitigation function had a monetary value of US$ 389 million each year, and the ratio to the rice production value R was estimated at 37%. Water resource fostering function was US$ 501 million and R at 47%; soil erosion reduction function was US$ 433 million and R at 41%; water quality purification function was US$ 3 million and R at 0.3%; cooling air temperature function was US$ 961 million and R at 91%; refreshing air function was US$ 196 million and R at 19%, health and recreation function was US$ 987 million and R at 93%, respectively. Due to the significant importance of these externalities, it is recommended that the government should properly take into account the multifunctionalities in policy making to ensure sustainable development of agriculture. 相似文献
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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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通过对邵东县肥料施用总量和农户施肥情况的调查和施肥对水稻产量及土壤肥力影响的分析,指出当前水稻施肥上存在的主要问题:一是重化肥轻有机肥,二是重氮肥轻磷钾肥,三是重单质肥轻复合肥.对水稻施肥提出的对策是一要增施有机肥,二要推广测土配方施肥技术. 相似文献
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In-Kyun Jung Jong-Yoon Park Geun-Ae Park Mi-Seon Lee Seong-Joon Kim 《Paddy and Water Environment》2011,9(3):275-290
A grid-based, KIneMatic wave STOrm Runoff Model (KIMSTORM) is described. The model adopts the single flow-path algorithm and
routes the water balance during the storm period. Manning’s roughness coefficient adjustment function of the paddy cell was
applied to simulate the flood mitigation effect of the paddy fields for the grid-based, distributed rainfall-runoff modeling.
The model was tested in 2296 km2 dam watershed in South Korea using six typhoon storm events occurring between 2000 and 2007 with 500 m spatial resolution,
and the results were tested through the automatic model evaluation functions in the model. The average values of the Nash–Sutcliffe
model efficiency (ME), the volume conservation index (VCI), the relative error of peak runoff rate (EQp), and the absolute error of peak runoff (ETp) were 0.974, 1.016, 0.019, and 0.45 h for calibrated storm events and 0.975, 0.951, 0.029, and 0.50 h for verified storm
events, respectively. In the simulation of the flood mitigation effect of the paddy fields, the average values of the percentage
changes for peak runoff, total runoff volume, and time to peak runoff were only −1.95, −0.93, and 0.19%, respectively. 相似文献
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Puddling and recurring intermittent irrigation, common praxis in wet rice cultivation, modify the soil structure and therewith cause a temporal variation of the infiltration properties. This study attempts to evaluate the temporal variation of the infiltration rates of plough pan (vertical infiltration) and paddy fields’ surrounding bunds (bund infiltration) by analyzing (i) the infiltration rate as a function of time, (ii) the relationship between ponding water depth and infiltration rate, and (iii) the influence of cultivation age on vertical water loss and cross-flow through bunds. Two experimental fields with respective cultivation ages of 30 (A) and 7 (B) years were investigated. The results revealed that the time series of vertical infiltration rate (IR v) was with time consistency and the persistency of the bund infiltration was uncertain. The mean infiltration rate into the plough pan of A and B was 3.34 and 1.01 cm d?1, respectively. A total water depth of 230 and 85 cm would be, respectively, lost in A and B through the plough pan during rice growing season. The correlation coefficient between ponding water depth and IR v was ?0.48 and ?0.81 in A and B, respectively, demonstrating that the dynamic IR v in the old paddy field was less affected by the drying and wetting cycles. It is concluded that rice paddies which have been taken into cultivation since only a few decades may contribute to water losses. Maintenance of equilibrium condition between ponding and drying stages and careful preparation of bunds may reduce water loss. 相似文献
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S. F. Mousavi F. Kamyab-Talesh M. R. Yazdani S. H. Saghaian-Nejad 《Paddy and Water Environment》2011,9(4):385-392
Percolation loss of water in rice fields is a major cause of low water use efficiency. Variation of infiltration rate and
soil compactness in four paddy fields (with clay, silty clay, clay loam, and loam textures) was investigated in northern Iran.
In each field, in longitudinal and transverse directions, points located 0.5, 2.5, 6.5, 12.5, … m from the bunds were selected
and water infiltration rate and resistance to penetration of a pocket penetrometer were measured. The results showed that
in clay soil, average final infiltration rate (f
c) in longitudinal direction, transverse direction, and center of the field was 0.216, 0.136, and 0.08 cm day−1, respectively. The f
c for loamy soil was 2.77, 2.32, and 0.409 cm day−1, respectively. Similar differences were observed in the other two soil textures. In general, effect of direction of the field
for measuring infiltration rate was not statistically significant. Loam and clay loam soils, with resistance to penetration
of 0.37 and 0.33 kg cm−2, were not significantly different. But, clay and silty clay soils with resistance to penetration of 0.25 and 0.14 kg cm−2 were significantly different (P < 0.05). Resistance to penetration of the penetrometer was not affected significantly (P < 0.05) by direction of measuring this parameter in the field. The conclusion is that if measured soil physical properties
in a paddy field are going to be representative of the whole field, they should be measured at different locations, especially
near the bunds. Another strategy for obtaining a representative infiltration rate or compactness for a paddy field is uniform
puddling of the field. 相似文献
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Ji-Hong Jeon Chun G. Yoon Jong-Hwa Ham Kwang-Wook Jung 《Paddy and Water Environment》2005,3(2):93-101
A field experiment was performed at two Korean research sites to evaluate water and nutrient behavior in paddy rice culture
operations for 2 years. One site was irrigated with groundwater, whereas the other site was irrigated with surface water.
Both sites received average annual rainfall of about 1,300 mm, and about 70–80% of it was concentrated during July–September
coinciding with rice growing season. Although most of the nutrient outflow was attributed to plant uptake, nutrient loss by
surface drainage was substantial. The simplified computer model, PADDIMOD, was developed to simulate water and nutrient behaviors
in the paddy rice field. The model predicts daily ponded water depth, surface drainage, and nutrient concentrations. It was
formulated with a few equations and simplified assumptions, but its application and a model fitness test indicated that the
simulation results reasonably matched the observed data. It is a simple and practical planning model that could be used to
evaluate nutrient loading from paddy rice fields alone or in combination with other complex watershed models. Further validation
might be required for general application of the PADDIMOD to the simulation of paddy rice fields with various agricultural
environments. 相似文献
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This research is to construct a water balance model to estimate the amount of return flow in an irrigation system. A simple computation framework for the model was established to include various irrigation applications in cropping seasons. The model was able to estimate evapotranspiration, deep percolation into groundwater aquifer, and return flow. Return flow can be split into two parts, which are surface and subsurface return flows. The water balance model was then applied at the irrigation system (rotational block No. 11-2 of five paddy field units) which is operated by the Taoyuan Irrigation Association in Taiwan as an example. Two study cases were simulated, in which one was for using return flow and the other one was for using no return flow. The study period for the model simulations is the first rice cropping term in 2010 which was from February 16 to July 10. As a result, return flows calculated by the model were 27, 27, 34, and 39% of outflows for sandy loam, sandy clay, clay loam, and light clay soil, respectively. Irrigation water at the downstream field unit with use of return flow was supplemented by the upstream field units, and the amount is 5?C8% of irrigation water for using no return flow. Furthermore, it can be seen from the simulations that increases in irrigation water provide increases of return flow. Increases of irrigation water result in slight increases of subsurface return flow, while increases of irrigation water cause nearly none of change in deep percolation. 相似文献