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1.
海南岛典型农业土壤产流与面源污染特征分析 总被引：1，自引：0，他引：1
采用径流场结合人工模拟降雨方式,研究各种降雨条件下海南岛不同土地类型产流产沙的规律与面源污染特征。结果表明：土壤（泥沙）产流系数与平均流失速率表现为暴雨＞大雨＞中雨,且暴雨时的泥沙平均流失速率为中雨时的416％、大雨时的261％,在中雨、大雨和暴雨强度下,平均径流系数分别为24.49％、33.97％和53.40％;雨强对土壤营养物质流失速率的影响达到显著水平,COD、有机质和氮素以径流流失为主,磷素以泥沙流失为主;土壤径流和泥沙中的COD、有机质、氮素和磷素流失速率随雨强的增大而增大,坡度也可明显影响面源污染物的流失;海南岛农业土壤平均流失量为3.79 t/（hm2·a）,中雨强度条件时为1.92 t/（hm2·a）,大雨强度条件时为2.57 t/（hm2·a）,暴雨强度条件时为6.87 t/（hm2·a）。海南岛农业土壤的水土流失强度较高,海南农业土壤的水土流失与农田污染物输出状况不容乐观。 相似文献
2.
This study compiles the latest regional topographic data from field investigation and remote-sensing images to recalculate parameters of the universal soil loss equation (USLE) model of the Shenmu watershed; also to compensate for reduced accuracy of this model on small-scale slopes, this study incorporates soil erosion pin data which were collected periodically to measure the extent of soil erosion. Firstly, this study utilized the USLE model and soil erosion pin data to compare the soil erosion potential of the Chushui and Aiyuzi subwatersheds and concluded that soil erosion drastically increased if accumulated rainfall exceeded 200 mm; also, erosion depths were greater in the Aiyuzi subwatershed while estimated total erosion volume was higher in the Chushui subwatershed; this was attributed to the larger area of Chushui subwatershed and based on field measurements which supported the results of the USLE model. Secondly, this study utilized modified USLE model to compare the extreme event erosion resulting from typhoon Morakot which revealed that high rainfall intensity and long-duration rainfall events can generate large volume non-point sources of sediment that is estimated to far exceed 7–10 times of the annual soil erosion. Thirdly, this study related the C parameter of the USLE model to the existing land use in the Shenmu watershed using current, real data. Finally, this study established a post-typhoon Morakot soil erosion risk map composed of five categories of risk which was compared with post-event land cover to suggest high-erosion risk zones that may require further monitoring, remediation, and engineering measures to limit soil loss. 相似文献
3.
A study was undertaken to estimate the sediment yield of the Karso watershed of Hazaribagh, Jharkhand State, India using modified
universal soil loss equation (MUSLE), remote sensing (RS) and geographic information system (GIS) techniques. The runoff factor
of MUSLE was computed using the measured values of runoff and peak rate of runoff at outlet of the watershed. The topographic
factor (LS) was determined using GIS while crop management factor (C) was determined from land use/land cover data, obtained from RS and field survey. The conservation practice factor (P) was obtained from the literature. Sediment yield at the outlet of the study watershed was simulated for 345 rainfall events
spread over a period of 1996–2001 and validated with the measured values. Nash–Sutcliffe simulation model efficiency of 0.8
and high value of coefficient of determination (0.83) indicated that MUSLE model estimated sediment yield satisfactorily. 相似文献
4.
Mehdi Vafakhah Amin Fakher Nikche Seyed Hamidreza Sadeghi 《Paddy and Water Environment》2018,16(3):411-424
The present study aims to evaluate performance of different infiltration models, namely initial and constant rate, soil conservation service (SCS) curve number and Green–Ampt in simulation of flood hydrographs for the small-sized Amameh Watershed, Iran. To achieve the study purpose, the infiltration rates were measured using rainfall simulator in work units acquired through overlaying topography, land use, drainage network and soil hydrologic group maps. All parameters of the study infiltration models were determined with the help of the Infilt. software package. The performances of the models in simulation of the observed output hydrographs from the entire watershed were ultimately evaluated for 28 rainfall–runoff events in the HEC-HMS environment. The different components of the observed and estimated hydrographs including time to peak, runoff volume, peak discharge, discharge values and peak time deviation were compared using relative error (RE), coefficient of determination (R2), peak-weighted root mean square error (PWRMSE) and Nash–Sutcliffe (NS) criteria. The general performance of estimations was also qualitatively assessed using scatter plot and distribution of study variables around standard lines of 1:1 slope. The results revealed that the SCS infiltration model with PWRMSE = 0.61 m3 s?1 and NS = 0.53 performed better than initial and constant rate model with PWRMSE = 1.1 m3 s?1 and NS = 0.54, and Green Ampt model with PWRMSE = 1.35 m3 s?1 and NS = 0.29 in estimation of flood hydrograph for the Amameh Watershed. 相似文献
5.
《Industrial Crops and Products》2006,23(3):327-332
Studies have indicated that vetiver oil and one of its components, nootkatone, possess insecticidal and herbicidal activities. The compounds appear to be good candidates as novel pesticides for substrate (soil, wood, and mulch) treatments. Phytotoxicity is a concern for substrate treatment agents against soil dwelling organisms. Using treated potting media the phytotoxic effect of vetiver oil and nootkatone was evaluated on the pea plants (Pisum sativum L.; cv, “Kelvedon Wonder”) in the laboratory and on citrus trees (Citrus unshiu Marcovitch) under field conditions. All the tested chemicals at various concentrations (20, 500, and 2000 μg/g soil) reduced the pea plant growth (plant height, root length, dry weight). Nootkatone treatments had the lowest inhibitory effect on growth, followed by vetiver oil and disodium octaborate tetrahydrate (Tim-bor®), a registered pesticide with known phytotoxicity. The most inhibitive and injurious effects occurred with Tim-bor® at concentrations of 500 and 2000 μg/g soil, causing plant mortality of up to 38.9%. No pea plant mortality was observed in nootkatone and vetiver oil treatments. Vetiver oil and nootkatone treatments at the rates of 30 and 100 μg/g potting media had no adverse effect on the citrus plant growth rates. These results support the possible usage of the two chemicals around buildings and in nurseries for the management of termites, ants, and weeds; or in the nursery industry where quarantines may be in place to prevent the movement of invasive pests. 相似文献
6.
Effect of surface cover on the reduction of runoff and agricultural NPS pollution from upland fields
Min Hwan Shin Chul Hee Won Jeong Ryeol Jang Yong Hun Choi Yong Chul Shin Kyoung Jae Lim Joong Dae Choi 《Paddy and Water Environment》2013,11(1-4):493-501
In this study, two types of simulations were performed. First, indoor rainfall simulation revealed that runoff ratio (0–63.3 %) decreased dramatically with surface cover, compared with no surface cover condition (55–85.3 %), and sediment load and concentration also decreased. With additions of PAM, sawdust, and rice hull to rice straw mat, the runoff ratio decreased to 52.8, 36.6, and 53.2 %, compared with only rice straw mat condition (runoff ratio of 63.3 %). When gypsum was added, no runoff was observed in case of rainfall intensity of 30 mm/h. Under 60 mm/h rainfall condition, 50 % or more runoff reduction was observed. These could be explained in that surface cover reduces detachment of soil particles and keeps infiltration rate by reducing surface sealing with detached soil particle which could happen under non-surface cover condition. Second, when rice straw mat was applied to soybean field, no runoff was observed until rainfall intensity of 5.8 mm/h or greater, while runoff was observed with rainfall intensity of 1.5 mm/h at no surface covered soybean field. In addition, 89.7–99.4 % of pollutant reductions were observed with rice straw mat at the soybean field. When rice straw mat with additions of wood shaves was applied to Chinese cabbage and radish fields, 4.3–75.8 % of runoff reductions and 28–80.8 % of pollutant reductions were observed. In case of Chinese cabbage, 122.1 % yield increase was observed and 153.4 % yield increase in case of radish. 相似文献
7.
Junichiro Takeuchi Toshihiko Kawachi Chie Imagawa Natsuki Buma Koichi Unami Shigeya Maeda 《Paddy and Water Environment》2010,8(2):145-156
A sophisticated modeling approach for simulating-coupled surface and subsurface flows in a watershed is presented. The watershed
model developed is a spatially distributed physically based model of composite dimension, consisting of 3-D variably saturated
groundwater flow submodel, 2-D overland flow submodel and 1-D river flow submodel. The 3-D subsurface flow is represented
by the complete Richards equation, while the 2-D and 1-D surface flows by the diffusive approximations of their complete dynamic
equations. For piecewise integration of these equations, the finite volume method (FVM) is employed assuming unknown variables
such as the water depth and the pressure head to be volume-averaged state ones. Problem plane geometry is meshed with the
unstructured cells of triangular shape which conforms to external as well as internal irregular boundaries such as those between
1-D and 2-D flows. A cell size controlling scheme, referred to as quasi-adaptive meshing scheme, is introduced to keep the
local discretization errors caused by topographic elevation gradient even over the entire-meshed geometry. Performance of
the model is tested through its practical application to a rugged intermountain watershed. Tuning the values of the three
key parameters ensures successful calibration of the model. Once the model is so calibrated, it could reproduce satisfactory
runoff response to any rainfall event. Expansion and shrinkage of the contributing area importantly affecting the direct runoff,
caused by the vicissitude of rainfall during its total duration, are well reproduced, like what the commonly accepted runoff
theory argues. It is thus concluded that the model developed could serve as a powerful watershed simulator usable for investigating
and assessing the hydrological aspect of a watershed. 相似文献
8.
本实验旨在探讨橡胶幼龄林下间作菠萝对水土流失的影响。采用单因素随机区组设计的方法,测定了顺坡种植菠萝,横坡种植菠萝和不间作(对照)条件下的径流量及土壤侵蚀量。结果表明：西双版纳雨季时,5～10月间,横坡和顺坡种植菠萝径流量均低于不间作菠萝,顺坡种植在6～9月间的径流量都高于横坡种植;6～10月间,顺坡种植和横坡种植菠萝能显著降低林间侵蚀量,横坡种植在6～9月间侵蚀量均低于顺坡种植;径流量、侵蚀量和降雨量的变化趋势基本相同;顺坡和横坡种植的总径流和总侵蚀量均显著减少。说明橡胶幼龄林下横坡种植菠萝可以有效减轻林地水土流失。 相似文献
9.
为探讨多种因素对麦田降雨产流时间的影响及其相应的定量关系,通过模拟降雨试验,研究了麦田降雨强度、冠层覆盖及初始土壤剖面含水量对降雨产流时间的影响。结果表明,在相同初始土壤剖面含水状态条件下,降雨强度与产流时间呈显著幂函数关系(P<0.01);产流时间与叶面积指数呈极显著线性正相关(P<0.01),与株高相关性较差;0～20、0～40cm土层初始土壤剖面含水量与产流时间具有较明显的线性正相关关系(P<0.01),40cm以下土层土壤含水量对产流时间影响相对较小。通过多元回归分析建立的产流时间幂函数计算模型具有较好的模拟效果。 相似文献
10.
Al-Mashreki MH Akhir JB Abd Rahim S Desa KM Rahman ZA 《Pakistan journal of biological sciences: PJBS》2010,13(23):1116-1128
In the present study, an assessment of land suitability potential for agriculture in the study area of IBB governorate, Republic of Yemen has been conducted through close examination of the indicators of land characteristics and qualities. The objective of this study is to evaluate the available land resource and produce the potential map of the study area. Remote sensing data help in mapping land resources, especially in mountainous areas where accessibility is limited. Satellite imagery data used for this study includes data from multi-temporal Landsat TM which dated June 2001. The parameters taken into consideration were 16 thematic maps i.e., slope, DEM, rainfall, soil, land use, land degradation as well as land characteristics maps. Satellite image of the study area has been classified for land use, land degradation and soil maps preparation, while topo sheet and ancillary data have been used for slope and DEM maps and soil properties determination. The land potential of the study area was categorized as very high, high, moderate, low and very low by adopting the logical criteria. These categories were arrived at by integrating the various layers with corresponding weights in a Geographical Information System (GIS). The study demonstrates that the study area can be categorized into spatially distributed agriculture potential zones based on the soil properties, terrain characteristics and analyzing present land use. This approach has the potential as a useful tool for guiding policy decision on sustainable land resource management. 相似文献
11.
12.
Le Van Chinh Haruka Iseri Kazuaki Hiramatsu Masayoshi Harada Makito Mori 《Paddy and Water Environment》2013,11(1-4):97-112
In watershed management, the determination of peak and total runoff due to rainfall and prediction of pollutant load are very important. Measurement of rainfall runoff and pollutant load is always the best approach but is not always possible at the desired time and location. In practice, diffuse pollution has a complex natural dependence on various land-use activities such as agriculture, livestock breeding, and forestry. Estimation of pollutant load is therefore essential for watershed management and water pollution control. In this study, a model of rainfall runoff and pollutant load, which uses a geographical information system (GIS) database, is a convenient and powerful tool for resolving the abovementioned complexities. This technology was applied in order to simulate the runoff discharge and the pollutant load of total nitrogen (TN) and total phosphorus (TP) in the Chikugo River basin of Kyushu Island, Japan. First, a hydrologic modeling system (HEC-HMS) and GIS software extension tool were used for simulations of elevation, drainage line definition, watershed delineation, drainage feature characterization, and geometric network generation. The spatial distributions of land cover, soil classes, rainfall, and evaporation were then analyzed in order to simulate the daily runoff discharge at the Chikugo Barrage from April 2005 to December 2007. An important point in this approach is that a new development for data input processing with HEC-HMS was introduced for optimizing parameters of the model. Next, the water quality indicators TN and TP were examined, and an efficient approach was investigated for estimating monthly pollutant loads directly from unit load and ground-observed hydrological data. Both nonpoint and point sources of pollutants were considered, including different land-cover categories, sewers, factories, and livestock farms. The observed and simulated results for the runoff discharges and pollutant loads were in good agreement and totally consistent, indicating that the proposed model is applicable to simulation of rainfall runoff and pollutant load in the Chikugo River basin. Further, this model will be able to provide managers with a useful tool for optimizing the water surface management of this river basin. 相似文献
13.
Kei Ishida Macarius Yangyuoru Koichi Unami Toshihiko Kawachi 《Paddy and Water Environment》2011,9(4):393-401
Analysis of runoff processes in farmlands during storm events in particular is an important engineering topic. The shallow
water equations describing the physical conservation laws are attractive tools for understanding motion of surface water.
A numerical model is developed to reproduce surface water flows during storm events, using the finite element method and the
finite volume method applied to the one-dimensional shallow water equations. The numerical model has the advantage of dealing
with transcritical flows, wet, and dry processes, irregular channel bed slopes, and channel junctions involving multiply connected
networks. Standard numerical tests demonstrated some of these features. Runoff processes from farmlands in a Japanese hilly
area is analyzed with the numerical model coupled with another runoff model of black-box type. Parameters of the models are
calibrated and validated using observed series of rainfall and runoff discharge data. Simulated results included submergence
of hydraulic jumps and flood storage in farming plots, which are very informative in terms of assessing diverse functions
of the farmlands. 相似文献
14.
Although a variety of rainfall-runoff models are available, selection of a suitable rainfall-runoff model for a given watershed
is essential to ensure efficient planning and management of watersheds. Such studies are relatively limited in developing
nations, including India. In this study, rainfall-runoff modeling was carried out using HEC-HMS and WEPP hydrologic models,
and remote sensing and GIS (geographical information system) techniques in the Upper Baitarani River basin of Eastern India
using daily monsoon season (June–October) rainfall and the corresponding streamflow data of 6 years (1999–2005). Other input
data such as soil map, land use/land cover map, and slope map were prepared using remote sensing and GIS techniques. The modeling
results revealed that both the models under predict streamflow for 1999, 2002, 2004, and 2005 and over predict for 2001 and
2003, whereas HEC-HMS under predicts and WEPP over predicts streamflow for the year 2000. The percent deviation of total runoff
volume simulated by HEC-HMS ranges between −2.55 and 31%, while it varies from −13.96 to 13.05% for the WEPP model which suggests
that the WEPP model simulates annual flow volumes more accurately than the HEC-HMS model for most years. However, the lower
values of root mean square error (RMSE) and RMSE-observation standard deviation ratio coupled with the higher values of Nash–Sutcliffe
efficiency, percent deviation and coefficient of determination for HEC-HMS during calibration and validation periods indicated
that the streamflow simulated by HEC-HMS is more reliable than that simulated by WEPP. Overall, it is concluded that the HEC-HMS
model is superior to the WEPP model for simulating daily streamflow in the Baitarani River basin of Eastern India. 相似文献
15.
Simulation of water quality with the application of system dynamics model for population and land-use changes 总被引：1，自引：0，他引：1
Tasuku Kato 《Paddy and Water Environment》2005,3(2):103-109
Water quality is degraded due to urbanization because it causes population growth and land-use changes in a watershed. These
changes are usually simulated using a linear equation; however, in reality, population and land use are very closely related.
A watershed system dynamics model (WSD model) was developed in the simulation of the relation among population, land use (paddy
fields, upland fields, forest, and household), and runoff. The model comprised of three sectors: the agricultural sector,
nature sector, and urban sector. The elements in the WSD model were selected based on interviews with local government officers
and references. The WSD model simulated population, land use, and runoff with an average relative error of about 5%. Total
nitrogen (T-N) and total phosphorus (T-P) were simulated using the results of the WSD model and unit effluent loads. Field
surveys were conducted to determine the rate of mitigation in paddy fields. In addition, correction equations for runoff and
phosphate-containing detergent were introduced. The model simulated T-N with an average relative error of 9%, and T-P with
27%; a sensitivity analysis for the principal elements in the WSD model showed reasonable results. 相似文献
16.
This experimental study assesses the effects of event rainfall on soil erosion characteristics in terraced rice paddy fields. A 0.75-ha terraced paddy field located in Northern Taiwan was used to investigate the soil erosion under the regular cultivation of rice during two crop seasons. The environmental changes were investigated in the neighboring areas in which terraced paddy fields have been converted to other land usages. The annual rate of soil erosion calculated from the observed rainfall runoff and suspended solid contained was 0.77 ton/ha, which is significantly less than the erosion rate associated with upland crop cultivation reported by other research conducted in Taiwan. Experimental results also showed that the terraced paddy field retained the highest percentages of clay, silt, and organic matter's content, as compared to those of other upland crops, indicating that the topsoil was less susceptible to rainfall erosion under flooded conditions of rice-cultivation. The results of this study show that the rice-planted terraced paddy offers the highest level of soil conservation. The function of soil and water conservation in terraced paddy fields could be further increased by effective maintenance of embankment and to raise the height of the bund. Poor management, abandoned cultivation, and converse to other upland crops of terraced paddy fields are regarded as major contributors to increased soil erosion in mountainous areas. The government in Taiwan should formulate effective measures and maintain sustainable rice cultivation in the terraced paddies. 相似文献
17.
《Field Crops Research》1999,63(3):211-224
Vertic Inceptisols are prone to land degradation because of excessive run-off and soil erosion during the rainy season. Productivity of soybean-based systems on these soils needs to be improved and sustained by better management of natural resources, particularly soil and water. During 1995–1997 a field study was conducted in Peninsular India on a Vertic Inceptisol watershed to study the effect of two soil depths, namely shallow (<50 cm soil depth) and medium-deep (≥50 cm soil depth) and two landform treatments, namely flat and broadbed-and-furrow (BBF) systems, on productivity and resource-use efficiency of soybean–chickpea rotation (soybean in rainy season followed by chickpea in post-rainy season). Soybean grown on flat landform on medium-deep soil had a higher leaf area index and more light interception compared to the soybean grown on the BBF landform. This resulted in an increase in mean seed yield for the flat landform (2120 kg ha−1) compared to the BBF landform (1870 kg ha−1). However, the landform treatments on shallow soil did not affect soybean yields. The soybean yield was higher on the medium-deep soil (1760 kg ha−1) than on the shallow soil (1550 kg ha−1) during 1995–1996, but were not different during 1996–1997. In both years chickpea yields and total system productivity (soybean + chickpea yields) were greater on medium-deep soil than on the shallow soil. Total run-off was higher on the flat landform (25% of seasonal rainfall) than on the BBF landform (20% of seasonal rainfall). This concomitantly increased profile water content (10–30 mm) of both soils in BBF compared to the flat landform treatment during 1995–1996, but not during 1996–1997. Deep drainage was higher in the BBF landform than in flat, especially for the shallow soil. Across landforms and soil depths, water use (evapotranspiration) by soybean–chickpea rotation during 1996–1997 ranged from 496 to 563 mm, which accounted for 54–61% of the rainfall. These results indicate that while the BBF system is useful in decreasing run-off and increasing infiltration of rainfall on Vertic Inceptisols, there is a need to increase light use by soybean on BBF during the rainy season to increase its productivity. A watershed-based farming system needs to be adopted to capture significant amount of rain water lost as run-off and deep drainage. The stored water can be used for supplemental irrigation to increase productivity of soybean-based systems leading to overall increases in resource-use efficiency, crop productivity, and sustainability. 相似文献
18.
Sareh Sayari Majid Rahimpour Mohammad Zounemat-Kermani 《Paddy and Water Environment》2017,15(4):879-887
In this study, a zero-inertia finite element model (ZIFEM) is developed and applied for simulating all phases of furrow irrigation based on Saint–Venant equations. The complexity and nonlinear behavior of the Saint–Venant equations are the major difficulty in developing a finite element model to simulate furrow irrigation. Therefore, through the Galerkin FEM approach, the model assesses the free surface flow on a variable cell length at each time step and determines the suitable element length for each individual cell and the model solves the equations by using an iterative method. Along with the free surface flow phase, the infiltration phase is estimated by the Kostiakov–Lewis equation. The ZIFEM model is verified using seven experimental data sets collected from the literature and observed data from the farm consisting of two free drainage furrows with a length of 72 m, a top width of 0.8 m, a depth of 0.25 m and a slope of 0.2%. The model accuracy is studied to simulate advance and recession trajectories and runoff by calculating the root-mean-square error (RMSE), relative error and percentage error. It is observed that in all irrigation events, the proposed model reasonably agreed with field measurements. An evaluation of the RMSE shows that in 81.25% irrigation events the ZIFEM is more accurate than the WinSRFR model. In overall, the results of the model suggest that the ZIFEM can be introduced as a potential numerical tool for analyzing and evaluating furrow irrigation. 相似文献
19.
对三峡地区玉米降水生产潜力及适宜开发度进行研究。结果表明:在玉米全生育期,自然降水总量的41.9%用于农田蒸散。坡地与平地相比,坡地地表径流量占降水总量的28.3%,平地地表径流量占降水总量的12.3%;耗水系数平均为0.136mm/(kg·hm2),比平地低0.007mm/(kg·hm2)。影响玉米降水生产潜力的主要障碍因子是施肥水平、降水量和土壤侵蚀。随着施肥水平的提高,降水生产潜力增大,且施肥水平对坡地降水生产潜力的影响比平地更加明显;水土流失增加,降水生产潜力降低,降水量对降水生产潜力的贡献值为-3.135kg/(mm·hm2),即每减少降水量1mm,坡地降水生产潜力平均下降3.135kg/hm2。在现有技术、土壤、投入水平及管理条件下,三峡地区大田玉米降水生产潜力开发程度(MKD)较低,坡地约60%～65%,平地约65%～70%。坡地玉米降水生产潜力适宜开发度(SKD)可达80%,平地可达90%。可开发程度(KKD)坡地平均为17.5%、平地平均为17.9%,平地降水生产潜力可开发程度比坡地稍大。 相似文献
20.
基于渗漏池法研究施肥对东北中部雨养区玉米氮素地下淋溶的影响 总被引：3，自引：0，他引：3
2010~2013年,对东北玉米土壤氮素地下淋溶年际发生规律和氮排放强度进行研究。结果表明,淋溶年平均发生7~8次,受降雨影响较大,其中6月和7月的淋溶次数占全年的2/3。农田氮素淋溶排放强度年际间差异较大,最高值与最低值差8倍左右,农田本底(不施肥)流失量平均为5 kg/hm2,各施肥处理在4.53~7.17 kg/hm2,农田本底氮素流失70%以上,整体来看,北方农区氮素的地下淋溶强度不高,约占施氮量的5%左右,受降雨、施肥、土壤类型等综合因素的影响。 相似文献