Non-point Source Pollution Management Research Articles

Nonpoint source pollution

A comprehensive review of the research papers published in 2018 focusing on nonpoint source (NPS) pollution is presented in this review article. The identification of pollution from different sources and estimation of NPS pollution using various models are summarized in this review paper. Various innovative techniques are also examined to abate NPS pollution. PRACTITIONER POINTS: The non-point source pollution in 2018 is systematically reviewed and documented. This review evaluates and summarizes the identification, quantification, reduction, and management of NPS pollution. Future perspectives of NPS pollution research are discussed.

비점오염 관리평가를 위한 부하지속곡선 작성시 모니터링 자료 활용 방안

비점오염 관리평가를 위한 부하지속곡선 작성시 모니터링 자료 활용 방안

Assessment and management of nonpoint source pollution based on multicriteria analysis.

Assessing the potential impacts of nonpoint source (NPS) pollution and proposing sound control strategies are significant global challenges. However, few studies have provided insights into the quantitative risk analysis and efficient management of NPS pollution. This study formulated four evaluation criteria to characterize both the generation and migration of diffuse phosphorus. Multicriteria analysis and the technique for order preference by similarity to ideal solution were combined to develop a NPS pollution risk index model for the evaluation of the potential phosphorus loss at the basin scale. The proposed model is a simple and efficient tool that considers most factors that affect diffuse phosphorus. In the GIS environment, the spatial distribution of the risk index of diffuse phosphorus could be mapped and visualized in the Huai River Basin. With the natural breaks classification method, the study area was divided into the following five regions: a potentially polluted region (3.5%), a lightly polluted region (15.4%), a moderately polluted region (40.7%), a highly polluted region (31.5%), and a seriously polluted region (8.9%). Based on land use composition, geographical location, and sources of diffuse phosphorus of these five regions, corresponding prevention measures were introduced, thus facilitating the management of NPS pollution for policy makers.

Methodology for Determining the Key Factors for Non-Point Source Management

Due to the growing significance of water quality degradation by non-point source (NPS) pollution, regions in which NPS management is required should be designated as the management areas. Relevant management measures should be established to control water quality items related to degradation. It is advantageous that the area where the water environment is negatively affected by NPS is provided with legal grounds for NPS management, namely the designation of an NPS management area. This is because if it is designated as an NPS management area, the government can support the budget necessary for the installation of non-point pollution reduction facilities. In order to effectively utilize the limited budget, it is necessary to select and concentrate the area that should be managed first in the NPS management area. For the efficiency of the NPS pollution management within a management region, priority locations or key management sub-regions should be determined to implement differential management plans. Also, in selecting priority management regions, evaluation factors that can reflect the effects of NPS, such as the water quality target excess ratio in the mid-level region (or the total maximum daily load (TMDL) management) which includes the target region (low-level region), the NPS load in land, and non-permeable area ratio, should be quantified and the management order should be defined. Since NPS has local characteristics, the management items should be determined based on turbidity, suspended solid (SS), or total phosphorus (TP) that affect the local water quality. When the water environment is polluted due to non-point pollutants, various materials such as turbidity, SS, TP, Escherichia coli, and heavy metals can be set as management items according to local characteristics. However, the most important items to be managed are turbidity, SS, and TP, because if the solid (SS) is present in the water, which is highly turbid and does not sink easily, people can feel unpleasant and feel that the water is not clean, even if they do not analyze the water quality. In addition, in the case of TP, nutrients accumulated in the land are introduced into the river by rainfall, causing eutrophication. People feel uncomfortable because it changes the water color. Other pollutants can only be found to be contaminated after water quality analysis is performed. The water quality target of the management items should be set realistically, based on the situation of the watershed by considering the watershed model, management flow, NPS pollutant reduction plan, the river flow in the management area, and load. All these reflect the characteristics of the region. To evaluate whether the water quality target is achieved after NPS management, a method similar to the one to set the water quality target should be used to review the performance of the management plan. This study introduces specific examples of key factors in establishing an NPS management plan, including consideration factors and methods for the designation of NPS management regions, consideration factors and the selection method for key management areas within a management region, the selection method of management items, the selection method of the water quality target, and an evaluation method of the water quality target.

A novel spatial optimization model for achieve the trad-offs placement of best management practices for agricultural non-point source pollution control at multi-spatial scales

The efforts to management agricultural non-point source pollution from the field to watershed scale is an ongoing challenge that needs to take into account trade-offs between environmental and economic objectives. Best management measures (BMPs) are considered as an effective means to achieve this balance in the management of agricultural non-point source pollution. Many studies have focused on a single spatial scale for placement of the BMPs, however, the effectiveness in improving water quality at different scale will affect by many factors such as the land use, soil type and the river network and so on. In order to demonstrating the relationship or impact of spatial scale changes on the allocation and effectiveness of BMPs. The present study attempts to development a novel multi-scale model framework and indices as a decision support platform for solve the impact of spatial scale change on the optimization of best management measures in the Chaohe River Watershed in Beijing and Hebei province. And used it in a drinking water source area which was affected by the agricultural nonpoint source pollution in recent decades in Beijing, China. A series of the utility functional between the utility of the water quality improvement and the number of watersheds, watershed size, the unit cost of BMPs and integrated these three functional relations by Generalized Reduced Gradient Algorithm. We found that the nonlinear threshold response function can play a key role in the configuration of BMPs from field to watershed scale. The results show that 1) the utility functions for pollution load reduction and the number of watersheds can be described by the log-sigmoid curve, and the optimal number of watershed for total nitrogen (TN) and total phosphorus (TP) control are 25 and 23 respectively, 2) the most utility function for the pollution load reduction and the mean sub-watershed area is exponential function curves, and the optimal mean sub-watershed areas are168 km2 and 214 km2 for TN and TP, respectively, 3) the relationship between pollution load reduction and cost of per unit after BMPs implemented can be drawing by the logistic curves, and the optimal average unit cost are 4622 and 7692 CNY·ha−1 for TN and TP, respectively, 4) the comprehensive optimal of these above functions shown that the total cost of BMP plans is 2.01 × 107 and 4.7 × 107 CNY for TN and TP, respectively at the trad-offs scenario. This study will provide a systematic approach to determine more reasonable and feasible management practices system on more reasonable spatial scale for the protection of water quality and safety in watershed.

Analysis of the environmental behavior of farmers for non-point source pollution control and management: An integration of the theory of planned behavior and the protection motivation theory

Agricultural non-point source (NPS) pollution in water source protection areas poses serious challenges for governments in developing countries. It is important to consider the environmental behavior of farmers when exploring the causes of NPS pollution as well as when establishing scientific controls and management measures. However, the poor understanding of factors influencing the environmental behavior of farmers and the lack of a suitable environmental socio-psychological model limit the application of the environmental behavior of farmers in NPS pollution management. In this study, we therefore integrated the theory of planned behavior (TPB) and the protection motivation theory (PMT) to identify the main determinants of the NPS pollution-related environmental behavior and intention of farmers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China. Results indicated that the integrated model provided a better understanding of the environmental behavior and intention of farmers than that provided by each component when used individually, and revealed that farmers perceived that the susceptibility and severity of threats caused by water deterioration influenced environmental intention through the mediating effects of subjective norm and attitude toward adopting pro-environmental behavior. At the same time, the perceived vulnerability of farmers was relatively high and their perceived severity was relatively low. Furthermore, the subjective norm, attitude, self-efficacy (i.e., the perceived behavioral control), and response efficacy positively and significantly influenced intention. However, response cost had a significantly negative effect on intention. Among them, subjective norm had the largest effect on intention. Intention was the key determinant for the actual environmental behavior of farmers, while self-efficacy also had a significantly positive effect on behavior. Managing and controlling agricultural NPS pollution requires a multi-disciplinary and comprehensive approach. Therefore, an integrated theoretical framework was developed in this study by integrating TPB and PMT to gain insight into the environmental behaviors and intention of farmers. The results provided a theoretical basis for NPS pollution control.

Effect of irrigation amount and fertilization on agriculture non-point source pollution in the paddy field

It is the key point to reveal the effect of irrigation water and fertilization conditions on the agriculture non-point pollution in the paddy field. In this study, the estimation model of agricultural non-point source pollution loads at field scale was established on the basis of agricultural drainage irrigation model and combined with pollutant concentration predication model. Based on the estimation model of agricultural non-point source pollution in the field and experimental data, the load of agricultural non-point source pollution in different irrigate amount and fertilization schedule in paddy field was calculated. The results showed that the variation of field drainage varies greatly under different irrigation conditions, and there is an "inflection point" between the irrigation water amount and field drainage amount. The non-point pollution load increased with the increase of irrigation water and showed a significant power correlation. Under the different irrigation condition, the increase amplitude of non-point pollution load with the increase of irrigation water was different. When the irrigation water is smaller, the non-point pollution load increase relatively less, and when the irrigation water increased to inflection point, the non-point pollution load will increase considerably. In addition, there was a positive correlation between the fertilization and non-point pollution load. The non-point pollution load had obvious difference in different fertilization schedule even with same fertilization level, in which the fertilizer pollution load increased the most in the period of turning green to tillering. The results provide some basis for the field control and management of agricultural non-point source pollution.

Temporal and spatial scaling effects of parameter sensitivity in relation to non-point source pollution simulation

Scale represents an important concept in all scientific disciplines, but the scaling effect related to non-point source (NPS) pollution simulation and sensitivity parameters has not yet been reported. In this study, the sliding window, the Fourier amplitude sensitivity test and the nested watershed idea were used with the Soil and Water Assessment Tool (SWAT) model to explore the temporal and spatial scaling effects of parameter sensitivity in a typical watershed of the Three Gorges Reservoir Region, China. The results indicated that a great scaling effect could be observed at varying spatio-temporal scales, while the scaling effect would be transferred and amplified from the hydrological modelling to the NPS simulation. Soil properties such as SOL_K and SOL_BD were identified as key parameters under smaller spatial and temporal scales, while channel-related parameters in terms of ALPHA_BF, CH_K and CH_N showed greater sensitivity at larger scales. Specifically, some parameters, such as CH_N, USLE_K, USLE_P and ERORGP, were always identified as key sensitive parameters for the sediment and NPS-TP simulations, but some parameters, such as CH_K, showed sensitivity only above a specific spatial scale (778 km2 in this study). These results could be used as a reference for studying the scaling effect of model parameter sensitivity and provide important information for model construction and the management of NPS pollution at different scales.

Seasonal Changes of the Pathways of Nitrogen Export from an Agricultural Watershed in China

Nonpoint source pollution has become a major factor influencing the water quality. Identifying the pathway of nitrogen (N) transport from the source to the watershed mouth is a critical step in taking measures to control this pollution. However, it is difficult to identify the pathway of N transport because the transport pathway varies among different watersheds depending on the difference in the terrain, hydrology, and land cover etc and changes over time. Additionally, there is little knowledge about the major pathway of N transport through agricultural watersheds in the Yunnan Plateau lake area. The pathways of N export and their temporal variations over time were investigated in this study based on a typical agriculture-dominated watershed in a plateau lake area, Yunnan Province, and two-year monitoring data (June 2011-May 2013) in combination with a base flow separation program. The results show that the base flow accounts for most of the streamflow discharge (80.0%) and N export (71.1%). The proportion of the stream flow discharge via storm flow increases significantly with increasing rainfall. Therefore, the percentage of total N (TN) export via storm flow increases with increasing storm flow, which is closely related to rainfall. The major pathway of N export shifts toward storm flow when the storm flow proportion of the stream flow discharge increases up to 40%. During the monitoring period, the proportion of the TN export via storm flow increases up to 65.6% in the rainy season. This study provides important information for the improvement of the management of nonpoint source pollution at the watershed scale.

Predictive ability of climate change with the automated statistical downscaling method in a freeze–thaw agricultural area

Precipitation and temperature in freeze–thaw agricultural area have different patterns under global warming. In this study, a statistical relationship between large-scale changes in climate variables and local weather data was built by applying an automated statistical downscaling (ASD) model in the Sanjiang Plain in China. We evaluated the prediction ability of the ASD model in terms of spatial–temporal changes in freeze–thaw agricultural area, and the temperature and precipitation changes in the twenty-first century under the representative concentration pathway 4.5 (RCP4.5) scenario were estimated. The results revealed that the explained variances in temperature were higher than 0.93 during the calibration and verification periods, which demonstrated good simulation capacity. The R2 of precipitation was acceptable due to the randomness and complexity of daily precipitation. Based on the Geophysical Fluid Dynamics Laboratory Earth System Model with the Generalized Ocean Layer Dynamics component (GFDL-CM3), the regional climate simulation provided good predictions. By 2100, the average, maximum and minimum temperatures in this area could increase by 2.0–2.5 °C, 2.5 °C and 2.5–4.0 °C, respectively. In terms of the spatial distribution, temperatures could increase faster in the northern region and slower in the central and southern regions. The warming trends in summer and winter were more significant than those in spring and autumn. There was no significant change in annual precipitation in the twenty-first century (increased approximately 10 mm by 2100). Precipitation decreased obviously in July and August (approximately 0.4 mm/day), and other months showed an increasing trend (approximately 0.5–0.9 mm/day). There will be large spatial variation of precipitation in the future changes. The results could serve as a reference for assessing non-point source pollution and agricultural management.

Design and development of a web-based interface for the Agricultural Policy Environmental eXtender (APEX) model

The diffuse nature of nonpoint source (NPS) pollution as well as that of the effectiveness of best management practices (BMP) to control NPS pollution necessitates BMP evaluation at the field scale. In this study, a web interface was developed for application of the Agricultural Policy Environmental eXtender (APEX) model at the field scale. The interface contains background databases for field location, soil, agricultural management and climate across the contiguous United States. Users can specify properties to run the model for an individual field and compare the results under various land management and conservation practice choices. A case study was conducted to demonstrate the capability of the web interface for simulating various land management scenarios. This tool can help provide on-site information for NPS pollution management related policies and serve as a communication tool among scientists, engineers, and stakeholders.

Analysis of the environmental behavior of farmers for non-point source pollution control and management in a water source protection area in China

The environmental behavior of farmers plays an important role in exploring the causes of non-point source pollution and taking scientific control and management measures. Based on the theory of planned behavior (TPB), the present study investigated the environmental behavior of farmers in the Water Source Area of the Middle Route of the South-to-North Water Diversion Project in China. Results showed that TPB could explain farmers' environmental behavior (SMC=0.26) and intention (SMC=0.36) well. Furthermore, the farmers' attitude towards behavior (AB), subjective norm (SN), and perceived behavioral control (PBC) positively and significantly influenced their environmental intention; their environmental intention further impacted their behavior. SN was proved to be the main key factor indirectly influencing the farmers' environmental behavior, while PBC had no significant and direct effect. Moreover, environmental knowledge following as a moderator, gender and age was used as control variables to conduct the environmental knowledge on TPB construct moderated mediation analysis. It demonstrated that gender had a significant controlling effect on environmental behavior; that is, males engage in more environmentally friendly behaviors. However, age showed a significant negative controlling effect on pro-environmental intention and an opposite effect on pro-environmental behavior. In addition, environmental knowledge could negatively moderate the relationship between PBC and environmental intention. PBC had a greater impact on the environmental intention of farmers with poor environmental knowledge, compared to those with plenty environmental knowledge. Altogether, the present study could provide a theoretical basis for non-point source pollution control and management.

Agricultural non-point source pollution management in a reservoir watershed based on ecological network analysis of soil nitrogen cycling.

The Miyun Reservoir plays a pivotal role in providing drinking water for the city of Beijing. In this research, ecological network analysis and scenario analysis were integrated to explore soil nitrogen cycling of chestnut and Chinese pine forests in the upper basin of the Miyun Reservoir, as well as to seek favorable fertilization modes to reduce agricultural non-point source pollution. Ecological network analysis results showed that (1) the turnover time was 0.04 to 0.37year in the NH4+ compartment and were 15.78 to 138.36years in the organic N compartment; (2) the Finn cycling index and the ratio of indirect to direct flow were 0.73 and 11.92 for the chestnut forest model, respectively. Those of the Chinese pine forest model were 0.88 and 29.23, respectively; and (3) in the chestnut forest model, NO3- accounted for 96% of the total soil nitrogen loss, followed by plant N (2%), NH4+ (1%), and organic N (1%). In the Chinese pine forest, NH4+ accounted for 56% of the total soil nitrogen loss, followed by organic N (34%) and NO3- (10%). Fertilization mode was identified as the main factor affecting soil N export. To minimize NH4+ and NO3- outputs while maintaining the current plant yield (i.e., 7.85e0kgN/year), a fertilization mode of 162.50kgN/year offered by manure should be adopted. Whereas, to achieve a maximum plant yield (i.e., 3.35e1kgN/year) while reducing NH4+ and NO3- outputs, a fertilization mode of 325.00kgN/year offered by manure should be utilized. This research is of wide suitability to support agricultural non-point source pollution management at the watershed scale.

An export coefficient based inexact fuzzy bi-level multi-objective programming model for the management of agricultural nonpoint source pollution under uncertainty

In this research, an export coefficient based inexact fuzzy bi-level multi-objective programming (EC-IFBLMOP) model was developed through integrating export coefficient model (ECM), interval parameter programming (IPP) and fuzzy parameter programming (FPP) within a bi-level multi-objective programming framework. The proposed EC-IFBLMOP model can effectively deal with the multiple uncertainties expressed as discrete intervals and fuzzy membership functions. Also, the complexities in agricultural systems, such as the cooperation and gaming relationship between the decision makers at different levels, can be fully considered in the model. The developed model was then applied to identify the optimal land use patterns and BMP implementing levels for agricultural nonpoint source (NPS) pollution management in a subcatchment in the upper stream watershed of the Miyun Reservoir in north China. The results of the model showed that the desired optimal land use patterns and implementing levels of best management of practices (BMPs) would be obtained. It is the gaming result between the upper- and lower-level decision makers, when the allowable discharge amounts of NPS pollutants were limited. Moreover, results corresponding to different decision scenarios could provide a set of decision alternatives for the upper- and lower-level decision makers to identify the most appropriate management strategy. The model has a good applicability and can be effectively utilized for agricultural NPS pollution management.

Aquatic Nitrate Retention at River Network Scales Across Flow Conditions Determined Using Nested In Situ Sensors

AbstractNonpoint pollution sources are strongly influenced by hydrology and are therefore sensitive to climate variability. Some pollutants entering aquatic ecosystems, e.g., nitrate, can be mitigated by in‐stream processes during transport through river networks. Whole river network nitrate retention is difficult to quantify with observations. High frequency, in situ nitrate sensors, deployed in nested locations within a single watershed, can improve estimates of both nonpoint inputs and aquatic retention at river network scales. We deployed a nested sensor network and associated sampling in the urbanizing Oyster River watershed in coastal New Hampshire, USA, to quantify storm event‐scale loading and retention at network scales. An end member analysis used the relative behavior of reactive nitrate and conservative chloride to infer river network fate of nitrate. In the headwater catchments, nitrate and chloride concentrations are both increasingly diluted with increasing storm size. At the mouth of the watershed, chloride is also diluted, but nitrate tended to increase. The end member analysis suggests that this pattern is the result of high retention during small storms (51–78%) that declines to zero during large storms. Although high frequency nitrate sensors did not alter estimates of fluxes over seasonal time periods compared to less frequent grab sampling, they provide the ability to estimate nitrate flux versus storm size at event scales that is critical for such analyses. Nested sensor networks can improve understanding of the controls of both loading and network scale retention, and therefore also improve management of nonpoint source pollution.

路桥区湿地资源现状及保护对策

通过对路桥区湿地资源现状调查分析，认为生产生活、海涂围垦、输入性污染、保护工作薄弱是影响湿地资源存在的主要问题。提出以划定湿地保护红线、加快湿地公园建设、开展湿地生态恢复、开展河流湿地综合整治和加强面源污染治理五方面对策措施，来改变路桥当前湿地保护存在的不足，使路桥湿地保护工作取得较好成效。 Through the investigation and analysis about the present situation of wetland resources in Luqiao district, it is considered that the production and living, the tidal flat reclamation, the imported pollution, and the weakness of protection are the main problems of wetland resources. And countermeasures have been offered from 5 aspects about protection of the wetland with designating red line as wet land protection, speeding up the construction of the wetland park, carrying out the wetland ecological restoration and the comprehensive improvement of the river wetland, and strengthening management of non-point source pollution, to improve the shortage of the current wetland protection in Luqiao, and make the wetland protection achieve good results.

Export of non-point source suspended sediment, nitrogen, and phosphorus from sloping highland agricultural fields in the East Asian monsoon region.

Excess sediment and nutrient export from agricultural fields with steep slopes is a major concern linked to surface water quality in Korea. In this study, the export of suspended sediment (SS), total nitrogen (TN), and total phosphorus (TP) and their event mean concentrations (EMCs) in surface runoff from a highland mixed land use (61% forested, 30% cropped, 9% other) watershed were quantified. In 2007, the Korean Ministry of Environment (MoE) declared the study area as a priority region for non-point source (NPS) pollution management and initiated various best management practices (BMPs) in the study watershed. SS, TN, and TP concentrations in Mandae Stream were monitored for 5years (2009-2013) to evaluate the effectiveness of BMPs. Average EMCs for SS, TN, and TP were as high as 986, 3.4 and 0.8mg/L, respectively. The agricultural export coefficients of agricultural land in the study watershed for SS, TN, and TP were 5611, 171, and 6.83kg/ha/year, respectively. A comparison with results from other studies shows that both EMCs and agricultural export coefficients in the study watershed were much higher than most of the results reported for watersheds in other regions. The results show that sediment and nutrient export from intensive agriculture areas with steep slopes continue to be a major concern for the downstream reservoir, Lake Soyang. Remedial strategies should be directed towards controlling sources of SS, TN, and TP to improve downstream water quality in sloping highland agricultural areas in Korea.

Identification of Phosphorus Loss Spatial Features in Typical Land Use Patterns Coupled with Remote Sense and Soil Analysis

The soil phosphorus (P) assessment is of great significance for agricultural non-point source pollution management in watersheds. Many of current studies provided data with limited accuracy and at relatively small spatial scale, due to the low spatial resolution of available remote sense data. This study used solid pollutants loss equation and high-resolution remote sense data source to determine the spatial characteristics of P loss, and then identified the critical polluted areas and corresponding underlying surface conditions within each land use type. Results showed that non-eroded region and slightly loss region covered more than 65% of the entire area. Although the severely-eroded region only accounted for 12.8% of the area, this region was distributed in the vicinity of downstream of two major inflow drainages. Hence, the harmful effect of this region on the watershed environment should not be neglected. The P loss varied significantly among different land use types, including forest land, arable land and orchard land. The forestland exhibited the lowest loss intensity, while the arable land exhibited the highest loss intensity. And the variation degree of P loss intensity within orchard land was probably greater than the other two land use patterns. Furthermore, this diversity in P loss largely resulted from different underlying surface features including topography, vegetation status, and key soil properties. The result from this study is suitable for practical use in different management strategies for non-point source pollution (NPS) management.

Landscaping practices, community perceptions, and social indicators for stormwater nonpoint source pollution management

This study sought to assess the relationship between regulatory and educational approaches to nutrient management and homeowner behaviors, perceptions, and knowledge of best management practices (BMPs). Fertilizers, and pesticides applied in excess by homeowners and landscapers can impair stormwater ponds and cause nuisance algae blooms, eutrophication and fish kills. They can also affect water quality in downstream creeks, and bays. To reduce the potential for nutrient-laden runoff to the aquatic environment, local and state governments passed different regulatory mechanisms that govern the use of BMPs and a fertilizer black out period. Interviews, surveys, and participant observation were used to gather quantitative and qualitative data in order to establish social indicator scores and evaluate knowledge and attitudes surrounding the fertilizer ordinance in a Master Planned community in Manatee County Florida. Results showed that most residents (69%) had not seen any materials related to the blackout period and lacked awareness of the components of the ordinance, including its restrictions on phosphorous and nitrogen applications and disposal of grass and landscape debris. The findings reveal the importance of social dimensions in sustainable stormwater management and suggest target areas for increasing awareness of the fertilizer ordinance and strengthening the link between social norms and environmental stewardship.

Distribution Characteristics of Solute Nitrogen in the Water-Sediment of Farmland Drainage Ditch

Along with the highlighted water environmental issues and the gradual effective renovation of the point source pollution (PSP) such as industrial waste, the agricultural non-point source pollution (AGNSP) caused by the non-scientific application of fertilizers and pesticides has attracted more and more attention. On the basis of strengthening the field "source control", making the best use of agricultural drainage ditch (pond) system "intercepting process" is a vital means of agriculture non-point source pollution control and management at the present stage. Ditch system is not only an important part of the farmland irrigation and drainage engineering, but also a vital corridor of AGNSP of solute transport. The unique farmland drainage ditch water-sediment-plant system in ecology and physics is similar to linear wetland function,and has effect of interception and purification on non-point source solute in farmland drainage. Non-point source solute transformation mechanism of each medium in the farmland drainage ditch water-sediment-plant system is unclear, in view of the current situation, the study took the natural channel as the object. Taking the non-point source solute nitrogen as an example, by field monitoring test during March 2014-February 2015, the distribution characteristics of non-point solute nitrogen in the water-sediment of the farmland drainage ditch were analyzed. The results indicated that the concentration of total nitrogen in water and the total nitrogen content in the sediment of the experimental ditches both showed a certain degree of decreasing trend along the longitudinal ditch, which represented a purification effect of the ditch system on the non-point source solute. The concentration of total nitrogen in water and the total nitrogen content in the sediment had big inhomogeneity in the ditch cross-sectional distribution, and its distribution characteristics were related to the shape of the cross-section, flow variation process, flow velocity distribution and other factors. The balance of the total nitrogen concentration was 76.89%, and the total nitrogen content in the sediment was 57.04%. During the trial period, the total nitrogen concentration in the water was "concave" shape, while in the sediment it was "convex" shape, showing opposite changing trends.