A method for estimating non-point source pollution load of paddy fields in irrigated areas based on water level regulation

Abstract

The invention relates to a water level regulation-based non-point-source pollution load estimation method of an irrigation-area water field. The method comprises the following steps: step 1, pothole configuration improvement; step 2, improvement of an evapotranspiration algorithm; step 3, improvement of an infiltration quantity calculation method; step 4, construction of an irrigation and water drainage control module; step 5, adjustment of a soil erosion quantity calculation method of the water field; step 6; a calculation method of nitrogen and phosphorus loss quantity of the water field; step 7, running of an improved model; and step 8, calculation of a non-point-source pollution load of the water field. According to the method of the invention, different hydrological characteristics ofthe water field in immersed status and in an emptying period are respectively considered, optimization and improvement are also carried out at the same time for various algorithms, and obtaining of amore accurate rice field hydrological-cycle process and nutrient loss process is facilitated.

Description

【Technical field】 [0001] The invention relates to a method for estimating non-point source pollution loads of paddy fields in irrigation areas. In particular, it relates to a method for estimating non-point source pollution loads of paddy fields in irrigated areas based on water level regulation, which belongs to agricultural environmental protection technology. 【Background technique】 [0002] Agricultural non-point source pollution in the watershed refers to the water pollution caused by some soil particles, nutrients, toxic pesticides and heavy metals entering the water body from the farmland along with the runoff during the process of precipitation, snowmelt and farmland dewatering. As an important driving factor for the formation of non-point source pollution, runoff plays a pivotal role in the generation, transport and transformation of non-point source pollution. Paddy fields are artificial wetland systems. The overflow and drainage of the surface layer and the underg...

AI Technical Summary

Problems solved by technology

However, the current mainstream watershed non-point source prediction models (such as SWAT, HSPF, and AnnAGNPS) also have obvious defects in the application process of irrigation areas: (1) The mainstream watershed non-point source prediction models do not have a built-in paddy field module, and only runoff Curve method, Green-Ampt infiltration model, etc. simplify paddy field to dry field treatment; (2) The submerged state of paddy field is not considered. When irrigation occurs, except part of irrigation water is calculated according to infiltration, the rest is regarded as surface runoff; (3) It is impossible to simulate the seasonal fluctuation characteristics of the water level of paddy fields, and it is impossible to establish a connection between non-point source pollution and water level regulation of paddy fields

[0004] The current non-point source pollution prediction methods are constantly developing, but the prediction methods that consider the actual irrigation characteristics of paddy fields are very scarce. For example, the application number is CN201410619286.1, and the name is a distributed nitrogen runoff load estimation based on GIS. The method, publication number CN104361523A, only uses GIS system, land use scenarios and fertilizer application to construct a simple output system model for evaluating non-point source pollution output load of paddy fields, lacks sufficient model mechanism support, and is useless to establish water level Correspondence between regulation and non-point source pollution

Another example is that the application number is CN201310232100.2, the name is the observation method and system of non-point source pollution outflow load of paddy fields, and the publication number is CN103294923A, which has constructed a field-scale non-point source pollution analysis and estimation method for paddy fields, but it is difficult to Expanded at the watershed scale

Another example is that the application number is CN201210326701.5, the name is a non-point source pollution calculation method based on remote sensing pixels, and the publication number is CN102867120A. However, this method is difficult to characterize the nitrogen and phosphorus release laws of paddy fields under submerged conditions.

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