本文選題：贛江　切入點(diǎn)：硝酸鹽　出處：《江西師范大學(xué)》2015年碩士論文

【摘要】：贛江是鄱陽湖的最大支流,贛江硝態(tài)氮(NO3--N)是鄱陽湖氮素輸入的主要來源,基于土地利用方式和氮穩(wěn)定同位素查明贛江流域硝酸鹽污染來源對鄱陽湖水環(huán)境污染監(jiān)測和維護(hù)湖區(qū)內(nèi)水體環(huán)境具有重大意義。分別在2013年1月(枯水期)和6月(豐水期)對贛江的干流和支流的硝酸鹽氮、氨氮、亞硝酸鹽氮質(zhì)量檢測,在土地利用結(jié)構(gòu)分類和空間尺度對比的基礎(chǔ)上,采用穩(wěn)定的氮同位素和相關(guān)分析研究贛江硝酸鹽的主要來源。在實(shí)地調(diào)查的基礎(chǔ)上合理布設(shè)采樣點(diǎn),利用GIS和RS技術(shù)為平臺,分析贛江流域的土地利用方式,在2013年豐水期和枯水期對贛江流域進(jìn)行定點(diǎn)調(diào)查與采樣,采用水化學(xué)研究手段分析贛江流域水體中無機(jī)氮和氯離子濃度的分布特征,結(jié)合流域的土地利用結(jié)構(gòu)類型和氮穩(wěn)定同位素分析其對無機(jī)氮的影響,為識別贛江流域的硝酸鹽污染的主要來源和鄱陽湖的水體保護(hù)提供了重要的依據(jù)。研究結(jié)果主要有以下幾個(gè)方面：(1)對贛江流域2013年1月和6月不同采樣點(diǎn)的無機(jī)氮濃度進(jìn)行分析,研究表明贛江流域水體無機(jī)氮輸出以硝氮(N03--N)形態(tài)為主,N03--N含量平均值為1.80mg/L,約占總無機(jī)氮的78%；其次為NH4+-N,平均值為0.52mg/L,約占總無機(jī)氮20%；NO2--N含量很小,多數(shù)采樣點(diǎn)低于監(jiān)測值0.02 mg/L。(2)對贛江流域無機(jī)氮分布特征進(jìn)行分析表明,N03--N含量和NH4+-N含量在1月均大于6月。1月N03--N含量從贛江的源頭到下游的波動(dòng)范圍大于6月,NH4+-N含量在1月表現(xiàn)出與6月的相似性,N03--N和NH4+-N的變化差異總體上是1月大于6月。(3)對贛江流域土地利用結(jié)構(gòu)進(jìn)行分析,結(jié)果表明林地面積比例達(dá)到62.5%,水田面積比例為18%,旱地和居民建設(shè)用地為16%,水田、水域?qū)ο跛猁}氮輸出起“源”作用,林地和草地等對硝酸鹽氮輸出起“匯”作用。(4)對贛江流域進(jìn)行不同空間尺度對比,子流域劃分法比緩沖區(qū)法更適于贛江流域硝酸鹽來源分析,在二級土地利用分類下可以更好的突出土地利用與無機(jī)氮之間的作用。二級分類中水田中的丘陵水田對N03--N含量貢獻(xiàn)最大。其他水田類型較小。贛江流域中N03--N的主要來源為農(nóng)村用地,NH4+N的主要來源為居民建設(shè)用地中的城鎮(zhèn)用地和其它工礦建設(shè)用地。(4)贛江流域內(nèi)的干流的δ1SN- NO3-值在變化幅度小在0.79-5.93%o之間,而支流的δ15N- NO3=值的變化范圍較寬在-1.31‰-8.6‰之間,枯水期均值顯著小于豐水期,贛江支流由于流經(jīng)的區(qū)域土地利用類型差異大導(dǎo)致硝酸鹽污染源出現(xiàn)較大差異性。(6)對贛江流域內(nèi)無機(jī)氮與氮同位素(δ15N- NO3-)相比分析,贛江流域的δ15N-NO3-值主要落合成化肥和土壤氮范圍內(nèi),說明贛江流域的硝態(tài)氮主要來源于農(nóng)業(yè)化肥污染和土壤無機(jī)氮。
[Abstract]:The Ganjiang River is the largest tributary of Poyang Lake, and the no _ 3-N _ 3-N of Ganjiang River is the main source of nitrogen input in Poyang Lake. It is of great significance to identify the sources of nitrate pollution in Ganjiang River basin based on land use patterns and nitrogen stable isotopes for monitoring water pollution and maintaining the water environment in Poyang Lake. In January 2013 (dry season) and 6. Nitrate nitrogen in the main and tributaries of the Ganjiang River, The quality of ammonia nitrogen, nitrite nitrogen, based on the classification of land use structure and spatial scale comparison, The main sources of nitrate in Ganjiang River were studied by using stable nitrogen isotope and correlation analysis. On the basis of field investigation, the sampling sites were reasonably set up, and the land use patterns in Ganjiang River Basin were analyzed on the platform of GIS and RS technology. The distribution characteristics of inorganic nitrogen and chloride ion concentration in Ganjiang river basin were analyzed by means of hydrochemical research during the high and low water periods in 2013, and the distribution characteristics of inorganic nitrogen and chloride ions in Ganjiang river basin were analyzed by means of hydrochemistry. The effects of land use structure types and nitrogen stable isotopes on inorganic nitrogen were analyzed. This paper provides an important basis for identifying the main sources of nitrate pollution in the Ganjiang River Basin and the water protection of Poyang Lake. The main results of the study are as follows: 1) the inorganic contents of different sampling sites in January and June 2013 in Ganjiang River Basin. Nitrogen concentration is analyzed, The results show that the inorganic nitrogen output of Ganjiang River basin is mainly composed of nitrate N ~ (03) -N (N _ (03) -N), the average content of which is 1.80 mg / L, accounting for 78% of the total inorganic nitrogen, followed by NH4 -N, with an average value of 0.52 mg / L, accounting for about 20% of the total inorganic nitrogen, the content of no _ 2--N is very small. The distribution characteristics of inorganic nitrogen in Ganjiang River basin were analyzed. The results showed that the contents of N ~ (03) -N and NH4 ~ (-N) in January were greater than in June. The range of fluctuation of N ~ (3 +) from the source of Ganjiang River to the lower reaches in January was larger than that of NH _ 4 in June. The variation of -N content in January was similar to that in June. The difference between N03-N and NH4 -N was generally greater in January than in June, and the land use structure of Ganjiang River basin was analyzed. The results showed that the proportion of forest land and paddy field was 62.5 and 18, and the proportion of dry land and residential construction land was 16. The paddy field and water area played a "source" role in nitrate nitrogen output. Forest land and grassland play a "sink" role in nitrate nitrogen output. (4) the different spatial scales of Ganjiang river basin are compared. The subbasin division method is more suitable than buffer zone method for nitrate source analysis in Ganjiang river basin. The role of land use and inorganic nitrogen can be better highlighted in the secondary land use classification. The hilly paddy fields in the secondary classification have the greatest contribution to the content of N03-N, while the other paddy fields are smaller. The main role of N03-N in the Ganjiang River basin is that of the hilly paddy fields in the secondary classification. The main sources of NH _ 4N from rural land are urban land and other industrial and mining construction land in residential construction land.) the 未 _ 1SN-no _ 3- value of the main stream in the Ganjiang River basin varies slightly in the range of 0.79-5.93o. The variation range of 未 15N- no _ 3 = of tributaries is from -1.31 鈥，

本文編號：1655097