發(fā)布時間：2017-12-27 19:40

  本文關(guān)鍵詞：南陵—涇縣國家商品糧基地農(nóng)田區(qū)土壤特征元素分布差異性及潛在生態(tài)效應(yīng)　出處：《中國地質(zhì)科學(xué)院》2017年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 農(nóng)田表層土壤 有益/重金屬元素 背景值 分區(qū)特征 潛在生態(tài)風(fēng)險

【摘要】：南陵-涇縣國家商品糧基地是我國著名的"南陵大米"產(chǎn)地、"國家優(yōu)質(zhì)米基地"和"國家商品糧基地",該區(qū)特色農(nóng)業(yè)發(fā)展亟需深入認識農(nóng)田表層土壤有益/重金屬(特征)元素分布特征、差異性和潛在生態(tài)效應(yīng)。本研究以安徽省南陵-涇縣國家重要商品糧基地分布區(qū)為重點研究區(qū),圍繞"農(nóng)田區(qū)表層土壤中有益/重金屬元素的分區(qū)特征、差異性及形成機制"關(guān)鍵科學(xué)問題,側(cè)重"土壤有益/重金屬(特征)元素或組份背景值識別與確定"、"農(nóng)田區(qū)水土環(huán)境系統(tǒng)分區(qū)單元識別與劃分"、"不同分區(qū)表層土壤中有益/重金屬元素或組份分布差異特征與成因"和"農(nóng)田表層土壤中重金屬元素潛在生態(tài)效應(yīng)與對策"研究,在1:5萬農(nóng)田區(qū)水文地質(zhì)與土地質(zhì)量地球化學(xué)綜合調(diào)查基礎(chǔ)上,通過增設(shè)縱-橫剖面加密采樣點、垂向剖面增加采樣密度等實物工作量和專項試驗及綜合研究,取得如下突破性進展和新認識。(1)根據(jù)地貌的單元特征、地表水系的流域特征和地下水系統(tǒng)的分區(qū)特征,同時,重視土地利用現(xiàn)狀和農(nóng)作物種植類型影響,將研究區(qū)劃分為5個分區(qū)單元,首次查明和確定了各分區(qū)32種元素或組份的土壤地球化學(xué)背景值,建立了本次研究的各分區(qū)環(huán)境基準值,奠定了該商品糧基地農(nóng)田區(qū)表層土壤有益/重金屬異常狀況的識別與研判科學(xué)基礎(chǔ)。(2)基于半方差變異函數(shù)理論,論證了全區(qū)541組土壤樣品及數(shù)據(jù)具有變異性較小的可靠性,并闡明研究區(qū)表層土壤中有益/重金屬元素分布差異性的成因。較小的塊金值反映出有益元素、重金屬等空間區(qū)域化變量由于誤差和隨機因素造成的變異性較小;塊金值與基臺值之比揭示了元素自相關(guān)程度。研究結(jié)果表明,在"南陵-涇縣商品糧基地"農(nóng)田,除有機質(zhì)、N、有效Mn外的大部分有益元素和全部重金屬元素均表現(xiàn)為"中等-強"的空間自相關(guān)性;該區(qū)表層土壤中各類特征元素空間分布差異性,是氣候、母質(zhì)、地貌和土壤類型等結(jié)構(gòu)性因素,以及隨機性人類活動共同影響結(jié)果,自然因素為主導(dǎo),局部農(nóng)田區(qū)人類活動起主要作用,包括上游區(qū)礦產(chǎn)資源開發(fā)、農(nóng)田區(qū)大量施用除草劑、農(nóng)藥和化肥等影響。(3)采用地質(zhì)累積指數(shù)法,揭示了南陵-涇縣國家商品糧基地表層土壤中9種重金屬元素分區(qū)特征及其對土地質(zhì)量潛在風(fēng)險影響程度和分布差異性。研究結(jié)果表明:Ⅰ分區(qū)呈現(xiàn)Hg對農(nóng)田土地質(zhì)量影響"輕度-中等"風(fēng)險范圍最大,僅有13.7%的區(qū)域未受到影響;65.3%的農(nóng)田區(qū)受到Cd的影響,14.5%的農(nóng)田區(qū)受到As的影響。Ⅱ分區(qū)95%以上的區(qū)域,表層土壤未受到重金屬潛在風(fēng)險影響。在Ⅲ分區(qū),表層土壤中Hg地質(zhì)累積指數(shù)的最大值為3.38,是該商品糧基地分布區(qū)的最大地質(zhì)累積指數(shù),影響區(qū)域占Ⅲ分區(qū)面積的90%以上,其中"輕度-中等"影響范圍占73.8%。ⅣV分區(qū)的表層土壤中Hg、Cd影響最為顯著,局部農(nóng)田Cd對土地質(zhì)量的潛在風(fēng)險影響呈"強"程度,Hg呈"中等-強"程度和As、Mn呈"中等"程度。在V分區(qū),As、Hg和Cd對土地質(zhì)量的潛在風(fēng)險影響比較明顯,受"中等"程度的As潛在風(fēng)險影響區(qū)域占18%,超過30%的區(qū)域受Hg、Cd潛在風(fēng)險影響達"中等"及以上程度。(4)采用潛在生態(tài)風(fēng)險指數(shù)法,闡明了南陵-涇縣國家商品糧基地的不同分區(qū)表層土壤重金屬對土地質(zhì)量潛在生態(tài)風(fēng)險影響的分區(qū)特征和分布差異性。研究結(jié)果表明:在5個研究分區(qū)中,As、Pb、Cr、Cu、Zn、Fe和Mn的潛在生態(tài)風(fēng)險指數(shù)介于0.74～23.86,對農(nóng)田表層土壤的潛在生態(tài)風(fēng)險影響"輕微",只有Cd、Hg和As潛在生態(tài)風(fēng)險影響比較明顯,其中Hg潛在生態(tài)風(fēng)險影響"強"的區(qū)域占70%以上,Cd以"中等"影響程度為主。在Ⅰ分區(qū),Cd潛在生態(tài)風(fēng)險影響"中等"的區(qū)域占75%;在V分區(qū),30%區(qū)域受Cd潛在生態(tài)風(fēng)險影響為"強-極強"程度。在Ⅳ、Ⅴ分區(qū),As潛在生態(tài)風(fēng)險影響"中等"區(qū)域占該研究區(qū)面積的10%以上;而Ⅰ、Ⅱ分區(qū)和Ⅲ分區(qū),基本不存在As的潛在生態(tài)風(fēng)險影響。(5)針對性提出:在南陵-涇縣國家商品糧基地需要進一步加強農(nóng)田區(qū)表層土壤中Hg分布狀況、來源和變化特征調(diào)查,盡快開展1:1萬土地質(zhì)量地球化學(xué)專項調(diào)查和異常查證,以及防控農(nóng)田區(qū)表層土壤中Hg潛在生態(tài)風(fēng)險關(guān)鍵技術(shù)和對策研究;應(yīng)加強Ⅰ、Ⅴ分區(qū)表層土壤中Cd的潛在生態(tài)風(fēng)險成因、主要來源和Ⅳ、Ⅴ分區(qū)As的潛在生態(tài)風(fēng)險影響趨勢和影響范圍核查,盡快形成有利于當(dāng)?shù)鼐G色農(nóng)業(yè)發(fā)展技術(shù)咨詢建議報告,服務(wù)地方經(jīng)濟社會可持續(xù)發(fā)展。
[Abstract]:Nanling - Jingxian County national commodity grain base in China is the famous "Nanling rice" origin, "national high quality rice base" and "national commodity grain base, the characteristics of agricultural development needs in-depth understanding of the farmland soil heavy metal elements (good / characteristic) distribution, diversity and potential ecological effects. In this study, Anhui Province, Nanling Jingxian County an important national commodity grain base region as the main study area, around the "key scientific problems in surface soil of farmland area in good / partition characteristics of heavy metal elements, the differences and the formation mechanism, focusing on" beneficial soil / heavy metals (features) elements or components identification and determination of background value "" the farmland soil and water environment system partition unit identification and classification, different partitions in the surface soil beneficial / heavy metal elements or components distribution characteristics and causes of "and" in the farmland soil heavy metal potential ecological effects and Countermeasures "research in the 1:5 million farmland hydrological and land quality comprehensive investigation of the chemical basis of the Earth last, through the addition of longitudinal cross section encryption sampling point, vertical profile density increased workload and special test and comprehensive research sample, made the following breakthroughs and new understanding. (1) according to the landform unit characteristics, surface water and groundwater system of watershed characteristics zoning characteristics, at the same time, pay attention to the influence of land use status and crop types, the study area was divided into 5 sub units, for the first time to identify and determine the partition of 32 elements or components of the soil geochemical background values, establish the study of the environment of each partition reference value, establishes the commodity grain base of farmland soil heavy metal anomaly recognition / beneficial and judged scientific basis. (2) based on the theory of half variance variogram, the reliability of the 541 groups of soil samples and data in the whole area is proved to be less variability, and the reason for the difference of the distribution of beneficial / heavy metals in the surface soil of the study area is clarified. A small nugget reflects less variability of regional variable beneficial elements and heavy metals due to space error and random factors; nugget value and base value of the element ratio reveals the extent of autocorrelation. The results show that the farmland in the "Nanling - Jingxian County commodity grain base, in addition to most of the useful elements of organic matter, N, Mn outside and all the heavy metals were" moderate spatial autocorrelation - strong "; the spatial distribution characteristics of various elements in the area of differences in surface soil, climate, parent material, topography the soil type and the structural factors, and the randomness of human activities affect the results, as the dominant natural factors, local farmland area of human activities play a major role, including mineral resources development, the upstream region of farmland utilization of herbicides, pesticides and chemical fertilizers and other effects. (3) using the index of geological accumulation, we have revealed the zoning characteristics of 9 heavy metals in surface soil of Nanling Jingxian County national commodity grain base and their influence degree and distribution difference to land quality potential risks. The results showed that: 1. The area of Hg showed the largest "light to medium" risk for farmland quality, and only 13.7% of the area was not affected. 65.3% of the farmland area was affected by Cd, and 14.5% of the farmland area was affected by As. The surface soil is not affected by the potential risk of heavy metals in more than 95% regions. In the third area, the maximum value of Hg geological accumulation index is 3.38, which is the largest geological accumulation index in the distribution area of the commodity grain base. The influence area accounts for more than 90% of the third area area, and the "mild to moderate" influence area accounts for 73.8%. The influence of Hg and Cd in the surface soil of V IV is the most significant. The effect of Cd on the potential risk of land quality is strong. The Hg is moderately strong, and As and Mn are "moderate". In the V partition, As, Hg and Cd have a significant impact on the potential risk of land quality. The area affected by the potential risk of "moderate" As accounts for 18%, and more than 30% of the area is affected by the potential risks of Hg and Cd to "medium" or above. (4) by using the potential ecological risk index method, the zoning characteristics and the distribution difference of the surface soil heavy metals on land quality and potential ecological risk in Nanling Jingxian County national commodity grain base were clarified. The results showed that: in the 5 of the partition, the potential ecological risk index between As, Pb, Cr, Cu, Zn, Fe and Mn from 0.74 to 23.86, the potential ecological risk influence on topsoil minor ", only Cd, Hg and As potential ecological risk effect is obvious, the potential ecological Hg the risk effect of" strong "region accounted for more than 70%, Cd to the" medium "influence mainly. In the I zoning, the potential ecological risk of Cd was 75% in the "medium" area; in the V zoning, the 30% region was affected by the potential ecological risk of Cd as a "strong - strong" degree. In Area IV and V, the potential ecological risk of As is more than 10% of the total area, while there is no potential ecological risk of As. (5) put forward: in Nanling - Jingxian County national commodity grain base to further strengthen the investigation of surface soil in the farmland area Hg distribution, sources and characteristics of 1:1 million land quality geochemical survey and the anomaly investigation carried out as soon as possible, and the prevention and control of farmland soil in surface Hg potential ecological risk key technology and countermeasure research; the potential ecological risk of I, should strengthen the potential ecological risk causes, V partition in surface soil of the main sources of Cd and IV and V partition As trend and the influence scope of verification, as soon as possible formation technology development advice to the local green agricultural industry, local economic and social sustainable development.
【學(xué)位授予單位】：中國地質(zhì)科學(xué)院
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S153.6

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1 王茜;南陵—涇縣國家商品糧基地農(nóng)田區(qū)土壤特征元素分布差異性及潛在生態(tài)效應(yīng)[D];中國地質(zhì)科學(xué)院;2017年

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