本文關(guān)鍵詞：凍融作用對棕壤團(tuán)聚體組成及其重金屬鎘賦存形態(tài)的影響　出處：《沈陽農(nóng)業(yè)大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 棕壤 凍融作用 團(tuán)聚體 重金屬鎘 賦存形態(tài)

【摘要】：重金屬Cd在土壤中的賦存形態(tài)直接影響著Cd在土壤中的生物有效性和毒性,在一定程度上決定著Cd在土壤中的真實污染程度。季節(jié)性凍融是北方地區(qū)常見的氣候現(xiàn)象,凍融作用能改變土壤結(jié)構(gòu)、顆粒大小等物理性質(zhì),從而間接影響Cd在土壤中的形態(tài)轉(zhuǎn)化。本文以沈陽地區(qū)的典型土壤—棕壤作為供試土壤,采用人工控溫的方法對不同凍結(jié)溫度、不同含水量條件下的土壤進(jìn)行凍融交替處理,測定凍融處理后棕壤團(tuán)聚體的粒徑分布及其中重金屬Cd的賦存形態(tài),探討凍融作用對棕壤團(tuán)聚體穩(wěn)定性及其中重金屬Cd賦存形態(tài)轉(zhuǎn)化的影響。得到的主要結(jié)論如下:(1)棕壤經(jīng)過凍融作用后,可變電荷量顯著降低(P0.05);但當(dāng)凍結(jié)溫度低于-20℃時,可變電荷量降低不明顯;凍融作用促進(jìn)了棕壤有機(jī)質(zhì)含量的增加(P0.05),但凍結(jié)溫度對棕壤有機(jī)質(zhì)含量影響不顯著,當(dāng)棕壤含水量大于田間持水量的40%時,含水量對有機(jī)質(zhì)含量影響不顯著。(2)土壤經(jīng)過不同凍結(jié)溫度處理后,2 mm團(tuán)聚體粒徑所占比例顯著增加(P0.05),1-2mm、0.25-0.5mm和0.25mm團(tuán)聚體粒徑所占比例明顯降低(P0.05),0.5-1 mm團(tuán)聚體粒徑所占比例變化不顯著。在一定凍結(jié)溫度(-20 ℃)條件下,2 mm團(tuán)聚體所占比例隨著土壤含水量的增加而增加,0.5-1 mm和0.25-0.5 mm團(tuán)聚體所占比例隨著含水量的增加而減少,1-2 mm團(tuán)聚體所占比例在土壤含水量為田間持水量的40%時最大,0.25 mm團(tuán)聚體所占比例在土壤含水量為田間持水量的30%時最大。(3)棕壤經(jīng)過凍融處理后,掃描電鏡結(jié)果顯示土體出現(xiàn)了"抱團(tuán)"現(xiàn)象,增加了土樣顆粒之間的團(tuán)聚能力。當(dāng)棕壤含水量達(dá)到田間持水量的60%時,團(tuán)聚體穩(wěn)定性達(dá)到最大,但不同凍結(jié)溫度對團(tuán)聚體穩(wěn)定性影響不顯著。(4)與未凍融土壤相比,土壤經(jīng)過不同凍結(jié)溫度處理后2mm、1-2mm和0.5-1 mm團(tuán)聚體粒徑中重金屬Cd的含量明顯增加(P0.05),0.25-0.5 mm和0.25 mm團(tuán)聚體粒徑中重金屬Cd所占比例明顯降低(P0.05),凍融作用促進(jìn)了 Cd在土壤大團(tuán)聚體中的富集,降低了 Cd的環(huán)境風(fēng)險。(5)與未凍融土壤相比,經(jīng)過凍融處理后棕壤中交換態(tài)Cd和有機(jī)結(jié)合態(tài)Cd含量降低,鐵錳氧化物結(jié)合態(tài)Cd與殘渣態(tài)Cd含量增加。隨著凍結(jié)溫度的降低,交換態(tài)Cd含量呈現(xiàn)先增加后降低的趨勢,鐵錳氧化物結(jié)合態(tài)Cd和有機(jī)結(jié)合態(tài)Cd含量先降低后增加,殘渣態(tài)Cd含量逐漸降低,但當(dāng)溫度降低到-20 ℃時,殘渣態(tài)Cd含量不再降低。(6)凍融作用對棕壤團(tuán)聚體中重金屬Cd的形態(tài)轉(zhuǎn)化有顯著影響(P0.05)。與未凍融土壤相比,在不同團(tuán)聚體粒徑中不同凍結(jié)溫度均使交換態(tài)Cd和有機(jī)結(jié)合態(tài)Cd含量降低,鐵錳氧化物結(jié)合態(tài)Cd與殘渣態(tài)Cd含量增加。
[Abstract]:Speciation of Cd in soil Cd in soil directly affects the bioavailability and toxicity, to a certain extent determines the real pollution degree of Cd in the soil. The seasonal freezing and thawing climate is common phenomenon in northern areas, freezing and thawing can change the soil structure, particle size and other physical properties. Thus indirectly affect the conversion of Cd in the soil form. The typical soil brown soil of Shenyang area as tested soil, using the artificial freezing temperature of different temperature, different water content under the condition of soil freezing and thawing cycles, measured after freeze-thaw treatment of soil aggregate size distribution and speciation of the the heavy metals of Cd, to investigate the effects of freezing and thawing on soil aggregate stability and the speciation of heavy metals Cd transformation. The main conclusions are as follows: (1) soil after freezing and thawing, the variable charge amount. Reduce (P0.05); but when the freezing temperature lower than -20 DEG C, the variable charge amount decreased; freezing and thawing increased soil organic matter content (P0.05), but the effect of freezing temperature on the soil organic matter content was not significant, when soil water content is greater than 40% of field capacity, influence of water content the organic matter content was not significant. (2) the soil after different freezing temperatures after treatment, 2 mm aggregate size proportion increased significantly (P0.05), 1-2mm, 0.25-0.5mm and 0.25mm aggregate size proportion was significantly lower (P0.05), 0.5-1 mm aggregate particle size proportion did not change significantly in a certain. The freezing temperature (-20 DEG C) condition, 2 mm aggregate proportion increases with the increase of soil water content, 0.5-1 mm and 0.25-0.5 mm aggregate proportion decreased with the increase of water content, 1-2 mm aggregates in the proportion of soil moisture to field water The maximum amount of 40%, 0.25 of the MM aggregates in the largest proportion of soil moisture was 30% of field capacity. (3) soil after freeze-thaw treatment, SEM results showed that the soil appeared "Baotuan" phenomenon, increase the agglomeration ability between the soil like particles. When the soil moisture at field capacity 60% of the water, the maximum aggregate stability, but different freezing temperature effect on aggregate stability is not significant. (4) and non freezing thawing soil compared to soil after different freezing temperature after 2mm treatment, the contents of 1-2mm and 0.5-1 mm aggregate size of heavy metals in a significant increase in Cd (P0.05), 0.25-0.5 mm and 0.25 mm aggregate the particle size of heavy metals in the proportion of Cd decreased significantly (P0.05), freeze-thaw action promoted the accumulation of Cd in soil aggregates, reduce the environmental risk of Cd. (5) and non freezing thawing soil than after freezing thawing treatment after Cd exchange in brown soil Organic state and decreased the content of Cd and Fe Mn oxide bound Cd and residual Cd content increased. With the temperature decrease, exchangeable Cd content increased first and then decreased, Fe Mn oxide bound Cd and organic bound Cd content decreased firstly and then increased, the content of residual Cd decreased gradually, but when the temperature is reduced to -20 degrees, the content of residual Cd was no longer reduced. (6) effects of freezing and thawing on the heavy metal Cd in brown soil under transformation had significant effect (P0.05). And the freezing thawing soil than in different aggregate size in different freezing temperatures were the exchangeable Cd and organic Cd content reduced iron manganese oxide bound Cd and residual Cd content increased.

【學(xué)位授予單位】：沈陽農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X53

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 高敏;李艷霞;張雪蓮;張豐松;劉蓓;高詩穎;陳興財;;凍融過程對土壤物理化學(xué)及生物學(xué)性質(zhì)的影響研究及展望[J];農(nóng)業(yè)環(huán)境科學(xué)學(xué)報;2016年12期

2 孫經(jīng)偉;堯水紅;李娜;尤孟陽;韓曉增;張斌;;農(nóng)田恢復(fù)措施對黑土母質(zhì)發(fā)育的新成土壤團(tuán)聚體微形態(tài)及孔隙結(jié)構(gòu)的影響[J];中國土壤與肥料;2016年04期

3 史瓊彬;趙秀蘭;常同舉;盧吉文;;耕作方式對紫色水稻土團(tuán)聚體中有機(jī)質(zhì)及重金屬的分布特征影響[J];環(huán)境科學(xué);2016年05期

4 謝志強(qiáng);許建林;朱兆龍;安韶山;;一種可用于評估土壤團(tuán)聚體穩(wěn)定性的超聲能量法[J];水土保持研究;2016年04期

5 孫躍嘉;田甜;何娜;葉祝弘;孫明慧;楊丹;;凍融周期對棕壤性質(zhì)及砷吸附解吸特性的影響[J];生態(tài)環(huán)境學(xué)報;2016年04期

6 張翠景;賀紀(jì)正;沈菊培;;全球變化野外控制試驗及其在土壤微生物生態(tài)學(xué)研究中的應(yīng)用[J];應(yīng)用生態(tài)學(xué)報;2016年05期

7 樊紅柱;秦魚生;陳慶瑞;陳琨;涂仕華;;長期施肥紫色水稻土團(tuán)聚體穩(wěn)定性及其固碳特征[J];植物營養(yǎng)與肥料學(xué)報;2015年06期

8 呂薇;李軍;岳志芳;陳寧寧;王淑蘭;;輪耕對渭北旱塬麥田土壤有機(jī)質(zhì)和全氮含量的影響[J];中國農(nóng)業(yè)科學(xué);2015年16期

9 任婧;袁旭;卞春梅;范成五;秦松;;貴陽白云區(qū)工業(yè)園區(qū)周邊水稻土重金屬含量狀況及風(fēng)險評價[J];西南農(nóng)業(yè)學(xué)報;2015年03期

10 趙曉東;謝英荷;李廷亮;龐嬌;劉雯艷;賀t，

本文編號：1364662