本文選題：黑土　切入點：旱田改種稻田　出處：《沈陽農(nóng)業(yè)大學》2017年碩士論文　論文類型：學位論文

【摘要】：黑土是我國東北地區(qū)重要的土壤資源,近年來,該區(qū)域由旱田改種稻田的面積逐年增加。旱田改種稻田后土壤環(huán)境發(fā)生明顯的變化,在短期淹水(年約4～5個月)環(huán)境條件下土壤碳(氮)的演變規(guī)律如何?目前尚不清楚。土壤有機碳(氮)作為衡量土壤肥力的重要指標,科學地評價黑土區(qū)旱田改種稻田后土壤有機碳(氮)的變化特征,對于東北黑土的合理利用和培肥具有重要意義。本文以東北典型黑土區(qū)旱田土壤(種植大豆年限大于60年)和改種不同年限的稻田土壤(3、5、10、17、20和25年,旱田改種稻田前種植歷史基本相同,均為大豆)為研究對象,利用穩(wěn)定性同位素技術(shù)、物理和化學分組技術(shù)等,研究了東北黑土區(qū)旱田開墾種稻后土壤有機碳(氮)、顆粒有機碳(氮)和鍵合有機碳的動態(tài)變化特征,有機碳(氮)及顆粒有機碳(氮)的穩(wěn)定性,分析了旱田改種稻田后土壤有機碳(氮)變化的影響因素,探討了旱田改種稻田后土壤有機碳(氮)的演變規(guī)律。主要研究結(jié)果如下:(1)東北黑土區(qū)旱田改種稻田25 a間,土壤有機碳、全氮含量及其0-60 cm 土層密度的變化趨勢均表現(xiàn)為:在改種的3 a間迅速下降,在3～25 a間隨改種年限延長呈逐漸增加的趨勢,在改種5～25 a間0-60 cm 土層有機碳、全氮密度分別增幅9.87%～21.48%和10.2%～19.3%,土壤有機碳和全氮的變化密切相關(guān)(P0.01)。土壤δ13C值和δ15N值均呈逐年下降趨勢,在5～25 a間二者數(shù)值均低于旱田土壤;相同年限土壤的δ13C值和δ15N值均隨著土層加深而增大。(2)東北黑土區(qū)旱田改種稻田25 a間,土壤顆粒有機碳(氮)的分配比例為4.96%～12.73%(4.03%～13.07%),與旱田土壤(0a)相比,其提高幅度為6.8%～106.4%(0.7%～224.0%)。各年限0-40 cm 土層稻田土壤顆粒有機物中的δ13C值和δ15N均高于旱田土壤,相同年限的δ13C值均隨土層加深而升高,而δ15N值則均隨土層加深而降低。(3)東北黑土區(qū)旱田改種稻田25 a間,土壤鍵合有機碳的分配比例為41.06%～66.48%,均低于相同土層旱田土壤,在改種3～25 a間呈逐年降低趨勢,且均隨土層加深而增加;0-60 cm 土壤Fe(Al)-SOC的分配比率與其鍵合有機碳的變化相同,20-60 cm土壤Ca-SOC的分配比率則呈逐年增加趨勢,但各年限土壤Fe(Al)-SOC明顯高于Ca-SOC,Fe(Al)-SOC為土壤鍵合有機碳的主體。(4)東北黑土區(qū)旱田改種稻田25 a間,土壤pH、CEC及交換性Ca2+、不同形態(tài)氧化鐵鋁均隨改種年限的延長而變化,但變化規(guī)律不相一致。通過相關(guān)分析和多元線性逐步回歸分析發(fā)現(xiàn),土壤陽離交換量(CEC)及交換性鈣和絡合態(tài)氧化鐵(鋁)是影響旱田改種稻田土壤有機碳及顆粒有機碳、鍵合有機碳變化的重要因素;土壤CEC及交換性Ca2+對土壤有機碳的變化起正作用,而絡合氧化鐵鋁則起負作用。綜上,東北黑土區(qū)旱田改種稻田25 a間,改種年限大于5 a后稻田土壤有機碳(氮)、顆粒有機碳(氮)逐年增加,化學鍵合有機碳則逐年下降,稻田土壤具有明顯的固碳(氮)能力,有機碳(氮)在20-60 cm 土層易于累積且相對穩(wěn)定;在0-20 cm 土層,易變化的顆粒有機碳相對累積,其分解性相對較為活躍。因此,旱田改種稻田年限小于5 a,應注重有機碳(氮)的補充,改種年限大于5 a,則應注重土壤有機碳(氮)的穩(wěn)定性,以維持和提高旱田改種稻田后土壤有機碳(氮)水平及其穩(wěn)定性。
[Abstract]:Black soil is an important soil resource in Northeast China in recent years, the area of upland rice by planting area increased year by year. Upland paddy field replant soil environment after obvious changes in short-term flooding (about 4~5 months) under the condition of soil carbon (nitrogen) how evolution law is not clear? Soil organic carbon (nitrogen) as an important indicator of soil fertility, the scientific evaluation of black soil area of upland rice after replant soil organic carbon (nitrogen) change characteristic, has important significance for rational utilization of black soil in Northeast China and fertilization. The typical upland black soil region of Northeast China (soybean planting age greater than 60 years) and from different years of paddy soil (3,5,10,17,20 and 25 years ago, upland paddy plant planting history is basically the same, are soybean) as the research object, the use of stable isotope techniques, physical and chemical technology research group. Upland rice cultivation in black soil region of Northeast China soil organic carbon (nitrogen), particulate organic carbon (nitrogen) and the key dynamic characteristics of combined organic carbon, organic carbon (nitrogen) and particulate organic carbon (nitrogen) stability analysis of upland rice after replant soil organic carbon (nitrogen) change of influencing factors. The paddy upland replant soil organic carbon (nitrogen) evolution. The main results are as follows: (1) to 25 upland black soil region of northeast paddy a, soil organic carbon, total nitrogen content and its change trend of 0-60 cm soil layer density are as follows: the rapid decline in the 3 to a, 3~25 in a with the plant life extension is gradually increasing, in the 5~25 a 0-60 cm to soil organic carbon, total nitrogen density were increased by 9.87% ~ 21.48% and 10.2% ~ 19.3%, the change of soil organic carbon and total nitrogen are closely related (P0.01). Soil 13C values and 15N values declined year by year, The value of 5~25 a between the two were lower than upland soil; the same soil Delta 13C values and 15N values increased with soil depth. (2) to 25 upland black soil region of northeast paddy field a, soil particulate organic carbon (nitrogen) proportion is 4.96% ~ 12.73% (4.03% ~ 13.07%), and upland soil (0A) compared to the increased from 6.8% to 106.4% (0.7% ~ 224%). The length of delta 13C 0-40 cm soil layer of paddy soil particulate organic matter in the value of 15N was higher than that of upland soils and delta, Delta 13C values were the same period with the soil depth increased, while the 15N values were decreased with soil further reduced. (3) to 25 upland black soil region of northeast paddy field a, the distribution proportion of soil organic carbon bond is 41.06% ~ 66.48%, were lower than the same soil in upland soils, to 3~25 A is decreasing year by year, and were increased with soil depth; 0-60 cm soil Fe (Al) distribution ratio with -SOC The change of organic carbon bond is the same as that of 20-60 cm soil Ca-SOC distribution ratio increased year by year, but the soil Fe (Al) -SOC was significantly higher than that of Ca-SOC, Fe (Al) -SOC as the main soil organic carbon bond. (4) to 25 upland black soil region of northeast paddy soil pH, a. CEC and exchangeable Ca2+, different forms of iron oxide aluminum was increased with the age to change, but the change is not consistent. Through correlation analysis and multivariate linear regression analysis showed that, soil cation exchange capacity (CEC) and exchangeable calcium and iron complexed (aluminum) is the effect of upland paddy soil organic carbon plant and particulate organic carbon, an important factor in bonding changes in organic carbon; soil CEC and exchangeable Ca2+ on changes of soil organic carbon is positive, and the complexation of Fe and Al oxides exerted negative effect. As a result, upland paddy field in the 25 A to the black soil region of Northeast China, to life is more than 5 A in paddy field Soil organic carbon (nitrogen), particulate organic carbon (nitrogen) increased year by year, chemical bonding of organic carbon in paddy soil decreased year by year, with significant carbon (nitrogen), organic carbon (nitrogen) is accumulated and relatively stable in the 20-60 cm soil layer; in 0-20 cm soil layer, easy to change particle organic carbon the relative cumulative, the decomposition of relatively active. Therefore, upland paddy replant years of less than 5 A, should pay attention to organic carbon (nitrogen) added to age greater than 5 A, should pay attention to soil organic carbon (nitrogen) stability, to maintain and enhance the upland rice after replant soil organic carbon (nitrogen) and its level stability.

【學位授予單位】：沈陽農(nóng)業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：S153.6
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本文編號：1579660