探究酸性土壤pH与碳氮矿化之间的相互关系

发布时间：2018-05-06 11:39

本文选题：酸性土壤 + 土壤改良剂　；参考：《浙江大学》2017年硕士论文

【摘要】：最近几十年,土壤酸化已经成为日益严重的问题,引起了广泛关注,酸性土壤改良也成为当下研究热点。本研究选取衢州酸性红壤开展大田试验。探寻有效改良剂(生物质炭、石灰和有机肥)及其组合用于酸性土壤改良效果,及其对土壤硝化作用和硝化细菌的影响,探究了有机物料(玉米粉和玉米秸秆)加入到三种改良剂处理的土壤(无改良剂处理、小麦秸秆生物质炭处理和有机肥处理)后土壤基础理化性质(pH和TOC)的变化规律,比较了土壤pH和物料可用性对改良土壤中细菌群落结构和组成的影响。得到了以下结果:(1)大田试验探究应用生物质炭、石灰、有机肥及其组合对酸性土壤改良的效果。结果表明,施用改良剂都增加了土壤的pH,其中小麦生物质炭的效果最好,土壤pH增加了约2个单位;混合处理(1/3稻壳生物质炭,1/3石灰和1/3有机肥)约增加了1个单位。总的来说,改良剂的碱性离子(Ca2+,Mg2+和K+)是土壤pH增加的主要因素,而氮矿化(主要是硝化作用)对pH降低的影响相对较小。(2)不同改良剂对硝化作用及其硝化微生物的研究表明氨氧化古菌(AOA)与氨氧化细菌(AOB)丰度的比率随着土壤pH的降低而大幅增加,这表明土壤pH是影响AOB丰度的重要因素。高通量MiSeq测序显示,土壤改良剂的添加显著地增加了土壤中亚硝化单胞菌属和硝化螺菌属的相对丰度。土壤pH是细菌群落组成和多样性的重要决定因素。综上所述,改良剂(生物质炭,石灰,有机肥料及其组合)通过土壤pH影响了硝化细菌丰度、多样性和组成,从而改变土壤硝化作用。(3)玉米粉在不同pH的土壤中(4.63至6.32)矿化速率比玉米秸秆要快,并且在最高pH(6.32)的土壤中矿化最快。在加入玉米粉(5mg C g-1土壤)后,土壤pH在第一天增加,然后下降,导致土壤pH变化的主要原因是从有机物质分解释放的碱性离子和硝化作用之间的相互作用。与玉米秸秆相比,玉米粉对土壤pH和微生物生物量的增加更加明显。高通量MiSeq测序显示,细菌群落在不同的处理呈现显著差异,其群落结构分别与土壤pH,微生物生物量碳和土壤有机质矿化呈现显著的相关性。α-变形菌纲,β-变形菌和腐生螺旋菌纲的相对丰度与土壤pH呈正相关关系,但酸杆菌纲,γ-变形菌和纤线杆菌纲的相对丰度与土壤pH呈负相关关系。有机物料的添加显著增加了变形菌纲的丰度和降低了纤线杆菌纲的丰度,但群落中主要纲与TOC间没有显著的相关性。本研究证明了土壤pH比有机物料对细菌群落结构与组成影响更大。
[Abstract]:Soil acidification has become an increasingly serious problem in recent decades. This study selected Quzhou acid red soil to carry out field experiment. To explore the effects of effective modifiers (biomass carbon, lime and organic fertilizer) and their combinations on soil nitrification and nitrifying bacteria, The changes of soil basic physical and chemical properties (pH and TOC) of organic materials (corn flour and corn straw) added to three modifiers (no modifier treatment, wheat straw biomass carbon treatment and organic fertilizer treatment) were studied. The effects of soil pH and material availability on the structure and composition of bacterial community in improved soil were compared. The results are as follows: 1) the effects of biomass carbon, lime, organic fertilizer and their combinations on the improvement of acid soil were investigated in the field experiment. The results showed that the soil pH was increased by applying the modifier, and the effect of wheat biomass carbon was the best, the soil pH was increased by about 2 units, and the mixed treatment of 1 / 3 rice husk biomass carbon (1 / 3 lime and 1 / 3 organic fertilizer) increased about 1 unit. In general, the basic ions of the modifier, Ca 2 +, mg 2 and K) are the main factors of the increase of soil pH. The effect of nitrogen mineralization (mainly nitrification) on pH reduction was relatively small. The study of nitrification and nitrifying microorganism by different modifiers showed that the ratio of AOAA to AOB was with soil pH. Decreased and increased substantially, This indicated that soil pH was an important factor affecting AOB abundance. High throughput MiSeq sequencing showed that the addition of soil modifier significantly increased the relative abundance of soil nitrifying bacteria and nitrifying Helicobacter. Soil pH is an important determinant of bacterial community composition and diversity. To sum up, improvers (biomass carbon, lime, organic fertilizers and their combinations) affect the abundance, diversity and composition of nitrifying bacteria through soil pH. Therefore, the mineralization rate of corn flour in different pH soils was faster than that of corn straw, and the highest pH value was 6.32). The pH of the soil increased on the first day and then decreased after adding corn flour 5mg / g soil. The main reason for the change of soil pH was the interaction between the alkaline ions released from the decomposition and release of organic matter and nitrification. Compared with corn straw, corn meal increased soil pH and microbial biomass more obviously. High throughput MiSeq sequencing showed that bacterial communities showed significant differences in different treatments. The community structure was significantly correlated with soil pH, microbial biomass, carbon and soil organic matter mineralization, and the relative abundance of 伪 -Proteus, 尾 -Proteus and Helicobacter saprophyta was positively correlated with soil pH. However, the relative abundance of acidobacterium, 纬 -Proteus and Fibrinobacterium was negatively correlated with soil pH. The addition of organic materials significantly increased the abundance of Proteus and decreased the abundance of Mycobacterium, but there was no significant correlation between the main class and TOC in the community. The results showed that soil pH had more influence on the structure and composition of bacterial community than organic materials.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S153

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