氮添加對楊樹人工林土壤微生物結(jié)構(gòu)的影響
發(fā)布時間：2018-10-05 15:46
【摘要】：人類活動導(dǎo)致陸地生態(tài)系統(tǒng)中的活性氮沉降量不斷增加,氮沉降增加已經(jīng)對森林生態(tài)系統(tǒng)特征和過程產(chǎn)生了很大影響。土壤微生物是森林生態(tài)系統(tǒng)中重要的組成部分,研究氮沉降增加對土壤微生物的影響對于探索生態(tài)系統(tǒng)碳貯存及養(yǎng)分循環(huán)變化具有十分重要的意義。本研究以江蘇東臺林場10年生和17年生楊樹人工林為研究樣地,人工施加氮肥模擬大氣氮沉降增加,應(yīng)用磷脂脂肪酸(PLFA)技術(shù),探討了不同水平氮添加對楊樹生長季(5月~10月)過程中土壤微生物生物量及群落結(jié)構(gòu)組成的影響,并結(jié)合土壤理化性質(zhì)的分析,初步探索了影響土壤微生物變化的因素。所得主要結(jié)果如下:1、短期(3 a)氮添加未對10年生和17年生楊樹人工林土壤總有機碳、總氮、C/N、土壤含水率有明顯的影響,但土壤pH有降低的趨勢。2、10年生楊樹人工林中,微生物總生物量及各微生物類群(細菌、革蘭氏陰性細菌、革蘭氏陽性細菌、真菌、放線菌、叢枝菌根真菌)生物量在生長季中期(8月份)達到最高。而17年生人工林中,生長季初期(6月份)和中期(8月份)微生物總生物量、細菌、叢枝菌根真菌生物量相當(dāng),均高于生長季后期(10月份);真菌、放線菌生物量生長季中期(8份)最高。3、在10年生楊樹人工林生長季,短期超高水平氮添加(300 kg?hm-2?a-1)使微生物總生物量、細菌、革蘭氏陰性細菌、真菌生物量降低。在17年生楊樹人工林生長季,短期氮添加對微生物總生物量及不同微生物類群(細菌、革蘭氏陰性細菌、革蘭氏陽性細菌、真菌、放線菌、叢枝菌根真菌)生物量的影響較小且沒有明顯的規(guī)律。4、在10年生楊樹人工林生長季,土壤有機碳是影響土壤微生物生物量的主要因素。氮添加后微生物生物量下降很可能是受碳限制的影響。在17年生楊樹人工林生長季,土壤水分是影響微生物生物量的重要因素,但當(dāng)土壤水分充足時,土壤C/N是限制微生物生長的因素。5、短期氮添加使10年生楊樹人工林生長季土壤微生物結(jié)構(gòu)發(fā)往了變化,表現(xiàn)為占主導(dǎo)地位的微生物類群生物量下降。除個別樣地外,短期氮添加使17年生楊樹人工林生長季微生物群落結(jié)構(gòu)發(fā)生了變化。
[Abstract]:The amount of active nitrogen deposition in terrestrial ecosystems is increasing due to human activities, and the increase of nitrogen deposition has had a great impact on the characteristics and processes of forest ecosystems. Soil microorganism is an important part of forest ecosystem. It is very important to study the effect of nitrogen deposition on soil microorganism in order to explore carbon storage and nutrient cycling in ecosystem. In this study, 10-year-old and 17-year-old poplar plantations in Dongtai Forest Farm, Jiangsu Province, were used to simulate the increase of atmospheric nitrogen deposition by applying nitrogen fertilizer. The phospholipid fatty acid (PLFA) technique was applied to simulate the increase of atmospheric nitrogen deposition. The effects of different nitrogen levels on soil microbial biomass and community structure during the growing season of poplar (May ~ October) were studied. The factors affecting soil microbial changes were preliminarily explored based on the analysis of soil physical and chemical properties. The main results were as follows: (1) the short-term (3 a) nitrogen addition had a significant effect on soil total organic carbon (TOC), total nitrogen (TN) C / N, soil moisture content in 10 years old and 17 year old poplar plantations, but soil pH had a decreasing trend of 0.2, 10 years old poplar plantations. The total biomass and the biomass of various microbial groups (bacteria, Gram-negative bacteria, Gram-positive bacteria, fungi, actinomycetes, arbuscular mycorrhizal fungi) reached the highest in the middle of growing season (August). In 17 years old plantation, the total biomass of microorganisms, bacteria and arbuscular mycorrhizal fungi in the early growth season (June) and the middle (August) were similar, which were higher than those in the late growing season (October). The biomass of actinomycetes was the highest in the middle of growth season (8 parts). In the growth season of 10 year old poplar plantation, the short term super high level nitrogen was added (300 kg?). Hm-2? A) the total microbial biomass, bacteria, Gram-negative bacteria and fungal biomass were decreased. In the growth season of 17 years old poplar plantation, the total biomass and different microbial groups (bacteria, Gram-negative bacteria, Gram-positive bacteria, Fungi, Actinomycetes) were added in short-term nitrogen. The effect of arbuscular mycorrhizal fungi on biomass was small and there was no obvious regularity. In the growing season of 10 years old poplar plantation, soil organic carbon was the main factor affecting soil microbial biomass. The decrease of microbial biomass after nitrogen addition is probably affected by carbon limitation. Soil moisture is an important factor affecting microbial biomass during the growth season of 17 years old poplar plantation, but when soil moisture is sufficient, Soil C / N was the limiting factor of microbial growth. Short-term nitrogen supplementation changed the soil microbial structure in the growing season of 10 year old poplar plantation, which showed that the dominant microbial biomass decreased. The microbial community structure of 17 year old poplar plantation was changed with the addition of short term nitrogen except for a few plots.
【學(xué)位授予單位】：南京林業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S792.11;S714
[Abstract]:The amount of active nitrogen deposition in terrestrial ecosystems is increasing due to human activities, and the increase of nitrogen deposition has had a great impact on the characteristics and processes of forest ecosystems. Soil microorganism is an important part of forest ecosystem. It is very important to study the effect of nitrogen deposition on soil microorganism in order to explore carbon storage and nutrient cycling in ecosystem. In this study, 10-year-old and 17-year-old poplar plantations in Dongtai Forest Farm, Jiangsu Province, were used to simulate the increase of atmospheric nitrogen deposition by applying nitrogen fertilizer. The phospholipid fatty acid (PLFA) technique was applied to simulate the increase of atmospheric nitrogen deposition. The effects of different nitrogen levels on soil microbial biomass and community structure during the growing season of poplar (May ~ October) were studied. The factors affecting soil microbial changes were preliminarily explored based on the analysis of soil physical and chemical properties. The main results were as follows: (1) the short-term (3 a) nitrogen addition had a significant effect on soil total organic carbon (TOC), total nitrogen (TN) C / N, soil moisture content in 10 years old and 17 year old poplar plantations, but soil pH had a decreasing trend of 0.2, 10 years old poplar plantations. The total biomass and the biomass of various microbial groups (bacteria, Gram-negative bacteria, Gram-positive bacteria, fungi, actinomycetes, arbuscular mycorrhizal fungi) reached the highest in the middle of growing season (August). In 17 years old plantation, the total biomass of microorganisms, bacteria and arbuscular mycorrhizal fungi in the early growth season (June) and the middle (August) were similar, which were higher than those in the late growing season (October). The biomass of actinomycetes was the highest in the middle of growth season (8 parts). In the growth season of 10 year old poplar plantation, the short term super high level nitrogen was added (300 kg?). Hm-2? A) the total microbial biomass, bacteria, Gram-negative bacteria and fungal biomass were decreased. In the growth season of 17 years old poplar plantation, the total biomass and different microbial groups (bacteria, Gram-negative bacteria, Gram-positive bacteria, Fungi, Actinomycetes) were added in short-term nitrogen. The effect of arbuscular mycorrhizal fungi on biomass was small and there was no obvious regularity. In the growing season of 10 years old poplar plantation, soil organic carbon was the main factor affecting soil microbial biomass. The decrease of microbial biomass after nitrogen addition is probably affected by carbon limitation. Soil moisture is an important factor affecting microbial biomass during the growth season of 17 years old poplar plantation, but when soil moisture is sufficient, Soil C / N was the limiting factor of microbial growth. Short-term nitrogen supplementation changed the soil microbial structure in the growing season of 10 year old poplar plantation, which showed that the dominant microbial biomass decreased. The microbial community structure of 17 year old poplar plantation was changed with the addition of short term nitrogen except for a few plots.
【學(xué)位授予單位】：南京林業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S792.11;S714
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