本文選題：土壤有機(jī)碳庫　切入點(diǎn)：水稻土　出處：《南京農(nóng)業(yè)大學(xué)》2015年碩士論文

【摘要】：土壤有機(jī)碳(Soil Organic Carbon,SOC)庫是陸地生態(tài)系統(tǒng)中最活躍的碳庫,與全球碳循環(huán)密切相關(guān),土壤有機(jī)碳的分解對大氣中CO2濃度有重要影響。資料表明,水稻土約占我國耕地總面積的1/5,生產(chǎn)的糧食約占我國糧食總產(chǎn)量的4/5,且水稻土SOC分解過程與旱地土壤SOC分解不同,研究水稻土 SOC分解的規(guī)律在緩解我國固碳減排壓力、緩解溫室效應(yīng)、穩(wěn)定糧食產(chǎn)量等方面有重要意義。將湖南省桃源縣水稻土剖面樣品(0～100 cm)在25 ℃:下培養(yǎng),將江蘇省句容市水稻土表層樣品(0～20cm)分別在5 ℃,15 ℃,25 ℃,35 ℃下培養(yǎng),基于SOC三庫一級動力學(xué)理論進(jìn)行三庫分離,從土層深度變化角度和培養(yǎng)溫度變化角度研究水稻土 SOC分解的特征和活性碳(Active Organic Carbon,Ca)、緩效性碳(Slow Organic Carbon,Cs)、惰性碳(Passive Organic Carbon,Cp)三庫參數(shù)的變化規(guī)律,并深入分析培養(yǎng)溫度對SOC分解的溫度敏感性系數(shù)(Q_(10))和三庫擬合結(jié)果的影響。研究取得的主要結(jié)果如下:1.SOC分解速率和累計(jì)分解量隨時(shí)間先快速變化,后慢速變化,最后穩(wěn)定在一定水平上。按照CO2-C釋放速率變化程度,可將土壤有機(jī)碳分解曲線劃分為快速分解(平均約5.53d)、緩慢分解(平均約28 d)和平衡分解三個(gè)階段。在同一培養(yǎng)溫度下,隨著土層加深,SOC分解速率和累積分解量逐層遞減。同一土壤在5～35℃范圍內(nèi),隨著培養(yǎng)溫度的升高,土壤SOC分解速率和累積分解量均升高,15、25和35℃時(shí)SOC累積分解量分別是5℃時(shí)的1.94倍、3.55倍、6.01倍。2.各土層中Ct(總有機(jī)碳,Total Organic Carbon)含量Cp含量Cs含量Ca含量,且Ca、Cs、Cp含量分別與土層深度成負(fù)相關(guān)關(guān)系,相關(guān)系數(shù)分別為0.841、0.833、0.773(P0.01),隨著土層加深Ca/Ct減小,Cp/Ct增大,SOC的穩(wěn)定性增大。SOC累積分解量與Ct含量、土壤全氮含量、碳氮比成顯著正相關(guān)關(guān)系,與土壤pH值、粘粒含量成顯著負(fù)相關(guān)關(guān)系。控制土層深度的偏相關(guān)關(guān)系表明,不同土層SOC各組分含量、SOC累積分解量與土壤全氮含量和土壤pH成顯著偏相關(guān)關(guān)系,而與全磷、全鉀、有效磷、速效鉀、碳氮比和粘粒含量之間不存在顯著偏相關(guān)關(guān)系。3.Q_(10)值取2時(shí),SOC三庫擬合結(jié)果受培養(yǎng)溫度影響較大,Ca擬合值隨培養(yǎng)溫度的升高而增大,Cs擬合值隨培養(yǎng)溫度的升高而減小,其中Ca擬合值之間的差異最大,潴育、潛育、淹育水稻土 Ca擬合值的變異系數(shù)分別為64.9%、66.7%、48.5%,培養(yǎng)溫度的設(shè)定對Ca擬合結(jié)果的影響較大。Q_(10)值按照定義式計(jì)算時(shí),Q_(10)值隨著培養(yǎng)溫度的升高而降低、隨著培養(yǎng)時(shí)間的增長而降低,Q_(10)變化范圍為1.48～2.88,且Q_(10)值與SOC含量和SOC分解速率成正相關(guān)關(guān)系,與SOC累積分解量成負(fù)相關(guān)關(guān)系。采用按照Q_(10)定義式計(jì)算出的Q_(10)值對SOC三庫進(jìn)行擬合,得到的Ca和Cs擬合值與按照Q_(10)取固定值2擬合的結(jié)果沒有差異,而得到的活性碳平均駐留時(shí)間(Mean Residue Time of Active Organic Carbon,MRTa)和緩效性破平均駐留時(shí)間(Mean Residue Time of Slow Organic Carbon,MRTs)的擬合值有差異。綜上,表層以下的SOC以其緩慢的速度按照與表層相似的過程參與全球破循環(huán),采取適當(dāng)?shù)拇胧┛梢栽黾悠鋵μ嫉墓潭�。表層SOC三庫擬合值受培養(yǎng)溫度的影響大,不能僅用25℃的培養(yǎng)結(jié)果確定三庫值。按照定義式計(jì)算的Q_(10)值對擬合出的MRTa和MRTs影響大,而對擬合出的三庫大小影響小,可以采用固定值2進(jìn)行三庫擬合。
[Abstract]:Soil organic carbon (Soil Organic Carbon, SOC) library is the most active carbon pool in terrestrial ecosystem, and is closely related to the global carbon cycle, the decomposition of soil organic carbon has important influence on the atmospheric concentration of CO2. The data showed that the paddy soil in China accounts for about 1/5 of the total area of arable land, the total grain production food production in China 4/5, and SOC in paddy soils and upland soil SOC decomposition process of paddy soil in different decomposition, SOC decomposition rules in ease China's carbon emission reduction pressure, alleviate the greenhouse effect, has important significance to stabilize grain yield. The rice in Taoyuan County of Hunan Province, soil samples (0~100 cm) in 25 C: culture, Jurong city in Jiangsu province paddy topsoil samples (0 ~ 20cm) respectively at 5 C, 15 C, 25 C, 35 C under cultivation, SOC three pool theory of three separated database based on the depth changes from culture angle and temperature change angle Study on paddy soil SOC decomposition characteristics and active carbon (Active Organic Carbon, Ca), slow carbon (Slow Organic Carbon Cs (Passive Organic), inert carbon Carbon, Cp) changes of the three reservoir parameters, and in-depth analysis of culture temperature on SOC decomposition temperature sensitivity coefficient (Q_ (10)) influence and fitting results of three libraries. The main results are as follows: 1.SOC decomposition rate and cumulative decomposition rate with time of rapid change, after the slow change, finally stabilized in a certain level. According to the degree of CO2-C release rate of change, the soil organic carbon decomposition curve is divided into rapid decomposition (average 5.53d) and the slow decomposition (approximately 28 d) and equilibrium dissociation in three stages. At the same temperature, with the increase of soil depth, SOC decomposition rate and decomposition rate of accumulation layer decreases. The same soil at 5~35 DEG C range, with the increase of culture temperature, soil SOC decomposition The decomposition rate and cumulative amount were increased, 15,25 and 35 degrees SOC cumulative solution quantity is respectively 1.94 times, 5 degrees 3.55 times, 6.01 times the depth of.2. in Ct (total organic carbon, Total Organic Carbon) Cp content Cs content Ca content, and Ca, Cs, Cp were negative correlation with soil depth, the correlation coefficients were 0.841,0.833,0.773 (P0.01), Ca/Ct decreased with the increase of soil depth, the increase of Cp/Ct, the stability of SOC increased.SOC accumulation decomposition rate and Ct content, the content of soil total nitrogen, carbon and nitrogen ratio was positively correlated with the soil pH, clay content, significant negative correlation between the partial. Correlation between the control of soil depth, soil SOC content, SOC content and accumulation of decomposition of soil total nitrogen content and soil pH significantly partial correlation, and total phosphorus, total potassium, available phosphorus, available potassium, no significant partial correlation between the presence of.3.Q_ carbon nitrogen ratio and clay content between (10)鍊煎彇2鏃，

本文編號：1664212