發(fā)布時間：2018-04-08 22:32

  本文選題：碳固定　切入點：全球變暖　出處：《中國農(nóng)業(yè)大學(xué)》2016年博士論文

【摘要】：理解農(nóng)作物根系生物量(RB)、空間和垂直分布模式及其主要驅(qū)動因子,對于評估生態(tài)系統(tǒng)功能,以及解決保障糧食安全和緩解全球變暖的農(nóng)業(yè)挑戰(zhàn)有重要意義。玉米作為全球分布最廣泛的作物,其龐大的根系系統(tǒng),可以通過地下部輸入,在土壤碳循環(huán)方面具有巨大作用。中國幅員遼闊,跨越眾多氣候帶和土壤帶,玉米種植遍布全國,使得中國玉米根系空間分布的研究在全球地下部生物地理學(xué)分布規(guī)律的探索中具有典型性和代表性。同時,中國全國尺度玉米根系數(shù)據(jù)信息對于發(fā)展生態(tài)系統(tǒng)模型、作物生長模型、氣候模型等也發(fā)揮著重要作用,鑒于全球性眾多生態(tài)系統(tǒng),特別是農(nóng)田生態(tài)系統(tǒng),根系數(shù)據(jù)的缺乏。本研究收集整理來自于311篇文獻和16個農(nóng)田生態(tài)系統(tǒng)實驗站的玉米根系數(shù)據(jù),最終篩選獲得共898個玉米根系剖面,其中257個剖面有大于4層的取樣深度,年份跨越1986-2012年。采用描述性統(tǒng)計分析、地統(tǒng)計分析等方法,分析中國玉米RB及其空間分布特征。同時,采用偏最小二乘法(PLS)結(jié)合氣候、土壤、地形、農(nóng)田管理等環(huán)境因子,探索玉米根系分布模式的主要驅(qū)動因子。在此基礎(chǔ)上,估算中國玉米根系生物量碳(RBC)輸入量,預(yù)測玉米RB及根系深度(RD)空間分布情況。全文主要結(jié)論如下：(1)全國范圍,單株玉米RB平均值為30.10 g plant-1 (8.20-88.90 g plant-1)或者每平方米0.18kgm-2 (0.05-0.38 kg m-2),不同玉米種植生態(tài)區(qū)RB分布模式不同。單株水平,北方春播玉米區(qū)RB最大,其余4個玉米種植生態(tài)區(qū)之間RB數(shù)值差異不顯著；群體水平,不同玉米種植生態(tài)區(qū)RB差異更明顯,北方春播玉米區(qū)RB顯著高于其余4區(qū),黃淮海夏播玉米區(qū)RB顯著高于南方丘陵玉米區(qū)。反距離權(quán)重(1DW)插值得到北方春播玉米區(qū)、黃淮海夏播玉米區(qū)和西北內(nèi)陸玉米區(qū)RB較大(密度圖),西南山地丘陵玉米區(qū)和南方丘陵玉米區(qū)RB較小(密度圖)。同時,北方春播玉米區(qū)和黃淮海夏播玉米區(qū)播種面積大,而西北內(nèi)陸玉米區(qū)、西南山地丘陵玉米區(qū)和南方丘陵玉米區(qū)播種面積較小。因此,總RB空間分布呈現(xiàn)明顯的從北像南、從東向西遞減的趨勢,以北方春播玉米區(qū)和黃淮海夏播玉米區(qū)總RB最大。在此基礎(chǔ)上估算中國玉米根系RBC平均為0.08kgC m-2,結(jié)合全國總播種面積,加權(quán)相加獲得共22.92 Tg C yr-1以干重的形式輸入到土壤碳庫。(2)全國范圍,玉米外推D50(50%根系所在深度)均值為11.33 cm (3.45-25.18 cm),外推D95(95%根系所在深度)均值為94.34 cm (12.62-175.95 cm).不同玉米種植生態(tài)區(qū)外推D50差異顯著,北方春播玉米區(qū)西北內(nèi)陸玉米區(qū)黃淮海夏播玉米區(qū)西南山地丘陵玉米區(qū)。外推D95差異也顯著,分布規(guī)律略有不同,黃淮海夏播玉米區(qū)北方春播玉米區(qū)西北內(nèi)陸玉米區(qū)西南山地丘陵玉米區(qū)�？傮w上,0-80 cm土層內(nèi),北方春播玉米區(qū)根系剖面分布最深,黃淮海夏播玉米區(qū)和西北內(nèi)陸玉米區(qū)根系剖面分布相似；然而,黃淮海夏播玉米區(qū)外推D95在各生態(tài)區(qū)中最深。此外,西南山地丘陵玉米區(qū)根系剖面分布最淺。反距離權(quán)重插值得到全國范圍RD空間分布特征也存在由北向南降低的趨勢,北方春播玉米區(qū)和黃淮海夏播玉米區(qū)整體根系剖面分布最深,西北內(nèi)陸玉米區(qū)次之,西南山地丘陵玉米區(qū)根系最淺。根據(jù)Logistic dose-response curve (LDR)模型計算全國范圍平均71.53%玉米根系分布在表層20 cm中,估算得到表層20 cm土層玉米RBC含量為16.39TgC。(3)包含氣候、土壤、地形以及農(nóng)田管理措施因子的PLS模型對全國范圍RB和RD變異的解釋量分別為42.40%和56.70%。本研究揭示了影響玉米RB及RD分布的不同驅(qū)動因子。在所有生物及非生物因素中,玉米RB與種植密度、籽粒產(chǎn)量、4月份降水量、年均降水量、5月份日照時數(shù)、土壤有機碳含量以及土壤砂粒含量成正比,與10月份降水、土壤pH、鉀肥施用量以及7月份降水量成反比。然而,玉米RD與土壤砂粒含量、pH、年均日照時數(shù)、9月日照時數(shù)以及土壤陽離子交換量成正比,與坡度、海拔、土壤黏粒含量、土壤容重以及7月份日照時數(shù)成反比。農(nóng)田管理措施(特別是種植密度)是玉米RB空間分布的主導(dǎo)因子,土壤發(fā)揮的作用較弱；然而,玉米RD對于土壤性質(zhì)(特別是砂粒含量和pH)及地形因子更敏感。影響RB和RD的氣候因子也不盡相同,RB受到降水量的強烈影響,而RD對日照時數(shù)的響應(yīng)更明顯。本研究認(rèn)為PLS模型預(yù)測RB和RD空間分布模式與IDW插值結(jié)果相比更為可靠。(4)1986-2012年中國玉米RB沒有發(fā)生顯著改變。近十年間(2002-2012),單株水平RB沒有顯著變化,但是群體水平RB顯著降低,而種植密度變化幅度不大。根系生物量下降的變化趨勢顯然與地上部籽粒產(chǎn)量升高的變化趨勢相反。在兩個玉米主產(chǎn)區(qū),北方春播玉米區(qū)近十年單株水平和群體水平RB都呈現(xiàn)顯著下降的趨勢,與地上部籽粒產(chǎn)量增加的趨勢相反。同時,外推D50和外推D95都顯著增加。黃淮海夏播玉米區(qū)RB變化不顯著,20022009年RB變化趨勢與籽粒產(chǎn)量相同,而2009-2012年RB變化趨勢與籽粒產(chǎn)量完全相反。引起思考的是,外推D95隨時間的變化趨勢與地上部籽粒產(chǎn)量的變化趨勢完全一致,表明近十年中國玉米產(chǎn)量增加很可能與根系深度增加有著密切的關(guān)聯(lián)。
[Abstract]:Crop root biomass (RB), and to understand the spatial vertical distribution pattern and its main driving factors for the evaluation of ecosystem function, and solve the food security and alleviate global warming challenges of agriculture has important significance. As the world's most widely distributed corn crop, its large root system, through the underground input, great role in soil carbon cycle. Chinese vast, across a wide range of climatic zones and soil with corn planting, all over the country, the distribution of maize root Chinese space is typical and representative in the exploration of global underground biogeography distribution. At the same time, the national scale Chinese maize root data information for the development of ecological system model, crop growth model, climate models also play an important role, many because of the global ecosystem, especially the farmland ecological system, Lack of root data. This study collected data from maize root experiment station in 311 documents and 16 of farmland ecosystem were obtained a total of 898 maize root profile, 257 of which have more than 4 layer sampling depth profile, the year spans 1986-2012 years. By analysis of descriptive statistics, statistical analysis methods of analysis Chinese maize RB and its spatial distribution characteristics. At the same time, by using partial least squares (PLS) combined with the climate, soil, topography, soil management and other environmental factors, explore the main driving factors of maize root distribution patterns. On this basis, estimates of root biomass carbon (RBC) Chinese input, RB forecast Maize root and depth (RD) spatial distribution. The main conclusions are as follows: (1) the scope of corn plant with an average RB of 30.10 g plant-1 (8.20-88.90 g plant-1) or 0.18kgm-2 per square meter (0.05-0.38 kg m -2), different maize planting ecological distribution of RB in different modes. Individual level, the northern spring maize region RB, the remaining 4 corn RB showed no significant difference between the numerical ecological zone; population level, different maize planting ecological zone RB more obvious differences, the northern spring maize region of RB was significantly higher than the other 4 areas, in summer sowing corn RB was significantly higher than that of Maize in hilly area. The inverse distance weighted (1DW) interpolation to get the northern spring maize region, Huanghuaihai Summer Maize Region and northwest inland region RB (corn density map), the larger southwest Maize Zone in Hilly and southern hilly region RB (small corn density map). At the same time, the northern spring maize and Huanghuaihai summer maize planting area of large area, and the Inland Northwest corn area, hilly area and southwest maize sowing maize in hilly area is smaller. Therefore, the distribution of total RB space obviously like South from the north, from east to West A decreasing trend, with the northern spring maize region and Huanghuaihai summer sowing maize total RB area. Based on the estimation of Chinese maize root RBC averaged 0.08kgC m-2, combined with the weighted sum of the total sown area, obtained a total of 22.92 Tg C yr-1 on a dry weight in the form of input to the soil carbon pool. (2) the scope of corn D50 extrapolation (50% roots depth) mean of 11.33 cm (3.45-25.18 cm), D95 (95% roots depth extrapolation) mean of 94.34 cm (12.62-175.95 cm). Different corn planting ecological zone extrapolation D50 significantly, corn area of southwest hilly area of maize Huanghuaihai summer maize area in Northwest inland region in North. Extrapolation D95 significantly, distribution is slightly different, the northern spring maize area area of northwest inland region in southwest hilly area of Maize in maize Huanghuaihai summer. In total, 0-80 cm soil layer, the northern spring maize area root profile The cloth is the deepest, Huanghuaihai Summer Maize Region and northwest region of maize root profile distribution is similar; however, Huanghuaihai Summer Maize Region in different ecological regions in the D95 extrapolation most. In addition, the southwest hilly area of maize root profile distribution of the shallow. Inverse distance weighted interpolation to get the nationwide distribution of RD space are reduced by North South trend, northern spring maize region and Huanghuaihai summer sowing maize root zone overall profile most inland Northwest corn region, southwest Maize Zone in mountainous and hilly areas of the shallow root. According to the Logistic dose-response curve (LDR) to calculate the average nationwide 71.53% maize root distribution on the surface of 20 cm in the model, the estimated surface 20 cm layer of maize RBC was 16.39TgC. (3) including climate, soil, topography and soil management measure factor PLS model of national RB and RD variation accounted for 42.40% and respectively. 56.70%. this study reveals the impact of maize RB and RD distribution in different driving factors. In all the biological and non biological factors in Maize RB and planting density, grain yield, April precipitation, annual precipitation, sunshine hours in May, the content of soil organic carbon and soil sand content is proportional to, and October precipitation, soil pH, dosage and potassium is inversely proportional to the precipitation in July. However, the maize RD and soil sand content, pH, the average annual sunshine hours, September sunshine hours and the soil cation exchange capacity is proportional to the slope, elevation, soil clay content, soil bulk density and sunshine hours in July is inversely proportional to the farmland management measures (especially the planting density) is the dominant factor of maize RB spatial distribution, weak soil play; however, RD for corn soil properties (especially the sand content and pH) and the terrain factor is more sensitive. The effects of RB and RD for the climate Children are not the same, RB is strongly influenced by precipitation, and RD on the sunshine duration response is more obvious. This study shows that the PLS model for predicting RB and RD spatial distribution pattern and IDW interpolation results compared to more reliable. (4) 1986-2012 years China corn RB did not change significantly. The last ten years (2002-2012), individual level of RB did not change significantly, but the level of RB group was significantly decreased, while the planting density has little change. The changing trends of root biomass decreased obviously with the increase in grain yield. In two maize producing areas, the northern spring maize region in recent ten years, individual level and group level RB all showed a significant downward trend, in contrast with the trend of upper grain yield increased. At the same time, D50 and D95 are extrapolated extrapolation increased significantly. In Huanghuaihai Summer Maize Region of RB did not change significantly, 20022009 years RB and grain yield the same trend, 2009-2012 years the change trend of RB and the grain yield is completely opposite. Thinking caused, trend extrapolation D95 trends over time and the grain yield is completely consistent, shows that with the increase of China maize yield nearly ten years and is likely to increase the root depth are closely related.

【學(xué)位授予單位】：中國農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S513
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本文編號：1723668